RT9718

2

DS9718-02 May 2011

www.richtek.com

Function Block Diagram

Pin No.

Pin Name

Pin Function

1

VIN

The input power source. The VIN can withstand up to 28V input.

2

GND

Analog Ground.

3

NC

No Internal Connection.

4

WRN

This is an open-drain logic output that turns LOW when any protection event occurs.

5

EN

Chip Enable (Active Low). Pull this pin to low or leave it floating to enable the IC and

force it to high to disable the IC.

6

VB

Battery voltage monitoring input. This pin is connected to the battery pack positive

terminal via an isolation resistor.

7

ILIM

Over current protection threshold setting pin. Connect a resistor between this pin

and GND to set the OCP threshold.

8

VOUT

Output through the power MOSFET.

9 (Expose Pad) GND

The exposed pad must be soldered to a large PCB and connected to GND for

maximum thermal dissipation.

Functional Pin Description

Typical Application Circuit

Control

Logic

Driver

OCP

OCP

Seting

BATOVP

Buffer

OTP

UVLO

INOVP

BASE

EN

Logic

WRN

GND

VOUT

ILIM

VB

VIN

EN

RT9718

VIN

WRN

GND

VOUT

ILIM

VB

EN

Charger IC

(RT9502)

+

7

6

5

1

2

4

8

To System

Battery

Chip Enable

1µF

1µF

200k

25k