PPMIC BU

www.belling.com.cn

BL9590 Rev 0.3

Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited

3/2010

©2010 Belling All Rights Reserved

3

BL9590

Six-String White LED Driver with Active Current

Balancing for LCD panel Applications

Pin Description

PIN

NAME

FUNCTION

1

OSC

converter’s oscillator frequency to 1MHz. Connect OSC to GND to set the

frequency to 500kHz. Float OSC to set the frequency to 750kHz.

2

ENA

Analog Dimming Enable. ENA sets the PWM control mode. Set ENA low to

enable direct DPWM dimming.

Set ENA HIGH to enable analog dimming. In both modes, the duty cycle of the

PWM signal at the BRT input controls the LED current characteristics. See the

Dimming Control section for a complete description.

3

BRT

Brightness Control Input. The duty cycle of this digital input signal controls the

LED current characteristics. The allowable frequency range is 100Hz to 500Hz

in analog dimming mode. The duty cycle can be 100% to 1%. The BRT

frequency can go above 500Hz in direct DPWM mode as long as the BRT pulse

width is greater than 50μs minimum. See the Dimming Control section for a

complete description.

4

/SHDN

Shutdown Control Input. The BL9590 shuts down when /SHDN is less than

0.8V. Pulling /SHDN above 2.1V enables the BL9590. /SHDN can be connected

to the input voltage if desired.

5

FB1

LED String 1 Cathode Connection. FB1 is the open-drain output of an internal

regulator, which controls current through FB1. FB1 can sink up to 27mA. If

unused, connect FB1 to GND.

6

FB2

LED String 2 Cathode Connection. FB2 is the open-drain output of an internal

regulator, which controls current through FB2. FB2 can sink up to 27mA. If

unused, connect FB2 to GND.

7

FB3

LED String 3 Cathode Connection. FB3 is the open-drain output of an internal

regulator, which controls current through FB3. FB3 can sink up to 27mA. If

unused, connect FB3 to GND.

8

GND

Ground

9

FB4

LED String 4 Cathode Connection. FB4 is the open-drain output of an internal

regulator, which controls current through FB4. FB4 can sink up to 27mA. If

unused, connect FB4 to GND.

10

FB5

LED String 5 Cathode Connection. FB5 is the open-drain output of an internal

regulator, which controls current through FB5. FB5 can sink up to 27mA. If

unused, connect FB5 to GND.

11

FB6

LED String 6 Cathode Connection. FB6 is the open-drain output of an internal

regulator, which controls current through FB6. FB6 can sink up to 27mA. If

unused, connect FB6 to GND.

12

CS

Step-Up Controller Current-Sense Input. Connect the CS input to a ground

referenced sense resistor to measure the current in the external MOSFET

switch.

13

EXT

External MOSFET Gate-Drive Output

14

OV

Overvoltage Sense. Connect OV to the center tap of a resistive detection

threshold for voltage limiting at OV is 1.23V (typ).

15

When /SHDN is low, the internal linear regulator is disabled.