A regulation circuit for powering a device while charging a battery is provided. The regulation circuit includes at least one analog feedback loop, and a digitally controlled feedback loop. The digitally controlled feedback loop includes first and second comparators. The first and second comparators compare an input power supply voltage to first and second threshold voltages, respectively. The second threshold voltage is lower than the first threshold voltage. In response to the comparisons, the digitally controlled feedback loop controls a charging current for charging a battery while also regulating a current to power circuits of the device. If the input power supply voltage drops, the digitally controlled feedback loop responds faster than the analog feedback loop, reducing the risk that to supply voltage will drop too much to reliably power to the device circuits. A method for digitally regulating an output current to charge a battery is also provided.