Coin cell supply to PPK voltage lower than supply directly to DUT

[badidearock]

I am using PPK to measure current. The system uses 2 CR2430 in parallel.

I observe that

1. When using the battery as external supply, the battery voltage drop to 2.5V. But when the battery attached to DUT directly, the battery still about 2.9v.

2. When using PPK to capture system current with battery, the battery voltage drops faster than normal.

System behavior has 2.5mA pulse(10ms) every 8 sec.

 Can we fix that or it is just PPK limitation?

[Stian Røed Hafskjold]

When connecting the battery to the external supply pin on the PPK, the whole PPK is powered by the battery. The PPK consumes tens of milliamps and will drain the battery quickly, and if the battery can't keep up with the current, the voltage will drop, and that's probably what you are seeing. I'm sorry but it's just not the intended way of using the PPK. You must connect a stable voltage supply to the external supply header and then use the PPK application to measure the current. Then you can calculate how long the battery will last.

[5IM00N]

Hi Stian,

I just made the same experience. I thought the when connecting a coin cell to the external power supply connector, only the DUT is powered by the coin cell.

I think this is not well documented in the PPK documentation.

And in which use-case do I need to supply it with an external voltage rather than the internal voltage regulator, if I can not use a real world coin cell?

Is there any option to profile/measure the current when the DUT is connected to a coin cell?

Best regards

5IM00N