RT9378

2

DS9378-03 April 2011

www.richtek.com

Function Block Diagram

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

C1N

Fly Capacitor 1 Negative Connection.

2

13 (Exposed Pad)

GND

Ground Pin. The exposed pad must be soldered to a large PCB and connected

to GND for maximum power dissipation.

3

C1P

Fly Capacitor 1 Positive Connection.

4

C2P

Fly Capacitor 2 Positive Connection.

5

VIN

Power Input.

6

EN

Chip Enable (Active High).

7

LED1

Current Sink for LED1. (If not in use, connect this pin to VIN)

8

LED2

Current Sink for LED2. (If not in use, connect this pin to VIN)

9

LED3

Current Sink for LED3. (If not in use, connect this pin to VIN)

10

LED4

Current Sink for LED4. (If not in use, connect this pin to VIN)

11

VOUT

Charge Pump Output.

12

C2N

Fly Capacitor 2 Negative Connection.

EN

LED1

LED4

LED2

LED3

1MHz

OSC

PWM Dimming

Controller

Soft Start

Circuit

Current Source

Shutdown Delay

VIN

VOUT

Gate Driver

UVLO

OVP

Min VDS

+

-

C1P

C2P C2N

C1N

Mode Decision

Current

Bias

Vr1

GND

2µA