LOW-DROP REGULATOR APPARATUS AND BUFFER STAGE CIRCUIT HAVING HIGHER VOLTAGE TRANSITION RATE

摘要

A low-drop regulator (LDO) apparatus includes an operational amplifier, a buffer stage circuit, and a power transistor. The operational amplifier is used for receiving a reference voltage and a feedback voltage to generate a first voltage. The buffer stage circuit is coupled to the power transistor and the operational amplifier and used for buffering the first voltage to generate a second voltage. The power transistor is coupled to the buffer stage circuit and used for generating an output voltage according to the second voltage wherein the output voltage is proportional to the feedback voltage. In addition, the buffer stage circuit is arranged to determine whether to mirror and generate a mirrored current according to the first voltage and to generate the second voltage for providing the second voltage to the power transistor to control on/off state of the power transistor when the mirrored current is generated.

主权项

1. A low-drop (LDO) regulator apparatus, comprising:
an operational amplifier, for receiving a reference voltage and a feedback voltage to generate a first voltage signal; a buffer stage circuit, coupled to a power transistor, for buffering the first voltage signal to generate a second voltage signal; and the power transistor, coupled to the buffer stage circuit, for generating an output voltage according to the second voltage signal, the output voltage being proportional to the feedback voltage; wherein the buffer stage circuit is arranged to determine whether to mirror and generate a mirrored current according to the first voltage signal, and to generate the second voltage signal for providing the second voltage signal to the power transistor to control on/off state of the power transistor according to the first voltage signal when the mirrored current is generated.