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UCC28251

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Advanced half-bridge/full-bridge PWM controller with pre-bias operation for offline applications

Product details

Topology Forward, Full bridge, Half bridge, Push pull Control mode Current, Feedforward, Voltage Duty cycle (max) (%) 100 Switching frequency (max) (kHz) 1000 Features Current limiting, Leading edge blanking, Multi-topology, Pre-bias startUp, Programmable slope compensation, SR logic, Soft start, Synchronization pin UVLO thresholds on/off (V) 4.3/4.1 Operating temperature range (°C) -40 to 125 Rating Catalog Gate drive (typ) (A) 0.2 Vin (max) (V) 17
Topology Forward, Full bridge, Half bridge, Push pull Control mode Current, Feedforward, Voltage Duty cycle (max) (%) 100 Switching frequency (max) (kHz) 1000 Features Current limiting, Leading edge blanking, Multi-topology, Pre-bias startUp, Programmable slope compensation, SR logic, Soft start, Synchronization pin UVLO thresholds on/off (V) 4.3/4.1 Operating temperature range (°C) -40 to 125 Rating Catalog Gate drive (typ) (A) 0.2 Vin (max) (V) 17
TSSOP (PW) 20 41.6 mm² 6.5 x 6.4 VQFN (RGP) 20 16 mm² 4 x 4
  • Prebiased Startup
  • Synchronous Rectifier Control Outputs with
    Programmable Delays (Including Zero Delay
    Support)
  • Voltage Mode Control with Input Voltage
    Feed-Forward or Current Mode Control
  • Primary or Secondary-Side Control
  • 3.3-V, 1.5% Accurate Reference Output
  • Lower Minimum Operating Frequency
  • 1% Accurate Cycle-by-Cycle Over Current
    Protection with Matched Duty Cycle Outputs
  • Programmable Soft-Start and Hiccup Restart
    Timer
  • Thermally Enhanced 4-mm × 4-mm VQFN-20
    Package and 20-pin TSSOP Package
  • Prebiased Startup
  • Synchronous Rectifier Control Outputs with
    Programmable Delays (Including Zero Delay
    Support)
  • Voltage Mode Control with Input Voltage
    Feed-Forward or Current Mode Control
  • Primary or Secondary-Side Control
  • 3.3-V, 1.5% Accurate Reference Output
  • Lower Minimum Operating Frequency
  • 1% Accurate Cycle-by-Cycle Over Current
    Protection with Matched Duty Cycle Outputs
  • Programmable Soft-Start and Hiccup Restart
    Timer
  • Thermally Enhanced 4-mm × 4-mm VQFN-20
    Package and 20-pin TSSOP Package

The UCC28251 PWM controller is designed for high power density applications that may have stringent prebiased startup requirements. The UCC28251’s integrated synchronous rectifier control outputs target high efficiency and high performance topologies such as half-bridge, full-bridge, interleaved forward, and push-pull. The UCC27210 half bridge drivers and UCC2752x MOSFET drivers used in conjunction with the UCC28251 provide a complete power converter solution.

The UCC28251 is a functional variant of the UCC28250 PWM Controller. While the same basic functionality of the UCC28250 is largely maintained, the UCC28251 is designed to enhance performance in both offline, 400-V input DC-to-DC applications and 48-V input full-bridge or half-bridge applications.

Externally programmable soft-start, used in conjunction with an internal pre-biased startup circuit, allows the controller to gradually reach a steady-state operating point under all output conditions. The UCC28251 can be configured for primary or secondary-side control and either voltage or current mode control can be implemented.

The oscillator operates at frequencies up to 1.8 MHz, and can be synchronized to an external clock. Input voltage feedforward, cycle-by-cycle current limit, and a programmable hiccup timer allow the system to stay within a safe operation range. Input voltage, output voltage and temperature protection can be implemented. Dead time between primary-side switch and secondary-side synchronous rectifiers can be independently programmed.

The UCC28251 PWM controller is designed for high power density applications that may have stringent prebiased startup requirements. The UCC28251’s integrated synchronous rectifier control outputs target high efficiency and high performance topologies such as half-bridge, full-bridge, interleaved forward, and push-pull. The UCC27210 half bridge drivers and UCC2752x MOSFET drivers used in conjunction with the UCC28251 provide a complete power converter solution.

The UCC28251 is a functional variant of the UCC28250 PWM Controller. While the same basic functionality of the UCC28250 is largely maintained, the UCC28251 is designed to enhance performance in both offline, 400-V input DC-to-DC applications and 48-V input full-bridge or half-bridge applications.

Externally programmable soft-start, used in conjunction with an internal pre-biased startup circuit, allows the controller to gradually reach a steady-state operating point under all output conditions. The UCC28251 can be configured for primary or secondary-side control and either voltage or current mode control can be implemented.

The oscillator operates at frequencies up to 1.8 MHz, and can be synchronized to an external clock. Input voltage feedforward, cycle-by-cycle current limit, and a programmable hiccup timer allow the system to stay within a safe operation range. Input voltage, output voltage and temperature protection can be implemented. Dead time between primary-side switch and secondary-side synchronous rectifiers can be independently programmed.

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Technical documentation

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Type Title Date
* Data sheet UCC28251 Advanced PWM Controller With Prebias Operation datasheet (Rev. E) PDF | HTML 29 Dec 2014
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Analog Design Journal Analog Applications Journal 3Q 2015 24 Jul 2015
Analog Design Journal Fast input-voltage transient response with digitally-controlled isolated DC/DC 24 Jul 2015
White paper Advancing Power Supply Solutions Through the Promise of GaN 24 Feb 2015
Application note Differences Between the UCC28251 and UCC28250 and Evaluation of the UCC28251 in (Rev. A) 15 Feb 2013

Design & development

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

Evaluation board

UCC28250EVM-501 — Evaluation Module for UCC28250 Advanced PWM Controller on Primary Side Control

The UCC28250EVM-501 is a fully assembled and tested circuit for evaluating the UCC28250 Advanced PWM Controller with Pre-Bias Operation. The UCC28250EVM-501 comprises a symmetrical half-bridge DC/DC converter, which converts a 36V to 72V DC input to a 3.3V DC output with a maximum 75W output power.
User guide: PDF
Not available on TI.com
Evaluation board

UCC28250EVM-564 — Evaluation Module for UCC28250 Adv.PWM Controller w/ Pre-biased Load Op. on Secondary Side Control

The UCC28250EVM-564 is a fully assembled and tested circuit for evaluating the UCC28250 Advanced PWM Controller with Pre-Bias Operation. The UCC28250EVM-564 comprises a symmetrical half bridge DC-DC converter which converts a 36V to 75V DC input to a 3.3V DC output with 100W maximum output power.
User guide: PDF
Not available on TI.com
Simulation model

UCC28251 TINA-TI Average Reference Design

SLUM389.TSC (96 KB) - TINA-TI Reference Design
Simulation model

UCC28251 TINA-TI Average Spice Model

SLUM390.ZIP (8 KB) - TINA-TI Spice Model
Simulation model

UCC28251 Unencrypted PSpice Average Model Package (Rev. A)

SLUM358A.ZIP (59 KB) - PSpice Model
Package Pins Download
TSSOP (PW) 20 View options
VQFN (RGP) 20 View options

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Information included:
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  • Assembly location

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