SLUA560D June   2011  – March 2022 UCC28950 , UCC28950-Q1 , UCC28951 , UCC28951-Q1

 

  1.   Trademarks
  2. 1 Design Specifications
  3. 2 Functional Schematic
  4. 3 Power Budget
  5. 4 Transformer Calculations (T1)
  6. 5 QA, QB, QC, QD FET Selection
  7. 6 Selecting LS
  8. 7 Output Inductor Selection (LOUT)
  9. 8 Output Capacitance (COUT)
  10. 9 Select FETs QE and QF
  11. 10Input Capacitance (CIN)
  12. 11Setting Up the Current Sense (CS) Network (CT, RS, RRE, DA)
  13. 12Voltage Loop and Slope Compensation
  14. 13Setting Turn-on Delays to Achieve Zero Voltage Switching (ZVS)
  15. 14Turning SR FETs-off Under Light Load Conditions
  16. 15600 W FSFB Detailed Schematic and Test Data
  17. 16References
  18. 17Revision History

1 Abstract

In high-power server applications to meet high-efficiency goals of greater than 92% some power-supply designers have found it easier to use a phase-shifted full-bridge (PSFB) converter (Figure 2-1). This is because the PSFB converter can obtain zero-voltage switching on the primary side of the converter reducing switching losses and increasing overall system efficiency. The purpose of this application note is to review the design of a 600-W, phase-shifted, full-bridge converter , using the UCC28950 or the newer UCC28951 PSFB controller. The design specifications for this design are presented in Table 1-1. Hopefully this information will aid other power supply designers in their efforts to design an efficient phase-shifted, full-bridge converter. Also note there is an Excel Design Tool that goes along with this application note as well to aid in the design process.