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TSZ02201-0333AD100130-1-2

©2012 ROHM Co., Ltd. All rights reserved.

2/17

06.Aug.2012 Rev.001

TSZ22111･15･001

BD1482EFJ

Datasheet

●Pin Configuration

●Block Diagram

Fig.2 Pin Configuration

Fig.3 Block Diagram

●Pin Description

Pin No.

Pin name

Function

1

BST

High-Side Gate Drive Boost Input

2

VIN

Power Input

3

SW

Power Switching Output

4

GND

Ground

5

FB

Feed Back Input

6

COMP

Compensation Node

7

EN

Enable Input

8

SS

Soft Start Control Input

●Block Operation

・VREG

A block to generate constant-voltage for DC/DC boosting.

・VREF

A block that generates internal reference voltage of 5.1 V (Typ.).

・TSD/UVLO

TSD (Thermal shutdown)/UVLO (Under Voltage Lockout) protection block.

The TSD circuit shuts down IC at high temperature.

The UVLO circuit shuts down the IC when the VIN is Low Voltage.

・Error amp block (ERR)

This is the circuit to compare the reference voltage and the feedback voltage of output voltage. The COMP pin voltage resulting from this

comparison determines the switching duty. At the time of startup, since the soft start is operated by the SS pin voltage, the COMP pin

voltage is limited to the SS pin voltage.

・Oscillator block (OSC)

This block generates the oscillating frequency.

・SLOPE block

This block generates the triangular waveform from the clock created by OSC. Generated triangular waveform is sent to the PWM

comparator.

・PWM block

The COMP pin voltage output by the error amp is compared to the SLOPE block's triangular waveform to determine the switching duty.

Since the switching duty is limited by the maximum duty ratio which is determined internally, it does not become 100%.

・DRV block

A DC/DC driver block. A signal from the PWM is input to drive the power FETs.

・OCP block

OCP (Over Current Protection) block. The current which flowed into FET is detected and OCP starts at 3.5A (min). After OCP, switching is

turned off and SS capacitor is discharged. OCP is not latch type but auto restart.

・Soft start circuit

Since the output voltage rises gradually while restricting the current at the time of startup, it is possible to prevent the output voltage

overshoot or the rush current.

(TOP

VIEW)

BST

VIN

SW

GND

FB

COMP

EN

SS