SWITCHING POWER-SUPPLY APPARATUS
First Claim
Patent Images
1. A switching power-supply apparatus comprising:
- a direct-current power-supply input unit arranged to input a direct-current input voltage;
a transformer including at least a first primary coil, a first secondary coil, and a second secondary coil;
a half-bridge primary-side power converter circuit that includes a first series circuit connected to both ends of the direct-current power-supply input unit and including a first switch circuit that includes a first switching element, a first capacitor, and a first diode connected in parallel with one another, and a second switch circuit that includes a second switching element, a second capacitor, and a second diode connected in parallel with one another, and both ends of a second series circuit including at least a first input inductor, the first primary coil and an input capacitor being connected to both ends of the first switch circuit or the second switch circuit;
a secondary-side synchronous rectifier circuit including a third switch circuit arranged to rectify a voltage generated by the first secondary coil and including a third switching element, a third capacitor, and a third diode connected in parallel with one another, and a fourth switch circuit arranged to rectify a voltage generated by the second secondary coil and including a fourth switching element, a fourth capacitor, and a fourth diode connected in parallel with one another, the secondary-side synchronous rectifier circuit being arranged to operate due to switching operations of the third switch circuit and the fourth switch circuit being controlled in accordance with complementary switching operations of the first switch circuit and the second switch circuit;
a first inductor arranged so as to smooth currents flowing in the first secondary coil and the second secondary coil; and
a smoothing capacitor connected downstream from the first inductor;
whereina load is connected downstream from the smoothing capacitor;
the first switch circuit and the second switch circuit are arranged to perform mutually complementary switching operations before and after a predetermined dead time and to control an on time ratio of an on time of the first switching element to an on time of the second switching element to control power supplied to the load; and
when the load is a light load, an operation mode is performed in which energy is regenerated from the secondary side to the primary side by causing a negative current to flow in a direction opposite to a rectification direction in at least one of the third switching element and the fourth switching element.
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Abstract
In a switching power-supply apparatus, a primary-side power converter circuit includes a half bridge system and a synchronous rectifier circuit is provided as a rectifier circuit of a secondary-side power converter circuit. An on time ratio of the on time of a first switching element to the on time of a second switching element is controlled so as to provide an operation mode in which energy is regenerated from the secondary side to the primary side when the load is light.
50 Citations
18 Claims
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1. A switching power-supply apparatus comprising:
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a direct-current power-supply input unit arranged to input a direct-current input voltage; a transformer including at least a first primary coil, a first secondary coil, and a second secondary coil; a half-bridge primary-side power converter circuit that includes a first series circuit connected to both ends of the direct-current power-supply input unit and including a first switch circuit that includes a first switching element, a first capacitor, and a first diode connected in parallel with one another, and a second switch circuit that includes a second switching element, a second capacitor, and a second diode connected in parallel with one another, and both ends of a second series circuit including at least a first input inductor, the first primary coil and an input capacitor being connected to both ends of the first switch circuit or the second switch circuit; a secondary-side synchronous rectifier circuit including a third switch circuit arranged to rectify a voltage generated by the first secondary coil and including a third switching element, a third capacitor, and a third diode connected in parallel with one another, and a fourth switch circuit arranged to rectify a voltage generated by the second secondary coil and including a fourth switching element, a fourth capacitor, and a fourth diode connected in parallel with one another, the secondary-side synchronous rectifier circuit being arranged to operate due to switching operations of the third switch circuit and the fourth switch circuit being controlled in accordance with complementary switching operations of the first switch circuit and the second switch circuit; a first inductor arranged so as to smooth currents flowing in the first secondary coil and the second secondary coil; and a smoothing capacitor connected downstream from the first inductor;
whereina load is connected downstream from the smoothing capacitor; the first switch circuit and the second switch circuit are arranged to perform mutually complementary switching operations before and after a predetermined dead time and to control an on time ratio of an on time of the first switching element to an on time of the second switching element to control power supplied to the load; and when the load is a light load, an operation mode is performed in which energy is regenerated from the secondary side to the primary side by causing a negative current to flow in a direction opposite to a rectification direction in at least one of the third switching element and the fourth switching element. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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2. A switching power-supply apparatus comprising:
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a direct-current power-supply input unit arranged to input a direct-current input voltage; a transformer including at least a first primary coil, a first secondary coil, a second primary coil, and a second secondary coil; a half-bridge primary-side power converter circuit that includes a series circuit including a first switch circuit that includes a first switching element, a first capacitor, and a first diode connected in parallel with one another, and a second switch circuit that includes a second switching element, a second capacitor, and a second diode connected in parallel with one another, both ends of a second series circuit including at least a first input inductor, the first primary coil, and an input capacitor being connected to both ends of the first switch circuit or the second switch circuit, a capacitor being connected to both ends of a third series circuit including the first switch circuit and the second switch circuit, and the direct-current input voltage being connected to both ends of a fourth series circuit including the first switch circuit and the input capacitor via the second primary coil and a second input inductor; a secondary-side synchronous rectifier circuit including a third switch circuit arranged to rectify a voltage generated by the first secondary coil and including a third switching element, a third capacitor, and a third diode connected in parallel with one another, and a fourth switch circuit arranged to rectify a voltage generated by the second secondary coil and including a fourth switching element, a fourth capacitor, and a fourth diode connected in parallel with one another, the secondary-side synchronous rectifier circuit being arranged to operate due to switching operations of the third switch circuit and the fourth switch circuit being controlled in accordance with complementary switching operations of the first switch circuit and the second switch circuit; a first inductor arranged to smooth currents flowing in the first secondary coil and the second secondary coil; and a smoothing capacitor connected downstream from the first inductor;
whereina load is connected downstream from the smoothing capacitor; the first switch circuit and the second switch circuit are arranged to perform mutually complementary switching operations before and after a predetermined dead time and to control an on time ratio of an on time of the first switching element to an on time of the second switching element to control power supplied to the load; and when the load is a light load, an operation mode is provided in which energy is regenerated from the secondary side to the primary side by causing a negative current to flow in a direction opposite to a rectification direction in at least one of the third switching element and the fourth switching element. - View Dependent Claims (3, 4)
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Specification