Other Parts Discussed in Thread: EV2400
Tool/software:
Hi experts,
Our customer is having some technical inquiries regarding the operation of BQ25756EVM. Could you please review and provide comments? Thank you
Based on EVM specs, initial charging output is around 29.4V (VBAT), so in order to suit our testing with 3S battery pack,
Using design calculator, we had changed the resistor R64 (13.7k > 36k) and set VFB_REG (1514mV), which should give around 12V output.
ICHG_REG set to 3000mA for 3A current output and ITERM set to 250mA for Termination current.
- Upon charge enabled, the charging process should go by Trickle > Pre-Charge > CC > CV > Term, however, it goes into CV mode immediately even when battery voltage still lesser than 12V.
Am I missing any steps at the moment?
*During CV, VBAT_ADC = Output voltage (12V) instead of Battery actual voltage (less than 12V).
*As above, once CV mode ended, battery pack is not fully charged (less than 12V) and it will transition between Charge termination and CV.
2. ADC readings for both voltage & current seems offset, is there any scaling factor?
Measurement BQ ADC
24.0 V 23.690 V
12.2 V 11.902 V
1028 mA 902 mA
I had tried on 2 battery pack sample and having same occurrence.
Best regards,
Hung
