RT8477A

2

DS8477A-02 April 2015

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Copyright

2015 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Function Block Diagram

Pin No.

Pin Name

Pin Function

1

VCC

Supply Voltage Input. For good bypass, a low ESR capacitor is required.

2

ISP

Positive Input Current Sense.

3

ISN

Negative Input Current Sense. Voltage threshold between ISP and ISN is 100mV.

4

VC

VC Compensation Node for Current Loop.

5

CTL

Analog Dimming Control Input. Effective programming range is 0.33V to 2V.

6

SENS

Current Sense Input for LED Current. Connect the current sense resistor

between external N-MOSFET switch and the ground.

7

DRV

External MOSFET Switch Gate Driver Output.

8

CREG

Regulator Output. Placed 1

F capacitor to stabilize the 5V regulator output.

9 (Exposed Pad)

GND

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

GND for maximum power dissipation.

Functional Pin Description

R

R

S

OSC

+

-

4.5V

+

-

+

-

GM

ISN

CTL

VCC

GND

CREG

DRV

5V

LDO

SENS

Soft-Start

VC

ISP