KA3511AS Intelligent Voltage Mode PWM IC
www.fairchildsemi.com
KA3511AS
Intelligent Voltage Mode PWM IC
Features
Description
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The KA3511AS is a fixed-frequency improvedperformance pulse-width modulation control circuit with complete housekeeping circuitry for use
in the secondary side of SMPS (Switched mode
power supply). It contains various functions, which
are precision voltage reference, over voltage protection, under voltage protection, remote on/off
control, power good signal generator and etc.
Complete PWM control and house keeping circuitry
Few external components
Precision voltage reference trimmed to 2%
Dual output for push-pull operation
Each output TR for 200mA sink current
Variable duty cycle by dead time control
Soft start capability by using dead time control
Double pulse suppression logic
Over voltage protection for 3.3V / 5V / 12V
Under voltage protection for 3.3V / 5V / 12V
One more external input for various protection (PT)
Remote on/off control function (PS-ON)
Latch function controlled by remote and protection input
Power good signal generator with hysteresis
Precision reference section
The reference voltage trimmed to ± 2%
(4.9V≤Vref≤5.1V)
PG (Power good signal generator) section
Power good signal generator is to monitor the voltage level of power supply for safe operation of a
microprocessor.
KA3511AS requires few external components to
accomplish a complete housekeeping circuits for
SMPS.
OVP (Over voltage protection) section
It has OVP functions for +3.3V,+5V,+12V and PT
outputs. The circuit is made up of a comparator
with four detecting inputs and without hysteresis
voltage. Especially, PT (Pin18) is prepared for an
extra OVP input or another protection signal.
UVP (Under voltage protection) section
It also has UVP functions for +3.3V, +5V, +12V outputs. The block is made up of a comparator with three
detecting inputs and without hysteresis voltage.
Remote on/off section
Remote on/off section is used to control SMPS externally. If a high signal is supplied to the remote
on/off input, PWM signal becomes a high state and
all secondary outputs are grounded. The remote on/
off signal is transferred with some on-delay and
off-delay time of 8ms, 24ms respectively.
24-SDIP
1
Rev. 5.0
©2000 Fairchild Semiconductor Interaltional
KA3511AS
Internal Block Diagram
RT
CT
COMP
V5
7
D
Q
CK
Q
OSCILLATOR
PWM
CONTROL
8
C1
22
C2
23
E
2
V12
DEAD TIME
CONTROLLER
3
E/A()
E/A(+
)
24
DELAY
CONTROLLER
R
5
REMOTE ON/OFF
TREM
Q
6
4
REM
(PS-ON)
S
1.25V
1.4V
0.1V
DEAD TIME
CONTROL
11
PG
21
5V
INTERNAL
BIAS
VREF
14
VREF
VREF
Start Up
VCC
1
VREF
PG
GENERATOR
Ichag
COMP1
OVP
COMP
PT
17
V12
16
V5
15
V3.3
1.25
V
5V
DET
18
COMP3
9
1.8V
0.6V 1.8V
0.6V
COMP2
1.25V
UVP
COMP
1.25
V
10
19
TPG
2.2u
F
20
TUVP
2.2uF
GND
Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
VCC
40
V
Collector output voltage
VC1, VC2
40
V
Collector output current
IC1, IC2
200
mA
PD
1.5
W
Operating temperature
TOPR
−25 to 85
°C
Storage temperature
TSTG
−65 to 150
°C
Supply voltage
Power dissipation(KA3511AS)
Temperature Characteristics
2
Parameter
Symbol
Temperature coefficient of Vref (-25°C≤Ta≤85°C)
∆Vref/∆T
Value
Min.
Typ.
Max.
–
0.01
–
Unit
%/°C
KA3511AS
Pin Definition : KA3511AS
C1
E
C2
DTC
GND
TUVP
PT
V12
V5
V3.3
Vref
NC
#24
#13
AS
KA3511D
#12
#1
Vcc
Pin
Number
Pin
Name
COMP
I/O
E/A(-)
EA(+)
TREM
REM
Pin Function
RT
CT
Pin
Number
DET
Pin
Name
PG
TPG
I/O
NC
Pin Function Descrition
1
VCC
I
Supply voltage
13
NC
-
NC
2
COMP
O
E/A output
14
Vref
O
Precision reference VTG
3
E/A(-)
I
E/A (-) input
15
V3.3
I
OVP, UVP input for 3.3V
4
E/A(+)
I
E/A (+) input
16
V5
I
OVP, UVP input for 5V
5
TREM
–
Remote on/off delay
17
V12
I
OVP, UVP input for 12V
6
REM
I
Remote on/off input
18
PT
I
Extra protection input
7
RT
–
Oscillation freq. setting R
19
TUVP
–
UVP delay
8
CT
–
Oscillation freq. setting C
20
GND
–
Signal ground
9
DET
I
Detect input
21
DTC
I
Deadtime control input
10
TPG
–
PG delay
22
C2
O
Output 2
11
PG
O
Power good signal output
23
E
–
Power ground
12
NC
-
NC
24
C1
O
Output 1
3
KA3511AS
Pin Number Pin Name
4
Pin Function Descrition
1
VCC
2
COMP
Error amplifier output. It is connect to non-inverting input of pulse width modulator
comparator.
3
E/A(-)
Error amplifier inverting input. Its reference voltage is always 1.25V.
4
E/A(+)
Error amplifier non-inverting input feedback voltage.This pin may be used to sense
power supply output voltage.
5
TREM
Remote on/off delay. Ton/Toff=8ms/24ms (Typ.) with C=0.1uF. Its high/low threshold
voltage is 1.8V/0.6V.
6
REM
Remote on/off input. It is TTL operation and its threshold voltage is 1.4V. Voltage at
this pin can reach normal 4.6V, with absolutely maximum voltage, 5.25V. If REM =
“Low”,
PWM = “Low”. That means the main SMPS is operational. When REM = “High”, then
PWM = “High” and the main SMPS is turned-off.
7
RT
Oscillation frequency setting R. (Test Condition RT=10kΩ)
8
CT
Oscillation frequency setting C. (Test Condition CT=0.01uF)
9
DET
Under-voltage detect pin. Its threshold voltage is 1.25V Typ.
10
TPG
PG delay. Td=250ms (Typ) with CPG=2.2uF. The high/low threshold voltage are 1.8V/
0.6V and the voltage of Pin10 is clamped at 2.9V for noise margin.
11
PG
Power good output signal. PG = “High” means that the power is “Good” for operation
and PG = “Low” means “Power fail”.
14
Vref
Precision voltage reference trimmed to 2%. (Typical Value = 5.03V)
15
V3.3
Over voltage protection for output 3.3V. (Typical Value = 4.1V)
16
V5
Over voltage protection for output 5V. (Typical Value = 6.2V)
17
V12
Over voltage protection for output 12V. (Typical Value = 14.2V)
18
PT
This is prepared for an extra OVP input or another protection signal.
(Typical Value = 1.25V)
19
TUVP
Timing pin for under voltage protection blank-out time. Its threshold voltage is 1.8V
and clamped at 2.9V after full charging. Target of delay time is 250ms and it is
realized through external (C=2.2uF).
20
GND
Signal ground.
21
DTC
Deadtime control input. The dead-time control comparator has an effective 120mV
input offset which limits the minimum output dead time. Dead time may be imposed
on the output by setting the dead time control input to a fixed voltage, ranging
between 0V to 3.3V.
22
C2
23
E
24
C1
Supply voltage. Operating range is 14V~30V. VCC=20V, Ta=25°C at test.
Output drive pin for push-pull operation.
Power ground.
Output drive pin for push-pull operation.
KA3511AS
AElectrical Characteristics (vcc=20v, ta=25°°c)
Parameter
Symbol
Condition
Value
Unit
Min.
Typ.
Max.
4.9
5
5.1
V
REFERENCE SECTION
Reference output voltage
Vref
Line regulation
Load regulation
Temperature coefficient of Vref
(1)
Short-circuit output current
Iref=1mA
∆Vref.LINE
14V≤VCC≤30V
-
2.0
25
mV
∆Vref.LOAD
1mA≤Iref≤10mA
-
1.0
15
mV
∆Vref/∆T
-25°C≤Ta≤85°C
-
0.01
-
%/°C
15
35
75
mA
ISC
Vref=0
fosc
CT=0.01uF, RT=12k
-
10
-
kHz
fosc/T
CT=0.01uF, RT=12k
-
2
-
%
OSCILLATOR SECTION
Oscillation frequency
Frequency change with
temperature (1)
DEAD TIME CONTROL SECTION
Input bias current
IB(DT)
Maximum duty voltage
DCMAX
Input threshold voltage
VTH(DT)
-
-2.0
-10
uA
Pin19 (DTC)=0V
-
45
48
50
%
Zero Duty Cycle
-
3.0
3.3
Max. Duty Cycle
0
-
-
1.20
1.25
1.30
V
-
-0.1
-1.0
uA
70
95
-
dB
-
650
-
kHz
V
ERROR AMP SECTION
Inverting reference voltage
Input bias current
IB(EA)
Open-loop voltage gain (1)
Unit-gain bandwidth
Vref(EA)
(1)
Output sink current
GVO
BW
VCOMP=2.5V
0.5V≤VCOMP≤3.5V
-
ISINK
VCOMP=0.7V
0.3
0.9
-
mA
ISOURCE
VCOMP=3.5V
-2.0
-4.0
-
mA
VTH(PWM)
Zero Duty Cycle
-
4
4.5
V
Output saturation voltage
VCE(SAT)
IC=200mA
-
1.1
1.3
V
Collector off-state current
Output source current
PWM COMPARATOR SECTION
Input threshold voltage
OUTPUT SECTION
IC(off)
VCC=VC=30V, VE=0V
-
2
100
uA
Rising time
TR
-
-
100
200
ns
Falling time
TF
-
-
50
200
ns
VOVP1
-
3.8
4.1
4.3
V
PROTECTION SECTION
Over voltage protection for 3.3V
5
KA3511AS
Electrical Characteristics (continued)
Parameter
Value
Symbol
Condition
Over voltage protection for 5V
VOVP2
-
5.8
6.2
6.6
V
Over voltage protection for 12V
VOVP3
-
13.5
14.2
15.0
V
VPT
-
1.20
1.25
1.30
V
Under voltage protection for 3.3V
VUVP1
-
2.1
2.3
2.5
V
Under voltage protection for 5V
VUVP2
-
3.7
4.0
4.3
V
Under voltage protection for 12V
VUVP3
-
9.2
10
10.8
V
Charging current for UVP delay
ICHG.UVP
Input threshold voltage for PT
Min.
Typ.
Max.
Unit
C=2.2uF, VTH=1.8V
−10
−15
−23
uA
TD.UVP
C=2.2uF
100
260
500
ms
REM on input voltage
VREMH
IREM=−200uA
2.0
-
-
V
REM off input voltage
VREML
-
-
0.8
V
UVP Delay Time
REMOTE ON/OFF SECTION
REM off input bias voltage
IREML
REM on open voltage
VREM=0.4V
-
VREM(OPEN)
REM on delay time
REM off delay time
REMOTE ON/OFF SECTION
-
-
-
−1.6
mA
2.0
-
5.25
V
Ton
C=0.1uF
4
8
14
ms
Toff
C=0.1uF
16
24
34
ms
(2)
Detecting input voltage
VIN(DET)
-
1.20
1.25
1.30
V
Detecting V5 voltage
V5(DET)
-
4.1
4.3
4.5
V
Hysteresis voltage 1
HY1
COMP1, 2
10
40
80
mV
Hysteresis voltage 2
HY2
COMP3
0.6
1.2
-
V
PG output load resistor
RPG
0.5
1
2
kΩ
C=2.2uF, VTH=1.8V
−10
−15
−23
uA
C=2.2uF
100
260
500
ms
IPG=10mA
-
0.2
0.4
V
-
-
10
20
mA
Charging current for PG delay
PG delay time
PG output saturation voltage
ICHG.PG
TD.PG
VSAT(PG)
-
TOTAL DEVICE
Stanby supply current
ICC
Notes:
1. These Parameters, although guaranteed over their recommended operating conditions are not 100% tested in production.
2. REM on delay time (Pin6 REM: “L” → “H”),
REM off delay time (Pin6 REM: “H” → “L”)
6
KA3511AS
Application Informations
300K
VCC=15V
IO - OSCILLATOR FREQUENCY
100K
0.001µF
10K
CT=0.01µF
1K
0.1µF
1.0µF
100
30
1K
2K
5K
10K
20K
50K 100K
200K
500K 1M
RT. TIMING RESISTANCE(Ω)
Figure 1. Oscillator Frequency vs. Timing Resistance
Ct
Feedback
Dead-time
control
Ck
Q
Q
Output Q1
Output Q2
Figure 2. Operating Waveform
7
KA3511AS
Housekeeping Circuit
2kΩ(1W
)
2kΩ(1W
)
Standby
Supply
VCC=20V
1
VCC
2
COMP
E
23
3
E/A(-)
C2
22
4
E/A(+)
DTC
21
GND
20
TUVP
19
C1
24
15kΩ
12V
5V
0.01u
F
11kΩ
33kΩ
1.8k
Ω
0.1uF
5
TREM
6
REM
+
1kΩ
Micom
7
RT
K
A
3
5
1
1
A
+
2.2uF
PT
18
V12
17
12V
16
5V
15
3V
S
12kΩ
8
+
CT
0.01u
F
2.2uF
9
DET
V5
10
TPG
V3.3
11
PG
Vref
+
PG
14
1uF
12
13
Note :
The KA3511AS requires few external components to accomplish a complete housekeeping circuits for SMPS.
8
+
KA3511AS
Typical Characteristics
0.014
5.010
0.012
5.008
Vref [V]
ICC [A]
0.010
0.008
0.006
0.004
5.006
5.004
0.002
5.002
0.000
0
10
20
30
-40
40
-20
0
20
40
Supply Voltage [V]
80
100
120
140
TEMP [°C]
Figure 1. VCC-ICC
Figure 2. Bandgap Reference Voltage
50
5
40
4
31.1%
3
30
VPG [V]
Duty Ratio [%]
60
21.8%
20
2
12.8%
10
1
0
0
0.0
0.5
1.0
1.5
2.0
3.6
2.5 2.73 3.0
3.8
4.0
Deadtime Control Voltage [V]
4.2
4.4
4.6
V3.3 [V]
Figure 3. PIN19(Dead Time Control Voltage)-Duty Cycle
Figure 3. OVP for 3.3V
7
5
5
4
4
3
VPG [V]
VPG [V]
6
3
2
2
1
1
0
0
5.0
5.5
6.0
V5 [V]
Figure 5. OVP for 5V
6.5
7.0
14.0
14.2
14.4
14.6
14.8
15.0
V12 [V]
Figure 6. OVP for 12V
9
5
5
4
4
3
3
VPG [V]
VPG [V]
KA3511AS
2
2
1
1
0
0
1.15
1.20
1.25
1.30
21
1.35
5
4
4
VPG [V]
VPG [V]
5
3
2
2
1
0
0
4.2
4.4
25
3
1
4.0
24
Figure 8. UVP for 3.3V
Figure 7. OVP for PT
3.8
23
Pin 13 (V3.3) Voltage [V]
Vpt [V]
3.6
22
4.6
4.8
9.0
5.0
9.5
10.0
10.5
11.0
Pin 15 (V12) Voltage [V]
Pin 14 (V5) Voltage [V]
Figure 10 . UVP for 12V
Figure 9 . UVP for 5V
-0.000016
5
4
VPG [V]
Irem [A]
-0.000018
-0.000020
-0.000022
3
2
1
-0.000024
0
0
50
100
150
200
250
0
1
2
3
4
Vrem [V]
Figure 11 . Remote ON Charging Current
10
Figure 12 . REM ON/OFF Vth
5
5
5
4
4
VPG [V]
Vrem [V]
KA3511AS
3
3
2
2
1
1
0
0
0
1
2
3
4
5
1.0
1.1
1.2
1.3
1.4
1.5
Pin 9 (DET) Voltage [V]
Figure 13. Remote ON Open Voltage
Figure 14. Detecting VCC Voltage (DET)
-0.000005
5
-0.000010
IPG [V]
VPG [V]
4
3
2
1
-0.000015
-0.000020
0
4.0
4.2
4.4
4.6
4.8
5.0
0
20
40
60
80
100
120
140 160
Pin 14 (5V) Voltage [V]
Figure 16. Charging Current for PG
Figure 15. Detecting V5 Voltage
5
-0.032
-0.033
VPG [V]
Iref [A]
4
-0.034
3
2
1
-0.035
0
0
100
200
300
400
0.0
0.5
1.0
1.5
2.0
2.5
Pin 10 (TPG) Voltage [V]
Figure 15. Short Circuit Current
Figure 16. Hysteresis Voltage 2
11
KA3511AS
0.002
5
4
-0.002
Vref [V]
Isink & Isource [A]
0.00
-0.004
3
2
-0.006
1
-0.008
0
0
20
40
60
80
100
120
140
0
10
20
30
Supply Voltage [V]
Figure 17. Error Amp Sink Current
12
Figure 18. Reference Voltage
40
KA3511AS
Experimental Result
CH1 : PS-ON
CH2 : +5Vdc Output
CH3 : PG Signal
Figure 3. Rising Time of +5Vdc Output Voltage
CH1 : PS-ON
CH2 : +5Vdc Output
CH3 : PG Signal
Figure 4. PG Signal Delay Time
13
KA3511AS
CH1 : PS-ON
CH2 : +5Vdc Output
CH3 : PG Signal
Figure 5. Power Down Warning
CH1 : +3.3Vdc Output
CH2 : +5Vdc Output
CH3 : +12Vdc Output
Figure 6. No Load Protection
14
KA3511AS
CH1 : Vcc
CH2 : +5Vdc Output
CH3 : PG Signal
Figure 7. Vcc, +5Vdc Output vs. PG Signal (High)
CH1 : Vcc
CH2 : +5Vdc Output
CH3 : PG Signal
Figure 8. Vcc, +5Vdc Output vs. PG Signal (Low)
15
KA3511AS
Application Circuit
47K
70K
R6
R5
VCC
3
15K
4
POWER ON
5
+
0.1uF
6
OUT REF
7
8
103
9
10
+
PG
2.2uF
11
12
COMP
E/A(-)
C1
E
C2
E/A(+)
DTC
TREM
GND
REM
TUVP
RT
PT
CT
V12
DET
TPG
PG
NC
NC
V5
V3.3
Vref
NC
NC
AR3511X
AS
C1
24
22
23
21
22
20
R4
1.2K
C2
19
21
20
18
17
19
18
16
R3
56K
+
2
Vcc
2.2uF
17
15
5V OUT
15
13
3.3V OUT
14
12
13
D9
C16
VR1
+
16
C6
22uF
12V OUT
16
14
D19
100K
+
IC1
1
103
CT
KA3511AS
Mechanical Dimensions
Package
Dimensions in millimeters
24-SDIP
17
KA3511AS
Ordering Information
18
Product Number
Package
Operating Temperature
KA3511AS
24-SDIP
0°C ~ 70°C
KA3511AS
19
KA3511AS
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
INTERNATIONAL. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
9/25/00 0.0m 001
Stock#DSxxxxxxxx
 2000 Fairchild Semiconductor International
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