Hi,
I'm new to the EHM units and BQ25504 based capacitor charging.
I'm trying to figure out how to calculate the charging time for a capacitor connected to the VSTOR of the BQ25504.
The VIN of the BQ25504 is connected to a power supply unit (for testing), 3mW power (1V, 1mA). The load is a MSP430.
The BQ25504 charges the VSTOR capacitor from 2.4V to 2.8V, but I would like to know the formula for calculating the charging time from V1 to V2, where V1 > 2.4V (i.e., after partial charge) and V2 = 2.8V.
Do we have to tweak the conventional RC circuit formulas ?
Vc = Vi (1-e^(-t/RC))
where Vc = capacitor voltage, Vi = capacitor charging voltage.
what is R ? is it the equivalent resistance of the BQ25504 unit ? (how do I find that ?)
What is Vi in our case? (i.e., the BQ25504 output ? does the BQ25504 always produce a 3V output ?)
thanks