Exploring Ideal Diodes

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Exploring Ideal Diodes

Post by parkview » Wed Sep 08, 2021 1:03 pm

I have used some Ideal Diode circuits in a few projects now, but have found that they leak a reverse voltage back through the Diode (MOSFET). Scouring the Internet, I have found three different designs all based around the idea of turning off a MOSFET if there is no voltage on one side of the MOSFET.

I have tried making some of them up on a piece of prototype PCB, but it's hard to swap components out, and some of them are quite small - SOT-236. I have bit the bullet and designed up an Ideal Diode Test PCB. This board tests out all three of the designs, using a variety (3 different footprints) of MOSFETs and matched transistors.

To boot, JLCPCB now offer a Purple solder mask PCB, so I ordered with that colour, PLUS, I see they are now offering much cheaper shipping, as low as A$6, so in theory, you can have 5 10x10cm PCB's made for around A$10!
Ideal-Diode-Tester.jpg (47.7 KiB) Viewed 38 times
The above pin headers give me a flexible input/output arrangements. I have included 5 or so test pads per test circuit. I have also included a MT9700 electronic switch IC, that apparently offers reverse voltage protection at 3A. We live in interesting times!

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