A power supply control circuit for controlling a charging process of a power supply capacitor to produce a power supply voltage to power a power control chip is disclosed. The power supply control circuit has a charging switch controlled by a charging control signal, and the power supply capacitor is coupled to an input voltage when the charging switch is on. The power supply control circuit further has a charging control circuit, configured to provide the charging control signal to control the charging switch based on the input voltage, the power supply voltage and a voltage threshold. Thus a high turns ratio of an auxiliary winding to a secondary winding is not necessary, high voltage devices are not needed and the power dissipation caused by the high voltage is also reduced.