Adaptive current limiting for any power source to limit power drain of one load on the power source to maintain a minimum power source voltage for proper operation of other loads on the power source. For battery applications, such as for flash systems, the invention allows the maximum output current of a boost converter to be utilized without having to calculate the system equivalent series resistance first. The invention also adjusts the current load up or down during a high load event to compensate for changes in other loads. The changes in current load are made in increments, with a hysteresis region avoiding constant up and down incrementing. Various embodiments are disclosed.