Resonant Switching Power Supply Device
First Claim
1. A resonant switching power supply device comprising:
- a power supply circuit for outputting a DC power, a switching circuit having multiple switching elements, to which the DC power of said power supply circuit is input, for carrying out switching operations complementarily, a resonance circuit, to which the output of said switching circuit is input, having series-connected devices comprising a first resonance capacitor and a resonance coil, a switching transformer, and a second resonance capacitor connected in parallel with the primary winding of said switching transformer, a rectifying/smoothing circuit to which the secondary output of said switching transformer is input and in which the input is rectified and smoothed and then output, a current detection circuit comprising a detection transformer having a primary winding in which a current substantially identical to the current flowing in the primary winding of said switching transformer flows, a rectifying circuit for rectifying the secondary output of said detection transformer, and a current-voltage conversion circuit for converting the output of said rectifying circuit into a voltage, and a control circuit, to which the outputs of said power supply circuit, said rectifying/smoothing circuit and said current detection circuit are input, for controlling the switching operations of said switching elements in said switching circuit.
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Accused Products
Abstract
For the purpose of providing a resonant switching power supply device having a wide output voltage variable range by changing its switching frequency, the resonance circuit thereof comprises a switching transformer, a first resonance section connected in series with the switching transformer, and a second resonance section connected in parallel with the switching transformer, wherein the resonance frequency characteristic in the case that the DC load current is large is formed using the series-connected devices of the first resonance section, and the resonance frequency characteristic in the case that the DC load current is small is formed using the first resonance section, the second resonance capacitor of the second resonance section and the switching transformer.
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Citations
11 Claims
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1. A resonant switching power supply device comprising:
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a power supply circuit for outputting a DC power, a switching circuit having multiple switching elements, to which the DC power of said power supply circuit is input, for carrying out switching operations complementarily, a resonance circuit, to which the output of said switching circuit is input, having series-connected devices comprising a first resonance capacitor and a resonance coil, a switching transformer, and a second resonance capacitor connected in parallel with the primary winding of said switching transformer, a rectifying/smoothing circuit to which the secondary output of said switching transformer is input and in which the input is rectified and smoothed and then output, a current detection circuit comprising a detection transformer having a primary winding in which a current substantially identical to the current flowing in the primary winding of said switching transformer flows, a rectifying circuit for rectifying the secondary output of said detection transformer, and a current-voltage conversion circuit for converting the output of said rectifying circuit into a voltage, and a control circuit, to which the outputs of said power supply circuit, said rectifying/smoothing circuit and said current detection circuit are input, for controlling the switching operations of said switching elements in said switching circuit. - View Dependent Claims (2, 3)
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4. A resonant switching power supply device for controlling its switching frequency depending on the output supplied to a load and outputting a DC output, comprising:
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a switching circuit for switching multiple switching elements at the switching frequency, a resonance circuit, to which the output of said switching circuit is input, having a switching transformer, a first resonance section connected in series with said switching transformer, and a second resonance section connected in parallel with said switching transformer, a rectifying/smoothing circuit for rectifying and smoothing the output of said switching transformer, a voltage detection circuit for detecting the DC output voltage from said rectifying/smoothing circuit, a current detection circuit for detecting a load current using the current flowing in the primary winding of said switching transformer, and a control circuit for controlling the switching frequency of said switching circuit depending on the outputs of said voltage detection circuit and said current detection circuit. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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Specification