Circuit and method for controlling a synchronous rectifier converter
First Claim
1. A power supply, comprising:
- switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; and
synchronous rectifier control circuitry capable of enabling and disabling said switching circuitry as a function of a characteristic associated with said power supply and adapted to transition said switching circuitry from said active bi-directional mode to said inactive unidirectional mode of operation by gradually decreasing a conduction interval of said at least one synchronous rectifier device thereby reducing a disruption in an output of said power supply while said switching circuitry is transitioning from said active bi-directional mode to said inactive unidirectional mode of operation.
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Accused Products
Abstract
For use in a power system having a power train, a rectifier having an input and an output and a method of controlling the rectifier. The rectifier comprises: (1) switching circuitry coupled between the input and the output, the switching circuitry adapted to operate in selected one of (a) a bidirectional mode of operation and (b) an unidirectional mode of operation to rectify substantially alternating current at the input to produce substantially direct current at the output; and (2) control circuitry coupled to a control input of the switching circuitry, the control circuitry capable of sensing a characteristic of the power system and transitioning the switching circuitry between the bidirectional mode and the unidirectional mode as a function of the characteristic thereby to prevent substantial reverse power flow through the rectifier.
175 Citations
54 Claims
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1. A power supply, comprising:
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switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; and synchronous rectifier control circuitry capable of enabling and disabling said switching circuitry as a function of a characteristic associated with said power supply and adapted to transition said switching circuitry from said active bi-directional mode to said inactive unidirectional mode of operation by gradually decreasing a conduction interval of said at least one synchronous rectifier device thereby reducing a disruption in an output of said power supply while said switching circuitry is transitioning from said active bi-directional mode to said inactive unidirectional mode of operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A power supply, comprising:
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switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; and synchronous rectifier control circuitry capable of enabling and disabling said switching circuitry as a function of a characteristic associated with said power supply and adapted to transition said switching circuitry from said inactive unidirectional mode to said active bi-directional mode of operation by gradually increasing a conduction interval of said at least one synchronous rectifier device thereby reducing a disruption in an output of said power supply while said switching circuitry is transitioning from said inactive unidirectional mode to said active bi-directional mode of operation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for controlling a synchronous rectifier circuit in a power supply, comprising:
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providing switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; and employing synchronous rectifier control circuitry to enable and disable said switching circuitry as a function of a characteristic associated with said power supply and transition said switching circuitry between said active bi-directional mode to said inactive unidirectional mode of operation by gradually varying a conduction interval of said at least one synchronous rectifier device thereby reducing a disruption in an output of said power supply while said switching circuitry is transitioning between said active bi-directional mode and said inactive unidirectional mode of operation. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A power supply, comprising:
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switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; a timing circuit capable of developing a control signal as a function of a time period of said power supply; and synchronous rectifier control circuitry capable of enabling and disabling said switching circuitry as a function of a characteristic associated with said power supply and adapted to employ said control signal to disable said at least one synchronous rectifier device during a substantial portion of a start-up period of said power supply thereby to prevent substantial reverse power flow through said power supply. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for controlling a synchronous rectifier circuit in a power supply, comprising:
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providing switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; developing a control signal with a timing circuit as a function of a time start-up period of said power supply; and employing synchronous rectifier control circuitry to enable and disable said switching circuitry as a function of a characteristic associated with said power supply and apply said control signal to disable said at least one synchronous rectifier device during a substantial portion of a start-up period of said power supply thereby to prevent substantial reverse power flow through said power supply. - View Dependent Claims (35, 36, 37, 38, 39)
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40. A power supply, comprising:
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at least one power switch that continuously and periodically conducts at a duty cycle (D) to couple an input of said power supply to a source of electrical power; switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; a sensor capable of sensing said duty cycle (D) of said at least one power switch; a level detector capable of comparing said duty cycle (D) with a threshold duty cycle and developing a control signal in accordance therewith; and synchronous rectifier control circuitry, coupled to said level detector, capable of enabling and disabling said switching circuitry as a function of a characteristic associated with said power supply and adapted to employ said control signal to disable said at least one synchronous rectifier device when said duty cycle (D) drops below said threshold duty cycle thereby to prevent substantial reverse power flow through said power supply. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48)
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49. A method for controlling a synchronous rectifier circuit in a power supply, comprising:
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employing at least one power switch that continuously and periodically conducts at a duty cycle (D) to couple an input of said power supply to a source of electrical power; providing switching circuitry including at least one synchronous rectifier device and adapted to operate in a selected one of (a) an active bi-directional mode of operation when enabled and (b) an inactive unidirectional mode of operation when disabled, said switching circuitry thereby rectifying substantially alternating current to produce substantially direct current; sensing said duty cycle (D) of said at least one power switch; comparing said duty cycle (D) with a threshold duty cycle and developing a control signal in accordance therewith; and employing synchronous rectifier control circuitry to enable and disable said switching circuitry as a function of a characteristic associated with said power supply and apply said control signal to disable said at least one synchronous rectifier device when said duty cycle (D) drops below said threshold duty cycle thereby to prevent substantial reverse power flow through said power supply. - View Dependent Claims (50, 51, 52, 53, 54)
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Specification