SEMICONDUCTOR

TECHNICAL DATA

FC9911

2012. 10. 31

1/13

Revision No : 0

LED Driver

Switch-Mode LED Driver IC with High Current Accuracy

Features

General Description

Typical Application Circuit - Boost

The FC9911 is a current mode control LED driver IC designed

to control single switch PWM converters (buck, boost, buck-

boost, or SEPIC), in a constant frequency or constant off-time

mode. The controller uses a peak current control scheme,

(with programmable slope compensation), and includes

an internal transconductance ampli

fier to control the output

current in closed loop, enabling high output current accuracy.

In the constant frequency mode, multiple FC9911s can be

synchronized to each other, or to an external clock, using

the SYNC pin. Programmable MOSFET current limit enables

current limiting during input under voltage and output overload

conditions. The IC also includes a 0.2A source and 0.4A sink

GATE driver for high power applications. An internal 9.0 -

250V linear regulator powers the IC, eliminating the need for

a separate power supply for the IC. FC9911 provides a TTL

compatible, PWM dimming input that can accept an external

control signal with a duty ratio of 0-100% and a frequency of

up to a few kilohertz. The IC also provides a FAULT output

which, can be used to disconnect the LEDs in case of a fault

condition, using an external disconnect FET.

The FC9911 based LED driver is ideal for RGB backlight

applications with DC inputs. The FC9911 based LED lamp

drivers can achieve

efficiency in excess of 90% for buck and

boost applications.

Switch mode controller for single switch drivers

♦ Buck

♦ Boost

♦ Buck-boost

♦ SEPIC

Works with high side current sensing

Closed loop control of output current

High PWM dimming ratio

Internal 250V linear regulator (can be extended

using external Zener diodes)

Internal 2% voltage reference (0°C < T

Constant frequency or constant off-time operation

Programmable slope compensation

Enable & PWM dimming

+0.2A/-0.4A GATE drive

Output short circuit protection

Output over voltage protection

Synchronization capability

Programmable MOSFET current limit

Applications

RGB backlight applications

Battery powered LED lamps

Other DC/DC LED drivers

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6

7

10

9

15

8

13

14

16

11

12

5

3

1

2

4

C

IN

C

DD

C

REF

R

R2

R

R1

R

L1

R

L2

R

T

R

SLOPE

R

SC

SC

R

CS

R

OVP1

R

OVP2

C

O

D1

Q1

L1

Q2

C

C

R

S

VIN

VDD

GND

SC

RT

REF

CLIM

IREF

SYNC

PWMD

COMP

FDBK

FAULT

OVP

CS

GATE