Single feedback input for regulation at both positive and negative voltage levels
AssigneeLinear Technology Corporation
InventorAlbert Wu
Life of this patent
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Abstract
A voltage regulator provides a regulated output load voltage at either a positive level or an inverted level relative to an input supply voltage. A switching circuit and control circuit are formed on an integrated circuit having a single pin for coupling to regulator feedback signal. The feedback signal is applied directly to the feedback pin during both positive voltage level regulation and inverted voltage level regulation. The feedback signal may be produced by a feedback circuit comprising an impedance element formed in the integrated circuit.
Claims16
A voltage converter comprising:
- a switching circuit having an input node coupled to receive a supply voltage;
- regulator circuitry coupled to the switching circuit, the regulator circuitry selectively configurable to provide at an output node a regulated load voltage either with the same polarity as the supply voltage or with an inverted polarity relative to the supply voltage;
- a control circuit comprising an input node and a control signal output node coupled to the control input of the switching circuit to provide a control signal thereto;
- and
- a feedback circuit comprising a feedback node having a voltage level related to the load voltage, the feedback node directly coupled to the control circuit input node for regulation at both the same voltage polarity and inverted voltage polarity relative to the polarity of the supply voltage;
- wherein the control signal is proportional to load current.
A method for controlling a voltage regulator that is selectively configurable to provide a regulated output load voltage either with the same polarity as the supply voltage or with an inverted polarity relative to the supply voltage, the method comprising the steps of:
- deriving a feedback signal that varies with load voltage;
- generating a control signal that is variable proportionately with load current;
- and
- applying the control signal to a switching circuit of the regulator;
- wherein the generating step comprises:
- supplying a control current from a current source to a control circuit of the switching circuit;
- diverting the current source current from the control circuit when the voltage of the feedback signal is greater than a first reference voltage and when the voltage of the feedback signal is less than a second reference voltage.
Dependencies are inferred from the claim text.