Multi-stage voltage regulator
AssigneeSeiko Instruments Inc.
InventorTakashi Imura
Life of this patent
Estimating the term…
Abstract
Provided is a voltage regulator capable of reducing an influence of an offset to obtain an accurate output voltage. The voltage regulator includes: a first stage amplifier for amplifying and outputting a difference between a reference voltage and a divided voltage obtained by dividing a voltage output by an output transistor, to thereby control a gate of the output transistor; and a cascode amplifier circuit, in which the first stage amplifier includes: a first high breakdown voltage NMOS transistor as an input transistor; and an NMOS transistor as a tail current source, and in which the cascode amplifier circuit includes a second high breakdown voltage NMOS transistor as a cascode transistor.
Claims18
A voltage regulator, comprising:
- an output transistor operable to adjust an output voltage of the voltage regulator;
- a first stage amplifier operable to amplify and output a first stage output signal representing a difference between a reference voltage and a divided voltage obtained by dividing the output voltage;
- and
- a second stage amplifier comprising a transistor coupled in series with a cascode amplifier circuit, the second stage amplifier operable to receive the first stage output signal and generate a second stage output signal to control the output transistor as a function of the first stage output signal,
- wherein the first stage amplifier comprises:
- a first high breakdown voltage NMOS transistor as an input transistor;
- and
- an NMOS transistor as a tail current source, and
- wherein the cascode amplifier circuit comprises a second high breakdown voltage NMOS transistor as a cascode transistor.
A voltage regulator, comprising:
- a reference voltage supply terminal;
- a first stage amplifier coupled with the reference voltage supply terminal;
- a second stage amplifier comprising a transistor coupled with an output of the first stage amplifier, and a cascode amplifier circuit coupled with the reference voltage supply terminal;
- an output transistor coupled with an output of the second stage amplifier;
- an output terminal coupled with the output transistor, the output terminal providing an output voltage of the voltage regulator;
- a voltage divider operable to divide the output voltage, the voltage divider coupled with the output terminal and the first stage amplifier, the first stage amplifier operable to provide, as the output of the first stage amplifier, a difference between the reference voltage and the divided output voltage, and the second stage amplifier is operable to control the output transistor to adjust the output voltage based on the output of the first stage amplifier.
A voltage regulator, comprising:
- an output terminal coupled with an output transistor, an output voltage of the voltage regulator provided on the output terminal;
- a voltage divider coupled with the output terminal, the voltage divider operable to divide the output voltage;
- a first stage amplifier coupled with voltage divider and a reference voltage supply terminal, an output of the first stage amplifier being a difference signal representative of a difference between the divided output voltage and a reference voltage present on the reference voltage supply terminal;
- and
- a second stage amplifier coupled to the output of the first stage amplifier and the output transistor, the second stage amplifier comprising a cascode amplifier circuit coupled with the reference voltage terminal, the second stage amplifier operable to generate an output signal based on the difference signal to control the output transistor to adjust the output voltage.
Dependencies are inferred from the claim text.