NPM1100 with non-chargeable battery

RE: NPM1100 with non-chargeable battery

Kazi Afroza Sultana — Tue, 08 Mar 2022 11:50:33 GMT

Hello,

The maximum operational voltage of VBAT is 4.35V (https://infocenter.nordicsemi.com/topic/ps_npm1100/chapters/recommended_op_conditions/doc/frontpage.html?cp=6_0_0_4#recommended_op_conditions) . So, it is not recommended to go over this.

Best Regards,

Kazi Afroza Sultana

RE: NPM1100 with non-chargeable battery

MMMarc — Thu, 03 Mar 2022 18:54:32 GMT

We ran into a limitation on what batteries to choose. The blocker is Vbat<=4.32. Looking at available schematics it was not obvious that this is a real limitation, might just be that for rechargeable batteries that is as high as they go.
For primary cells, can I go higher, say 4.5V for three alkaline cells ?

RE: NPM1100 with non-chargeable battery

PeterLjung — Wed, 09 Feb 2022 09:45:58 GMT

Just to confirm my understanding ...

By connecting NTC to ground in configuration 3 you will:

- Disable charging of battery
- Still have BUCK regulator enabled through VOUT (1.8-3.0 V)
- Allow regulated output (VOUT) both from VBUS (USB) and/or VBAT (from non rechargeable battery)

This would allow design with very flexible battery options.

RE: NPM1100 with non-chargeable battery

MMMarc — Tue, 08 Feb 2022 15:04:01 GMT

Thx!

RE: NPM1100 with non-chargeable battery

Kazi Afroza Sultana — Tue, 08 Feb 2022 14:45:50 GMT

Hello,

Yes it is possible to set 1K resistor to the ground. When VBUS is connected, the NTC pin is only behaving as 10kohm impedance voltage source. So, even a direct ground will work here also.

You can see this reference circuit https://infocenter.nordicsemi.com/topic/ps_npm1100/chapters/hw_layout/ref_circuitry/doc/frontpage.html?cp=6_0_0_7_2_2#config_3

Hope it helps.

Best Regards,

Kazi Afroza Sultana