nPM1100 LEDs

[Pallav Aggarwal]

Hi,

could you please share how charging LED / Error LED will behave in various conditions. I could not find this information anywhere.

BR

Pallav

[ketiljo]

This is explained here: https://infocenter.nordicsemi.com/topic/ps_npm1100/chapters/charger.html#charging_indication and https://infocenter.nordicsemi.com/topic/ps_npm1100/chapters/charger.html#charger_error_cond

[Pallav Aggarwal]

I am talking about how blinking will happen when it will be OFF when it will be ON?

[ketiljo]

It should not do that. Can you try another battery? What it is the battery voltage when the LED is on and off? 

It could be a battery with too high internal resistance such that, it reaches End of Charge, but when charging stop, the battery voltage drop below the Recharge Threshold

[Pallav Aggarwal]

Battery is a new Phone battery and it gives good backup.

When LED is ON the voltage is 4.221V and when LED is off the voltage is 4.167V

Vterm is set for 4.2V

[ketiljo]

Can you provide a scope plot of VBUS, VSYS and VBAT please? 

[Pallav Aggarwal]

I have connected again for the measurements but this time, that blinking is not coming. Looks like the jumper wires could be the issue, not sure though.

I will do some more tests and confirm in a day or so.

[Kyrre Aalerud]

Did this get resolved?
I can see from video the blinking was slow so I expect it was not same issue as I am now seeing.

I am getting an approx 10 Hz (9.65Hz) short spike of 400us length on CHG when battery has been full for a long time. I am using approx 157mA chargerate (2.4k ICHG resistor) and battery is a 320mAh cell. I can not see any spikes on VBUS, VBAT or VSYS.

It appears to only happen when battery is fully charged and have been so for a while.

[Kyrre Aalerud]

I discovered this behavior can come about from low voltage on the bus (long thin cables) or overloaded usb port. Just in case others search and find this...