NPM1300 high current draw

[robsrick]

Hi

I'm having an issue with my NPM1300. drawing high current. I've had 50 of these boards fabricated and the majority are fine, but with the same hw configuration, same fw i sometimes see high current draws of varying between 1 and 7mA.

I've narrowed it down to the NPM1300 in the following manner:

- First, i place the PPK2 in series with my battery and measure current during my BLE advertising state and get 1-7mA dependent on the board. On a good board i get 20uA.

- I then, one by one isolate VOUT1 and VOUT2 of the NPM1300 and place the ppk2 in series with all downstream circuitry. I see in the case of VOUT1 i get nanoamps which is expected, and in the case of VOUT2 i see 20uA which is expected because this is powering an NRF52840 which is advertising. 

I've included some screenshots from power profiler. the first shows a good board measured on the battery, the next two are examples of bad boards and the next two are isolating the vout1 and vout2 on a bad board.

Firstly, Do you agree in that case that it is likely the npm1300 is the cause?

and secondly do you have any ideas what might be causing such a high current draw?

I've included a snip of my schematics for the power supply, along with the layout.

below are the specs for the components in this part of the circuit:

1uF ±10% 10V X5R 0603

10uF ±10% 10V XS6 0603

L1 = Samsung CIGT201610EH2R2MNE

[Andy Sinclair]

Hi.

Could you try forcing the BUCK mode to PFM to see what effect that has please?

If you are using zephyr, please add this to your overlay:

&npm1300_ek_buck1 {
	regulator-initial-mode = <NPM1300_BUCK_MODE_PFM>;
};

&npm1300_ek_buck2 {
	regulator-initial-mode = <NPM1300_BUCK_MODE_PFM>;
};

Thanks

Andy

[robsrick]

Hi Andy

This made no difference

Robert

[dacr]

Hi Robert,

I see you supply LDO1 from VSYS, can you confirm there is no current load downstream from VOUTLDO1(3V0_C)?

Thanks,

Dan

[Andy Sinclair]

Hi.

Thanks for checking, could you try a couple of things to try and narrow down the cause please:

1.  Reset the PMIC, to check if the issue is related to the software configuration.
     You can do this by holding SHPHLD/RESET for 10 seconds.

2.  Send a TWI transaction (read or write), to see if that has any effect.
     There is an errata that can be cleared with a TWI message.

Andy     

[robsrick]

Hi Dan

Yes, good point i did check this. All downstream circuitry from 3V0_C is isolated by a 0ohm link which i removed to give the same results.

Regards

Robert