How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Fri, 13 Feb 2026 13:04:59 GMT

Yes, that is the information I got.

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Fri, 13 Feb 2026 12:37:01 GMT

Hi Michal,

Understood

Just to be sure, is what you're saying that setting the limit to 1A means that it will guaranteed never drop the VSYS when the discharge current is below 1A? The actual limit will be anywhere above 1A and never below?

Best regards,

Silvia

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Fri, 13 Feb 2026 09:19:18 GMT

Hello Silvia,

[quote user="sillvi"]1. What is the tolerance of this limit? You say setting 1 A may result in reset at around 1400 mA, but how much higher can we expect the 1 A limit to actually be? We saw no reset even at 1600 mA[/quote]

I don't have any specific data, but we have 290 mA and 1470 mA as typical values for the low/high limits in the electrical specification currently

https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/charger.html#ariaid-title12

[quote user="sillvi"]2. Is there an errata regarding this?[/quote]

It is not a silicon issue, but an easy to misunderstand documentation, which we are working on improving, so I am very sorry for that.

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Wed, 11 Feb 2026 14:05:58 GMT

Hello Michal,

Thank you for the explanation! We have two questions:

1. What is the tolerance of this limit? You say setting 1 A may result in reset at around 1400 mA, but how much higher can we expect the 1 A limit to actually be? We saw no reset even at 1600 mA

2. Is there an errata regarding this?

Best regards,

Silvia

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Wed, 11 Feb 2026 13:44:25 GMT

Hello again Silvia,

I have learnt that the 200 mA and 1 A are not hard limits and can also vary quite a bit based on the device. Those are just the lowest values that we guarantee for the limit, but then it may take for example around 290 mA or 1400 mA for the limit to drop the VSYS enough depending on the device.

Also it will cause a reset, so for a proper current limiting you may need some external circuitry (for example in case of a continuous overcurrent).

Best rergards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Wed, 11 Feb 2026 08:29:24 GMT

Okay. Thank you for looking into it

Best regards,

Silvia

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Tue, 10 Feb 2026 15:30:03 GMT

Thank you Silvia, that sounds correct.

I am discussing this internally and I will let you know when I will have more information (or questions).

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Tue, 10 Feb 2026 15:01:34 GMT

When we set the limit to ~1200 mA we set BCHISETDISCHARGEMSB to 0xBA and BCHISETDISCHARGELSB to 0x00

When we tried setting it to 1000 mA according to the data sheet, we set BCHISETDISCHARGEMSB to 0xCF and BCHISETDISCHARGELSB to 0x01

Best regards,

Silvia

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Tue, 10 Feb 2026 14:48:53 GMT

Thank you!

[quote user="sillvi"]3. We are using registers 0x030A and 0x030B[/quote]

And what values did you write to them?

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Tue, 10 Feb 2026 13:40:27 GMT

Hi,

1. We are using v3.0.1

2. We have tried it on two 'D' devices and both show the same behavior

3. We are using registers 0x030A and 0x030B

Best regards,

Silvia

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Tue, 10 Feb 2026 10:25:02 GMT

In general it looks like you should be doing it correctly, but I have a few questions:

Which NCS version are you using?
Have you tried that on several 'D' devices or just one?
Also just to make sure, can you tell me the exact register values that you were using, just to double check?

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Wed, 04 Feb 2026 16:57:01 GMT

Hello again,

Just a quick update. To my knowledge this is going to be updated in a new version of the datasheet, but I am still trying to find out the details.

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Wed, 28 Jan 2026 07:23:01 GMT

Hello Silvia,

I will check with Audun or some others from the PMIC team and get back to you.

Best regards,

Michal

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

sillvi — Fri, 23 Jan 2026 07:59:03 GMT

Hi Audun,

I'm not quite understanding what you mean. Are you saying the high limit is 1000 mA or 1470 mA?

We have tried setting the limit to 1000 mA by following the settings described in the data sheet and have read the registers back to confirm they were set correctly. We have also used only the zephyr device tree property

dischg-limit-microamp = <1000000>;

With both of these methods, we have manage to load the system with 1600 mA.

We are using a battery that can handle maximum 1200 mA so this is way too high.

If we can't get exactly 1200 mA, how can we at least get the guaranteed 1000 mA limit?

Best regards,

Silvia

Edit:

When I first posted we were working with an nPM1300 with hardware version code 'C' and tracking code '2503AG' and on that one we did manage to set a discharge current limit slightly below 1200 mA. Just now we saw that in the new version of our hardware, we have an nPM1300 with hardware version code 'D' and tracking code '2521AA' instead (the rest of the IC marking is the same as before).

Could the hardware version have something to do with why the discharge current limit setting no longer works?

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Audun — Wed, 10 Sep 2025 07:50:01 GMT

Hi sillvi ,

the nPM1300 datasheet was changed from originally showing a wider range of discharge limits to now only two limits, high (1000 mA) and low (200 mA). The electrical specification states a typical value of 1470 mA for the high limit, but this can be lower due to device variation. The 1000 mA and 200 mA limits are guaranteed however.

Best regards,

Audun

RE: How to set nPM1300 BCHISETDISCHARGEMSB/-LSB

Michal — Wed, 03 Sep 2025 21:55:35 GMT

Hello Silvia,

I will check this internally and I will get back to you.

Best regards,

Michal