MP1517 - BB Electronic

MP1517 - BB Electronic
MP1517
3A White LED
Camera Flash Driver
Monolithic Power Systems
General Description
The MP1517 is a 4A, fixed frequency step-up
converter ideal for camera flash circuits driving
up to 4 white LEDs.
The high 1.2MHz
switching frequency allows for smaller external
components producing a compact solution for
size constrained cameras, PDAs and cell
phones as well as medium-to-high current
step-up, flyback, and SEPIC applications.
The MP1517 regulates the output voltage up
to 25V with efficiencies as high as 93%. Softstart, cycle-by-cycle current limiting, and input
undervoltage lockout prevent overstressing or
damage to sensitive external circuitry at
startup and output short-circuit conditions.
Fixed frequency operation eases control of
noise, making the MP1517 optimal for noise
sensitive applications such as mobile
handsets. Current-mode regulation and
external compensation components allow the
MP1517 control loop to be optimized over wide
variety of input voltage, output voltage and
load current conditions.
The MP1517 is offered in a tiny 4mm x 4mm
16 lead QFN.
PRELIMINARY
Features
4A Peak Current Limit
Low 700mV Feedback Threshold
Internal 150mΩ Power Switch
VIN range of 2.6V to 25V
>93% Efficiency
Zero Current Shutdown Mode
Under Voltage Lockout Protection
Open Load Protection
Soft Start Operation
Thermal Shutdown
Tiny 4mm x 4mm 16 pin QFN Package
Applications
White Flash Circuits found on:
o Handheld Computers, PDAs
o Cell phones
o Digital Still and Video Cameras
Ordering Information
Part Number
Package
Temperature
MP1517DR
QFN16 (4x4)
-40° to +85°C
∗ For Tape & Reel use suffix - Z (e.g. MP1517DR-Z)
Figure 1: Typical Application Circuit
MP1517
MP1517 Rev 1.0_07/31/03
Monolithic Power Systems, Inc.
1
MP1517
3A White LED
Camera Flash Driver
Monolithic Power Systems
PRELIMINARY
Absolute Maximum Ratings
Recommended Operating Conditions
Input Supply Voltage VIN
-0.3V to 28V
SW Pin Voltage VSW
-0.3V to 28V
Voltage at All Other Pins except OLS
-0.3V to 6V
Storage Temperature
-55°C to +150°C
IN Input Supply Voltage VIN
Operating Temperature
2.6V to 25V
-40°C to +85°C
Package Thermal Characteristics
Thermal Resistance ΘJA
100°C/W
Electrical Characteristics (VIN = 5.0V, TA = 25°C Unless specified otherwise)
Parameters
IN Input Voltage Range
IN Shutdown Supply Current
IN Operating Supply Current
BP Output Voltage
IN Undervoltage Lockout Threshold
IN Undervoltage Lockout Hysteresis
Output Voltage Range
EN Input Low Voltage
EN Input High Voltage
EN Input Hysteresis
EN Input Bias Current
SW Switching Frequency
SW Maximum Duty Cycle
Error Amplifier Voltage Gain
Error Amplifier Transconductance
COMP Maximum Output Current
FB Regulation Threshold
FB Input Bias Current
SS Charging Current
SW On Resistance
Conditions
Typ
2.6
VEN<0.3V
VEN>2V, VFB=0.8V
VIN = 2.6V to 25V
VIN Rising
0.5
900
2.4
2.15
Max
Units
25
5
V
µA
µA
V
V
mV
V
V
V
mV
nA
MHz
%
V/V
µS
µA
mV
nA
µA
mΩ
mΩ
A
µA
°C
V
2.35
100
3.3
25
0.3
2
100
VFB = 0.6V
1.08
85
Sourcing and Sinking
679
FB=0.7V
During Soft-Start
VIN =5V
VIN =3V
Note 1
VSW = 25V
SW Current Limit
SW Leakage Current
Thermal Shutdown
Open Load Shutdown Threshold
Measured at OLS pin
Note 1: Guaranteed by design. Not tested.
MP1517 Rev 1.0_07/31/03
Min
Monolithic Power Systems, Inc.
1.2
90
400
400
40
700
-100
2
150
225
4.0
0.5
160
28
100
1.32
721
2
MP1517
3A White LED
Camera Flash Driver
Monolithic Power Systems
PRELIMINARY
SS
16
15 14
COMP
1
NC
2
BP
3
EN
45
11
PGND
10
SW
SW
6
7
8 9
IN
PGND
OLS
13
12
NC
SGND
Top
View
SGND
FB
NC
Pin Descriptions
Table 1: Pin Description
QFN
Pin
Name
Function
1
COMP
Compensation: Error Amplifier output. Connect to a series RC network to compensate
the regulator control loop.
2, 6, 14
NC
3
BP
4
EN
5, 13
SGND
7
OLS
8
IN
9, 10
SW
11, 12
PGND
15
SS
16
FB
MP1517 Rev 1.0_07/31/03
No Connect
Output of the internal 2.4V low dropout regulator. Connect a 10nF bypass capacitor
between BP and SGND. Do not apply an external load to BP.
Regulator On/Off Control Input. A logic high input (VEN>2V) turns on the regulator, a
logic low puts it into low current shutdown mode.
Signal Ground
Open Load Shutdown pin senses regulator output voltage to protect IC during open
load operation. When this pin’s voltage exceeds 28V, the output switch is shut off.
The device then restarts in soft start mode (see Soft Start Input).
Input Supply Pin. This pin can be connected to the regulator’s input supply or to the
output for boot-strapped operation.
Output Switching Node. SW is the drain of the internal n-channel MOSFET. Connect
the inductor and rectifier to SW to complete the step-up converter.
Power Ground
Soft-Start Input. Connect a 10nF to 22nF capacitor from SS to SGND to set the softstart. SS sources 2µA to an external soft-start capacitor during start-up. As the
voltage at SS increases to 1.2V, the voltage at COMP is clamped to 0.7V above the
voltage at SS limiting the startup current. The external capacitor at SS is discharged to
ground when under voltage lockout, thermal shutdown occurs or open load shutdown
occurs.
Regulation Feedback Input. The MP1517 regulates the voltage across the current
sense resistor between FB and GND. Connect a current sense resistor from the
bottom of the LED string to GND. Connect the bottom of the LED string to FB. The
regulation threshold is 0.7V.
Monolithic Power Systems, Inc.
3
MP1517
3A White LED
Camera Flash Driver
Monolithic Power Systems
PRELIMINARY
Figure 2: Flash Circuit driving 4 white LEDs (150mA peak LED current)
PGND
10
FB
SS
COMP
NC
SW
BP
SW
EN
IN
OLS
9
8
7
5.3
47nF
PGND
SGND
11
NC
12
SGND
NC
13 14 15 16
6
5
1
2
3
4
MP1517\QFN16
Figure 3: Driving 3 strings of 6 white LEDs
R8
R9
R10
LED6
LED12
LED18
LED5
LED11
LED17
LED4
LED10
LED16
LED3
LED9
LED15
LED2
LED8
LED14
LED1
LED7
LED13
FB
SS
BP
SW
EN
MP1517\QFN16
MP1517 Rev 1.0_07/31/03
NC
NC
SW
SGND
9
PGND
NC
10
COMP
IN
11
PGND
OLS
12
SGND
13 14 15 16
8
7
6
5
1
2
3
4
Monolithic Power Systems, Inc.
4
MP1517
3A White LED
Camera Flash Driver
Monolithic Power Systems
PRELIMINARY
Packaging
QFN16 (4x4)
Pin 1 Dot
By marking
3.950 (0.156)
4.050 (0.159)
0.550 (0.217)
0.650 (0.256)
3.950 (0.156)
4.050 (0.159)
QFN 16L
(4 X 4mm)
Pin 1 Identification
2.35 (0.093)
2.45 (0.097)
16
13
1
0.40 (0.0158)
0.50 (0.0197)
4
0.28 (0.011)
0.38 (0.015)
0.650
BSC
R0.030Max.
9
8
5
2.280 (0.898)
Ref.
Top View
Btm View
Side View
0.850 ( 0.0335)
0.950 (0.0374)
0.000-0.025
0.178 (0.007)
0.228 (0.009)
NOTICE: MPS believes the information in this document to be accurate and reliable. However, it is subject to change
without notice. Please contact the factory for current specifications. No responsibility is assumed by MPS for its use or fit to
any application, nor for infringement of patent or other rights of third parties.
MP1517 Rev 1.0
07/3103
© 2003 MPS, Inc.
Monolithic Power Systems, Inc.
983 University Ave, Building D, Los Gatos, CA 95032 USA
Tel: 408-395-2802 ♦ Fax: 408-395-2812 ♦ Web: www.monolithicpower.com
5
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