Paralleling voltage regulators
AssigneeLinear Technology Corporation
InventorRobert C. Dobkin
Life of this patent
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Abstract
Circuits and methods for paralleling voltage regulators are provided. Improved current sharing and regulation characteristics are obtained by coupling control terminals of the voltage regulators together which results in precise output voltages and proportional current production. Distributing current generation among multiple paralleled voltage regulators improves heat dissipation and thereby reduces the likelihood that the current produced by the voltage regulators will be temperature limited.
Claims47
A method of coupling two or more voltage regulators in parallel to provide a combined output current, the method comprising:
- providing a first voltage regulator that generates a substantially constant voltage, the first voltage regulator having a power output stage;
- the power output stage having a control input and an output;
- providing a second voltage regulator that generates a substantially constant voltage, the second voltage regulator having a power output stage;
- the power output stage having a control input and an output;
- coupling the control input of the first voltage regulator output stage to the control input of the second voltage regulator output stage such that the voltage at an output of the first voltage regulator and an output of the second voltage regulator is substantially equal;
- and
- coupling the output of the first voltage regulator to the output of the second voltage regulator in parallel such that the combined output current produced is substantially equal to the sum of current produced by the first voltage regulator and the second voltage regulator.
A device that provides a substantially constant output voltage suitable for coupling to one or more devices in parallel to provide a combined output current, the device comprising:
- a first voltage regulator that generates a substantially constant voltage, the first voltage regulator having a power output stage;
- the first voltage regulator power output stage having a control input and an output;
- wherein the control input of the first voltage regulator power output stage is configured to be coupled to a second voltage regulator, which causes a voltage at the output of the first voltage regulator to be substantially equal to a voltage at an output of the second voltage regulator;
- and which causes an output current produced by the first voltage regulator through a first ballast impedance to be proportional to an output current of produced by the second voltage regulator through a second ballast impedance.
A voltage regulator disposed on an integrated circuit that provides a substantially constant output voltage suitable for coupling to one or more voltage regulators in parallel to provide a combined output current, the voltage regulator circuit comprising:
- a current reference circuit for providing a substantially constant output current;
- a set impedance coupled to the current reference circuit for generating a substantially constant set voltage from the substantially constant output current;
- an amplifier circuit coupled to the current reference circuit and the set impedance that generates a substantially constant output voltage based on the set voltage, and;
- a ballast impedance coupled to the output of the amplifier circuit for establishing an output impedance of the voltage regulator circuit.
Dependencies are inferred from the claim text.