UCC24624DR Texas Instruments MCU

UCC24624DR Overview

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Description

The UCC24624 high-performance synchronous rectifier (SR) controller is dedicated forLLCresonant converters to replace the lossy diode output rectifiers with SR MOSFETs andimprove the overall system efficiency.

The UCC24624 SR controller uses drain-to-source voltage sensing method to achieve on andoff control of the SR MOSFET. Proportional gate drive is implemented to extend the SR conductiontime, minimize the body diode conduction time. To compensate for the offset voltage caused by theSR MOSFET parasitic inductance, the UCC24624 implements an adjustable positive turn-off thresholdto accommodate different SR MOSFET packages. UCC24624 has a built-in 475-ns on-time blanking and afixed 650-ns off-time blanking to avoid SR false turn-on and turn-off. UCC24624 also integrates atwo-channel interlock function that prevents the two SRs from being on at the same time. With 230-Vvoltage-sensing pins and 28-V ABS maximum VDD rating, it can be directly used in converters withoutput voltage up to 24.75 V. The internal clamp allows the controller to support 36-V outputvoltage easily by adding an external current limiting resistor on VDD.

With the built-in standby mode detection based on average switching frequency, UCC24624enters the standby mode automatically without using external components. The low standby modecurrent of 180μA supports meeting modern no-load power consumption requirements suchas CoC, and DoE regulations. UCC24624 can be used with theUCC25630x LLC andUCC28056 PFC controllers to achieve highefficiency while maintaining excellent light load and no-load performances. Other PFC controllers,such as UCC28064A,UCC28180, andUCC28070 can be used to achieve higherpower levels. 1.5-A peak source and 4-A peak sink driving capability allows UCC24624 to support LLCconverters up to 1 kW.

Features

230-V VD Pins Rating
23-ns Turn-Off Delayto Support LLC Operating Above Resonant Frequency and Up to 625-kHz Switching Frequency
Proportional Gate Drive to Extend the SR ConductionTime
Adjustable Turn-Off Threshold for Minimum Body DiodeConduction
Automatic Standby Mode Detection With 180 μAof Low Standby Current
Wide 4.25-V to 26-V VDD OperationRange With Internal Clamp
Adaptive Turn-on Delay forBetter DCM Ring Rejection
Two-Channel Interlock to PreventShoot-Through
Integrated 1.5-A Source and 4-A SinkCapability Gate Driver for N-Channel MOSFETs
8-Pin SOICPackage