Patent ID: 7626367

Claim:
An integrated circuit for providing an output voltage substantially equal to a reference voltage, the integrated circuit comprising: a low drop-out (LDO) regulator coupled to the reference voltage for producing the output voltage at an output terminal; a fast turn-on circuit coupled to the LDO regulator for quickly supplying an output current at the output terminal according to a first control signal; and a fast turn-off circuit coupled to the LDO regulator for quickly drawing a discharge current from the output terminal according to a second control signal; wherein the fast turn-on circuit comprises a charge current source for supplying the output current to the output terminal according to the first control signal, and for modulating supply of the output current according to a third control signal; and the charge current source comprises: a reference current source having a first end and a second end for providing a predetermined reference current; a first transistor having a first terminal coupled to a first supply voltage, and a second terminal coupled to a control terminal of the first transistor; a first switch for selectively coupling the second terminal of the first transistor to the first end of the reference current source according to the first control signal; a second switch for selectively coupling the second end of the reference current source to a second supply voltage according to the third control signal; and a second transistor having a first terminal coupled to the first supply voltage, a control terminal coupled to the control terminal of the first transistor, and a second terminal coupled the output voltage.