Patent ID: 7835640

Claim:
A method of operating a camera flash on a mobile device powered by a battery module, wherein upon determination that the camera flash needs to be activated the method comprises: measuring battery parameters of the battery module without operating the camera flash; determining an equivalent series resistance (ESR) of the battery module based on one of the measured battery parameters; determining a maximum flash current based on the measured battery parameters, the ESR of the battery module, potential current loads that may occur during the operation of the camera flash and a minimum battery voltage for operation of the mobile device; and generating a camera flash current while drawing a current from the battery module with an amplitude less than or equal to the maximum flash current; wherein the measured battery parameters comprise a battery voltage and a battery temperature of the battery module; wherein the method comprises using a look-up table of battery temperature values and associated ESR values of the battery module to determine the ESR of the battery module from the measured battery temperature; and wherein the method further comprises using additional look-up tables for different pulse lengths in the camera flash current.