Dual buck-boost converter with single inductor
AssigneeTexas Instruments Incorporated
InventorsRussell M. Kinder, Marco Corsi
Life of this patent
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Abstract
A dual output buck-boost power converter operates with a single inductor to achieve high efficiency with automatic or inherent load balancing. Switches associated with the opposite polarity outputs are driven based on feedback signals, with one feedback signal being a reference voltage and another feedback signal being related to an opposite polarity output. The opposite polarity feedback signal is provided to a comparator with a reversed polarity to achieve a simple balanced control that maintains polarity outputs. The power converter delivers power to each output with each switching cycle and uses a single inductor to achieve high efficiency performance.
Claims6
A power converter circuit, comprising:
- (a) first and second inputs for connection to first and second input voltage sources, respectively;
- (b) first and second nodes for connection to terminals of an inductor;
- (c) a first switch between said first input and said first node;
- (d) a second switch between said second input and said second node;
- (e) first and second power outputs coupled to said first and second nodes, respectively;
- and
- (f) a controller for said first and second switches, said controller operable to control said first switch in response to a first error signal determined by a voltage at said first output and a reference voltage, and said controller operable to control said second switch in response to a second error signal determined by said voltage at said first output and a voltage at said second output.
A dual buck-boost converter, comprising:
- (a) first and second inputs connected to negative polarity and positive polarity input voltage sources, respectively;
- (b) first and second nodes connected to terminals of an inductor;
- (c) a first switch between said first input and said first node;
- (d) a second switch between said second input and said second node;
- (e) positive polarity and negative polarity power outputs connected through first and second diodes to said first and second nodes, respectively;
- and
- (f) a controller for said first and second switches, said controller operable to control said first switch in response to a first error signal determined by a voltage at said positive polarity output and a reference voltage, and said controller operable to control said second switch in response to a second error signal determined by said voltage at said positive polarity output and a voltage at said negative polarity output.
A method of power conversion, comprising the steps of:
- (a) determining a first error voltage as VREF−β*VOUT+ where VREF is a reference voltage, β is a feedback factor, and VOUT+ is the voltage at a positive polarity output;
- (b) determining a second error voltage as −β*VOUT−−β*VOUT+ where VOUT− is the voltage at a negative polarity output;
- (c) using said first error voltage to drive a first voltage-to-duty-cycle converter to control a first switch where said first switch connects a negative polarity input to a first terminal of an inductor and through a diode to said positive polarity output;
- and
- (d) using said second error voltage to drive a second voltage-to-duty-cycle converter to control a second switch where said second switch connects a positive polarity input to a second terminal of said inductor and through a diode to said negative polarity output.
Dependencies are inferred from the claim text.