ROHM BD9207FPS Technical data
LED Driver series for lighting
Step-down type
with 1.5A output
BD9207FPS
No.09093EAT01
●Description
BD9207FPS is a LED driver with built-in step-down switching regulator and incorporates the bui lt-in switching MOS EFT of
Pch.
Feedback voltage is as low as 0.2V and can suppress the loss on the sense resistance of LED.
It is operated by PWM method with an oscillating frequency of 900 KHz and can use smaller coil than a switching regulator
of low-frequency operation.
●Features
1) Maximum switching current of 1.5A
2) Built-in Pch switching MOS FET for high efficiency
3) Low loss because feedback voltage is as low as 0.2V
4) High oscillating frequency of 900KHz (Fixed)
5) Built-in soft start function
6) Built-in overcurrent protection circuit (OCP)
7) Built-in thermal shutdown circuit (TSD)
8) ON/OFF of output is possible by STBY terminal.
9) Compact surface-mount TO252S-5 package
●Applications
・For use in the light sources of PPC
・Printer etc. and the LCD backlights of LED lighting apparatus & monitor
・Note PC etc.
●Absolute maximum ratings（Ta=25℃）
Parameter Symbol
Supply voltage（VCC-GND） Vcc 36 V
STBY-GND Voltage V
OUT-GND Voltage V
INV-GND Voltage V
Maximum switching output current. Iout 1.5(*1) A
Allowable loss Pd 800(*2) mW
Operating temperature range Topr -20 ~ +85 ℃
Storage temperature range Tstg -55 ~ +150 ℃
(*1)Regardless of the listed rating, do not exceeded Pd, ASO or Tjmax=150℃.
(*2) Without heat sink, reducing by the 16 mW every 1℃ rise in temperature. (above 25℃)
36 V
STBY
36 V
OUT
5 V
INV
Rating Unit
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.07 - Rev.A
BD9207FPS
●Operating range (Ta=-40～+85℃)
Parameter Symbol
Supply voltage VCC 8.0 - 35.0 V
Output voltage Vo 2.5 -
●Electrical characteristics（Unless otherwise specified, Ta=25℃,VCC=24V,STBY=3V）
Parameter Symbol
Output MOS ON resistance Ron - 1.0 1.5 Ω
Oscillating frequency fosc 810 900 990 kHz
Overcurrent detection current Iocp 1.6 - - A
INV terminal threshold
voltage
INV terminal bypass current IINV - 1 2 μA
STBY terminal control
voltage
STBY terminal inflow current Istby 5 15 30 μA
Circuit current Icc - 5 12 mA
Standby current Ist - 0 5 μA
Soft start time Tss - - 10 ms
Without radiation-proof design.
ON VSTBYON 2.0 - 36 V
OFF VSTBYOFF -0.3 - 0.3 V
Min. Typ. Max.
VINV 0.194 0.200 0.206 V
Limit
0.8×
(VCC-Io×Ron)
Limit
Min. Typ. Max.
Unit Conditions
V
Technical Note
Unit Conditions
VINV=0.2V
STBY=3V
STBY＝0V
STBY＝0→3V
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.07 - Rev.A
BD9207FPS
●Block diagram
VCC
1
VREF
PWM COMP
DRIVER
STBY
5
OSC
STBY
TSD
CTL
LOGIC
OUT
2
OCP
Error AMP
INV
4
SS
FIN
GND
●Outline drawing of package ●Explanation of terminal
Pin No. Pin Name Function
1 VCC
2 OUT
3※
OUT
FIN GND Ground terminal
4 INV
5 STBY
※Used normally in open-circuit condition
TO252S-5（Unit：mm）
Technical Note
Supply voltage
terminal
Drain terminal of
built-in PMOS FET
Drain terminal of
built-in PMOS FET
Output voltage
feedback
terminal
ON/OFF control
terminal
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.07 - Rev.A
BD9207FPS
●Functional explanation of block
・ VREF
The constant voltage to be temperature-compensated is created from the voltage inputted from VCC terminal.
・ OSC
Triangular wave with an oscillating frequency of 900 KHz is created, as an input of PWM comparator, by built-in resistor
and capacitor.
・ Error AMP
It detects, at INC terminal, the voltage of sense resistance terminal created by LEC current, and compares it to the
reference voltage, and amplifies and outputs the differential voltage.
(The reference voltage is 0.2V±3%)
・ PWM COMP
PWM COMP converts the output voltage of error amplifier into the pu lse-width modulation waveform and outputs it to
DRIVER.
・ DRIVER
Push-pull FET driver takes in the PWM waveform and directly drives the Pch MOS FET that is built-in in the IC.
・ STBY
The ON/OFF control of output is performed by STBY terminal. The output becomes ON if STBY voltage is High level.
・ Thermal shutdown circuit (TSD)
TSD circuit protects the IC from runaway thermal operation or heat damage.
TSD circuit detects the temperature of chip, and the circuit becomes off if the temperature reaches 175℃. For TSD
detection and release, the hysteresis of 15℃ is set, so the malfunction caused by temperature variation is prevented.
・ Over Current Protection（OCP）
Out is turned off if the voltage difference between VCC – OUT, caused by the current flowing in the Pch MOS EFT built-in
in OCP circuit, is detected and reaches the reference value of OCP. The OCP is not of latch type but of self-return type.
・ Soft start circuit (SS)
Soft start time is set by the built-in capacitor connected to SS circuit. The capacitor is charged when STBY terminal
becomes High level and the IC is started. The soft start time is set at 4ms or so.
Technical Note
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.07 - Rev.A
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