A capacitor charging circuit, comprising: a charging power supply, for outputting a charging voltage; a voltage comparison module, connected to the charging power supply, and configured to output a drive signal indicating charging upon judging that the charging voltage is higher than a preset threshold; a current adjustment module, connected to the voltage comparison module and the charging power supply separately, the charging current adjustment module receiving the drive signal and, upon receiving the drive signal indicating charging, causing the charging power supply to charge the capacitor with a maximum charging current. The present application enables adjustment of the charging current of the charging capacitor according to the power supply voltage, thus increasing the charging speed.