BQ24171 - Question on input voltage at 12V vs. charging current

Q: BQ24171 - Question on input voltage at 12V vs. charging current by 24727

Question on the BQ24171 charger IC.  I know this is a very flexible IC but want to find out if it can produce our required charging voltage and current from a higher voltage input. 

 

We are wanting to charge a 1S2P battery configuration using 2 cells in parallel, 3.7V nominal @ 3Ah per cell. 

We would like to keep our adapter cable fairly small in diameter which means keeping the input current low. 

Therefore we would like the ac adapter to be ~12V @ 2A or 1.5A and still charge our battery pack at 4.2V @ 3A. 


Q: Re: BQ24171 - Question on input voltage at 12V vs. charging current by 10449

The bq24171 can operate with a 97% duty cycle.  Maximum Vout is equal to Vin times the duty cycle.  12V in to 4.2V out is not a problem.  A 12V adaptor at 1.5A is 18W which is more than enough power to charge a 4.2V Li-Ion at 3A which is only 12.6W.  Figure 1 in the datasheet shows a 12V input to 2S battery charger (8.4V).