Low noise, high frequency synchronous rectifier
First Claim
1. In a high efficiency synchronous rectifier circuit of the type including switching devices whose conductive state is controlled by an external control signal, a transformer for supplying an AC voltage to said switching devices for rectification and an output terminal, the improvement comprising:
- each of said switching devices comprising;
an insulated gate field effect transistor in which all of the semiconductor material is of a single conductivity type, anda diode connected in parallel with said field effect transistor in an orientation to conduct transient currents in its forward direction when said field effect transistor is non-conductive; and
said switching devices, said transformer and said output terminal being interconnected so that a current path from said transformer to said output terminal is free of series connections of said switching devices.
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Accused Products
Abstract
A synchronous rectifier is able to operate at higher frequencies and provides an output having lower noise than prior art FET synchronous rectifier system by using field effect switching devices which contain only one conductivity type of semiconductor material and connecting a high speed, low charge storage diode in parallel. Schottky diodes are preferred whereby there is no junction diode in the structure. Conventional FETs may be used when paralleled with a Schottky diode which prevents the FET'"'"'s parasitic internal diode from becoming conductive.
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Citations
20 Claims
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1. In a high efficiency synchronous rectifier circuit of the type including switching devices whose conductive state is controlled by an external control signal, a transformer for supplying an AC voltage to said switching devices for rectification and an output terminal, the improvement comprising:
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each of said switching devices comprising; an insulated gate field effect transistor in which all of the semiconductor material is of a single conductivity type, and a diode connected in parallel with said field effect transistor in an orientation to conduct transient currents in its forward direction when said field effect transistor is non-conductive; and said switching devices, said transformer and said output terminal being interconnected so that a current path from said transformer to said output terminal is free of series connections of said switching devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a high efficiency synchronous rectifier circuit of the type including switching devices whose conductive state is controlled by an external control signal, a transformer for applying an AC voltage to said switching devices for rectification and an output terminal, the improvement comprising:
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each of said switching devices comprising; an insulated gate field effect transistor in which all of the semiconductor material is of a single conductivity type, and a Schottky diode connected in parallel with said field effect transistor in an orientation to conduct transient current in its forward direction when said field effect transistor is non-conductive; and said switching devices, said transformer and said output terminal being interconnected so that a current path from said transformer to said output terminals is free of series connections of said switching devices. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification