I almost submitted my PCB design, but our fabricator still has questions which I still don't know how to answer. So I postponed the submission for now.
I have a TP4056 Li-ion charging module (the newer one with protection circuit) and I connected the Battery out (-) to the bottom ground plane. I am also trying to monitor the analog voltage of the battery using Arduino's ADC.
My question is simple. Should I connect the Battery out (-) to the ground plane or isolate it in the PCB design?
Always use a resistor (4k7 or 10k) between battery(+) and analogue input.
So you don't fry the A/D if you make a mistake, like connecting the battery to an unpowered Arduino.
The resistor has no influence on the A/D result.
Leo..
@jremington
I forgot because I still lack sleep and have a lot of things running in my mind. Sorry and I will remember next time. Thank you for reminding.
@CrossRoads
Thank you very much. I already scaled it down using a voltage divider and the internal 1.1 V reference of the Arduino.
It's a 3.7-4.2 battery
@Wawa
Pardon me I wasn't able to attach an image of my schematic. Like I was asking for general answers but yeah thanks too for that.
For anyone seeing this in the future, never connect the TP4056 B ground to Out ground. The TP4056 switches the ground to control current in low voltage conditions. The B+ and OUT+ are directly tied together the ground is what gets disconnected. Join those two and you just removed all protection you paid for.
It must be the board. TP4056 IC is a pmosfet device with tied ground according to the data sheet. Is there something on that board that switches the ground? I prefer high side switching for power supplies.
Yep confirmed. It’s due to the DW01A on that module which is a protection chip which switches the battery ground.
I already scaled it down using a voltage divider and the internal 1.1 V reference of the Arduino.
