US6191964B1 — Circuit and method for controlling a synchronous …

Claim 1

Independent Claim 104 words

For use with a power converter including a synchronous rectifier circuit having switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current, a control circuit, comprising: a sensor capable of sensing a characteristic of said power converter; comparison circuitry capable of comparing said characteristic with a reference and developing a control signal in accordance therewith; and synchronous rectifier control circuitry, coupled to said comparison circuitry, adapted to disable said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 2

Dependent Claim 104 words

For use with a power converter including a synchronous rectifier circuit having switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current, a control circuit, comprising: a sensor capable of sensing a characteristic of said power converter; comparison circuitry capable of comparing said characteristic with a reference and developing a control signal in accordance therewith; and synchronous rectifier control circuitry, coupled to said comparison circuitry, adapted to disable said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 3

Dependent Claim 48 words

The control circuit as recited in claim 1 wherein said power converter, further comprises: a power transformer having primary and secondary windings, said secondary winding being coupled to said switching circuitry; and at least one power switch occasionally coupling said primary winding to a source of electrical power.

Claim 4

Dependent Claim 46 words

The control circuit as recited in claim 2 wherein said power converter further comprises a clamping circuit, coupled to said power transformer, adapted to limit a voltage across said transformer during at least a portion of a non-conduction interval of said at least one power switch.

Claim 5

Dependent Claim 37 words

The control circuit as recited in claim 1 wherein said synchronous rectifier control circuitry is adapted to disable said at least one synchronous rectifier device during one of a start-up and shut-down period of said power converter.

Claim 6

Dependent Claim 47 words

The control circuit as recited in claim 1 wherein said power converter is parallel-coupled to a second power converter, said synchronous rectifier control circuitry adapted to disable said at least one synchronous rectifier device thereby preventing said second power converter from causing said substantial reverse power flow.

Claim 7

Dependent Claim 28 words

The control circuit as recited in claim 5 further comprising an active load-sharing circuit adapted to effect load sharing between said power converter and said second power converter.

Claim 8

Dependent Claim 18 words

The control circuit as recited in claim 1 wherein said switching circuitry comprises at least one discrete diode.

Claim 9

Dependent Claim 52 words

The control circuit as recited in claim 1 wherein said sensor is selected from the group consisting of: a current transformer in electrical communication with an output of said power converter; a resistor in electrical communication with said output; and a Hall effect current sense device coupled in series with said output.

Claim 10

Dependent Claim 35 words

The control circuit as recited in claim 1 wherein said switching circuitry comprises a plurality of synchronous rectifier devices, said synchronous rectifier control circuitry adapted to disable all of said plurality of synchronous rectifier devices.

Claim 11

Dependent Claim 56 words

The control circuit as recited in claim 1 further comprising detection circuitry capable of detecting parallel operation between said power converter and a second power converter, said detection circuitry allowing said synchronous rectifier control circuitry to disable said at least one synchronous rectifier device only when said power converter is parallel-coupled to said second power converter.

Claim 12

Dependent Claim 90 words

For use with a power converter including a synchronous rectifier circuit having switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current, a method for controlling said synchronous rectifier circuit, comprising: sensing a characteristic of said power converter; comparing said characteristic with a reference and developing a control signal in accordance therewith; and disabling said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 13

Dependent Claim 90 words

For use with a power converter including a synchronous rectifier circuit having switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current, a method for controlling said synchronous rectifier circuit, comprising: sensing a characteristic of said power converter; comparing said characteristic with a reference and developing a control signal in accordance therewith; and disabling said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 14

Dependent Claim 47 words

The method as recited in claim 11 wherein said power converter, further comprises: a power transformer having primary and secondary windings, said secondary winding being coupled to said switching circuitry; and at least one power switch occasionally coupling said primary winding to a source of electrical power.

Claim 15

Dependent Claim 46 words

The method as recited in claim 12 wherein said power converter further comprises a clamping circuit, coupled to said power transformer, adapted to limit a voltage across said power transformer during at least a portion of a non-conduction interval of said at least one power switch.

Claim 16

Dependent Claim 30 words

The method as recited in claim 11 wherein said disabling said at least one synchronous rectifier device occurs during one of a start-up and shut-down period of said power converter.

Claim 17

Dependent Claim 40 words

The method as recited in claim 11 wherein said power converter is parallel-coupled to a second power converter, said disabling said at least one synchronous rectifier device thereby preventing said second power converter from causing said substantial reverse power flow.

Claim 18

Dependent Claim 30 words

The method as recited in claim 15 wherein said power converter further comprises an active load-sharing circuit that effects load sharing between said power converter and said second power converter.

Claim 19

Dependent Claim 17 words

The method as recited in claim 11 wherein said switching circuitry comprises at least one discrete diode.

Claim 20

Dependent Claim 55 words

The method as recited in claim 11 wherein said sensing is performed by a sensor selected from the group consisting of: a current transformer in electrical communication with an output of said power converter; a resistor in electrical communication with said output; and a Hall effect current sense device coupled in series with said output.

Claim 21

Dependent Claim 37 words

The method as recited in claim 11 wherein said switching circuitry comprises a plurality of synchronous rectifier devices, said disabling further disabling all of said plurality of synchronous rectifier devices as said function of said control signal.

Claim 22

Dependent Claim 29 words

The method as recited in claim 11 wherein said power converter further comprises detection circuitry capable of detecting parallel operation between said power converter and a second power converter.

Claim 23

Dependent Claim 150 words

A power converter having an input and an output, comprising: at least one power switch coupled to said input; a power transformer having primary and secondary windings, said primary winding coupled to said at least one power switch; a synchronous rectifier circuit, interposed between said secondary winding and said output, including switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current; and a control circuit, coupled to said synchronous rectifier circuit, including: a sensor capable of sensing a characteristic of said power converter, comparison circuitry capable of comparing said characteristic with a reference and developing a control signal in accordance therewith, and synchronous rectifier control circuitry, coupled to said comparison circuitry, adapted to disable said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 24

Dependent Claim 150 words

A power converter having an input and an output, comprising: at least one power switch coupled to said input; a power transformer having primary and secondary windings, said primary winding coupled to said at least one power switch; a synchronous rectifier circuit, interposed between said secondary winding and said output, including switching circuitry with at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current; and a control circuit, coupled to said synchronous rectifier circuit, including: a sensor capable of sensing a characteristic of said power converter, comparison circuitry capable of comparing said characteristic with a reference and developing a control signal in accordance therewith, and synchronous rectifier control circuitry, coupled to said comparison circuitry, adapted to disable said at least one synchronous rectifier device as a function of said control signal to thereby prevent substantial reverse power flow through said power converter.

Claim 25

Dependent Claim 43 words

The power converter as recited in claim 21 further comprising a clamping circuit, coupled to said power transformer, adapted to limit a voltage across said power transformer during at least a portion of a non-conduction interval of said at least one power switch.

Claim 26

Dependent Claim 37 words

The power converter as recited in claim 21 wherein said synchronous rectifier control circuitry is adapted to disable said at least one synchronous rectifier device during one of a start-up and shut-down period of said power converter.

Claim 27

Dependent Claim 47 words

The power converter as recited in claim 21 wherein said power converter is parallel-coupled to a second power converter, said synchronous rectifier control circuitry adapted to disable said at least one synchronous rectifier device thereby preventing said second power converter from causing said substantial reverse power flow.

Claim 28

Dependent Claim 32 words

The power converter as recited in claim 21 wherein said control circuit further comprises an active load-sharing circuit adapted to effect load sharing between said power converter and said second power converter.

Claim 29

Dependent Claim 18 words

The power converter as recited in claim 21 wherein said switching circuitry comprises at least one discrete diode.

Claim 30

Dependent Claim 48 words

The power converter as recited in claim 21 wherein said sensor is selected from the group consisting of: a current transformer in electrical communication with said output; a resistor in electrical communication with said output; and a Hall effect current sense device coupled in series with said output.

Claim 31

Dependent Claim 35 words

The power converter as recited in claim 21 wherein said switching circuitry comprises a plurality of synchronous rectifier devices, said synchronous rectifier control circuitry adapted to disable all of said plurality of synchronous rectifier devices.

Claim 32

Dependent Claim 60 words

The power converter as recited in claim 21 wherein said control circuit further comprises detection circuitry capable of detecting parallel operation between said power converter and a second power converter, said detection circuitry allowing said synchronous rectifier control circuitry to disable said at least one synchronous rectifier device only when said power converter is parallel-coupled to said second power converter.

Claim 33

Dependent Claim 24 words

The power converter as recited in claim 21 further comprising an output capacitor and inductor interposed between said synchronous rectifier circuit and said output.

Claim 34

Dependent Claim 116 words

A power system having first and second power converters, each of said first and second converters, comprising: a synchronous rectifier circuit including switching circuitry having at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current; a control circuit, coupled to said switching circuitry, adapted to control said at least one synchronous rectifier device as a function of a characteristic of said power system thereby to prevent one of said first and second power converters from creating substantial reverse power flow through another of said first and second power converters; and an active load-sharing circuit coupled to said first and second power converters adapted to effect load sharing therebetween.

Claim 35

Dependent Claim 116 words

A power system having first and second power converters, each of said first and second converters, comprising: a synchronous rectifier circuit including switching circuitry having at least one synchronous rectifier device and adapted to rectify substantially alternating current to produce substantially direct current; a control circuit, coupled to said switching circuitry, adapted to control said at least one synchronous rectifier device as a function of a characteristic of said power system thereby to prevent one of said first and second power converters from creating substantial reverse power flow through another of said first and second power converters; and an active load-sharing circuit coupled to said first and second power converters adapted to effect load sharing therebetween.

Claim 36

Dependent Claim 53 words

The power system as recited in claim 31 wherein each of said first and second power converters, further comprises: a power transformer having primary and secondary windings, said secondary winding being coupled to said switching circuitry; and at least one power switch occasionally coupling said primary winding to a source of electrical power.

Claim 37

Dependent Claim 51 words

The power system as recited in claim 32 wherein each of said first and second power converters further comprises a clamping circuit, coupled to said power transformer, adapted to limit a voltage across said transformer during at least a portion of a non-conduction interval of said at least one power switch.

Claim 38

Dependent Claim 35 words

The power system as recited in claim 31 wherein said control circuit is adapted to disable said at least one synchronous rectifier device during one of a start-up and shut-down period of said power system.

Claim 39

Dependent Claim 46 words

The power system as recited in claim 31 wherein said first power converter is parallel-coupled to said second power converter, said control circuit adapted to control said at least one synchronous rectifier device thereby preventing said second power converter from causing said substantial reverse power flow.

Claim 40

Dependent Claim 24 words

The power system as recited in claim 31 said at least one synchronous rectifier device is a metal oxide semiconductor field effect transistor (MOSFET).

Claim 41

Dependent Claim 18 words

The power system as recited in claim 31 wherein said switching circuitry comprises at least one discrete diode.

Claim 42

Dependent Claim 64 words

The power system as recited in claim 31 wherein said control circuit includes a sensor adapted to measure said characteristic of said power system selected from the group consisting of: a current transformer in electrical communication with an output of said power system; a resistor in electrical communication with said output; and a Hall effect current sense device coupled in series with said output.

Claim 43

Dependent Claim 33 words

The power system as recited in claim 31 wherein said switching circuitry comprises a plurality of synchronous rectifier devices, said control circuit adapted to control all of said plurality of synchronous rectifier devices.

Claim 44

Dependent Claim 53 words

The power system as recited in claim 31 further comprising detection circuitry capable of detecting parallel operation between said first and second power converters, said detection circuitry allowing said control circuit to control said at least one synchronous rectifier device only when said first power converter is parallel-coupled to said second power converter.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2004-02-20	2004-08-21	2005-02-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2008-02-20	2008-08-21	2009-02-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2012-02-20	2012-08-21	2013-02-20	$7700.00	Window Closed / Lapsed

Circuit and method for controlling a synchronous rectifier converter

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