PCB

Before I picked any case, I wanted to “modularize” each stage to know how much space I needed. Also, to get better temperature readings of the MOSFET, it seems that having two MOSFETS in “parallel” would distribute the heat propagated. And a thermal resistor could be placed in between, with some thermal paste; that way, the temperature readings would be more accurate. Currently, 2 inches x 2 inches will be good enough per stage [not counting the heat sink area]. So I will probably need a case 10 inches x 4 inches.

Thermal sensors

In addition to having a single thermistor circuit, there will be another pair of resistors as a reference. That way, a differential pair can be made, and the measurements will be more accurate.

Test points

I have wanted to add proper “high speed” test points that are 50 ohms, so I could hook a high-end scope to the various design stages. Since connecting the 50-ohm probe to the voltage rails would overwhelm the controllers/regulators, I used a π-matching circuit. The image below shows such a circuit below. Note that even R48 is not needed; I left it for “good luck/practice.”

Encoders instead of Potentiometers

I have also been wanting to add encoders since they have an unlimited turn count—one for voltage and one for current limit.

The first draft of the PCB

The first loose draft of the PCB seems to be 37cm long and 26 cm wide. So a nice aluminum case that is 21 cm long and 10 cm wide could be the target size after I clean stuff up.

Front

Back

Case

The case chosen is linked here

The inner dimensions for the PCB are 200.6 mm x 300 mm

Final PDFs

https://github.com/edmugu/arduino_adjustable_power_supply/blob/master/Rev_B/Jekyll_page/PCB.pdf

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