Soft-Start Isolated Power Supply Reference Design


Design files


This reference design demonstrates a Soft-Start Isolated Power Supply. It utilizes a TPS22965 Load-Switch and SN6501 Transformer Driver to slew-rate limit the ramp-up power on the primary supply, and utilizes a Transformer plus a full-wave rectifier to generate the isolated secondary power.

  • Operates with 3.3V or 5V primary supplies
  • 50uA load switch quiescent current
  • High primary-side current drive
    • 350mA with 5V supply
    • 150mA with 3.3V supply
  • Primary side rise time = ~2ms
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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.

TIDU591.PDF (290 K)

Reference design overview and verified performance test data

TIDRB99.PDF (25 K)

Detailed schematic diagram for design layout and components


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


Files used for 3D models or 2D drawings of IC components


Includes TI products in the design and potential alternatives.

Load switches

TPS229655.7-V, 6-A, 16-mΩ load switch with adj. rise time and optional output discharge

Data sheet: PDF | HTML
Transformer drivers

SN6501Low-noise, 350-mA, 410-kHz transformer driver for isolated power supplies

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
Design guide Soft-Start Isolated Power Supply Design Guide (TIDA-00326) Oct. 10, 2014

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