A charging device comprises a charging chip and a processor. The charging chip is configured to convert a power supply voltage into a battery voltage to charge the battery, where the power supply voltage is greater than a limiting power supply voltage, and the battery voltage is less than a limiting battery voltage. The processor is configured to: when a first condition is met, increase both the limiting power supply voltage and the limiting battery voltage, or decrease a charging current while increasing the limiting battery voltage; or when a second condition is met, decrease both the limiting power supply voltage and the limiting battery voltage, or increase the charging current while decreasing the limiting battery voltage.