DC-DC flyback converter having a synchronous rectification self-driven circuit
First Claim
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1. A DC-DC flyback converter, which comprises:
- a three-winding transformer;
a primary power circuit including a first MOSFET connected to a first winding of the transformer;
a secondary power circuit connected to a second winding of the transformer, the secondary power circuit further including a synchronous rectifier comprising a second MOSFET having first and second output terminals; and
a self-driven circuit including connected to a third winding of the transformer, wherein the self-driven circuit further includes a negative voltage removal circuit for removing negative voltage between the output terminals of the synchronous rectifier and a synchronous rectifier trigger switch-off circuit for switching the synchronous rectifier to an off condition, wherein the negative voltage removal circuit is formed by a third MOSFET and a resistor, while the synchronous rectifier trigger switch-off circuit includes the third MOSFET, the second winding of the transformer and a Zener diode.
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Abstract
A DC-DC flyback converter, includes a three-winding transformer; a primary power circuit having a first MOSFET connected to a first winding of the transformer; a secondary power circuit connected to a second winding of the transformer terminals; and a self-driven circuit connected to a third winding of the transformer. The secondary power circuit includes a synchronous rectifier in the form of a second MOSFET and the self-driven circuit further includes a delay drive circuit, an isolation differential circuit, a negative removal circuit having a third MOSFET and a synchronous rectifier trigger switch-off circuit for switching the synchronous rectifier to an off condition.
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Citations
12 Claims
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1. A DC-DC flyback converter, which comprises:
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a three-winding transformer; a primary power circuit including a first MOSFET connected to a first winding of the transformer; a secondary power circuit connected to a second winding of the transformer, the secondary power circuit further including a synchronous rectifier comprising a second MOSFET having first and second output terminals; and a self-driven circuit including connected to a third winding of the transformer, wherein the self-driven circuit further includes a negative voltage removal circuit for removing negative voltage between the output terminals of the synchronous rectifier and a synchronous rectifier trigger switch-off circuit for switching the synchronous rectifier to an off condition, wherein the negative voltage removal circuit is formed by a third MOSFET and a resistor, while the synchronous rectifier trigger switch-off circuit includes the third MOSFET, the second winding of the transformer and a Zener diode. - View Dependent Claims (2, 3, 4)
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5. A DC-DC flyback converter, which comprises:
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a three-winding transformer; a primary power circuit including a first MOSFET connected to a first winding of the transformer; a secondary power circuit connected to a second winding of the transformer, the secondary power circuit further including a synchronous rectifier having first and second output terminals, the synchronous rectifier being a second MOSFET; and a self-driven circuit including a third MOSFET connected to a third winding of the transformer, wherein the self-driven circuit further includes a delay drive circuit, an isolation differential circuit, a negative voltage removal circuit and a synchronous rectifier trigger switch-off circuit for switching the synchronous rectifier to an off condition, wherein the delay drive circuit includes a delay circuit and a drive circuit. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A DC-DC flyback converter, which comprises:
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a three-winding transformer; a primary power circuit connected to a first winding of the transformer, wherein the primary power circuit further includes a first MOSFET, and an input capacitor; a secondary power circuit connected to a second winding of the transformer, the secondary power circuit further including a second MOSFET and an output capacitor; and a self-driven circuit connected to a third winding of the transformer, wherein the self-driven circuit further includes a delay drive circuit, an isolation differential circuit, a synchronous rectifier trigger switch-off circuit, a negative voltage removal circuit including a third MOSFET, a Zener Diode and a resistor and a synchronous rectifier trigger switch-off circuit for switching the synchronous rectifier to an off condition.
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Specification