UCC28951-Q1 (ACTIVE)

Phase-Shifted Full-Bridge Controller for Wide Input Voltage Range



The UCC28951-Q1 enhanced phase-shifted full bridge controller builds upon Texas Instrument’s industry standard UCx895 controller family with enhancements that offer best in class efficiency in today’s high performance power systems. The UCC28951-Q1 implements advanced control of the full-bridge along with active control of the synchronous rectifier (SR) output stage.

Programmable delays ensure ZVS operation over a wide range of operating conditions, while the load current naturally tunes the switching delays of the secondary-side SRs, maximizing overall system efficiency.

The UCC28951-Q1 offers multiple light-load management features including burst mode and dynamic SR on/off control when transitioning in and out of Discontinuous Current Mode (DCM) operation.

In addition, the UCC28951-Q1 includes support for current or voltage mode control. Programmable switching frequency up to 1 MHz and a wide set of protection features including cycle-by-cycle current limit, UVLO and thermal shutdown.

The UCC28951-Q1 is available in TSSOP-24 package and is RoHS compliant.


  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40ºC to +125ºC Ambient Operating Temperature Range
    • Device HBM ESD Classification Level H2
    • Device CDM ESD Classification Level C3B
  • Enhanced Zero-Voltage Switching (ZVS) Range
  • Direct Synchronous Rectifier (SR) Control
  • Light-Load Efficiency Management Including
    • Burst Mode Operation
    • Discontinuous Conduction Mode (DCM), Dynamic SR On/Off Control With Programmable Threshold
    • Programmable Adaptive Delay
  • Average- or Peak-Current Mode Control With Programmable Slope Compensation and Voltage-Mode Control
  • Closed-Loop Soft-Start and Enable Function
  • Programmable Switching Frequency up to 1 MHz with Bidirectional Synchronization
  • (±3%) Cycle-by-Cycle Current Limit Protection With Hiccup Mode Support
  • 150-µA Start-Up Current
  • VDD Undervoltage Lockout
  • Wide Temperature Range, –40°C to +125°C

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Parametrics Compare all products in PWM and Resonant Controller

Control Method
Vin (Min) (V)
Vin (Max) (V)
Frequency (Max) (kHz)
UVLO Thresholds On/Off (V)
Duty Cycle (Max) (%)
Gate Drive (Typ) (A)
Operating Temperature Range (C)
UCC28951-Q1 UCC28950-Q1
Phase-Shifted Full-Bridge    Phase-Shifted Full-Bridge   
Peak Current Mode
8    8   
20    20   
1000    1000   
7.3/6.7    7.3/6.7   
97    97   
0.2    0.2   
Adjustable Switching Frequency
Current Limiting
Error Amplifier
Green Mode
Programmable Slope Compensation
Soft Start
Soft Switching
Synchronization Pin
Thermal Shutdown   
Automotive    Automotive   
-40 to 125    -40 to 105
-40 to 125