MP3378

– 4-CHANNEL WLED CONTROLLER PLUS BUCK CONVERTER

MP3378 Rev. 1.01

www.MonolithicPower.com

11

5/26/2017

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Pin #

Name

Description

14

VCC2

Bias supply for buck converter. Decouple with a 0.1

μF-0.22 μF capacitor. The

capacitance should be no more than 0.22

μF.

15

VIN2

Supply voltage input for buck converter. A ceramic capacitor is needed to decouple

the input rail. Use a wide PCB trace to make the connection.

16

SW

Switch output for buck converter. Use a wide PCB trace to make the connection.

17,18

GND2

Ground for buck converter.

19

AGND

Analog ground for buck converter.

20

BST

Bootstrap for buck converter. A capacitor and a 47

Ω resistor connected between SW

and BST are required to form a floating supply across the high-side switch driver.

21

SYNC

Synchronization for buck converter. Apply a clock signal with a frequency higher than

250 KHz; the frequency of the buck converter can be synchronized by the external

clock. The internal clock

’s rising edge is synchronized to the external clock’s falling

edge.

22

ISENSE

Current sense input for WLED controller. During normal operation, ISENSE senses

current

–mode control. Also, it limits the inductor current during every switching cycle.

23

GATE

Power switch gate output for WLED controller. GATE drives the external power

N-channel MOSFET.

24

VIN1

Supply input for WLED controller.

25

VCC1

The internal 6 V linear regulator output for WLED controller. VCC1 provides a

power supply for the external MOSFET switch gate driver and the internal control

circuitry. Bypass VCC1 to GND with a ceramic capacitor.

26

COMP

Error amplifier output of WLED controller. Connect a capacitor and resistor in series

to stabilize the boost converter loop.

27

EN

Enable input for WLED controller.

28

PWM

Input signal for PWM brightness control. If PWM is floated, pull internally to GND.