Hi, might be a trivial question but putting this through your expertise would help a newbie!
I am using a deepsleeping ATtiny85 on standby for external interrupt to wake up Arduino Uno and perform certain tasks and go back to sleep. To power the Uno upon interrupt, I plan on using a MOSFET for now (later might replace with a relay but might stick with MOSFET for compactness) to switch on/off. I’m personally a fan of grounding everything so was wondering if there’s a downside of using high gate switching using a P-MOSFET.
Rather, would you say in such cases that high side switching is better than low side switching?
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Hi Prithul
I think in this case a high side switch using a P channel Mosfet device would be the way to go. If you use a low side switch you will have a ground conflict as all UNO grounds will be above the “real” ground due to the small voltage drop across the N Mosfet. Having several grounds at different potentials will cause no end of problems overall.
Cheers Bob
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Hi Prithul,
I have also gone down this path - albiet with WS2812 strip’s and poor grounding.
I came across this product in Core’s new product feed: Pololu Isolated Solid State Relay/Switch, SPST, 30V, 11A | Buy in Australia | POLOLU-5421 | Core Electronics
And have been meaning to deploy something similar to your project for ESP32’s, much like Core’s Nano power timer, but with a variable (controllable) sleep.
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Hi Liam
That is a pretty useful device. Could be ideal for this project. Very small too. If you dropped it at my place it would be lost. Still needs to be high side switch though. The ground problems don’t go away.
Cheers Bob
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Hi Bob,
Have been meaning to get my hands on one since I saw it come out.
Yeah didn’t hone in on the measurements until you mentioned, quite a bit smaller than Cores current FET offering.
In the description it does mention that this product is capable of high-side switching,
(for example, this board can be used for high-side or low-side switching). The board can be used as a replacement for a mechanical relay in many situations.
I’ll pick one up and report back with my findings when I have a moment.
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Thanks for sharing @Liam120347! Pretty exciting, especially 'cause it costs almost as much as a MOSFET.
Ordering a few to play with
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