LLC resonant controller with high voltage start up enabling low standby power


Product details


Topology Half-Bridge, Resonant LLC Control method Current VCC (Min) (V) 13 VCC (Max) (V) 30 Duty cycle (Max) (%) 50 Frequency (Max) (kHz) 1000 Operating temperature range (C) -40 to 125 Gate drive (Typ) (A) 0.6 Features HV Start-up, Integrated Gate Drivers, Light Load Efficiency, Thermal Shutdown Rating Catalog open-in-new Find other PWM controllers & resonant controllers

Package | Pins | Size

SOIC (DDB) 14 59 mm² 9.9 x 6 open-in-new Find other PWM controllers & resonant controllers


  • Integrated High Voltage Startup
    • Eliminates Need for External
      Bias Supply
  • Best-in-Class Transient Response
  • Hybrid Hysteretic Control (HHC)
    • Best-in-Class Transient Response
    • Easy Compensation Design
  • Optimized Low Power Features Enable 75 mW
    Standby Power Design with PFC on
    • Advanced Burst Mode
      Opto-Coupler Low Power Operation
    • Helps Enable Compliance to CoC Tier II Standard
  • Fast Exit from Burst Mode
  • Improved Capacitive Region Avoidance Scheme
  • Adaptive Dead-Time
  • Internal High-Side Gate Drivers
    (0.6-A and 1.2-A Capability)
  • Robust Soft Start with No Hard Switching
  • Over Temperature, Output Over Voltage, Input
    Over and Under Voltage Protection with
    Three Levels of Over Current Protections
  • Wide Operating Frequency Range
    (35 kHz to 1 MHz)
  • Select the appropriate LLC resonant controller for your design with UCC25630x Selection GuideUCC25630x Selection Guide
  • Create a Custom Design Using the UCC256302 With the WEBENCH® Power Designer

All trademarks are the property of their respective owners.

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The UCC256302 is a fully featured LLC controller with integrated high-voltage gate driver. It has been designed for use in offline AC-DC or isolated DC-DC to provide a complete power system using a minimum of external components. The resulting power system is designed to meet the most stringent requirements for standby power without the need for a separate standby power converter.

UCC256302 includes an integrated, high voltage startup function which eliminates the need for an external bias supply, reducing BOM count and minimizing solution size. UCC256302 uses hybrid hysteretic control to provide best in class line and load transient response. The control makes the open loop transfer function a first order system so that it’s very easy to compensate.

UCC256302 provides a high efficient burst mode with consistent burst power level during each burst on cycle. The burst power level is programmable and adaptively changes with input voltage, making the optimization of efficiency very easy.

Select the appropriate LLC resonant controller for your design with UCC25630x Selection Guide

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Technical documentation

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Type Title Date
* Datasheet UCC256302 Hybrid Hysteretic Mode Wide VIN LLC Resonant Controller datasheet Nov. 02, 2017
Application note Improving Transient Response in LLC Converters Using Hybrid Hysteretic Control (Rev. B) Apr. 07, 2021
Application note Migrating to UCC25640x from UCC25630x (Rev. A) Dec. 10, 2019
Application note Exceeding Modern Energy Standards with 'Always On' PFC and LLC Controllers​ (Rev. B) Aug. 01, 2019
Application note Improving ZVS and efficiency in LLC converters Nov. 05, 2018
Application note UCC25630x Practical Design Guidelines (Rev. A) Dec. 08, 2017
Selection guide UCC25630x Selection Guide Aug. 29, 2017

Design & development

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

Hardware development

document-generic User guide

UCC25630-1EVM-291 is an EVM of LLC resonant half-bridge DC-DC power converter with LLC controller UCC256301. UCC25630-1EVM-291 accepts DC line input from 340Vdc to 410Vdc, AC input voltage from 85 VAC to 264 VAC, and outputs nominal 12Vdc with full load output power 120W, or full output current 10A (...)

  • Optimized low power features enable extreme low standby power
  • Advanced burst mode with adaptive threshold
  • Improved capacitive region avoidance scheme
  • Adaptive dead-time
  • X-capacitor discharge

Design tools & simulation

SLUM596.ZIP (108 KB) - SIMPLIS Model
SLUC634B.ZIP (358 KB)

Reference designs

500-W, single stage LLC power supply reference design for audio amplifier
PMP40379 This single-stage LLC converter reference design illustrates how to convert AC input voltage (100-120 Vac and 200-240 Vac) to isolated ±42-V DC output with the UCC256302 resonant controller. The design has a regulated ±42-V output that can handle up to 6 A of continuous output current (...)
document-generic Schematic document-generic User guide
48-V/550-W resonant converter reference design
PMP21683 — 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.
document-generic Schematic document-generic User guide
110 VAC to 38 V at 2 A single stage LLC resonant converter reference design
PMP30522 — This reference design is a half bridge LLC resonant converter, typically combined to PFC front end. It works directly from mains (100 VAC - 127 VAC) and supplies 38 V at 2 A. The burst mode feature keeps the curve flat in a range of 86% - 94% when load is varied between 1% and 100%.
document-generic Schematic document-generic User guide
260 W off-line multiple-output LLC-SRC reference design
PMP21582 — This reference design uses UCC256302 LLC resonant controller to provide US-line AC input to a 30-V, 250-W output and a 13.8-V, 11-W output conversion. The low profile design has a maximum height of 1 inch. This design achieves 94% peak efficiency at 120-VAC input.
document-generic Schematic document-generic User guide
Single stage AC-DC auxless LLC resonant converter reference design
PMP21000 — This reference design provides a 12-V/100-W output from either 120-Vac or 230-Vac input with a single LLC resonant converter stage. The bill of materials (BOM) cost of this design is highly optimized with the single-stage structure and the use of UCC256302 LLC resonant controller. High voltage (...)
document-generic Schematic document-generic User guide
LLC Resonant Converter Control Card Reference Design
PMP40281 — This reference design is a a control card for LLC converter. It integrates all of the essential functions for controlling a LLC converter including the HV start-up, X-capacitor discharge and the drivers for the power FETs. By employing the advanced burst mode, it can also help the LLC converter to (...)
document-generic Schematic document-generic User guide

CAD/CAE symbols

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