Part Number: BQ24171
Hello,
IC: BQ24171RGYT
Battery: 3P2S pack of 18650s
Thermistor: the pack has a 10k NTC thermistor in it which I have connected to TS as described in the BQ24171RGYT datasheet.
Ext power: 12V wall plug to power the charger
Extra TS connection: TS is also connected to ADC of an MCU so MCU can read battery temperature and turn on a fan as needed.
Problem: when 12V charger cable not plugged in, Vref = 0V. When Vref = 0V, TS circuit is off and MCU can't read thermistor value.
Proposed solution: replace Vref with an external 3.3V supply that can be controlled by MCU.
Question 1: does proposed solution sound reasonable?
Question 2: how stable does 3.3V supply need to be? Is 3.3V from main system buck regulator reasonable or should I add a dedicated LDO?
Question 3: should I replace all Vref with the external 3.3V supply or only TS. I only need it for TS.
Question 4: do you have any other solutions to consider?