Capless low drop-out voltage regulator having discharge circuit compensating for on-chip output capacitance and response time

Abstract

A voltage regulator is provided having one or more discharger circuits that compensate for low on-chip output capacitance and a slow loop response time. In one embodiment, the voltage regulator includes an output transistor coupled to an output voltage line, an output voltage sensing arrangement coupled to the output voltage line for producing an output feedback voltage, and an error amplifier coupled to the output feedback voltage, the output transistor, and a reference voltage for applying feedback control to the output transistor. A first discharger circuit is coupled to the output voltage line and to a reference potential, the first discharger circuit being triggered by a steep-rise overvoltage condition. In another embodiment, a combination of fast and slow discharger circuits is used to improve the load step response—i.e., to stop the output voltage from jumping too high and to pull it back to stable value very quickly, such that the load circuits are protected.