RT9728B

3

DS9728B-00 August 2013

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Copyright 2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Function Block Diagram

UVLO

Current

Limit

7.5ms

Deglitch

4ms

Deglitch

Thermal

Sense

Drive

Reverse Voltage

Comparator

Switch

well

Current

Sense

+

-

VOUT

ILIM

GND

EN/EN

VIN

FAULT

Operation

The RT9728B is a current-limited power switch using

P-MOSFET for applications where short-circuit or heavy

capacitive loads will be encountered. These devices allow

users to adjust the current limit threshold between 75mA

and 1.8A (typ.) via an external resistor. Additional device

shutdown features include over-temperature protection and

reverse-voltage protection.

The RT9728B provides built-in soft-start function. The driver

controls the gate voltage of the power switch. The driver

incorporates circuitry that controls the rising time and

falling time of the output voltage to limit large inrush current

and voltage surges. The RT9728B enters constant-current

mode when the load exceeds the current limit threshold.