BD9701FP_09 ROHM [Rohm], BD9701FP_09 Datasheet - Page 8

• Manufacturer Part Number: BD9701FP_09
• Description: Simple Step-down Switching Regulators with Built-in Power MOSFET
• Manufacturer: ROHM [Rohm]

●Block Function Explanations
●Timing Chart
© 2009 ROHM Co., Ltd. All rights reserved.
BD9701FP/CP-V5/T/T-V5,BD9703FP/CP-V5/T/T-V5,BD9702CP-V5/T/T-V5
www.rohm.com
・VREF
・OSC
・Error AMP
・PWM COMP
・DRIVER
・STBY
・Thermal Shutdown (TSD)
・Over Current Protection (OCP)
Generates the regulated voltage from VCC input, compensated for temperature.
Generates the triangular wave oscillation frequency using an internal resistors and capacitor. Used for PWM comparator input.
This block, via the INV pin, detects the resistor-divided output voltage, compares this with the reference voltage, then
amplifies and outputs the difference.
Outputs PWM signals to the Driver block, which converts the error amp output voltage to PWM form.
This push-pull FET driver powers the internal Pch MOSFET, which accepts direct PWM input.
Controls ON/OFF operation via the STBY pin. The output is ON when STBY is High.
This circuit protects the IC against thermal runaway and damage due to excessive heat. A thermal sensor detects the
junction temperature and switches the output OFF once the temperature exceeds a threshold value (175deg). Hysteresis
is built in (15deg) in order to prevent malfunctions due to temperature fluctuations.
The OCP circuit detects the voltage difference between VCC and OUT by measuring the current through the internal Pch
MOSFET and switches the output OFF once the voltage reaches the threshold value. The OCP block is a self-recovery
type (not latch).
OUTPIN
VOLTAGE WAVE
VOLTAGE WAVE
VCC PIN
OUTPUT
VOLTAGE WAVE
Fig.29
Timing Chart
8/16
(Internal Oscillation Wave)
OSC
Error AMP OUTPUT
Technical Note
2009.04- Rev.B