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UCC28781

ACTIVE

High-density, zero-voltage switching (ZVS) flyback controller with integrated SR control

Product details

Control mode Secondary-side regulation UVLO thresholds on/off (V) 17/10.5 Switching frequency (max) (kHz) 1500 Features Adaptive burst mode, Overvoltage protection, Secondary-side regulated, USB C/PD compatible, X-capacitor discharge, Zero voltage switching Operating temperature range (°C) -40 to 125 Rating Catalog Device type Controllers Topology Flyback
Control mode Secondary-side regulation UVLO thresholds on/off (V) 17/10.5 Switching frequency (max) (kHz) 1500 Features Adaptive burst mode, Overvoltage protection, Secondary-side regulated, USB C/PD compatible, X-capacitor discharge, Zero voltage switching Operating temperature range (°C) -40 to 125 Rating Catalog Device type Controllers Topology Flyback
WQFN (RTW) 24 16 mm² 4 x 4
  • Switching frequency: > 500 kHz
  • Enables peak efficiency > 93 %
  • Enables < 45 mW stand-by power
  • Adaptive control for zero-voltage-switching (ZVS) and dead-time optimization
  • EMI frequency-dithering without trade-offs on transient response or audible noise
  • Programmable adaptive burst mode (ABM) with internal compensation
  • X-capacitor discharge capability
  • Over-temperature, overvoltage, output short-circuit, overcurrent, over-power, and pin-fault protections
  • Auto-recovery fault-responses
  • 4 mm × 4 mm, 24-pin, QFN package
  • Switching frequency: > 500 kHz
  • Enables peak efficiency > 93 %
  • Enables < 45 mW stand-by power
  • Adaptive control for zero-voltage-switching (ZVS) and dead-time optimization
  • EMI frequency-dithering without trade-offs on transient response or audible noise
  • Programmable adaptive burst mode (ABM) with internal compensation
  • X-capacitor discharge capability
  • Over-temperature, overvoltage, output short-circuit, overcurrent, over-power, and pin-fault protections
  • Auto-recovery fault-responses
  • 4 mm × 4 mm, 24-pin, QFN package

The UCC28781 is a zero-voltage-switching (ZVS) controller which can be used at very high switching frequencies to minimize the size of the transformer and enable high power density.

With direct synchronous rectifier (SR) control, the controller does not need a separate SR controller, as it can drive the SR FET directly to maximize efficiency and simplify design. (For isolated applications, an isolated gate-driver IC is required.)

Using adaptive dead-time control for ZVS, switching losses and EMI are minimized. This design results in a controller with extremely high conversion efficiency across the entire operating range.

The programmable adaptive burst mode (ABM) gives flexibility to control when the controller enters and exits standby mode to optimize standby power in light and no-load conditions. ABM also helps to reduce ripple and minimize audible noise.

The controller offers multiple protection modes with automatic restart (retry) responses.

The UCC28781 is a zero-voltage-switching (ZVS) controller which can be used at very high switching frequencies to minimize the size of the transformer and enable high power density.

With direct synchronous rectifier (SR) control, the controller does not need a separate SR controller, as it can drive the SR FET directly to maximize efficiency and simplify design. (For isolated applications, an isolated gate-driver IC is required.)

Using adaptive dead-time control for ZVS, switching losses and EMI are minimized. This design results in a controller with extremely high conversion efficiency across the entire operating range.

The programmable adaptive burst mode (ABM) gives flexibility to control when the controller enters and exits standby mode to optimize standby power in light and no-load conditions. ABM also helps to reduce ripple and minimize audible noise.

The controller offers multiple protection modes with automatic restart (retry) responses.

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Technical documentation

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Type Title Date
* Data sheet UCC28781 Zero-Voltage-Switching Flyback Controller with Dedicated Synchronous Rectifier Gate-Drive datasheet PDF | HTML 08 Dec 2021
User guide Using the UCC28781EVM-053 Zero-Voltage-Switching Flyback Converter (Rev. A) PDF | HTML 15 Sep 2022
Application brief Flyback Selection Guide PDF | HTML 23 Jun 2022
Certificate UCC28781EVM-053 EU RoHS Declaration of Conformity (DoC) 19 Aug 2021

Design & development

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

Evaluation board

UCC28781EVM-053 — UCC28781-Q1 evaluation module for automotive 500-Vdc input ZVS-flyback power supply applications

UCC28781EMV-053 demonstrates high-efficiency, high-density, high-voltage automotive bias supply with 60-W , 15-V ouput using a zero-voltage-switching flyback (ZVSF) controller. The UCC28781-Q1 drives a primary-side silicon MOSFET directly and drives a secondary-side synchronous rectifier through (...)

User guide: PDF | HTML
Not available on TI.com
Reference designs

PMP23331 — 19-W, AC/DC multioutput 5-V and 12-V ZVS flyback reference design for server applications

This reference design converts a universal AC input to an isolated 12-V, 1.5-A output and an isolated 5-V, 0.2-A output. The design achieves a peak efficiency of 92.7%. This reference design features UCC28781-Q1 which is a zero-voltage switching (ZVS) flyback controller to minimize switching (...)
Test report: PDF
Package Pins Download
WQFN (RTW) 24 View options

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