Reference Design - Universal Line Input AC-DC 3W High Side Buck Converter using UCC28720


Design files


The PMP9649 reference design is a simple, low-cost high side Buck converter to convert universal AC input voltage (85Vac to 265Vac) to a non-isolated 20V/150mA DC output with UCC28720 controller. BJT is applied as the buck switch for cost optimization, and simplicity is achieved with bulit-in sample and hold regulation function in UCC28720.

  • Universal AC Input (85Vac to 265Vac)
  • Simple, low cost solution with BJT employed as buck switch
  • Small 14.6mm2 two layer PCB footprint with 24 BOM components (excluding test points)
  • Greater than 77% full-load efficiency at high line
  • Conducted EMI tested (confirms EN550022 and CISPR-22 Class B)
Output voltage options PMP9649.1
Vin (Min) (V) 85
Vin (Max) (V) 265
Vout (Nom) (V) 20
Iout (Max) (A) .15
Output Power (W) 3
Isolated/Non-Isolated Non-Isolated
Input Type AC
Topology Buck- Non Sync
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDU686.PDF (1198 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more

TIDRC37.PDF (80 K)

Detailed schematic diagram for design layout and components

TIDRC38.PDF (108 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDC807.ZIP (188 K)

Design file that contains information on physical board layer of design PCB


Includes TI products in the design and potential alternatives.

AC/DC & DC/DC controllers (external FET)

UCC28720Constant-voltage, constant-current controller with primary-side regulation for bipolar power devices

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
Test report PMP9649 Test Results Dec. 10, 2014

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