Texas Instruments | Build High-Density, High Refresh Rate, Multiplexing Panel with the TLC59581 | Application notes | Texas Instruments Build High-Density, High Refresh Rate, Multiplexing Panel with the TLC59581 Application notes

Texas Instruments Build High-Density, High Refresh Rate, Multiplexing Panel with the TLC59581 Application notes
Application Report
SLVA744 – January 2016
Build a High-Density, High Refresh Rate, Multiplexing
Panel With the TLC59581
Ge, Rosley
ABSTRACT
The application note describes the detailed steps to build a high-density, high refresh rate, multiplexing
panel with the TLC59581. Detailed configurations and system structure guidelines are included in this
report.
1
2
3
Contents
Introduction ................................................................................................................... 2
Device Specification ......................................................................................................... 5
2.1
Basic Information ................................................................................................... 5
2.2
Switching Characteristics .......................................................................................... 5
2.3
Parameter Measurement Information ............................................................................ 6
2.4
Timing Diagrams .................................................................................................... 7
Detailed Description ......................................................................................................... 8
3.1
How to use the TLC59581 ......................................................................................... 8
3.2
Step 1 — Choose BC and CC, Select RIREF ..................................................................... 8
3.3
Step 2 — Write Function Control Register FC1 and FC2 .................................................... 11
3.4
Step 3 — Write GS Data Into One Memory BANK ........................................................... 18
3.5
Step 4 — Send Vsync Command to Switch the BANK Purpose............................................ 23
3.6
Step 5 — Input GCLK to Begin Displaying the Image of One New Frame ................................ 23
3.7
Step 6 — During the Same Period of Step 5, Write GS Data for Next Frame Into Another BANK .... 28
3.8
Step 7 — When the Time of One Frame Ends, Input the Vsync Command to Swap the Purpose
of the Two BANKs ................................................................................................ 28
3.9
LED Open Detection (LOD) ...................................................................................... 29
3.10 How to Read the Function Control Register ................................................................... 33
3.11 Function Commands Summary ................................................................................. 34
3.12 Power-Save Mode (PSM) ........................................................................................ 35
3.13 Pre-Charge Function .............................................................................................. 36
3.14 1st-Line Enhancement ............................................................................................. 38
3.15 HG-LG Interference Enhancement.............................................................................. 38
3.16 Low Gray-Scale Enhancement .................................................................................. 39
3.17 LOD Caterpillar Cancelling ....................................................................................... 40
3.18 Protection ........................................................................................................... 41
3.19 System Structure Guidelines .................................................................................... 41
List of Figures
1
Typical Application Circuit (Multiple Daisy Chained TLC59581s) ..................................................... 4
2
Pin Schematic Diagrams .................................................................................................... 6
3
Rise Time and Fall Time Test Circuit ..................................................................................... 6
4
Constant Current Test Circuit for OUTXn
5
6
................................................................................ 7
Output Timing ................................................................................................................ 7
Common Shift Register and Data Latch Configuration ................................................................ 11
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Introduction
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7
FC Write Enable (FCWRTEN) and FC Data Write (WRTFC) Command ........................................... 14
8
BANK Select Mode Change .............................................................................................. 18
9
Vertical Synchronization (Vsync) Command............................................................................ 19
10
Bit Arrangement of One Memory Unit ................................................................................... 19
11
Latch Common Shift Register Data Into One Memory Unit
12
Memory Structure .......................................................................................................... 21
13
48-bit GS Data Write (WRTGS) Command ............................................................................. 22
14
Memory Write Sequence .................................................................................................. 23
15
Multiplexed ES-PWM Operation (8+8 Mode) ........................................................................... 25
16
Controller Timing Sequence, 8+8 Mode, 32 Multiplexing ............................................................. 26
17
Multiplexed ES-PWM Operation (7+9 Mode) ........................................................................... 27
18
Timing Sequence, 7+9 Mode ............................................................................................. 28
19
LOD Detect Circuit Of One Channel ..................................................................................... 29
20
Bit Arrangement of the SID Holder....................................................................................... 29
21
LOD Information Latch Into SID Holder ................................................................................. 30
22
LOD Information Read (READSID) Timing ............................................................................. 31
23
Example of LOD Detection Process (8+8 Mode)
32
24
FC1 Data Read (READFC1) Command
33
25
26
27
28
..........................................................
......................................................................
................................................................................
FC2 Data Read (READFC2) Command ................................................................................
Enter/Exit Power-Save Mode .............................................................................................
Pre-Charge FET Working Mode ..........................................................................................
LED Caterpillar Phenomenon Mechanism ..............................................................................
20
33
35
37
40
List of Tables
1
CC Data vs Current Ratio and Set Current Value ....................................................................... 9
2
Current Gain Versus BC Code ............................................................................................. 9
3
WRTFC/FCWRTEN Commands Description ........................................................................... 12
4
FC1 Register Bit Assignment ............................................................................................. 13
5
LOD Threshold Voltage Truth Table ..................................................................................... 15
6
TD0 Definition and Selection
7
8
9
10
11
12
13
14
1
.............................................................................................
FC2 Register Bit Assignment .............................................................................................
Scan Line Number VS MAX_LINE Setting..............................................................................
Vsync Commands Description............................................................................................
Function Commands Summary ..........................................................................................
Pre-Charge Function Mode ...............................................................................................
1st-Line Enhancement Summary .........................................................................................
Interference Compensation Summary ...................................................................................
Low Grayscale Enhancement Setting ...................................................................................
15
16
17
18
34
36
38
38
39
Introduction
The TLC59581 is a 48-channel, constant-current sink driver for multiplexing system with a 1-to-32 duty
ratio. Each channel has an individually-adjustable, 65536-step, pulse width modulation (PWM) grayscale
(GS). 48Kb display memory is implemented to increase the visual refresh rate and to decrease the GS
data writing frequency.
The TLC59581 implements Low Grayscale Enhancement (LGSE) technology to improve the display
quality at low grayscale conditions. This feature makes the TLC59581 more suitable for high-density
multiplexing applications.
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The output channels are categorized into three groups, each group has 16 channels. Each group has a
512-step color brightness control (CC) function. The maximum current value of all 48 channels can be set
with an 8-step global brightness control (BC) function. CC and BC are used to adjust the brightness
deviation between LED drivers. GS, CC, and BC data are accessible via a serial interface port.
The TLC59581 has one error flag: LED open detection (LOD), which can be read via a serial interface
port. The TLC59581 also has a power-save mode that sets the total current consumption to 0.8 mA (typ)
when all outputs are off. Each constant-current has a pre-charge field-effect transistor (FET), which can
reduce ghosting and improve display performance on the multiplexing LED display. The TLC59581 also
has an enhanced circuit that can cancel the caterpillar effect caused by a broken LED.
The TLC59581 has the following features:
• 48 channel constant current sink output
• Low Grayscale Enhancement (LGSE) technology
• Sink current capability with max BC/CC data:
– 25 mA at 5 V VCC
– 20 mA at 3.3 V VCC
• Global Brightness Control (BC) : 3 bit (8 Step)
• Color Brightness Control (CC) for each color group: 9 bit (512 Step), three groups
• Grayscale (GS) control with multiplexed enhanced spectrum (ES) PWM: 16 bit
• 48Kb Grayscale data memory support 32-multiplexing
• LED power-supply voltage up to 10 V
• VCC = 3.0 V to 5.5 V
• Constant current accuracy
– Channel to channel = ±1% (Typ), ±3% (Max)
– Device to device = ±1% (Typ), ±2% (Max)
• Data transfer rate: 25 MHz
• Grayscale clock: 33 MHz
• LED open detection (LOD)
• Thermal shut down (TSD)
• IREF resistor short protection (ISP)
• Power-save mode (PSM) with high-speed recovery
• Delay switching to prevent inrush current
• Pre-charge FET to avoid ghosting phenomenon
• Operating temperature : –40°C to 85°C
The TLC59581 is mainly targeted for the following applications:
• LED video displays with a multiplexing system
• LED signboards with a multiplexing system
• High refresh rate and high-density LED panels
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Introduction
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Figure 1 represents a typical application circuit of TLC59581.
VLED
SW
COM n
COM n
VLED
SW
COM 1
COM 1
VLED
SW
COM 0
COMSEL 0
COMSEL 1
COMSEL n
COM 0
DATA
CONTROLLER
SCLK
LAT
GCLK
FLAGS
READ
X 48
X 48
OUTR0
OUTB15
SIN
OUTR0
SIN
SOUT
TLC59581
VCC
SCLK
IC1
LAT
OUTB15
SOUT
TLC59581
SCLK
ICn
LAT
VCC
GCLK
VCC
VCC
GCLK
Thermal
Pad
IREF
IREFGND
Thermal
Pad
IREF
GND
GND
IREFGND
GND
GND
3
Figure 1. Typical Application Circuit (Multiple Daisy Chained TLC59581s)
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Device Specification
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2
Device Specification
2.1
Basic Information
Basic information, such as electrical characteristics, thermal, package information, and recommended
operation conditions, are found in TLC59581 datasheet (SLVSCZ9). The TLC59581 function block
diagram, pin-out information, and pin descriptions are also found in datasheet.
2.2
Switching Characteristics
The following table contains the TLC59581 switching characteristics.
At VCC = 3.0–5.5 V, TA = –40 to 85°C, CL = 15 pF, RL = 4 kΩ, target at 1 mA IOLC, VLED = 5.0 V,
Typical values are at VCC = 3.3 V, TA = 25°C (unless otherwise noted).
Parameter
tr0 (1)
tr1
tf0
Rise time
td2
(1)
OUTx0-15, x = R/G/B, BC = 0h, CCR/G/B = 1FFh,
RIREF = 976 Ω (25-mA target), Ta = 25°C, RL = 160 Ω
Propagation
delay time
TYP
MAX
2
5
2
OUTx0-15, x = R/G/B, BC = 0h, CCR/G/B = 1FFh,
RIREF = 2.46 kΩ (10-mA target), Ta = 25°C, RL = 400 Ω
5
15
SCLK ↑ to SOUT, SEL_TD0 = 00b
8
15
27
SCLK ↑ to SOUT, SEL_TD0 = 01b
13
25
45
SCLK ↑ to SOUT, SEL_TD0 = 10b
19
35
60
SCLK ↓ to SOUT, SEL_TD0 = 11b
6
10
22
LAT ↓ to SOUT, ReadFC1/2, ReadSID
26
50
GCLK↓ to OUTR0/7/8/15 turn
on or turn off
15
td3
Propagation delay time
between group and next group
td4
Propagation delay time
between color and next color
in same group
RIREF = 976 Ω (25-mA target),
BC = 0h,
CCR/G/B = 1FFh, Ta = 25°C,
SEL_GDLY = 1
Unit
35
SOUT
Fall time
td0 (1)
td1 (1)
MIN
SOUT
(1)
tf1
Test Conditions
ns
5
1.67
Ensure by design.
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Device Specification
2.3
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Parameter Measurement Information
Figure 2, Figure 3, and Figure 4 illustrate the parameter measurement information.
VCC
VCC
OUTPUT
INPUT
GND
GND
SIN/SCLK
SOUT
VCC
VCC
LAT
GCLK
GND
GND
LAT
GCLK
OUTXn
(1) X=R or G or B, n=0~15
(1)
GND
Figure 2. Pin Schematic Diagrams
RL
VCC
VCC
VLED
VCC
OUTXn
(2)
GND
VCC
SOUT
CL
(1)
GND
CL
(1)
(1) CL includes measurement probe and jig(1) CL includes measurement probe and jig capacitance.
capacitance.
Figure 3. Rise Time and Fall Time Test Circuit
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VCC
OUTR0
VCC
OUTXn
(1)
GND
VOUTXn
(1)
OUTB15
VOUTfix
Figure 4. Constant Current Test Circuit for OUTXn
2.4
Timing Diagrams
tR0, tR1, tF0, tF1, tD0, tD1, tD2, tD3, tD4
VCC or VOUTXnH
INPUT (1)
50%
GND or VOUTXnL
tD
VOH or VOUTXnH
90%
OUTPUT
50%
10%
VOL or VOUTXnL
tR or tF
(1)
(2)
Input pulse rise and fall time is 1~3nS.
X=R or G or B, n=0~15
Figure 5. Output Timing
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Detailed Description
3
Detailed Description
3.1
How to use the TLC59581
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After power on, all OUTXn of TLC59581 are turned off. All the internal counters and function control
registers (FC1/FC2) are initialized. A brief summary of the sequence to operate the TLC59581 follows,
providing a general idea how this part works. After that, the function block related to each step is detailed
in the following sections.
1. According to required LED current, choose BC and CC code, select the current programming resistor
RIREF.
2. Send the WRTFC command to set FC1/2 register value if the default value needs changing.
3. Write GS data of all lines (max 32 lines) into one of the two memory BANKs.
4. Send Vsync command, the BANK with the GS data just written is displayed.
5. Input GCLK continuously, 257 GCLK (or 129 GCLK) as a segment. Between the interval of two
segments, switch supply voltage from one line to the next line accordingly.
6. During the same period of step 5, write GS data for the next frame into another BANK.
7. When the time of one frame ends, input the Vsync command to swap the purpose of the two BANKs.
Repeat steps 5–7…
3.2
3.2.1
Step 1 — Choose BC and CC, Select RIREF
What is the BC function?
The TLC59581 is able to adjust the output current of all constant-current outputs simultaneously. This
function is called global brightness control (BC). The global BC for all outputs is programmed with a 3-bit
word, thus all output currents can be adjusted in 8 steps from 12.9% to 100% (see Table 1) for a given
current programming resistor (RIREF).
BC data are set via the serial interface. When the BC data changes, the output current also changes
immediately. When the device is powered on, the BC data in the function control (FC) register FC1 is set
to 4h as the initial value.
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3.2.2
What is the CC Function?
The TLC59581 is able to adjust the output current of each of the three color groups OUTR0-OUTR15,
OUTG0-OUTG15, and OUTB0-OUTB15 separately. This function is called color brightness control (CC).
For each color, there is 9-bit data latch CCR, CCG, or CCB in FC1 register (see Table 3 for FC1 register
bit assignment). Thus, all color group output currents can be adjusted in 512 steps from 0% to 100% of
the maximum output current, IOLCMax. See Section 3.2.3 for more detail about IOLCMax. The CC data are
entered via the serial interface. When the CC data changes, the output current also changes immediately.
When the IC is powered on, the CC data are set to ‘100h’. Equation 1 calculates the actual output current.
IOUT (mA) = IOLCMax (mA) × (CCR/511d or CCG/511d or CCB/511d)
where
•
IOLCMax = the maximum channel current for each channel determined by BC data and RIREF (see
Equation 2)
CCR/G/B = the color brightness control value for each color group in the FC1 register (000h to
1FFh)
•
(1)
Table 1 shows the CC data versus the constant-current against IOLCMax.
Table 1. CC Data vs Current Ratio and Set Current Value
CC Data (CCR, CCG, or CCB)
Binary
3.2.3
Decimal
Ratio of Output Current to
IOLCMax (%, typical)
Hex
Output Current (mA, RIREF = 7.41 kΩ)
BC = 7h
(IOLCMax = 25 mA)
BC = 0h
(IOLCMax = 3.2 mA)
0 0000 0000
0
00
0
0
0
0 0000 0001
1
01
0.2
0.05
0.006
0 0000 0010
2
02
0.4
0.10
0.013
…
…
…
…
…
…
1 0000 0000
(Default)
256
(Default)
100
(Default)
50.1
12.52
1.621
…
…
…
…
…
…
1 1111 1101
509
1FD
99.6
24.90
3.222
1 1111 1110
510
1FE
99.8
24.95
3.229
1 1111 1111
511
1FF
100.0
25
3.235
How to Select RIREF for a Given BC
The maximum output current per channel, IOLCMax, is decided by a resistor, RIREF, which is placed between
the IREF and IREFGND pins, and the BC code in FC1 register (see Table 4 for FC1 register bit
assignment). The voltage on IREF is typically 1.209 V. Calculate RIREF with Equation 2.
RIREF (kΩ) = VIREF (V) / IOLCMax (mA) × Gain
(2)
Table 2. Current Gain Versus BC Code
BC Data
Gain
Ratio of Gain/Gain_max
(at max BC)
0 (recommend)
20.4
12.9%
001
1
40.3
25.6%
010
2
59.7
37.9%
011
3
82.4
52.4%
100 (default)
4 (default)
101.8
64.7%
101
5
115.4
73.3%
110
6
144.3
91.7%
111
7
157.4
100%
Binary
Hex
000 (recommend)
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Detailed Description
3.2.4
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How to Choose BC/CC for Different Applications
BC is mainly used for global brightness adjustment between day and night. Suggested BC is 4h, which is
in the middle of the range, thus, one can change brightness up and down flexibly.
CC can be used to fine tune the brightness in 512 steps, this is suitable for white balance adjustment
between RGB color groups. To get a pure white color, the general requirement for the luminous intensity
ratio of R, G, B LED is 3:6:1. Depending on LED’s characteristics (Electro-Optical conversion efficiency),
the current ratio of R, G, B LED is much different from this ratio. Usually, the Red LED requires the largest
current. Choose 511d (the max value) CC code for the color group which needs the largest current at first,
then choose proper CC code for the other two color groups according to the current ratio requirement of
the LED used.
Example 1: Red LED current is 2 0 mA, Green LED requires 12 mA, Blue LED requires 8 mA.
1. Red LED needs the largest current, so choose 511d for CCR.
2. 511 × 12 mA / 20 mA = 306.6, thus choose 307d for CCG. With the same method, choose 204d for
CCB.
3. According to the required Red LED current, choose 7h for BC.
4. According to Equation 2, RIREF = 1.209 V / 20 mA × 157.4 = 9.5 kΩ
In this example, we choose 7h for BC, instead of using the default 4h. This is because the Red LED
current is 20 mA, which is approaching the upper limit of current range. To prevent the constant output
current from exceeding the upper limit in case a larger BC code is input accidently, we choose the max
BC code here.
Example 2: Red LED current is 5 mA, Green LED requires 2 mA, Blue LED requires 1 mA.
1. Red LED needs the largest current, so choose 511d for CCR.
2. 511 × 2 mA / 5 mA = 204.4, thus choose 204d for CCG. With the same method, choose 102d for CCB.
3. According to the required Blue LED current, choose 0h for BC.
4. According to Equation 2, RIREF = 1.209 V / 5 mA × 20.4 = 4.93 kΩ
In this example, we choose 0h for BC, instead of using the default 4h. This is because that the Blue LED
current is 1 mA, which is approaching the lower limit of current range. To prevent the constant output
current from exceeding the lower limit in case a lower BC code is input accidently, we choose the min BC
code here.
In general, if LED current is in the middle of range (that is, 10 mA), one can just use the default 4h as BC
code.
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3.3
Step 2 — Write Function Control Register FC1 and FC2
3.3.1
Input Data for FC1/2 Through Common Shift Register
The common shift register is 48 bits long and is used to shift data from the SIN pin into the TLC59581.
The data shifted into the register can be latched into GS memory unit, or latched into function control (FC)
registers FC1/2 depending on which command received.
Figure 6 shows the configuration of the common shift register and the data latches.
Common shift register (48bits)
SOUT
MSB
Common Common Common
Data bit
Data bit Data bit
47
46
45
47
46
45
LSB
Common Common
Data bit
Data bit
44
43
44
43
Common
Data bit
5
---
5
Common Common Common Common Common
Data bit
Data bit
Data bit Data bit Data bit
4
3
2
1
0
4
3
2
1
SIN
SCK
0
48bit
Lower 44bit
FC1 data latch (44bits)
LSB
MSB
48bit
BC Bit2
BC Bit1
43
42
BC Bit0
41
Reserve
d
SEL_GD
LY
5
4
---
FC2 data latch (17bits)
SEL_tD0 SEL_tD0 LODVTH LODVTH
Bit1
Bit0
Bit1
Bit0
3
2
1
0
Lower 17bit
LSB
MSB
Reserve
d
Reserve
d
SEL_
PWM
16
15
14
---
MAX_LI
NE Bit3
MAX_LI
NE Bit2
MAX_LI
NE Bit1
3
2
1
MAX_LI
NE Bit0
0
LSB
MSB
Bit14 of
Blue
Bit13 of
Blue
Bit12 of
Blue
47
46
45
44
This latch pulse is
generated when
WRTFC command
input with ‘0110b’ in
common shift register
bit47~44
48bit
GS memory data latch (48bits)
Bit15 of
Blue
This latch pulse is
generated when
WRTFC command
input with ‘1001b’ in
common shift register
bit47~44
Bit11 of
Blue
43
---
Bit5 of
Red
Bit4 of
Red
Bit3 of
Red
Bit2 of
Red
Bit1 of
Red
5
4
3
2
1
Bit0 of
Red
0
This latch pulse is
generated when
WRTGS command
input. Which portion of
memory be written is
selected by CH counter,
line write counter, and
bank selection bit.
Figure 6. Common Shift Register and Data Latch Configuration
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Detailed Description
3.3.2
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How to Write to the Function Control Register
The TLC59581 uses the FCWRTEN and WRTFC commands to latch the data of the common shift register
into FC1/FC2. These commands are distinguished by the number of SCLK rising edges included in the
LAT pulse. Table 3 describes more about these two commands.
Table 3. WRTFC/FCWRTEN Commands Description
Command Name
SCLK Rising Edges
While LAT is High
Description
WRTFC (FC data write)
5
The lower 44-bit data or the lower 17-bit data in the common shift
register are copied to the FC1 or FC2 register. Bit 47–44 of the
common shift register is used to choose which FC register is written
to. If ‘1001b’ is received for bit 47–44 of the common shift register,
then the lower 44 bits in the common shift register are copied to the
FC1 register. If ‘0110b’ is received for bit 47–44 of the common shift
register, then the lower 17 bits in the common shift register are
copied to the FC2 register. Refer to Figure 7 for a timing diagram of
this command operation.
FCWRTEN (FC write enable)
15
FC writes are enabled by this command. This command must
always be input before the FC data write occurs. Refer to Figure 7
for a timing diagram of this command operation.
Note that FCWRTEN command must be input first, before the WRTFC command, otherwise this WRTFC
command is neglected.
When inputting the WRTFC command, bit 47–bit 44 of the common shift register is used to choose which
FC register be written to. See Table 3 for more detail.
Refer to Figure 7 for a detailed command input timing diagram.
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3.3.3
Function Control (FC) Register FC1
FC1 is used to select BC/CC code, precharge enable, LOD caterpillar removal enable and LED open
detection (LOD) voltage.
Table 4 shows the FC1 register bit assignment.
Table 4. FC1 Register Bit Assignment
Bit
Number
Bit Name
Default
Value (Binary)
1-0
LODVTH
01b
LOD detection threshold voltage. These two bits select the detection
threshold voltage for the LED open detection (LOD). Table 5 shows
the detect voltage truth table.
3-2
SEL_TD0
01b
TD0 select. SOUT hold time is decided by TD0 definition and
selection. Table 6 shows the detail.
4
LOD_Removal_EN
1b
LOD caterpillar Removal function enable.
When this bit is ‘0’, the LOD caterpillar removal function is disabled.
When this bit is ‘1’, the LOD caterpillar removal function is enabled.
7-5
RSV
000b
8
PREC_EN
0b
Pre-charge function enable.
0b — Pre-charge function enable (default)
1b — Pre-charge function disable
9
PREC_MODE3
0b
This bit is used to control a new pre-charge mode when SEL_PREC
(bit 7 in FC2) = 1.
0b — Pre-charge MODE3 disable (default)
1b — Pre-charge MODE3 enable
12 - 10
RSV
000b
13
Center Uniformity
Enhancement
0b
22 - 14
CCB
1 0000 0000b
Color brightness control data for BLUE color group (Data = 000h1FFh. See Table 1.)
31 - 23
CCG
1 0000 0000b
Color brightness control data for GREEN color group (Data = 000h –
1FFh. See Table 1.)
40 - 32
CCR
1 0000 0000b
Color brightness control data for RED color group (Data = 000h1FFh. See Table 1.)
43 - 41
BC
100b
Global brightness control data for all output (Data = 0h- 7h. See
Table 2.)
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Description
Reserved data. Input ‘0’ in this bit. Don’t care.
Reserved data. Input ‘0’ in these bits. Do not change.
Center Uniformity Enhancement
0b — Center Uniformity Enhancement enable
1b — Center Uniformity Enhancement disable
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*1
*1
*1
*1: Don’t care
*1
*1
‘0b’
‘1b’
‘0b’
‘1b’
FC
5
FC
4
FC
3
FC
1
FC
0
SCLK
1
2
14
15
1
2
3
4 … 43
44
45 … 47
48
15 SCLK rising edge must be
input while LAT is high. Then FC
register is enabled to be written
LAT
44-bit FC1
Data Latch
Old data
17-bit FC2
Data Latch
New data
FC2 register content unchanged
5 SCLK rising edge must be input while LAT is high. If the
bit47~44 of the common shift register is ‘1001b’, then the
lower 44-bit of common shift register is copied to FC1
register at the falling edge of LAT
SIN
*1
*1
*1
*1: Don’t care
*1
*1
‘0b’
‘1b’
‘0b’
‘1b’
FC
5
FC
4
FC
3
FC
1
FC
0
SCLK
1
LAT
44-bit FC1
Data Latch
2
14
15
1
2
3
4 … 43
44
45 … 47
48
15 SCLK rising edge must be
input while LAT is high. Then FC
register is enabled to be written
FC1 register content unchanged
17-bit FC2
Data Latch
New data
Old data
5 SCLK rising edge must be input while LAT is high. If the
bit47~44 of the common shift register is ‘0110b’, then the
lower 17-bit of common shift register is copied to FC2
register at the falling edge of LAT
Figure 7. FC Write Enable (FCWRTEN) and FC Data Write (WRTFC) Command
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Table 5. LOD Threshold Voltage Truth Table
LODVTH
LED Open Detection (LOD)
Threshold Voltage
Bit 1
Bit 0
0
0
VLOD0 (0.2-V typ)
0
1
VLOD1 (0.4-V typ, default value)
1
0
VLOD2 (0.6-V typ)
1
1
VLOD3 (0.8-V typ)
Table 6. TD0 Definition and Selection
SEL_TD0
Bit 3
TD0 Definition and Selection
Bit 2
0
TD0 is the time from SCLK↑ to SOUT↑↓, typical value 15 ns.
Once SCLK↑ is received, after a 15 ns delay, SOUT begins change.
0
1
TD0 is the time from SCLK↑ to SOUT↑↓, typical value 25 ns (default value when powered up).
Once SCLK↑ is received, after a 25 ns delay, SOUT begins change.
1
0
TD0 is the time from SCLK↑ to SOUT↑↓, typical value 35 ns.
Once SCLK↑ is received, after a 35 ns delay, SOUT begins change.
1
1
TD0 is the time from SCLK↓ to SOUT↑↓, typical value 10 ns.
Once SCLK↓ is received, after a 10 ns delay, SOUT begins change. The hold time is adjustable
from SCLK↑ to SOUT↑↓ by changing the duty of SCLK.
0
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Function Control (FC) Register FC2
FC2 is used to select ES-PWM mode, pre-charge function, power save mode, Low-grayscale
Enhancement and the multiplexing ratio.
Table 7 shows the FC2 register bit assignment.
Table 7. FC2 Register Bit Assignment
16
Bit
Number
Bit Name
Default
Value (Binary)
Description
4-0
MAX_LINE
0 0000b
5
PSAVE_ENA
0b
Power save mode select.
When this bit is ‘0’, the power save function is disabled. This is the default
value when the power is on.
When this bit is ‘1’, power save function is enabled.
The TLC59581 will enter power save mode if all ‘0’ GS data is input. If a non ‘0’
GS data input is detected, normal mode is resumed.
Refer to Figure 26 for the timing diagram of enter/exit power save mode.
6
SEL_GCLK_EDGE
0b
GCLK edge select. When this bit is ‘0’, OUTn only turns on/off at the rising
edge of GCLK, this is the default setting;
When this bit is ‘1’, OUTn turns on/off at both edges (rising and falling) of
GCLK. At this condition, the maximum input GCLK is 16.5 MHz.
7
SEL_PCHG
0b
Pre-charge working mode select.
Pre-charge starting point and time depend on this bit and PREC_MODE3 in
FC1 register.
See Figure 27 for more details.
10 - 8
RSV
000b
11
EMI_REDUCE_B
0b
EMI reduce select for blue channels.
When this bit is ‘0’, EMI noise contributed by blue channels is reduced.
When this bit is ‘1’, EMI noise contributed by blue channels is at default value.
However, low grayscale visual effect will be better.
12
EMI_REDUCE_G
0b
EMI reduce select for green channels.
When this bit is ‘0’, EMI noise contributed by green channels is reduced.
When this bit is ‘1’, EMI noise contributed by green channels is at the default
value. However, low grayscale visual effect will be better.
13
EMI_REDUCE_R
0b
EMI reduce select for red channels.
When this bit is ‘0’, EMI noise contributed by red channels is reduced. When
this bit is ‘1’, EMI noise contributed by red channels is at default value.
However, low grayscale visual effect is better.
14
SEL_PWM
0b
ES-PWM mode select.
When this bit is ‘0’, 8MSB + 8LSB mode is chosen. The whole 65536 GCLK
display period is divided into 256 segments. Each segment includes 257
GCLK. LED turn on time is scattered in these 256 segments.
When this bit is ‘1’, 7MSB + 9LSB mode is chosen. The whole 65536 GCLK
display period is divided into 512 segments. Each segment includes 129
GCLK. LED turn on time is scattered in these 512 segments.
See Section 3.6.2, Multiplexed Enhanced Spectrum (ES) PWM Control for
more details.
16 - 15
1st-Line
Enhancement
01b
These two bits improve the first line issue at low grayscale condition.
00b — no improvement
01b — Typical value
10b — medium improvement
11b — strong improvement
18 - 17
RSV
00b
Reserved data. Input ‘0’ in this bit. Do not change.
19
RSV_HIGH
1b
Reserved data. Input ‘1’ in this bit. Do not change.
23 - 20
LGSE1-B
0000b
These four bits improve blue low-grayscale uniformity. Total of 16 steps.
The compensation level increases with the value of LGSE1-B. For example,
‘0000b’ means no compensation. ‘1111b’ means highest compensation.
27 - 24
LGSE1-G
0000b
These four bits improve green low-grayscale uniformity. Total of 16 steps.
The compensation level increases with the value of LGSE1-G. For example,
‘0000b’ means no compensation. ‘1111b’ means highest compensation.
Multiplexing ratio select. Based on the multiplexing ratio in a real application,
select the correct scan line number here. Table 8 shows the scan line number
vs MAX_LINE setting.
Reserved data. Input ‘0’ in this bit. Do not change.
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Table 7. FC2 Register Bit Assignment (continued)
Bit
Number
Bit Name
Default
Value (Binary)
Description
31 - 28
LGSE1-R
0000b
These four bits improve red low-grayscale uniformity. Total of 16 steps.
The compensation level increases with the value of LGSE1-R. For example,
‘0000b’ means no compensation. ‘1111b’ means highest compensation.
33 - 32
Interference_B
00b
These two bits improve the interference issue between high GS data and low
GS data in blue color.
00b — low improvement
01b — typical value
10b — medium improvement
11b — strong improvement
35 - 34
Reverse_V_B
00b
These two bits control reverse voltage in blue color.
00b — High
01b — Medium High
10b — Medium
11b — Low
37 - 36
Interference_G
00b
These two bits improve the cross interference issue between high GS data and
low GS data in green color.
00b — low improvement
01b — typical value
10b — medium improvement
11b — strong improvement
39 - 38
Reverse_V _G
00b
These two bits control reverse voltage in green color.
00b — High
01b — Medium High
10b — Medium
11b — Low
41 - 40
Interference_R
00b
These two bits improve the interference issue between high GS data and low
GS data in red color.
00b — low improvement
01b — typical value
10b — medium improvement
11b — strong improvement
43 - 42
Reverse_V_R
00b
These two bits control reverse voltage in red color.
00b — High
01b — Medium High
10b — Medium
11b — Low
Table 8. Scan Line Number VS MAX_LINE Setting
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MAX_LINE (Bit 4–bit 0)
Scan Line Number
0 0000b
1
0 0001b
2
0 0010b
3
…
…
0 1111b
16
…
…
1 1101b
30
1 1110b
31
1 1111b
32
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3.4
3.4.1
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Step 3 — Write GS Data Into One Memory BANK
Overview of the Memory Structure
The bottleneck for a traditional PWM LED driver to realize a high visual refresh rate is the GS data
transmission limitation. To remove this limitation, the TLC59581 has 48Kb display memory implemented.
With this memory size, a multiplexing LED display system with from 1 up to 32 duty ratio (that is, 32
multiplexing) is supported.
The memory is divided into two BANKs: BANK A and BANK B. One is read for the current display image,
the other one is written with GS data of the next display image. This BANK selection is decided by the
BANK_SEL bit which is an internal flag bit. At power on, BANK_SEL = 0, thus BANK A is selected to be
written with GS data for next frame, while the GS data in BANK B is read out for current frame display.
When the time of one frame has elapsed, input the Vsync command (see Section 3.4.2 for details) and the
usage of these two BANKs is exchanged.
With this method, TLC59581 can display the image of current frame at a very high refresh rate, without
the limitation of GS data transmission. See Figure 8 for this BANK select mode change.
SOUT
SIN
48bits common shift register
SCLK
SOUT
48bits common shift register
Selector
Memory BANK A
Store GS data for
next frame
SIN
SCLK
Selector
Memory BANK A
Used for current
frame display
Memory BANK B
Used for current
frame display
Memory BANK B
Store GS data for
next frame
Selector
Selector
Multiplexing ES-PWM
Multiplexing ES-PWM
OUTR0 – OUTB15
OUTR0 – OUTB15
Vsync command
BANK select mode A
BANK select mode B
Figure 8. BANK Select Mode Change
3.4.2
What is the Vsync Command?
Vsync is the vertical frame synchronization command. When the period of one frame ends, input this
command to exchange the usage of the two memory BANKs, then the new image in the other BANK is
displayed in the coming frame period.
If 3 SCLK rising edges are detected during LAT high period, then the TLC59581 considers this as a Vsync
command.
Table 9. Vsync Commands Description
18
Command Name
SCLK Rising
Edges While LAT
is High
Vsync (Vertical
Synchronization)
3
Description
Vertical synchronization signal. When this command is received, BANK_SEL bit is
toggled, and all counters are reset to 0. A new frame image is displayed in the
coming frame period. Refer to Figure 9 for a timing diagram of this command
operation.
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All the internal counters are initiated once the Vsync command is received. Figure 9 shows the timing of
the Vsync command.
SIN
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1: Don’t care
SCLK
1
2
3
3 SCLK rising edge must
be input while LAT is high
LAT
BANK_SEL
(internal bit)
0(or 1)
Toggled to 1(or 0)
BANK_SEL is toggled, all counters are reset to 0 at the falling edge of LAT
Line Write
Counter
Old counter value
Reset to 0
Channel
Counter
Old counter value
Reset to 0
GS Counter
Old counter value
Reset to 0
Line Read
Counter
Old counter value
Reset to 0
Sub-Period
Counter
Old counter value
Reset to 0
Figure 9. Vertical Synchronization (Vsync) Command
3.4.3
Detail of the Memory BANK
Each BANK contains all the GS data of 32 scan lines. Each line is comprised of sixteen 48-bits-width
memory units. Each unit contains the R/G/B grayscale (GS) data of one channel. For example, the
memory unit for channel 0 contains 16-bit GS data for OUTR0, 16-bit GS data for OUTG0, and 16-bit GS
data for OUTB0. Figure 10 shows the bit arrangement of this memory unit. In this example, bit 32–47
contain the 16-bit GS data for OUTB0 (pin 10 of the IC) for line x.
Bit 47
Bit15 for
OUTB0
Bit 46
Bit 32
Bit 31
Bit 30
Bit16
Bit 15
Bit 14
Bit 0
Bit14 for
OUTB0
Bit0 for
OUTB0
Bit15 for
OUTG0
Bit14 for
OUTG0
Bit0 for
OUTG0
Bit15 for
OUTR0
Bit14 for
OUTR0
Bit0 for
OUTR0
One Memory Unit
(Channel 0 of line x)
Figure 10. Bit Arrangement of One Memory Unit
Depending on the scan line number selected in the FC2 register (bit 4–0), the total memory units that
must be written in one BANK is: 16 × scan_line_number. For example, if choosing 32 multiplexing, then
write 512 (32 × 16 = 512) memory units during one frame period. Figure 12 shows the detailed memory
structure.
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Write GS Data to One Memory Unit (48-bit Width) With the WRTGS Command
If TLC59581 detected one SCLK rising edge during the LAT high period, it considers this as a WRTGS
command, and will latch the data of the common shift register into one memory unit (48-bit width) at the
falling edge of LAT.
The data of the common shift register is latched into the memory unit according to the following bit
sequence. When shifting GS data into the common shift register, input bit 15 of OUTBn (Blue color) first.
48bits common shift register
Bit 47
SOUT
Bit15 for
OUTBn
Bit 46
Bit 32
Bit 31
Bit 30
Bit16
Bit 15
Bit 14
Bit 0
Bit14 for
OUTBn
Bit0 for
OUTBn
Bit15 for
OUTGn
Bit14 for
OUTGn
Bit0 for
OUTGn
Bit15 for
OUTRn
Bit14 for
OUTRn
Bit0 for
OUTRn
Higher 16bits
for OUTBn
Bit 47
Bit15 for
OUTBn
SIN
SCLK
Lower 16bits
for OUTRn
Middle 16bits
for OUTGn
Bit 46
Bit 32
Bit 31
Bit 30
Bit16
Bit 15
Bit 14
Bit 0
Bit14 for
OUTBn
Bit0 for
OUTBn
Bit15 for
OUTGn
Bit14 for
OUTGn
Bit0 for
OUTGn
Bit15 for
OUTRn
Bit14 for
OUTRn
Bit0 for
OUTRn
One Memory Unit
(Channel n)
Figure 11. Latch Common Shift Register Data Into One Memory Unit
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SIN
SCLK
48bits common shift register
SOUT
Bit47
Bit32 Bit31
Higher 16bits
Bit0
Bit16 Bit15
Middle 16bits
When WRTGS command received,
the 48bits data in common shift
register will be copied to one
unit(48bits width) of the memory.
BANK_SEL bit(an internal bit), Line
write counter, and Channel address
counter will decide which unit be
written to.
Lower 16bits
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit0
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit0
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit0
Line 0
Line 1
BANK A
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit0
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit0
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Bit15
Channel 0, Blue GS
Bit0 Bit15
Channel 0, Green GS
Bit0 Bit15
Channel 0, Red GS
Bit0
Bit15
Channel 1, Blue GS
Bit0 Bit15
Channel 1, Green GS
Bit0 Bit15
Channel 1, Red GS
Bit0
Bit15
Channel 2, Blue GS
Bit0 Bit15
Channel 2, Green GS
Bit0 Bit15
Channel 2, Red GS
Bit0
Bit15
Channel 15, Blue GS
Bit0 Bit15
Channel 15, Green GS
Bit0 Bit15
Channel 15, Red GS
Bit0
Line 31
Line 0
Line 1
BANK B
Line 31
Figure 12. Memory Structure
BANK_SEL bit (an internal bit), line write address counter, and channel address counter decide which unit
is written.
Figure 13 shows the timing of this command.
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B15
B14
B13
R1
R2
B15
R0
B14
B13
R2
R1
R0
SCLK
1
2
3
46
47
48
1
2
3
1 SCLK rising edge must
be input while LAT is high
46
47
48
LAT
BANK_SEL
(internal bit)
=0
Line Write
Counter
Channel
Counter
‘00000b’
The channel address counter value is increased
by 1 for each WRTGS command input
‘0’
‘1’
‘2’
The data in the 48-bit common shift register are copied to the memory unit selected
by BANK_SEL, Line write counter, and channel counter
Memory unit
(BANKA, Line0,
Channel 0)
Old GS data
New GS data
Memory unit
Old GS data
(BANKA, Line0,
Channel 1)
Memory unit
(BANKA, Line0,
Channel 15)
New GS data
Old GS data
Memory unit
(BANKA, Line1,
Channel 0)
Old GS data
Figure 13. 48-bit GS Data Write (WRTGS) Command
3.4.5
Write GS Data to One Memory BANK
One BANK contains maximum memory units (48-bits-width) number is: 32 lines × 16 channels = 512.
Depending on the multiplexing ratio selected in the FC2 register (bit 4–0), the total memory units must be
written in one BANK is: 16 × scan_line_number. Users should write to these memory units one by one,
sequentially. A detailed description follows.
After power on, the BANK_SEL bit, line write counter, and channel counter are reset to 0. Thus, the
memory unit of BANK A, line 0, channel 0 is selected to be written with the 48-bit GS data in the common
shift register when the WRTGS command is received.
After that, the channel counter increments 1, then the memory unit of BANK A, line 0, and channel 1 are
copied with the 48-bit data in the common shift register with the next WRTGS command input.
In this sequence, when all sixteen channels of the memory unit of line 0 have been written, the channel
counter is higher than 15. At this moment, the channel counter is reset to 0, and the line counter
increments 1.
Next, the sixteen-channel memory unit of line 1 is written one by one in same method. When line1 is
finished, line counter increments 1, and the sixteen channels of line 2 are written.
In this manner, when the line counter goes higher than MAX_LINE (see Table 8), all scan lines have been
updated with new GS data, then the line counter is reset to 0. See Figure 14 for this timing diagram.
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See Figure13 for the detail
timing of WRTGS command
Input command
Channel
Counter
WRTGS
‘0’
WRTGS
‘1’
WRTGS
‘2’
The channel address counter value is increased
by 1 for each WRTGS command input
WRTGS
‘15’
WRTGS
‘0’
WRTGS
WRTGS
‘2’
‘1’
WRTGS
‘15’
‘0’
Line write counter increased by 1 when channel counter reset to 0
Line Write
Counter
Input command
Channel
Counter
Line Write
Counter
‘0’
WRTGS
‘0’
WRTGS
‘1’
‘1’
WRTGS
‘2’
WRTGS
‘15’
‘31’
WRTGS
‘0’
WRTGS
‘1’
‘2’
WRTGS
‘2’
‘0’
WRTGS
‘0’
‘15’
‘1’
Line write counter is reset to 0 when it reached the programmed max scan line
number (in this example, we assume MAX_LINE=1Fh)
Figure 14. Memory Write Sequence
3.5
Step 4 — Send Vsync Command to Switch the BANK Purpose
Send Vsync command, then the BANK to which the GS data had been written in the previous step is
displayed in the coming frame period. See Figure 9 to learn how to send the Vsync command.
3.6
Step 5 — Input GCLK to Begin Displaying the Image of One New Frame
Input GCLK continuously, 257 GCLK (or 513 GCLK) as a segment. Between the interval of two segments,
switch LED supply voltage from one line to next line accordingly.
Since the TLC59581 needs time to prepare GS data for the 1st line of a new frame, after sending the
Vsync command (falling edge of LAT pulse), some wait time (2.5 µs) is needed before sending the first
GCLK.
3.6.1
Basic Knowledge: What is PWM Control?
PWM control means pulse width modulation (PWM) control scheme, which controls the OUTx pin turn on
ratio during one display period proportional to the grayscale (GS) data of this channel. The use of 16-bits
GS data per channel results in 65536 brightness steps, from 0% up to 100% brightness.
For example:
• If GS = 0, then OUTx will not turn on during one display period (65536 GCLK period totally), the
brightness is 0%
• If GS = 500, then during one display period, OUTx turns on 500 GCLK period, then the brightness ratio
is 500/65535 = 0.763% (Assume 100% brightness if 65535 GCLK period is turn on during one display
period)
• If GS = 65534, then during one display period, OUTx turns on 65534 GCLK period, then the brightness
ratio is 65534/65535 = 99.9985%
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Multiplexed Enhanced Spectrum (ES) PWM Control
The TLC59581 is designed mainly for multiplexed display systems, using an innovative multiplexed ES
PWM method to improve the visual refresh rate while maintaining the best grayscale performance.
Two PWM modes can be selected: 8-bit MSB + 8-bit LSB (8+8) mode, and 9-bit MSB + 7-bit LSB (9+7)
mode. This is decided with the SEL_PWM (bit 14 of FC2 register).
3.6.2.1
8+8 Mode ES PWM Control
When SEL_PWM (bit 14 of FC2 register) = 0, ES-PWM is in 8MSB + 8LSB mode.
In the conventional 8MSB + 8LSB ES-PWM control, one total display period (include 65536 GCLK period)
is divided to 256 display segments. Each segment has 256 GCLK periods. The OUTx total on-time during
one display period is distributed evenly in these 256 segments. By this means, the visual refresh rate is
increased by 256 times.
This is a good method for a static display system, but not good for a multiplexed (dynamic) display
system. If one finished all 256 segments of one scan line, then changes to display another scan line, the
refresh rate is very low.
In the TLC59581’s multiplexed ES PWM control, one display period is divided into 256 sub-periods, which
corresponds to the 256 segments of the conventional ES-PWM. During one sub-period, all scan lines
display their corresponding segment sequentially. When all scan lines finish their segment, this sub-period
ends, and next sub-period starts. Because each scan line has a chance to display in one sub-period, the
visual refresh rate is 256 times higher than that of the conventional ES-PWM control.
The time of one sub-period determines the visual refresh rate, as Equation 3 shows:
fRefresh = 1/tSub-period
where
•
•
fRefresh is the visual refresh rate
tSub-period is the time of one sub-period needed
(3)
Figure 15 shows the timing of multiplexed ES PWM operation in 8+8 mode.
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Conventional ES-PWM (8+8 mode)
(Static Driver)
255 257
256 258
1 2 3
16382 16385
16383 16386
16384 16387
32766 32769
32767 32770
32768 32771
49153
49151 49154
49152
65278 65281
65279 65282
65280 65283
65534
65535 1 2 3
65536
GCLK
Segment 0
Seg
63
Seg 1
(Voltage Level = High)
OUTXn OFF
ON
(GS Data = 0000h)
Seg
64
Seg
127
Seg Seg
191 192
Seg
128
Seg
254
Segment 255
Seg 0
Segment 255
Seg 0
(Voltage Level = Low)
OUTXn OFF
ON
(GS Data = 0001h)
t = GCLK
t = GCLK
OUTXn OFF
(GS Data = 0002h)
ON
OUTXn OFF
ON
(GS Data = 0003h)
Segment 0
Seg 1
Seg 63 Seg 64
Seg 127Seg 128
Seg 191Seg 192
Seg 254
Multiplexed ES-PWM (8+8 mode)
(32 multiplexing ratio)
1 Total Display Period
Selected Scan line
number for PWM control
Sub-Period 1
Sub-Period 0
Sub-Period
2 ~ 254
Sub-Period 255
257 x 32 x
253 GCLK
257 x 32 GCLK
Sub-Period 0
Scan line 0
Scan line 1
Scan line 30
Scan line 31
257 x 32 GCLK
257 x 32 GCLK
External LED anode
side switch
ON
SWCOM 0
ON
OFF
ON
OFF
ON
OFF
OFF
SWCOM 1
SWCOM 30
SWCOM 31
Figure 15. Multiplexed ES-PWM Operation (8+8 Mode)
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7+9 Mode ES PWM Control
When SEL_PWM (bit 14 of FC2 register) = 1, ES-PWM is in 7MSB + 9LSB mode.
In the conventional 7MSB +9LSB ES-PWM control, one total display period (include 65536 GCLK period)
is divided to 512 display segments. Each segment has 129 GCLK periods. The OUTx total on-time during
one display period is distributed evenly in these 512 segments. By this means, the visual refresh rate is
increased by 128 times.
This is a good method for a static display system, but not good for a multiplexed (dynamic) display
system. If one finished all 512 segments of one scan line, then changes to display another scan line, the
refresh rate is very low.
In the TLC59581’s multiplexed ES PWM control, one display period is divided into 512 sub-periods, which
correspond to 512 segments of the conventional ES-PWM. During one sub-period, all scan lines display
their corresponding segment sequentially. When all scan lines finish their segment, this sub-period ends,
and next sub-period starts. Because each scan line has a chance to display in one sub-period, thus the
visual refresh rate is 512 times higher than that of the conventional ES-PWM control.
Figure 17 shows the timing of multiplexed ES PWM operation in 7+9 mode.
3.6.3
How to Input GCLK and Address of Lines for Multiplexing
Example: 8+8 Mode, Multiplexing Ratio 1/32
Interval between segments. This time depends on the discharge circuit of scan
lines. It can be as short as possible, as long as no ghost phenomena observed.
Suggested range is 0.5uS~1uS
Tsu3 >2.5uS
GCLK
257GCLK
257GCLK
257GCLK
257GCLK
257GCLK
257GCLK
Sub-Period 0
Address (A4~A0) for
selection of scan lines
Vsync command
(SCLK/LAT)
Write GS data
(SIN/SCLK/LAT)
‘0d’
‘1d’
‘2d’
257GCLK
257GCLK
Sub-Period 1
‘31d’
‘0d’
‘1d’
‘2d’
‘31d’
‘0d’
Vsync command. New frame start here
Start writing GS data to another BANK for next frame display image
Figure 16. Controller Timing Sequence, 8+8 Mode, 32 Multiplexing
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Example: 7+9 Mode, Multiplexing Ratio 1/32
Same timing sequence as 8+8 mode, except 129 GCLK per segment instead of 257 GCLK per segment.
Conventional ES-PWM (7+9 mode)
(Static Driver)
128 130
129 131
1 2 3
16382 16385
16383 16386
16384 16387
32766 32769
32767 32770
32768 32771
49153
49151 49154
49152
65022 65025
65023 65026
65024 65027
65534
65535 1 2 3
65536
GCLK
Segment 0
Seg
63
Seg 1
(Voltage Level = High)
OUTXn OFF
ON
(GS Data = 0000h)
Seg
64
Seg
95
Seg Seg
191 192
Seg
96
Seg
510
Segment 511
Seg 0
Segment 511
Seg 0
(Voltage Level = Low)
OUTXn OFF
ON
(GS Data = 0001h)
t = GCLK
t = GCLK
OUTXn OFF
(GS Data = 0002h)
ON
OUTXn OFF
ON
(GS Data = 0003h)
Segment 0
Seg 1
Seg 63 Seg 64
Seg 95 Seg 96
Seg 191Seg 192
Seg 510
Multiplexed ES-PWM (7+9 mode)
(32 multiplexing ratio)
1 Total Display Period
Selected Scan line
number for PWM control
Sub-Period 1
Sub-Period 0
Sub-Period
2 ~ 510
Sub-Period 511
129 x 32 x
509 GCLK
129 x 32 GCLK
Sub-Period 0
Scan line 0
Scan line 1
Scan line 30
Scan line 31
129 x 32 GCLK
129 x 32 GCLK
External LED anode
side switch
ON
SWCOM 0
ON
OFF
ON
OFF
ON
OFF
OFF
SWCOM 1
SWCOM 30
SWCOM 31
Figure 17. Multiplexed ES-PWM Operation (7+9 Mode)
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Step 6 — During the Same Period of Step 5, Write GS Data for Next Frame Into
Another BANK
See Figure 16 for details.
3.8
Step 7 — When the Time of One Frame Ends, Input the Vsync Command to Swap the
Purpose of the Two BANKs
Example: A big picture of the timing sequence, 7+9 mode
Write GS to BANK A
Write GS to BANK A
Write FC1/2
Write GS to BANK A
Write GS to BANK B
Write GS to BANK B
SIN/SCLK/LAT
Vsync
Address (A4~A0) for
selection of scan lines
GCLK
Vsync
Vsync
Address sequence repeat
Address sequence repeat
Display BANK A
Display BANK B
Vsync
Address sequence repeat
Display BANK A
Vsync
Address sequence repeat
Display BANK B
Include many clusters of GCLK. Each cluster includes 129 GCLK pulses. There is ~0.5uS interval between two
clusters. During this interval, power supply should be changed from one scan line to next line.
Power on
1st Frame Period
2nd Frame Period
3rd Frame Period
4th Frame Period
Normal Operation Phase
Initialization Phase
Figure 18. Timing Sequence, 7+9 Mode
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3.9
3.9.1
LED Open Detection (LOD)
How Does LOD Operate?
LOD function detects a fault caused by an open circuit in any LED string or a short from OUTXn to ground
with low impedance, by comparing the OUTXn voltage to the LOD detection threshold voltage level set by
LODVLT in the FC1 register (see Table 5). If the OUTXn voltage is lower than the programmed voltage,
the corresponding output LOD bit is set to '1' to indicate an open LED. Otherwise, the output of that LOD
bit is '0' (see Figure 19). LOD data output by detect circuit are valid only during the ‘on’ period of that
OUTXn output channel. LOD data are always ‘0’ for outputs that are turned off.
VLED
LED lamp
LOD data
“1” = Error
OUTXn
VLOD
1~25 mA
with maximum
BC/CC data
On-Off
control
GND
Figure 19. LOD Detect Circuit Of One Channel
The output of the LOD detect circuit is loaded into the 48-bit register called SID holder (Figure 20 shows
the bit arrangement of this SID holder) at the rising edge of the 33th GCLK in each segment. To get a
correct detecting result, it is necessary to make sure OUTXn is kept ‘on’ in the 33th GCLK period in one
segment. See Figure 21 for the timing diagram.
Bit 47
Bit 46
LOD for LOD for
OUTR15 OUTR14
Bit 32
LOD for
OUTR0
Bit 31
Bit 30
LOD for LOD for
OUTG15 OUTG14
Bit16
LOD for
OUTG0
Bit 15
Bit 14
LOD for LOD for
OUTB15 OUTB14
Bit 0
LOD for
OUTB0
Figure 20. Bit Arrangement of the SID Holder
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8+8 mode (SEL_PWM=0):
GCLK
1
GS Counter
256
32
2
1
0
31
33
256
34
255
32
1
257
0
256
32
2
1
31
33
34
256
257
256
255
32
The 48-bit output of LOD detector are copied to SID
register at the 33th GCLK rising edge(when GS
counter =32) in each segment
Output of LOD
Detector
Detected LOD data ‘0’ or ‘1’
‘0’
Old LOD data
SID holder
Detected LOD data ‘0’ or ‘1’
‘0’
‘0’
New LOD data
New LOD data
7+9 mode (SEL_PWM=1):
GCLK
1
GS Counter
128
32
2
0
1
31
33
34
128
127
32
1
129
128
0
32
2
1
31
33
34
32
128
127
129
128
The 48-bit output of LOD detector are copied to SID
register at the 33th GCLK rising edge(when GS
counter =32) in each segment
Output of LOD
Detector
SID holder
‘0’
Detected LOD data ‘0’ or ‘1’
Old LOD data
‘0’
Detected LOD data ‘0’ or ‘1’
New LOD data
‘0’
New LOD data
Figure 21. LOD Information Latch Into SID Holder
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3.9.2
Read LOD Information With the READSID Command
Once the TLC59581 detected 7 rising edges of SCLK during LAT high period, it considers this as a
READSID command. The 48-bit data in SID holder is latched into common shift register at the falling edge
of LAT signal. After that, input 48 SCLK pulse to shift out the LOD data at the SOUT pin. Figure 22 shows
this timing diagram.
SIN
*1
*1
*1: Don’t care
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
SCLK
1
2
1
7
2
3
4
5
6
…
44
45
46
47
48
7 SCLK rising edge must
be input while LAT is high.
LAT
LOD
R15
SOUT
LOD
R14
LOD
R13
LOD
R12
LOD
R11
LOD
B4
LOD
R10
LOD
B3
LOD
B2
LOD
B1
LOD
B0
The 48-bit LOD information in SID data latch are copied to common shift register at the LAT
signal falling edge. The sequence of these LOD information in common shift register is
shown as below
LOD information(48bit) hold in SID data latch
LOD for LOD for
OUTR15 OUTR14
SOUT
Bit 47
Bit 46
LOD for
OUTR0
Bit 32
LOD for LOD for
OUTG15 OUTG14
Bit 31
Bit 30
LOD for
OUTG0
Bit16
LOD for LOD for
OUTB15 OUTB14
Bit 15
Bit 14
LOD for
OUTB0
Bit 0
SIN
SCK
LSB
MSB
Common shift register (48bits)
Figure 22. LOD Information Read (READSID) Timing
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Suggested LED Open Detection Process
Figure 23 shows the flow of the LOD detection process.
Write GS=FFFFh for all channels in one page memory
Input “Vsync” command
Apply VLED to line 0
Input 257 GCLK (if choose 7+9 mode, then 129GCLK should be input)
Input “READSID” command
Input 48xN(N is the IC number in series) SCLK, read LOD data at SOUT
All line finished?
YES
END
NO
Apply VLED to next line
Figure 23. Example of LOD Detection Process (8+8 Mode)
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3.10 How to Read the Function Control Register
Once TLC59581 detected 10 rising edges of SCLK during the LAT high period, it considers this as a
READFC1 command. The 44-bit data in the FC1 register is latched into the lower 44 bits of the common
shift register at the falling edge of the LAT signal. Other bits in the common shift register are reset to 0.
Once the TLC59581 detected 11 rising edges of SCLK during the LAT high period, it considers this as a
READFC2 command. The 17-bit data in the FC2 register is latched into the lower 17 bits of the common
shift register at the falling edge of the LAT signal. Other bits in the common shift register are reset to 0.
Next, the loaded data can be read out from SOUT synchronized with the SCLK rising edge.
Refer to Figure 24 and Figure 25 for the timing diagram of these two commands.
SIN
*1
*1
*1: Don’t care
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
SCLK
1
2
1
10
2
3
4
5
6
…
44
45
46
47
48
10 SCLK rising edge must
be input while LAT is high.
LAT
Bit45 Bit44
‘0’b
‘0’b
Bit47 Bit46
‘0’b
‘0’b
SOUT
FC1
Bit43
FC1
Bit4
FC1
Bit42
FC1
Bit3
FC1
Bit2
FC1
Bit1
FC1
Bit0
*1
*1
The 44-bit data in FC1 register are copied to the lower 44-bit of common shift register at the
LAT signal falling edge. The other bits in common shift register are reset to 0.
Figure 24. FC1 Data Read (READFC1) Command
SIN
*1
*1
*1: Don’t care
*1
*1
*1
*1
*1
*1
*1
*1
*1
*1
SCLK
1
LAT
SOUT
2
11
1
2
3
…
30
31
32
33
…
46
47
48
11 SCLK rising edge must
be input while LAT is high.
Bit47 Bit46
‘0’b
‘0’b
Bit45
‘0’b
Bit18
‘0’b
Bit17
‘0’b
FC2
Bit16
FC2
Bit15
FC2
Bit2
FC2
Bit1
FC2
Bit0
The 17-bit data in FC2 register are copied to the lower 17-bit of common shift register at the
LAT signal falling edge. The other bits in common shift register are reset to 0.
Figure 25. FC2 Data Read (READFC2) Command
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3.11 Function Commands Summary
Table 10 lists a summary of all the seven commands that can be input with SCLK and LAT signals:
WRTGS, VSYNC, WRTFC, READSID, READFC1, READFC2, and FCWRTEN.
Table 10. Function Commands Summary
Command Name
SCLK Rising
Edges While LAT
is High
WRTGS (48-bit GS data write)
1
The 48-bit data in the common shift register are copied to the memory unit
selected by channel address counter, line write counter, and BANK_SEL bit.
Refer to Figure 13 for a timing diagram of this command operation.
3
Vertical synchronization signal. When this command is received, the
BANK_SEL bit is toggled, and all counters are reset to 0. New frame images
are displayed in the coming frame period.
Refer to Figure 9 for a timing diagram of this command operation.
5
The lower 44-bit data or the lower 17-bit data in the common shift register
are copied to the FC1 or FC2 register. Bit 47–44 of the common shift
register are used to choose which FC register is written to. If ‘1001b’ is
received for bit 47–44 of the common shift register, then the lower 44-bits in
the common shift register are copied to the FC1 register. If ‘0110b’ is
received for bit 47–44 of the common shift register, then the lower 17 bits in
the common shift register are copied to the FC2 register.
Refer to Figure 7 for a timing diagram of this command operation.
7
The 48-bit LOD data in the SID data latch are copied to the 48-bit shift
register. The loaded data can be read out from SOUT synchronized with the
SCLK rising edge.
Refer to Figure 21 for a timing diagram of this command operation.
10
The 44-bit data in the FC1 register are copied to the lower 44 bits of the shift
register. Other bits in the shift register are reset to 0. The loaded data can
be read out from SOUT synchronized with the SCLK rising edge.
Refer to Figure 24 for a timing diagram of this command operation.
READFC2 (FC2 data read)
11
The 17-bit data in the FC2 register are copied to the lower 17 bits of the shift
register. Other bits in the shift register are reset to 0. The loaded data can
be read out from SOUT synchronized with the SCLK rising edge.
Refer to Figure 25 for a timing diagram of this command operation.
FCWRTEN (FC write enable)
15
FC writes are enabled by this command. This command must always be
input before the FC data write occurs.
Refer to Figure 7 for a timing diagram of this command operation.
Vsync (Vertical
Synchronization)
WRTFC (FC data write)
READSID (SID data read)
READFC1 (FC1 data read)
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3.12 Power-Save Mode (PSM)
The power-save mode (PSM) is enabled by setting PSAVE_ENA (bit5 of FC2 register) to ‘1’. When the
power is on, this bit default is ‘0’.
When this function is enabled, if all the GS data received for next frame are ‘0’, IC enters power-save
mode at the moment the Vsync command is input.
In power-save mode, the IC detects if non-zero GS data is input for next frame. Among all the GS data for
next frame, if anyone is non-zero, it starts to resume normal mode once finishing the whole GS input for
next frame. See Figure 26 for the timing diagram.
In power-save mode, if all analog circuits like constant current output, LOD circuit, and so forth, do not
work, the device total current consumption ICC is below 1 mA.
All the GS data written during this period
are ‘0’, IC will enter power-save mode
once receive Vsync command at the
falling edge of LAT
SIN/SCLK/LAT
Write GS to BANK A
Write GS to BANK B
Vsync
GCLK
Among all the GS data written during this period, if
anyone is not ‘0’, IC will begin resume to normal
mode once receive the last WRTGS command at
the falling edge of LAT
Display BANK B
Working mode
Write GS to BANK B
Vsync
Vsync
Display BANK A
Display BANK A
Display BANK B
50uS (Max)
Normal mode
Normal mode
Power-Save Mode
Enter Power-Save
mode immediately
Start to resume
normal mode
Fully recovered
TSU4
One should make
sure Tsu4 > 50uS
N-1 th Frame Period
N th Frame Period
N+1 th Frame Period
N+2 th Frame Period
Figure 26. Enter/Exit Power-Save Mode
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3.13 Pre-Charge Function
The internal pre-charge FET is implemented to remove ghosting of multiplexed LED modules. One cause
of this phenomenon is the charging current for parasitic capacitance of OUTXn through the LED when the
supply voltage switches from one common line to next common line.
To prevent this unwanted charging current, the TLC59581 uses an internal FET to pull OUTXn during the
common line switching period. Thus, no charging current flows through the LED and the ghosting is
eliminated.
Three pre-charge working modes can be selected by SEL_PCHG, bit 7 of FC2 and PREC_MODE3, bit 9
of FC1. Table 11 shows the pre-charge function truth table.
Table 11. Pre-Charge Function Mode
EL_PCHG
Bit 7 of FC2
PREC_MODE3
Bit 9 of FC1
Pre-Charge
Function Mode
0
--
Mode 1
1
0
Mode 2
1
1
Mode 3
Take the 8+8 mode as the example. Pre-charge mode1, the pre-charge FET only remains off during the
period in which the channel is on.
Pre-charge mode2, the pre-charge FET remains off during the whole segment period (257 GCLK period),
and only remains on during the dead-time (the time between two adjacent segments).
Pre-charge mode3, the pre-charge FET remains off during the first half segment period (1 to 128 GCLK of
the 257 GCLK period), and only keep on during the last half segment period (129 to 257 GCLK of the
257GCLK period) and the dead-time (the time between two adjacent segments).
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Figure 27 shows these differences (take 8+8 mode as example).
At this GCLK edge, channel is turned off, Pre-charge
FET will be turned on at same time.
Pre-charge Mode1, take 8+8
mode as example:
GCLK
1
OUTXn
OFF
2
32
33
34
256
1
257
ON
2
32
33
34
256
257
OFF
In this segment, channel will not be
turned on. As a result, the Pre-charge
FET remains on.
Line N
Line N+1
Pre-charge
FET
OFF
ON
ON
Pre-charge Mode2, take 8+8
mode as example:
GCLK
1
OUTXn
OFF
2
32
33
34
256
1
257
ON
2
32
33
34
256
257
OFF
Pre-charge FET only turns on
during the dead-time
Line N
Pre-charge FET remains off
during the whole segment
Line N+1
Pre-charge
FET
ON
ON
OFF
ON
OFF
Pre-charge Mode3, take 8+8
mode as example:
GCLK
1
OUTXn
OFF
2
32
129
ON
256
1
257
2
128
129
130
256
257
OFF
Pre-charge FET only turns on
during the last half segment
and the dead-time
Line N
Pre-charge FET remains off
during the first half segment
Line N+1
Pre-charge
FET
ON
OFF
ON
OFF
ON
Figure 27. Pre-Charge FET Working Mode
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st
3.14 1 -Line Enhancement
The 1st-line issue is a common phenomenon in multiplexing applications, especially in high density, high
refresh rate panels. This issue can be solved with a specific circuit in the TLC59581. We can choose a
different setting in the FC2 register according to hardware structure. A typical value is ‘01’.
Table 12. 1st-Line Enhancement Summary
1st-Line (FC2)
1st-Line Enhancement Effect
Bit 16
Bit 15
0
0
No
0
1
Weak (Typ)
1
0
Medium
1
1
Strong
3.15 HG-LG Interference Enhancement
When high grayscale and low grayscale patterns are displayed at the same time, the low grayscale part is
affected by the high grayscale part. HG-LG interference is solved by choosing different settings of
Interference-R, Interference-G, and Interference-B in the FC2 register of TLC59581.
Table 13. Interference Compensation Summary
Interference-R
(FC2)
Interference Compensation Effect
Bit 41
Bit 40
0
0
Normal
0
1
Weak (Typ)
1
0
Medium
1
1
Strong
Interference-G
(FC2)
Interference Compensation Effect
Bit 37
Bit 36
0
0
Normal
0
1
Weak (Typ)
1
0
Medium
1
1
Strong
Interference-B
(FC2)
38
Interference Compensation Effect
Bit 33
Bit 32
0
0
Normal
0
1
Weak (Typ)
1
0
Medium
1
1
Strong
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3.16 Low Gray-Scale Enhancement
Low grayscale uniformity is a common issue in multiplexing applications, especially under low current
conditions. This issue is solved by choosing different setting of LGSE1-R, LGSE1-G, LGSE1-B in the FC2
register. Adjusting these control bits also helps improve the white balance at low grayscale condition.
Table 14. Low Grayscale Enhancement Setting
LGSE1-R
(Bit 31–28)
LGSE1-G
(Bit 27–24)
LGSE1-B
(Bit 23–20)
Compensation Effect
0000b
0
0001b
1
0010b
2
…
…
1011b
11
1100b
12
1101b
13
1110b
14
1111b
15
Different multiplexing ratios require a different setting. The guidelines follow:
1. The higher the multiplexing ratio is, the higher enhancement is needed.
2. The enhancement of G/B should be higher than that of Red.
For example, one suggested setting for a 1/32 multiplexing panel is: LGSE1-R = 2d, LGSE1-G = LGSE1-B
= 9d
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3.17 LOD Caterpillar Cancelling
The caterpillar effect is a phenomenon caused by broken LEDs. The TLC59581 has an internal circuit to
remove the caterpillar issue in multiplexed LED modules. One cause of this phenomenon is the electric
charge on the parasitic capacitor of line goes through the LED when the OUT is pulled down to GND due
to the LED open of another line. This makes all the LED multiplexing with the open LED turn on during the
special time.
To prevent the caterpillar issue, the TLC59581 has integrated internal circuits for LED open detection.
When LED open is detected, the output channel is turned off for this specific line and then the caterpillar
effect is eliminated. The LOD caterpillar cancelling function is enabled by choosing different settings of bit
4 in the FC1 register of the TLC59581. Figure 28 illustrate is a detailed explanation of the caterpillar effect.
VLED (Power Supply for LED)
VLED
SW
PMOS0
SW
PMOS1
LINE0
LED0-1
LED drive line selector
C0
SW
NMOS1
LED0-2
LINE0 VLED
Vz
Voltage
Va
SW
PMOS1
LED0-0
VLED
Parasitic
Capacitor
SW
PMOS0
ON
OFF
LINE1 VLED
Voltage
Vz
Ichrg
High
LINE1
GCLK
C1
SW
NMOS0
ON
OFF
LED1-0
LED1-2
LED1-1
OUT0
OUT0
OUT1
OUT2
ON
OFF
LED Open
General
LED driver
Low
VLED
OUT0
Voltage VLED-Vf
Vchg
GND
OUT0
ON
OUT1
ON
OUT2
ON
LED0-0 20mA
Current
0mA
LED1-0 20mA
Current 0mA
Constant current
output
GND
GND
(1)
(2)
(3)
(4)
Caterpillar phenomenon is observed
when OUT0 is on
Figure 28. LED Caterpillar Phenomenon Mechanism
40
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3.18 Protection
3.18.1
Thermal Shutdown (TSD)
The thermal shutdown (TSD) function turns off all constant-current outputs of the IC when the junction
temperature (TJ) exceeds 170°C (typ). The TSD function resumes normal work once Tj is lower than
160°C (typ).
3.18.2
IREF Resistor Short Protection (ISP)
The Iref resistor short protection (ISP) function prevents unwanted large current from flowing though the
constant-current output when the Iref resistor is shorted accidently. TLC59581 turns off all output channels
when the Iref pin voltage goes lower than 0.125 V (typ). When the Iref pin voltage goes higher than 0.35 V
(typ), the TLC59581 resumes normal work again.
3.19 System Structure Guidelines
Follow these system structure guidelines:
1. Use less than 60 tri-color LED lamps in one MOSFET line.
2. If not all 48 output channels are used, the separate distribution of empty channels is suggested. For
example, if 6 of 48 channels in one IC are empty, empty channel RGB 0 and RGB 15. If 12 of 48
channels in one IC are empty, empty channel RGB 0, 1, 14 and 15.
3. If the empty channels are more than 6 channels, do not place all empty channels in one IC. Distribute
the empty channels into different ICs.
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