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I need to disconnect the rest of the circuit when battery is charging for safety reasons. I use a LiPo battery which it's charged with an IC that is powered by 5V DC thought a micro USB connector.

This is the original circuit.

enter image description here

SW1 is a slider switch to power on/off the device.

My goal is disable U3 when USB voltage is present (VUSB).

After reading and searching I've chosen the load switch TPS22910A for my purpose. TPS22910A is active low.

I've thought these two options.

Option A. Controlling U3 Vin enter image description here

Being SW1 in 3 position, if VUSB is 5V, then TPS22910A VOUT will be 0 V (active low), so VIN of U3 will be 0 V and my device will be powered off.

Being SW1 in 3 position, if VUSB is floating (cable disconnected), R1 will forced TPS22910A ON pin to be GND and then, VOUT will be VBAT and U3 will be powered on.

Option B. Controlling U3 EN enter image description here

This option is basically the same as Option A by instead of controlling VIN, EN is controlled.

I think Option B is better. What do you think? If you think there are better options than using TPTPS22910A, please say them to me; I'm a bit lost in these matters.

Thank you so much!

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  • \$\begingroup\$ Why are you thinking B is better? This isn't a discussion forum with open-ended openers, so please be very specific in what you ask! \$\endgroup\$
    – Marcus Müller
    Feb 16, 2021 at 12:12
  • \$\begingroup\$ Hi, I think B is better because I think power consumption would be less since TSP22910A is only used to source EN of U3 instead of VIN. \$\endgroup\$
    – Alpha
    Feb 16, 2021 at 13:03
  • \$\begingroup\$ My goal is to disconnect all the device when battery is charging; I've designed a circuit that I think it works, but I ask in this forum because I'm not totally sure about it. If someone thinks that another option would be better, please, tell me. Thanks! \$\endgroup\$
    – Alpha
    Feb 16, 2021 at 13:06
  • \$\begingroup\$ A load switch seems excessive, why not just a BJT or MOSFET to pull EN low when Vbus is connected? \$\endgroup\$
    – Finbarr
    Feb 16, 2021 at 13:36
  • \$\begingroup\$ Yes, a load switch is excesive, but this is for a wearable and I think the load switch is smaller (and cheaper) than a MOSFET. What do you think? \$\endgroup\$
    – Alpha
    Feb 16, 2021 at 14:40

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