MP4655–PURE, SINGLE-STAGE, LLC, LED CURRENT AND SYSTEM VOLTAGE CONTROLLER

MP4655 Rev 1.0

www.MonolithicPower.com

16

2/2/2016

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© 2016 MPS. All Rights Reserved.

Pin #

Name

Description

13

ICOMP

Feedback compensation node of the current control loop.

Connect a compensation

capacitor or an R-C network from ICOMP to GND. The ICOMP voltage is internally

clamped between 1.02V and 2.28V, which limits the operating frequency range. ICOMP

also functions as the short LED to GND protection. When ICOMP is saturated and the

IFB voltage is lower than 50% of the reference current for 1024 cycles, IC uses it as the

fault condition and triggers an LED fault protection.

14

IOCP/FAULT

LED stage over-current protection and fault indicator.

IOCP/FAULT feeds back the

secondary side current of the LED driver stage. When the voltage on IOCP/FAULT is

less than -320mV for 7μs, the IC disables the output of the DIMO signal. After 270μs,

the IC outputs the fault indicator. If the IOCP voltage is always lower than -320mV for

270μs, the IC latches up the LLC.

15

VLED1

Voltage feedback of LED string 1.

VLED1 and VLED2 cooperate for the protection of

the LED driver stage. The maximum voltage and the voltage difference among VLED1

and VLED2 are detected and used for LED stage protection. For 1-string applications,

connect VLED1 and VLED2; for two-string applications, feed back the LED strings

voltages to VLED1 and VLED2; for applications with more than two strings, feed back

the maximum voltage of the LED strings and the minimum voltage of the LED strings to

VLED1 and VLED2.

16

VLED2

Voltage feedback of LED string 2.

17

EN_LED

The enable signal for the LED driver.

Logic high enables the LED stage; logic low

disables the LED stage.

18

ADIMP

The pulse input signal for analog dimming.

The duty cycle 0 to 100% of this pulse

signal programs the amplitude of the LED current from 0 to 100%. Place a 100nF

capacitor from ADIM to GND for this type of dimming. If this dimming is not being used,

pull it high to VCC through a 100k resistor or leave it open.

19

ADIM

Analog dimming input with DC voltage.

The LED current is set by 0~2.4V from 0 to

100%. ADIMP should be disabled if using this DC input analog dimming. If this dimming

is not being used, pull it high to VCC through a 100kΩ resistor.

20

PWMIN

PWM dimming control input.

Apply a 100Hz to 2kHz PWM signal to PWMIN for PWM

dimming.

21

VIN

Supply input.

22

PS_ON

On/off signal for the system power supply

. PS_ON is the enable signal for the IC.

This signal determines the operation mode of the IC. If PS_ON is less than 0.8V, the IC

works in standby mode. IC operates in deep burst mode, and the system bus voltage is

controlled with a larger ripple voltage to decrease the power consumption. If PS_ON is

greater than 0.8V but less than 2V and this saturation lasts for 1ms, the IC shuts down.

If PS_ON is greater than 2V, the IC works in normal operation mode.

23

VCC

Power supply for the gate driver of the LLC MOSFETs and internal circuit.

Bypass

24

DIMO

Output of the driving signal for the dimming MOSFET.

25

GL

LLC driving signal output.

180 degree phase shift of GR.

26

GND

Ground reference.

27

GR

LLC driving signal output.

180 degree phase shift of GL.

28

CFLY

Output of the pulse signal for the charge pump.

Connect a flying cap higher than

100nF of the charge pump to CFLY. Please refer to the typical application circuit for

connection details.