nPM2100 current draw in passthru

[cliffelion]

We are experiencing unexpected behavior using the PMIC. See the three cases below:

Test	Vin	Vout	i	comment
1	3v	3v	7.9uA	expected supply current similar to system current
2	2.5v	3v	12.6uA	expected supply current increases as supply voltage decreases
3	3v	2.5v	17.5uA	UNEXPECTED PMIC in pass through mode draws more than 2x system current

All tests done in auto mode.
In test 3, current is the same in auto/passthru/lowpower/etc

You can also see the current waveforms on the connected PPK for these three tests below.

Thanks

Cliff Elion

[cliffelion]

Just to Clarify ... Vout - is the programmed output voltage of the PMIC. 

[Tomi Koskela]

Hello,

Is this measured with nPM2100 EK or something else? The current peaks seem to be quite high when boost is operating in ULP mode. It can be difficult for PPK2 to sample those short/high current pulses correctly. What is the boost output capacitor (input/output) configuration? To reduce the peak current, you can increase input capacitance and reduce output capacitance. 

In PT mode the average input current should drop compared to the ULP mode. 

[cliffelion]

HI Tomi,

Appreciate the response. 

Yes, we are using the nPM2100 EK with a nRF54L15 DK communicates with the PMIC over i2c. I believe you are correct that the PPK is the issue and distorting the measurements due to the fast transients which explains the issue we saw. 

Thanks

Cliff