Bandgap reference having power supply ripple rejection
AssigneeAnalog Devices, Inc.
InventorsCarl W. Moreland, Marvin J. Young
Life of this patent
Estimating the term…
Abstract
A bandgap reference circuit provides an output reference voltage that is generally insensitive to fluctuations in supply voltage, ambient temperature, and output load current. A current regulator establishes an output whose variations are reduced, preferably logarithmically, relative to variations in a supply voltage. A bandgap generator fed by the output current provides an output reference voltage with similarly suppressed variations. A control amplifier biases the bandgap generator to provide a high level common-mode rejection of various error sources.
Claims14
A voltage regulator that provides a regulated output voltage, comprising:
- a current regulator that provides a regulated current;
- a bandgap reference generator that includes first and second transistors which respectively have first and second current terminals that respectively respond to coupled first and second control terminals wherein said bandgap reference generator receives a first portion of said regulated current and generates a reference voltage on said coupled first and second control terminals;
- a control amplifier that receives a second portion of said regulated current and varies the magnitude of said second portion in response to a voltage difference between said first and second current terminals;
- and
- a buffer output circuit that receives a third portion of said regulated current, provides said regulated output voltage and couples a portion of said regulated output voltage to said coupled first and second control terminals.
A voltage regulator that provides a regulated output voltage, comprising:
- a current regulator that provides a regulated current;
- a bandgap reference generator that includes first and second transistors which respectively have first and second current terminals that respectively respond to coupled first and second control terminals wherein said bandgap reference generator receives a first portion of said regulated current and generates a reference voltage on said coupled first and second control terminals;
- and
- a feedback circuit that generates said regulated output voltage and couples a portion of said regulated output voltage to said coupled first and second control terminals in response to a difference voltage between said first and second current terminals wherein said feedback circuit includes:
- a) a control amplifier that receives a first portion of said regulated current and varies said first portion in response to said difference voltage;
- b) a voltage divider;
- and
- c) a buffer transistor that receives a second portion of said regulated current and drives said voltage divider to generate said regulated output voltage across said voltage divider and couple a portion of said regulated output voltage from said voltage divider to said coupled first and second control terminals.
Dependencies are inferred from the claim text.