MP3308 – STEP-UP WHITE LED DRIVER WITH DUAL PWM DIMMING INPUT CONTROL

MP3308 Rev. 1.02

www.MonolithicPower.com

4

7/19/2012

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PIN FUNCTIONS

Pin #

Name

Description

1

SW

Power Switch Output. Drain of the internal MOSFET switch. Connect to the power

inductor and the output rectifier. SW can swing between GND and 40V.

2

PGND,

Exposed Pad

Power Ground. Connect exposed pad to GND plane for proper thermal performance.

3

IN

Input Supply Pin. Locally bypassed.

4

PWMIA

PWM Input A. Apply one PWM signal on this pin for brightness control. This signal is

uniform and filtered at PWMOA pin.

5

PWMIB

PWM Input B. Apply the other PWM signal on this pin for brightness control. This signal

is uniform and filtered at PWMOB pin.

6

EN

ON/OFF Control. Hold EN pin low to turn off part, high to turn of part.

7

FSET

PWM Dimming Frequency Programmer. Connect a capacitor from this pin to GND to set

8

PWMOB

PWM Filtered Output B. Connect a capacitor from this pin to GND.

9

PWMOA

PWM Filtered Output A. Connect a capacitor from this pin to GND.

10,14

GND

Ground.

11

OVP

Over-Voltage Protection. Connect a resistor divider from output to this pin to adjust the

OVP threshold. When this pin voltage reaches the shutdown threshold 0.9V, the switch

turns off.

12

LED

LED Current Input. Open-drain output of an internal dimming control switch. Connect the

LED cathode to this pin.

13

ISET

LED Current Set. This pin is the source output of an internal dimming control switch. The

MP3308 regulates the voltage across the current setting resistor. Tie a current-setting

resistor from this pin to ground. Regulates the voltage to 200mV.