Parallel power supply with active droop current sharing circuit having current limiting function

摘要

An active droop current sharing technique combined with current limiting function is employed in a parallel power supply. The parallel power supply is characterized with a current sensing amplifier that generates a current feedback signal representing a difference between a nominal output voltage and a fractional output voltage. The current sensing amplifier is coupled to a threshold level generator providing a threshold level defining a voltage level corresponding to a maximum allowed output current of the parallel power supply. If the voltage level of the current feedback signal exceeds the threshold level, the threshold level generator is turned on and the current feedback signal is coupled to a switching controller to adjust the output voltage of the power converter for properly addressing the current imbalance among plural parallel power supplies. Meanwhile, the threshold level generator induces a current to the current sense input of the switching controller, thereby limiting the output current of the power converter from exceeding the maximum allowed output current.