Switching power supply circuit
First Claim
1. A switching power supply circuit, comprising:
- a rectifying and smoothing circuit including a rectifying element and a smoothing capacitor, the rectifying element rectifying an AC voltage input from a commercial AC power source to produce a rectified voltage, and the smoothing capacitor smoothing the rectified voltage to generate a rectified and smoothed voltage as a voltage across the smoothing capacitor;
a switching element for receiving the rectified and smoothed voltage as a DC input voltage to perform a switching operation;
a switching driving section operable to drive the switching element to perform the switching operation;
a first inductor disposed in a path through which the rectified and smoothed voltage is input to the switching element;
a first primary side series resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the first primary side series resonance circuit including an inductance of a second inductor and a capacitance of a primary side series resonance capacitor connected in series with the inductance of the second inductor;
a second primary side series resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the second primary side series resonance circuit including an inductance of the first inductor and the capacitance of the primary side series resonance capacitor connected in series with the inductance of the first inductor;
a first primary side parallel resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the first primary side parallel resonance circuit including the inductance of the first inductor, the inductance of the second inductor connected in series with the inductance of the first inductor, and a capacitance of a primary side parallel resonance capacitor connected in parallel with a series connection circuit including the first inductor and the second inductor;
a converter transformer having a core with a primary winding on a primary side and a secondary winding on a secondary side, the primary winding being formed by the second inductor, the secondary winding having an AC voltage induced therein by the primary winding, a coupling coefficient between the primary side and the secondary side being set for loose coupling; and
a secondary side DC output voltage generating section operable to perform a rectifying operation on the AC voltage induced in the secondary winding of the converter transformer and input to the secondary side DC output voltage generating section to thereby generate a secondary side DC output voltage.
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Accused Products
Abstract
The invention aims at putting a single ended resonance type converter capable of obtaining a ZVS operation over an overall corresponding load region to practical use. A switching power supply circuit includes a primary side switching converter of a class-E resonance type, and a choke coil of a primary side series resonance circuit of the class-E resonance type converter is used as a primary winding of an insulating converter transformer. With this structure, a choke coil winding to be inserted into an input line of a DC input voltage is arranged between a positive-polarity end portion of a smoothing capacitor, and a node between the primary winding and a primary side series resonance capacitor. Thus, a resonance pulse voltage generated in the choke coil winding is superimposed on an AC voltage in the primary winding. Also, a primary series resonance current is caused to separately flow through the choke coil winding.
25 Citations
10 Claims
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1. A switching power supply circuit, comprising:
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a rectifying and smoothing circuit including a rectifying element and a smoothing capacitor, the rectifying element rectifying an AC voltage input from a commercial AC power source to produce a rectified voltage, and the smoothing capacitor smoothing the rectified voltage to generate a rectified and smoothed voltage as a voltage across the smoothing capacitor; a switching element for receiving the rectified and smoothed voltage as a DC input voltage to perform a switching operation; a switching driving section operable to drive the switching element to perform the switching operation; a first inductor disposed in a path through which the rectified and smoothed voltage is input to the switching element; a first primary side series resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the first primary side series resonance circuit including an inductance of a second inductor and a capacitance of a primary side series resonance capacitor connected in series with the inductance of the second inductor; a second primary side series resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the second primary side series resonance circuit including an inductance of the first inductor and the capacitance of the primary side series resonance capacitor connected in series with the inductance of the first inductor; a first primary side parallel resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the first primary side parallel resonance circuit including the inductance of the first inductor, the inductance of the second inductor connected in series with the inductance of the first inductor, and a capacitance of a primary side parallel resonance capacitor connected in parallel with a series connection circuit including the first inductor and the second inductor; a converter transformer having a core with a primary winding on a primary side and a secondary winding on a secondary side, the primary winding being formed by the second inductor, the secondary winding having an AC voltage induced therein by the primary winding, a coupling coefficient between the primary side and the secondary side being set for loose coupling; and a secondary side DC output voltage generating section operable to perform a rectifying operation on the AC voltage induced in the secondary winding of the converter transformer and input to the secondary side DC output voltage generating section to thereby generate a secondary side DC output voltage. - View Dependent Claims (2, 3, 4, 5)
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6. A switching power supply circuit, comprising:
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a switching element operable to receive a DC input voltage and to perform a switching operation; a switching driving section operable to drive the switching element to perform the switching operation; a first inductor and a second inductor arranged in series with a path through which the DC input voltage is input to the switching element; a first primary side series resonance circuit and a second primary side series resonance circuit for performing resonance operations in correspondence with the switching operation performed by the switching element, the first primary side series resonance circuit and the second primary side series resonance circuit including a primary side series resonance capacitor connected in series with the first inductor and the second inductor; a primary side parallel resonance circuit for performing a resonance operation in correspondence with the switching operation performed by the switching element, the primary side parallel resonance circuit including a primary side parallel resonance capacitor connected in parallel with the second inductor or the switching element; a converter transformer having a core with a primary winding on a primary side and a secondary winding on a secondary side, the primary winding being formed by the second inductor, the secondary winding having an AC voltage induced therein by the primary winding, a coupling coefficient between the primary side and the secondary side being set for loose coupling; and a secondary side DC output voltage generating section operable to perform a rectifying operation on the AC voltage induced in the secondary winding of the converter transformer and input to the secondary side DC output voltage generating section to thereby generate a secondary side DC output voltage. - View Dependent Claims (7, 8, 9, 10)
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Specification