Using PPK to measure low-side current consumption of a battery-powered device

RE: Using PPK to measure low-side current consumption of a battery-powered device

Boaz — Thu, 29 Nov 2018 15:27:15 GMT

Thanks Stian. Most helpful 🙂

RE: Using PPK to measure low-side current consumption of a battery-powered device

Stian Røed Hafskjold — Thu, 29 Nov 2018 15:22:55 GMT

Yes, so if you disconnect the load from ground you basically disconnect the load from the battery as well. Then you can power the load directly from the PPK.

Like this:

Of course, if everything is inside a casing and you don't have access to anything other than the solder bridge, then you can't use the PPK to measure current unfortunately.

RE: Using PPK to measure low-side current consumption of a battery-powered device

Boaz — Thu, 29 Nov 2018 13:41:53 GMT

I mean, I can't connect the PPK in place of the battery (i.e. disconnect the battery from the load). I can disconnect the load from ground using the SB

RE: Using PPK to measure low-side current consumption of a battery-powered device

Stian Røed Hafskjold — Thu, 29 Nov 2018 13:00:28 GMT

But in your question you said you had a solder bridge between DUT and ground. If it's not possible to open the solder bridge then there's no way to measure current at all?

RE: Using PPK to measure low-side current consumption of a battery-powered device

Boaz — Thu, 29 Nov 2018 12:34:16 GMT

I can't. At the stage of the test, the device is already assembled, the batteries soldered, and unfortunately there is not solder bridge to disconnect the batteries from the load.

RE: Using PPK to measure low-side current consumption of a battery-powered device

Stian Røed Hafskjold — Thu, 29 Nov 2018 12:28:05 GMT

You need to somehow be able to power the device from the PPK. What if you remove the measurement resistor (leave the solder bridge open). Then power the board using the PPK, between the + terminal on the battery and on the DUT side of the solder bridge?