System and method for determining output current and converter employing the same
First Claim
1. For use with a power converter having an output capacitor and a component coupled thereto, a system for determining an output current of said power converter, comprising:
- an observer circuit, including one of a series-coupled capacitor and resistor, and a series-coupled resistor and inductor, parallel-coupled to said output capacitor that develops a capacitor signal representing a current through said output capacitor from a voltage observed across one of said resistor of said series-coupled capacitor and resistor, and said inductor of said series-coupled resistor and inductor;
a sensor circuit, coupled to said component, that senses a characteristic of said component and develops therefrom a component signal representing a current through said component; and
a summer circuit, coupled to said observer and sensor circuits, that derives an output signal representing said output current from said capacitor signal and said component signal.
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Accused Products
Abstract
A system and method for determining an output current of a power converter having an output capacitor and a component coupled thereto. In one embodiment, the system includes (1) an observer circuit, parallel-coupled to the output capacitor, that senses a voltage across the output capacitor and develops therefrom a capacitor signal representing a current through the output capacitor, (2) a sensor circuit, coupled to the component, that senses a characteristic of the component and develops therefrom a component signal representing a current through the component and (3) a summer circuit, coupled to the observer and sensor circuits, that derives an output signal representing the output current from the capacitor signal and the component signal.
148 Citations
25 Claims
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1. For use with a power converter having an output capacitor and a component coupled thereto, a system for determining an output current of said power converter, comprising:
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an observer circuit, including one of a series-coupled capacitor and resistor, and a series-coupled resistor and inductor, parallel-coupled to said output capacitor that develops a capacitor signal representing a current through said output capacitor from a voltage observed across one of said resistor of said series-coupled capacitor and resistor, and said inductor of said series-coupled resistor and inductor;
a sensor circuit, coupled to said component, that senses a characteristic of said component and develops therefrom a component signal representing a current through said component; and
a summer circuit, coupled to said observer and sensor circuits, that derives an output signal representing said output current from said capacitor signal and said component signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
a series-coupled capacitor and resistor; and
a series-coupled resistor and inductor.
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6. The system as recited in claim 1 wherein said sensor circuit is series-coupled to said component, said sensor circuit comprising an element selected from the group consisting of:
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a resistor; and
a current-sensing transformer.
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7. The system as recited in claim 1 further comprising a scaling circuit that adjusts a gain of said capacitor signal relative to said component signal.
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8. The system as recited in claim 1 further comprising a filter circuit that limits a bandwidth of said output signal.
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9. For use with a power converter having an output capacitor and a component coupled thereto, a method of determining an output current of said power converter, comprising:
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developing a capacitor signal representing a current through said output capacitor from a voltage observed across one of a resistor of an observer circuit having a capacitor series-coupled to said resistor and an inductor of an observer circuit having a resistor series-coupled to said inductor;
sensing a characteristic of said component and developing therefrom a component signal representing a current through said component; and
deriving an output signal representing said output current from said capacitor signal and said component signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
a series-coupled capacitor and resistor; and
a series-coupled resistor and inductor.
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14. The method as recited in claim 9 wherein said sensing said characteristic is performed by a sensor circuit series-coupled to said component, said sensor circuit comprising an element selected from the group consisting of:
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a resistor; and
a current-sensing transformer.
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15. The method as recited in claim 9 further comprising adjusting a gain of said capacitor signal relative to said component signal.
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16. The method as recited in claim 9 further comprising limiting a bandwidth of said output signal.
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17. A power converter, comprising:
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a power switching circuit;
a rectifier, coupled to said power switching circuit;
an output filter coupled between said rectifier and an output of said power converter and having an output capacitor and a component coupled thereto; and
a system for determining an output current of said power converter, including;
an observer circuit, including one of a series-coupled capacitor and resistor, and a series-coupled resistor and inductor, parallel-coupled to said output capacitor that develops a capacitor signal representing a current through said output capacitor from a voltage observed across one of said resistor of said series-coupled capacitor and resistor, and said inductor of said series-coupled resistor and inductor;
a sensor circuit, coupled to said component, that senses a characteristic of said component and develops therefrom a component signal representing a current through said component; and
a summer circuit, coupled to said observer and sensor circuits, that derives an output signal representing said output current from said capacitor signal and said component signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
a series-coupled capacitor and resistor; and
a series-coupled resistor and inductor.
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22. The power converter as recited in claim 17 wherein said sensor circuit is series-coupled to said component, said sensor circuit comprising an element selected from the group consisting of:
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a resistor; and
a current-sensing transformer.
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23. The power converter as recited in claim 17 wherein said system further comprises a scaling circuit that adjusts a gain of said capacitor signal relative to said component signal.
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24. The power converter as recited in claim 17 wherein said system further comprises a filter circuit that limits a bandwidth of said output signal.
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25. The power converter as recited in claim 17 further comprising a transformer having a primary winding coupled to said power switching circuit and a secondary winding coupled to said rectifier.
Specification