Patent ID: 7405545

Claim:
A voltage-regulator having a current-sharing circuit, comprising at least an input terminal, an output terminal and an enabling terminal, wherein said enabling terminal enables or disables said voltage-regulator and provides a current-sharing control interface, comprising: a pass transistor, having a first terminal connected to said input terminal of said voltage-regulator to receive an input voltage; a second terminal connected to said output terminal of said voltage-regulator to provide an output voltage and an output current to said output terminal; and a third terminal; a band-gap unit, for generating a reference voltage; a feedback control circuit, coupled to said output terminal of said voltage-regulator and said pass transistor for detecting said output current, outputting a current-sense signal in response to said output current, and regulating and outputting a control signal to said third terminal of said pass transistor for controlling said voltage-regulator in response to a reference signal; and a current-sharing unit, coupled to said enabling terminal and said feedback control circuit for generating a bus signal in response to said current-sense signal and said reference voltage and generating said reference signal in response to said reference voltage, said bus signal and said current-sense signal, wherein said current-sharing unit comprises: a pull-up voltage unit, for generating a pull-up voltage according to said reference voltage; a pull-up resistor, coupled between said pull-up voltage unit and said enabling terminal; a current generating unit, for generating a first current signal and a second current signal in response to said current-sense signal; an input unit, coupled to said enabling terminal for generating a third current signal in response to said pull-up voltage and said bus signal; an output unit, coupled to said enabling terminal for generating said bus signal in response to said second current signal and said pull-up voltage; and a regulating unit, coupled to said input unit and said current generating unit for generating and regulating said reference signal in response to said reference voltage, said first current signal and said third current signal.