Patent ID: 8072186

Claim:
A USB charger circuit comprising: a converter having a first transistor; a control circuitry coupled to the first transistor, the control circuitry producing a drive signal to the first transistor; a first resistor coupled between an output node of the converter and a first node; a second resistor coupled between the first node and a second node; a second transistor having a gate coupled to a forth node, a source coupled to a third node, and a drain coupled to the second node; an error amplifier coupled to receive a voltage divided by the first resistor and the second resistor to compare to a reference voltage; a sense resistor coupled between the third node and ground; a fifth resistor coupled between the first node and ground; a first diode coupled between the output node of the converter and the first node; a second diode coupled between the output node of the converter and a forth node; and a forth resistor coupled between the forth node and the third node.