1 Features

• 230-V VD pins rating

• 23-ns turn-off delay to support LLC operating

above resonant frequency and up to 625-kHz

switching frequency

• Proportional gate drive to extend the SR

conduction time

• Adjustable turn-off threshold for minimum body

diode conduction

• Automatic standby mode detection with 180 μA of

low standby current

• Wide 4.25-V to 26-V VDD operation range with

internal clamp

• Adaptive turn-on delay for better DCM ring

rejection

• Two-channel interlock to prevent shoot-through

• Integrated 1.5-A source and 4-A sink capability

gate driver for N-channel MOSFETs

• 8-pin SOIC package

2 Applications

• Desktop PC, AIO PC, ATX and server power

• AC-DC adaptors

• LCD, LED, and OLED TVs

• Industrial AC/DC and isolated DC/DC power

• Power tool chargers, LED lighting power

• Create a custom design using the UCC24624 with

WEBENCH® Power Designer

3 Description

The UCC24624 high-performance synchronous

rectifier (SR) controller is dedicated for LLC resonant

converters to replace the lossy diode output rectifiers

with SR MOSFETs and improve the overall system

efficiency.

The UCC24624 SR controller uses drain-to-source

voltage sensing method to achieve on and off

control of the SR MOSFET. Proportional gate

drive is implemented to extend the SR conduction

time, minimize the body diode conduction time. To

compensate for the offset voltage caused by the

SR MOSFET parasitic inductance, the UCC24624

implements an adjustable positive turn-off threshold

to accommodate different SR MOSFET packages.

UCC24624 has a built-in 475-ns on-time blanking and

a fixed 650-ns off-time blanking to avoid SR false

turn-on and turn-off. UCC24624 also integrates a twochannel

interlock function that prevents the two SRs

from being on at the same time. With 230-V voltagesensing

pins and 28-V ABS maximum VDD rating, it

can be directly used in converters with output voltage

up to 24.75 V. The internal clamp allows the controller

to support 36-V output voltage easily by adding an

external current limiting resistor on VDD.