Switching power supply, and a method of driving the same
First Claim
Patent Images
1. A switching power supply capable of translating a.c. voltage into d.c. voltage, comprising:
- (a) a pair of a.c. input terminals for inputting a.c. voltage having a known frequency;
(b) an a.c.-to-d.c. converter circuit connected to the pair of a.c. input terminals for translating the input a.c. voltage into d.c. voltage, the a.c.-to-d.c. converter circuit having power factor improvement means including an a.c.-to-d.c. converter switch;
(c) a first switch control circuit connected to the a.c.-to-d.c. converter switch for driving the a.c.-to-d.c. converter switch at a repetition frequency higher than the frequency of the input a.c. voltage;
(d) a d.c.-to-d.c. converter circuit connected to the a.c.-to-d.c. converter circuit for translating the d.c. voltage output of the a.c.-to-d.c. converter circuit into desired d.c. voltage, the d.c.-to-d.c. converter circuit having a d.c.-to-d.c. converter switch;
(e) a second switch control circuit connected to the d.c.-to-d.c. converter switch for driving the d.c.-to-d.c. converter switch at a repetition frequency higher than the frequency of the input a.c. voltage;
(f) a voltage detector circuit connected to the a.c.-to-d.c. converter circuit for providing a voltage output indicative of the d.c. voltage output from the a.c.-to-d.c. converter circuit;
(g) a voltage decision circuit connected to the voltage detector circuit for ascertaining whether the voltage output of the voltage detector circuit is higher than a predefined value or not; and
(h) a starter circuit connected to the voltage decision circuit and the second switch control circuit for causing the second switch control circuit to start driving the d.c.-to-d.c. converter switch when the voltage output from the voltage detector circuit grows higher than the predefined value.
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Abstract
A switching power supply comprising an a.c.-to-d.c. converter circuit for connection to a source of commercial alternating current, and a d.c.-to-d.c. converter circuit for translating the d.c. output voltage of the a.c.-to-d.c. converter into desired d.c. voltage for application to a load. The d.c.-to-d.c. converter circuit is set into operation only after the output voltage of the a.c.-to-d.c. converter circuit has built up sufficiently, in order to preclude instability in the output voltage of the power supply during a startup period.
63 Citations
16 Claims
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1. A switching power supply capable of translating a.c. voltage into d.c. voltage, comprising:
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(a) a pair of a.c. input terminals for inputting a.c. voltage having a known frequency;
(b) an a.c.-to-d.c. converter circuit connected to the pair of a.c. input terminals for translating the input a.c. voltage into d.c. voltage, the a.c.-to-d.c. converter circuit having power factor improvement means including an a.c.-to-d.c. converter switch;
(c) a first switch control circuit connected to the a.c.-to-d.c. converter switch for driving the a.c.-to-d.c. converter switch at a repetition frequency higher than the frequency of the input a.c. voltage;
(d) a d.c.-to-d.c. converter circuit connected to the a.c.-to-d.c. converter circuit for translating the d.c. voltage output of the a.c.-to-d.c. converter circuit into desired d.c. voltage, the d.c.-to-d.c. converter circuit having a d.c.-to-d.c. converter switch;
(e) a second switch control circuit connected to the d.c.-to-d.c. converter switch for driving the d.c.-to-d.c. converter switch at a repetition frequency higher than the frequency of the input a.c. voltage;
(f) a voltage detector circuit connected to the a.c.-to-d.c. converter circuit for providing a voltage output indicative of the d.c. voltage output from the a.c.-to-d.c. converter circuit;
(g) a voltage decision circuit connected to the voltage detector circuit for ascertaining whether the voltage output of the voltage detector circuit is higher than a predefined value or not; and
(h) a starter circuit connected to the voltage decision circuit and the second switch control circuit for causing the second switch control circuit to start driving the d.c.-to-d.c. converter switch when the voltage output from the voltage detector circuit grows higher than the predefined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a switching power supply comprising an a.c.-to-d.c. converter circuit for translating input a.c. voltage into d.c. voltage, the a.c.-to-d.c. converter circuit having power factor improvement means including an a.c.-to-d.c. converter switch, a first switch control circuit for on-off control of the a.c.-to-d.c. converter switch with a repetition frequency higher than the frequency of the input a.c. voltage, a d.c.-to-d.c. converter circuit for translating the d.c. output voltage of the a.c.-to-d.c. converter circuit into desired d.c. voltage, and a second switch control circuit for on-off control of a d.c.-to-d.c. converter switch with a repetition frequency higher than the frequency of the input a.c., a method of driving the switching power supply which comprises:
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(a) detecting the output voltage of the a.c.-to-d.c. converter circuit;
(b) comparing the detected output voltage of the a.c.-to-d.c. converter circuit with a predefined value;
(c) starting the on-off control of the a.c.-to-d.c. converter switch by the first switch control circuit; and
(d) starting the on-off control of the d.c.-to-d.c. converter switch by the second switch control circuit when the detected output voltage of the a.c.-to-d.c. converter circuit proves higher than the predefined value.
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Specification