Hi Support team,
Refer to your reference circuit of datasheet of bq24133, the RsR ,10mohm resistor have been used for charge current sensor resistor. if we want to design the around charge current is 620mA with 9V5 input,
the resistor divider value of the VIset ,
RsR =10m ohm
R4 =100K
R3= 3.9K
and VISET = 3.3 x (3.9K /(100K+3.9K) =123mV. Refer to the datasheet. it is close the limiter of VISET_CE Charge Enable Threshold 120mV.
and also using RsR =10m ohm, the VSRP-SRN = 10m x 620mA,=6.2mV, according to the datasheet, the charge regulation accuracy will very high (+/-25%)
We just worry about the charging is stable or not if using RsR=10 ohm.
if changing the RsR =20m ohm , R4=100K and 8.2K, the VISET = 3.3 x (8.2K /(100K+8.2K) =250mV , more margin of the VISET_CE Charge Enable Threshold
and the VSRP-SRN =20m x625mA=12.5mV, the charge regulation accuracy will less than +/-25% and more accuracy than before.
Please advise which one is better, if changing RsR=20m ohm. any potential problem will occur.
Regards
Kelvin Lo
