Disabling Charge Mode to Avoid External Battery Charging

RE: Disabling Charge Mode to Avoid External Battery Charging

Simonr — Wed, 09 Apr 2025 12:52:53 GMT

Ah, okay. And the transistors then will be a voltage divider I assume, that makes sense then and this circuit seems just fine here.

Best regards,

Simon

RE: Disabling Charge Mode to Avoid External Battery Charging

Gabriel Mergh Oliveira — Tue, 08 Apr 2025 11:09:44 GMT

Hello Simon,

BAT_MON and BAT_MON_EN would go into the GPIO of my Minew MS88SF3. Just to read the voltage of the external battery.

And my V_BAT is where the external battery would connect to the npM1100, right after.

RE: Disabling Charge Mode to Avoid External Battery Charging

Simonr — Mon, 07 Apr 2025 08:16:56 GMT

Hi Gabriel

Can you share some additional information on what BAT_MON and BAT_MON_EN will be connected to here, and how is the battery connected to the circuit altogether, as this isn't clear here and I don't want to make any assumptions when reviewing your circuit. This should indeed make sure the nPM1100 won't try charging your battery.

Best regards,

Simon

RE: Disabling Charge Mode to Avoid External Battery Charging

Gabriel Mergh Oliveira — Fri, 04 Apr 2025 18:24:36 GMT

Hello Simon,

I developed a layout with the npm1100, as it is the one I am finding available stock for use. With that, I customized the circuit design so that the battery would not be charged. Could you analyze it for me and tell me if it would work the way I expect, using the npm1100 as power management, but without recharging the battery?

RE: Disabling Charge Mode to Avoid External Battery Charging

Simonr — Mon, 31 Mar 2025 10:26:20 GMT

Hi Gabriel

Regarding the charging on nPM1100:

If you use a non-rechargeable battery, you can just leave VBUS disconnected altogether, and that should make it not able to charge at all. However, if VBUS is used as I.E. a power source, there is no way to ensure that it won't try to charge the battery on the PMIC itself.

One thing you can do to work around this is to connect a 1kΩ resistor between the NTC pin and GND. A 10k thermistor would be 85°C at 1kΩ, and the PMIC will never charge a battery at 85°C.

Best regards,

Simon

RE: Disabling Charge Mode to Avoid External Battery Charging

Gabriel Mergh Oliveira — Fri, 28 Mar 2025 13:32:11 GMT

Yes, you will check the use of the npM2100 in the project. My real question is whether I could use the npM1100 without it trying to charge the battery.

Best regards,
Gabriel

RE: Disabling Charge Mode to Avoid External Battery Charging

Simonr — Fri, 28 Mar 2025 11:56:56 GMT

If you're creating a design with a non-rechargeable battery, I would suggest checking out the nPM2100 which is a PMIC for just that. https://docs.nordicsemi.com/category/npm2100-category

I will have to ask the developers whether we can confirm that the nPM1100 won't try to charge connected batteries.

Best regards,

Simon