Patent ID: 8258752

Claim:
A charging switch circuit for coupling a power source and a battery to be charged, the charging switch circuit comprising: a first and a second integrated devices, and a transistor controlling the first integrated device, wherein each integrated device includes: a PMOS transistor which includes a gate, a source, a drain and a channel region between the source and the drain, wherein the source, drain and channel region are formed in a substrate, and a parasitic diode is formed between the drain and the channel region; and a Schottky diode formed in the substrate and connected in reverse series with the parasitic diode, the Schottky diode having one end connected with the parasitic diode and the other end connected with the source; wherein the first integrated device is coupled between the power source and the battery, the source of the first integrated device being coupled to the power source and the drain of the first integrated device being coupled to the battery; the second integrated device is coupled between the gate and the drain of the first integrated device, the source of the second integrated device being coupled to the gate of the first integrated device, the drain of the second integrated device being coupled to the drain of the first integrated device, and the gate of the second integrated device being controlled by the power source; and the transistor controlling the first integrated device has a first end controlled by the power source, a second end receiving a control signal for controlling the first integrated device, and a third end controlling the gate of the first integrated device.