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I need to be able to switch off my product for long term storage. I also need it to shut off automatically on low power. The device software needs to do housekeeping before shutting down. I found a tutorial online that uses a load switch circuit to accomplish half of the task. The problem with this circuit is it only shuts off in code.

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How can I adapt this circuit to use a slide switch as opposed to a momentary push button switch?

Thanks for your time. Tim Cerka

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    \$\begingroup\$ put the slide switch in series with the power supply \$\endgroup\$
    – jsotola
    Nov 21, 2022 at 2:57
  • \$\begingroup\$ Something I should have mentioned in the post. The device software needs to do housekeeping before shutting down. I believe that means I can't simply run the switch in series with the power supply. \$\endgroup\$
    – Tim Cerka
    Nov 21, 2022 at 22:31

1 Answer 1

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Replace the switch with a 1-10uF capacitor and add the slide switch in series with the power supply.

The capacitor has to effect to momentarily pull down the gate of the P mos, which allows it to switch the circuit on. Connect the "Off" side of the switch to GND to discharge the capacitor when it's off.

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  • \$\begingroup\$ When changing the switch to off, would this just cut power, or could I do some housekeeping before cutting power? \$\endgroup\$
    – Tim Cerka
    Nov 22, 2022 at 3:16
  • \$\begingroup\$ yes it would just switch the power off \$\endgroup\$
    – Damien
    Nov 22, 2022 at 5:41
  • \$\begingroup\$ Wanted to confirm the size of that capacitor 1-10 µF. That's a big one. Can I send you an updated schematic to be sure I'm on the right track? \$\endgroup\$
    – Tim Cerka
    Nov 23, 2022 at 16:47
  • \$\begingroup\$ I'm also confused about where to put the switch. On side of the switch to VDC and Off side of the switch to GND \$\endgroup\$
    – Tim Cerka
    Nov 23, 2022 at 16:58
  • \$\begingroup\$ @TimCerka What are your size limitations, if 1 μF is too big? I'm pretty sure you can get 1 μF caps in 0201. \$\endgroup\$
    – Hearth
    Nov 23, 2022 at 20:30

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