The MP4655 is a pure, single-stage, LLC, LED current and system voltage controller for LED backlighting, especially in larger TVs, and is located on the secondary side. The MP4655 uses an LLC power stage and an extra N-channel MOSFET to regulate both the LED current and the system supply voltage. The MP4655 is powered by input supplies ranging from 9V to 35V that output two 180 degree phase shifted driving signals for the external LLC power stages. Its enhanced 12V gate driver provides sufficient driving capability and can drive the external LLC MOSFETs directly through an external gate-driving transformer. The MP4655 also provides a direct driving signal to control the extra N-channel MOSFET and regulate the system supply voltage.
The MP4655 incorporates both PWM dimming and analog dimming for the LED current. A driving signal is output to directly drive the dimming MOSFET, which helps achieve fast and high-contrast ratio PWM dimming. The analog dimming can be achieved through a DC signal on ADIM or a pulse signal on ADIMP.
The MP4655 employs smart protection methods to protect the LED driver stage and system power stage in the event that a fault occurs, increasing system reliability.
Full protection features for the LED include open LED protection, short LED protection, over-LED current protection, feedback open loop protection, and protection for any point of the LED string shorting to ground.
Full protection features for the system supply voltage stage include over-vol