Energy transfer device and energy transfer control semiconductor device
First Claim
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1. An energy transfer device comprising:
- a transformer having a primary winding, a secondary winding, and an auxiliary winding;
a switching element series-connected to the primary winding;
a control circuit that controls a switching operation of the switching element to perform switching control on a first DC voltage to be inputted to the switching element via the primary winding;
an output voltage generating unit that converts an AC voltage generated on the secondary winding by the switching control into a second DC voltage and supplies power to a load; and
an output voltage detecting circuit that detects a variation in the second DC voltage and transfers a feedback signal for the switching control generated in accordance with the variation to the control circuit, whereinthe control circuit includes;
a feedback signal control circuit that determines a level of a current flowing through the switching element based on the feedback signal from the output voltage detecting circuit;
a switching element current detecting circuit that generates a signal that turns off the switching element when the current flowing through the switching element reaches the level value determined by the feedback signal control circuit;
a turn-on detecting circuit that detects, from a voltage of the auxiliary winding, a state of a ringing voltage generated after a secondary current flowing through the secondary winding ceases to flow after the switching element is turned off, and generates a signal for turning on the switching element; and
a current peak modulator that performs modulation so that a peak of the current flowing through the switching element periodically and continuously varies within a current range from a first current value to a second current value.
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Abstract
The present invention includes a turn-off signal modulating circuit that periodically varies a turn-off timing of a switching element 2 at a preset modulation time after a current detection by a drain current detecting circuit 15, and by modulating the peak of a current flowing through the switching element 2, diffuses switching noise while preventing concentration of an oscillating frequency at a constant frequency even under a constant input voltage and a constant load.
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Citations
25 Claims
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1. An energy transfer device comprising:
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a transformer having a primary winding, a secondary winding, and an auxiliary winding; a switching element series-connected to the primary winding; a control circuit that controls a switching operation of the switching element to perform switching control on a first DC voltage to be inputted to the switching element via the primary winding; an output voltage generating unit that converts an AC voltage generated on the secondary winding by the switching control into a second DC voltage and supplies power to a load; and an output voltage detecting circuit that detects a variation in the second DC voltage and transfers a feedback signal for the switching control generated in accordance with the variation to the control circuit, wherein the control circuit includes; a feedback signal control circuit that determines a level of a current flowing through the switching element based on the feedback signal from the output voltage detecting circuit; a switching element current detecting circuit that generates a signal that turns off the switching element when the current flowing through the switching element reaches the level value determined by the feedback signal control circuit; a turn-on detecting circuit that detects, from a voltage of the auxiliary winding, a state of a ringing voltage generated after a secondary current flowing through the secondary winding ceases to flow after the switching element is turned off, and generates a signal for turning on the switching element; and a current peak modulator that performs modulation so that a peak of the current flowing through the switching element periodically and continuously varies within a current range from a first current value to a second current value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification