SWITCHING-MODE POWER SUPPLY WITH HELPER CURRENT SOURCE
Power supplies combining a switching-mode power supply in parallel with a current source can improve maximum load current capability. The current source can be turned on, or the amount of current supplied by the current source increased, when there is a heavy load current demand, for example, when the load current demand is more than the current rating of the switching-mode power supply. The duty cycle of the output stage of the switching-mode power supply can be used to determine the load current demand. The current source may increase the maximum output current of the power supply beyond the maximum output current of the switching-mode power supply. For example, the current source may add 0.5 A to the current capability of a 2.5 A switching-mode power supply.