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.