Abstract: A charging circuit integrated into a chip, comprising a charging unit, a switch unit, a biasing unit, a voltage-dividing unit, and a comparing unit. The charging unit is connected between a power supply input and a load for outputting a constant current based on a constant bias voltage supplied by the power supply input in order to charge the load. The switch unit is connected between the charging unit and the power supply input for turning on or cutting off the charging unit. The voltage-dividing unit generates a first signal to the comparing unit according to a voltage of the load. The biasing unit outputs a second signal having a constant voltage to the comparing unit. The comparing unit compares the first signal with the second signal for cutting off or turning on the switch unit, bringing the charging unit to charge or stop charging the load, respectively.

Abstract: A charging circuit integrated into a chip, comprising a charging unit, a switch unit, a biasing unit, a voltage-dividing unit, and a comparing unit. The charging unit is connected between a power supply input and a load for outputting a constant current based on a constant bias voltage supplied by the power supply input in order to charge the load. The switch unit is connected between the charging unit and the power supply input for turning on or cutting off the charging unit. The voltage-dividing unit generates a first signal to the comparing unit according to a voltage of the load. The biasing unit outputs a second signal having a constant voltage to the comparing unit. The comparing unit compares the first signal with the second signal for cutting off or turning on the switch unit, bringing the charging unit to charge or stop charging the load, respectively.