US Patent 10389228 Power supply circuit with surge-supression

A power supply circuit which can suppress current surges comprises a first switch unit, a first control unit, a second switch unit, and a second control unit. The first switch unit is coupled between a voltage input terminal and a load, the load comprising a capacitor. The second switch unit is coupled between the voltage input terminal and the load. The second control unit turns on the second switch unit to charge the capacitor to a predetermined voltage before the first control unit controls the first switch unit to turn on. The second control unit controls the second switch unit to turn off when a voltage of the capacitor is greater than the predetermined voltage, and the first control unit controls the first switch unit to then turn on to supply power to the load.