Patent ID: 8487692

Claim:
A charging circuit comprising: a driver circuit for receiving an input voltage to generate an initiation current; a first current mirror comprising: a first branch circuit for generating a first conduction current according to the input voltage and the initiation current; a second branch circuit for generating a second conduction current according to the input voltage and the initiation current; and a third branch circuit for generating a third conduction current according to the input voltage and the initiation current; a second current mirror comprising: a fourth branch circuit coupled to the first branch circuit and comprising a first channel width; and a fifth branch circuit coupled to the second branch circuit and comprising a second channel width; a third current mirror coupled to the first current mirror and comprising a sixth branch circuit and a seventh branch circuit for receiving the input voltage; a switch transistor coupled to the second branch circuit of the first current mirror and the sixth branch circuit of the third current mirror for determining a conduction condition of the switch transistor according to a switch signal; a first resistor comprising a first resistance, one end coupled to the switch transistor and another end grounded; and a second resistor comprising a second resistance, one end coupled to the seventh branch circuit of the third current mirror and another end grounded; wherein the first current mirror and the second current mirror are utilized to correspondingly adjust values of the first conduction current, the second conduction current and the third conduction current according to the first channel width as well as the second channel width, or the third current mirror is utilized to process the charging operation of the load circuit according to the first resistance as well as the second resistance.