DCM220 dual power module

A project log for EEZ Bench Box 3

DIY modular T&M chassis for programmable power DC sources and more

DenisDenis 08/17/2019 at 17:580 Comments

I've just finished the latest DCM220 dual power module. It is built around LT3763 sync buck that offers current programming and monitoring. Unfortunately it does not provide CC mode of operation indication. Therefore I derived it from FB signal. A 4-channel 12-bit DAC (MAX5715) is used for set output voltage and current (times two for two channels). Instead of using dedicated ADC for measuring output voltage and current a STM32F373 MCU is used which comes with attractive multichannel 16-bit ADC!

Output terminals are for 4 mm banana plugs and bi-color LED indicator is used to indicate OE (Output Enable) and CC mode of operation. Output voltage is limited to 20 V (but can be much more since Vin is 48 Vdc) and output current to approx. 4 A.

Power outputs are "floated" in regard to other module's GND, but two channels share the same GND on board.

Output ripple is pretty good, if we take into account that is SMPS, and e.g. for Iout = 2 A it's below 5 mVpp or 1 mVrms (measured on the output capacitor):

So, with three DCM220 one could count on up to 6 programmable power sources packed into EEZ BB3.