RE: Project PITS Soft Latch Circuits

genebren — Mon, 17 Dec 2018 23:52:03 GMT

Donald,

Trying out the MOSFET before re-spining the PCB is a great idea. You might be able to tack the new part onto your existing PCB.

Good luck!

Gene

RE: Project PITS Soft Latch Circuits

genebren — Mon, 17 Dec 2018 22:02:13 GMT

Donald,

Well done on finding the problem with the initial circuit and also for doing a great comparison of the characteristics of the two circuits. You could like correct the shutdown issue of the second circuit by using a MOSFET with a lower Vgs, like FDN340PCT-ND https://www.newark.com/search?st=FDN340PCT-ND . This part would likely work in either circuit and it is a cheaper and likely a closer match to your needs (the IRF9540 is a pretty hefty MOSFET for a Li-ion circuit, unless you plan on very high currents).

Best of luck!

Gene