Step-down regulator

摘要

The step-down regulator includes a first error amplifying circuit that receives a first reference voltage and the first voltage and supplies a first control signal to a control terminal of the first transistor so that the first reference voltage and the first voltage are equal to each other. The step-down regulator includes a second error amplifying circuit that receives a voltage at the second end of the current controlling circuit and a second reference voltage and supplies a second control signal to the current controlling circuit so that the voltage at the second end of the current controlling circuit and the second reference voltage are equal to each other. The step-down regulator includes a diode that is connected to the second end of the current controlling circuit at an anode thereof and to the second potential at a cathode thereof.

主权项

1. A step-down regulator, comprising:
a first transistor connected to a first potential at a first end thereof; a voltage generating circuit that is connected between a second end of the first transistor and a second potential lower than the first potential and outputs a first voltage that is based on a voltage at the second end of the first transistor; a first error amplifying circuit that receives a first reference voltage and the first voltage and supplies a first control signal to a control terminal of the first transistor so that the first reference voltage and the first voltage are equal to each other; an output terminal at which an output voltage is output; a second transistor that is connected to the first potential at a first end thereof, to the output terminal at a second end and to the control terminal of the first transistor at a control terminal thereof and receives the first control signal at the control terminal thereof; a current controlling circuit that is connected to the output terminal at a first end thereof and is capable of controlling a current that flows between the first end thereof connected to the output terminal and a second end thereof; a second error amplifying circuit that receives a voltage at the second end of the current controlling circuit and a second reference voltage and supplies a second control signal to the current controlling circuit so that the voltage at the second end of the current controlling circuit and the second reference voltage are equal to each other; a diode that is connected to the second end of the current controlling circuit at an anode thereof and to the second potential at a cathode thereof; and a linear load that is connected in parallel with the diode between the second end of the current controlling circuit and the second potential.