CONTROL CIRCUIT FOR SYNCHRONOUS RECTIFYING AND SOFT SWITCHING OF POWER CONVERTERS
First Claim
1. A control circuit for soft switching and synchronous rectifying of a power converter, comprising:
- an integrated synchronous rectifier comprising;
a cathode terminal, coupled to a secondary side of a power transformer;
an anode terminal, coupled to an output of the power converter;
a first input-signal terminal; and
a second input-signal terminal,wherein the integrated synchronous rectifier includes a controller and a power transistor connected between the cathode terminal and the anode terminal; and
the first input-signal terminal and the second input-signal terminal are coupled to the controller to receive a pulse signal for switching on/off the power transistor;
a switching-signal circuit comprising;
an input terminal coupled to receive a switching signal;
a first output-signal terminal; and
a second output-signal terminal,wherein the switching signal is used for regulating the power converter by switching the power transformer;
the first output-signal terminal and the second output-signal terminal are coupled to a pulse generation circuit to generate the pulse signal in response to a leading edge and a trailing edge of the switching signal; and
an isolation device, coupled between the first input-signal terminal and the second input-signal terminal of the integrated synchronous rectifier, and the first output-signal terminal and the second output-signal terminal of the switching-signal circuit.
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Accused Products
Abstract
A control circuit for soft switching and synchronous rectifying is provided for power converter. A switching-signal circuit is used for generating drive signals and a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is developed for regulating the power converter. Drive signals are coupled to switch the power transformer. A propagation delay is developed between drive signals to achieve soft switching of the power converter. An isolation device is coupled to transfer the pulse signal from a primary side of a power transformer to a secondary side of the power transformer. A controller of the integrated synchronous rectifier is coupled to the secondary side of the power transformer for the rectifying operation. The controller is operated to receive the pulse signal for switching on/off the power transistor. The pulse signal is to set or reset a latch circuit of the controller for controlling the power transistor.
35 Citations
30 Claims
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1. A control circuit for soft switching and synchronous rectifying of a power converter, comprising:
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an integrated synchronous rectifier comprising; a cathode terminal, coupled to a secondary side of a power transformer; an anode terminal, coupled to an output of the power converter; a first input-signal terminal; and a second input-signal terminal, wherein the integrated synchronous rectifier includes a controller and a power transistor connected between the cathode terminal and the anode terminal; and
the first input-signal terminal and the second input-signal terminal are coupled to the controller to receive a pulse signal for switching on/off the power transistor;a switching-signal circuit comprising; an input terminal coupled to receive a switching signal; a first output-signal terminal; and a second output-signal terminal, wherein the switching signal is used for regulating the power converter by switching the power transformer;
the first output-signal terminal and the second output-signal terminal are coupled to a pulse generation circuit to generate the pulse signal in response to a leading edge and a trailing edge of the switching signal; andan isolation device, coupled between the first input-signal terminal and the second input-signal terminal of the integrated synchronous rectifier, and the first output-signal terminal and the second output-signal terminal of the switching-signal circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A control apparatus for soft switching and synchronous rectifying of a power converter, comprising:
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a switching-signal circuit, for generating drive signals and a pulse signal in response to a leading edge and a trailing edge of a switching signal; an isolation device, coupled to transfer the pulse signal from a primary side of a power transformer to a secondary side of the power transformer; and a synchronous rectifying circuit, having a power transistor and a controller;
wherein the power transistor is coupled to the secondary side of the power transformer for the rectifying operation; and
the controller is operated to receive the pulse signal for switching on/off the power transistor;wherein the switching signal is coupled to switch the power transformer through drive signals; and
the pulse signal is coupled to set or reset a latch circuit of the controller for controlling the power transistor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for controlling synchronous rectifying of a power converter, comprising:
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generating a pulse signal in response to a leading edge and a trailing edge of a switching signal; transferring the pulse signal from a primary side of a power transformer to a secondary side of the power transformer through an isolation barrier; setting or resetting a latch in response to the pulse signal; and turning on/off a power transistor in accordance with a status of the latch; wherein the switching signal is used for regulating the power converter through switching the power transformer; and
the power transistor is equipped in the secondary side of the power transformer for the rectifying operation. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method for controlling soft switching of a power converter, comprising:
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generating drive signals in response to a leading edge and a trailing edge of a switching signal; generating a propagation delay between drive signals; and producing a minimum on time of drive signal for achieving the soft switching of the power converter; wherein the switching signal is used for regulating the power converter; and
drive signals are coupled to switch the power transformer. - View Dependent Claims (29, 30)
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Specification