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UCC24624

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High-frequency, dual synchronous rectifier controller for LLC converters

Product details

Topology LLC UVLO thresholds on/off (V) 4.5/4 Switching frequency (max) (kHz) 700 Features Automatic Standby Mode, Dual Channel, Proportional gate drive, Synchronous Rectifier Operating temperature range (°C) -40 to 125 Vin (max) (V) 26 Control mode VDS sensing Device type Controllers Rating Catalog
Topology LLC UVLO thresholds on/off (V) 4.5/4 Switching frequency (max) (kHz) 700 Features Automatic Standby Mode, Dual Channel, Proportional gate drive, Synchronous Rectifier Operating temperature range (°C) -40 to 125 Vin (max) (V) 26 Control mode VDS sensing Device type Controllers Rating Catalog
SOIC (D) 8 29.4 mm² 4.9 x 6
  • 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
  • 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

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 two-channel interlock function that prevents the two SRs from being on at the same time. With 230-V voltage-sensing 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.

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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 two-channel interlock function that prevents the two SRs from being on at the same time. With 230-V voltage-sensing 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.

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Technical documentation

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

PFCLLCSREVM034 — AC to isolated DC EVM with UCC28056B, UCC256404 and UCC24624

PFCLLCSREVM034 is a 168-W AC/DC supply with a transition-mode power-factor-correction front end and isolated half-bridge LLC resonant converter with synchronous rectification. This EVM accepts AC input from 90 Vrms to 264 Vrms and outputs 12-V DC with 168-W full-load output power.

User guide: PDF
Not available on TI.com
Daughter card

UCC24624EVM — UCC24624 LLC gated driver evaluation Module

The UCC24624EVM-015 evaluation module (EVM) is used to convert the output rectifier of a LLC converter from diodes to synchronous rectifiers (SR) FETs to investigate and evaluate the efficiency benefits of using an SR over a rectifier diode.
User guide: PDF
Not available on TI.com
Simulation model

UCC24624 SIMPLIS Model (Rev. A)

SLUM645A.ZIP (1115 KB) - SIMPLIS Model
Reference designs

TIDA-010080 — 500-W, >94.5% efficiency analog control AC/DC reference design for 5G telecom rectifier

This compact, high efficiency reference design with a 48-V DC, 500-W output targets 5G telecom power and industrial AC/DC power supplies. The circuit consists of a front-end continuous conduction mode (CCM) power factor correction (PFC) circuit based on the UCC28180, followed by a robust LLC stage (...)
Design guide: PDF
Schematic: PDF
Reference designs

TIDA-010081 — >95% Efficiency, 1-kW analog control AC/DC reference design for 5G telecom rectifier

This compact, high efficiency reference design with a 54-V DC, 1000-W output targets 5G telecom power and industrial AC/DC power supplies. The circuit consists of a front-end continuous conduction mode (CCM) power factor correction (PFC) circuit based on the UCC28180, followed by a robust LLC (...)
Design guide: PDF
Schematic: PDF
Reference designs

PMP21683 — 48-V/550-W resonant converter reference design

This resonant converter reference design takes a 380-V to 420-V DC input and generates a 48-V up to 550-W output. With the UCC256302 driver-integrated resonant converter controller and UCC24624, a two-channel synchronous rectifier (SR) driver, this design can achieve 97.95% peak efficiency.
Test report: PDF
Schematic: PDF
Package Pins Download
SOIC (D) 8 View options

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