WD2002SJ Bench Power Supply

Modifying a $10 LTC3780-based Buck/Boost converter for use as a bench power supply

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I've been slowly assembling electronics tools and components. To keep costs low, I decided to buy a cheap (Ebay $10.88 shipped) DC-DC power regulator designed for solar/automotive/manufacturing industries and modify it for bench use. The board is named WD2002SJ, but it's built around Linear Technology's LTC3780 integrated circuit. I've found the board ranging in price from $9-30 (shipped) from multiple vendors/manufacturers and with several implementations varying in component choice - mostly notably the heatsinks and shunt resistors.

Design Goals:

  1. allow nearly full board specifications on inputs/outputs (90%+)
  2. allow for multiple external dc power sources for easy powering via wall wart, battery, atx, solar, etc. 
    1. switchable to internal source (plan to include this later)
      1. led indicator
    2. 2.1mm barrel plug
    3. 4mm through-hole binding posts
    4. fused input bus (probably overkill, just for shits)
    5. pass earth ground to front panel for grounding options
  3. Outputs - 4mm through-hole binding posts
    1. fused outputs with decent housings for easy replacement
    2. reverse protection diodes
  4. easy operation mode switching; possibly using led indicator
    1. if complexity hinders development, prioritize constant voltage/constant current mode (CV/CC)
  5. pass board fault/power leds to front panel
  6. standard bench PSU dimensions 16cm (w) x 25cm (h) x 28cm (d)
    1. allow internal room for an onboard (atx? ) power supply
  7. volt/ammeter front panel, 100v/10A
  8. switchable load?
  9. replace pots with high precision digital pot modules
  10. rubber feet
  11. folding handle?
  12. fan - if necessary?
    1. switch-off?
    2. auto-on?

There will possibly be more added to this list. While all these features may not be implemented immediately, I'd like to plan for them so they may be easily and cheaply added later.

Adobe Portable Document Format - 150.45 kB - 04/09/2018 at 06:47


  • 1 × WD2002SJ board (can also be found by searching for ltc3780) (Ebay, $10.88 shipped)
  • 1 × 500kΩ 1/2w potentiometer
  • 1 × 200kΩ 1/2w potentiometer
  • 1 × 100V 10A Digital Voltmeter Ammeter Display (Ebay, $3.45 shipped)
  • 6 × 4mm binding posts

View all 8 components

View all 3 project logs

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