MP4653—REAL LIPS CC/CV MODE LLC TV LED DRIVER

MP4653 Rev 1.01

www.MonolithicPower.com

18

6/28/2012

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turn off the dimming MOSFET and also to

disconnect the LED driver stage from the power

stage. The current loop compensation node

ICOMP is disconnected from the internal

amplifier and holds its value until the fault

condition on the LED driver stage disappears. A

2μA current source charges the ICOMP pin

capacitor till ICOMP voltage hits 3V, and then a

2μA current source discharges ICOMP pin until

0.45V and then the LED driver stage recovers.

The gate driving signals for the MOSFETs in the

power stage are continuous and the DC bus

voltage is regulated at the fault condition of LED

driver stage. Therefore, the system power

supplies are not influenced by the fault protection

of the LED driver stage.

Thermal protection is integrated in MP4653.

400V

5V STBY

VIN

Vbus

12V/5V

PWM,EN

LED current

Figure 2—Real LIPS Power System and Start Up Sequence