Isolated dual converter having primary side internal feedback for output regulation
First Claim
1. A power converter, comprising:
- a pulse width modulated switching power converter having a power switch for regulating an internal voltage output; and
an alternating current tank coupled to the internal voltage output, the alternating current tank having a storage capacitor and a transformer having a primary winding, a first switch that, when ON, couples the storage capacitor to the internal voltage output wherein the storage capacitor is charged and a first current flows in a first direction through the primary winding, a second switch that, when ON, permits the charged storage capacitor to discharge, wherein a second current flows in a second direction opposite to the first direction through the primary winding, and duty cycle control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and the second switch being ON when the first switch is OFF, the duty cycle control circuitry alternately switching the first and second switches at a constant duty cycle and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch.
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Accused Products
Abstract
The present invention comprises an isolated dual power supply having an internal feedback loop. The dual power supply comprises a modulated switched power converter generating an internal regulated voltage output coupled to an alternating current tank. The alternating current tank has a first and a second power switch that are alternately switched ON at a 50% duty cycle. When the first switch is ON, the internal regulated voltage output is coupled to a storage capacitor and a primary winding of a transformer in the alternating current tank wherein the storage capacitor is charged and a current flows in a first direction through the primary winding. Alternatively, when the second switch is ON, the charged storage capacitor discharges and a current flows in a second direction opposite to the first direction through the primary winding. In this fashion, the transformer becomes a linear device, allowing the use of internal feedback to control the external output of the transformer.
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Citations
40 Claims
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1. A power converter, comprising:
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a pulse width modulated switching power converter having a power switch for regulating an internal voltage output; and
an alternating current tank coupled to the internal voltage output, the alternating current tank having a storage capacitor and a transformer having a primary winding, a first switch that, when ON, couples the storage capacitor to the internal voltage output wherein the storage capacitor is charged and a first current flows in a first direction through the primary winding, a second switch that, when ON, permits the charged storage capacitor to discharge, wherein a second current flows in a second direction opposite to the first direction through the primary winding, and duty cycle control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and the second switch being ON when the first switch is OFF, the duty cycle control circuitry alternately switching the first and second switches at a constant duty cycle and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch. - 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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26. A circuit for use in a power supply, comprising:
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a power switch coupled to a voltage input;
a pulse width modulator for controlling a duty cycle of the power switch;
a diode having its anode coupled to the voltage input;
a first switch coupled to the cathode of the diode and to a voltage output;
a second switch coupled to the voltage output; and
control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and vice versa, the control circuitry alternately switching the first and second switches at a constant duty cycle, and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch. - View Dependent Claims (27)
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28. A power converter, comprising:
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a pulse width modulated switching power converter having a power switch for regulating an internal voltage output;
a plurality of alternating current tanks coupled to the internal voltage output, each alternating current tank in the plurality of alternating current tanks having a storage capacitor and a transformer having a primary winding, a first switch that, when ON, couples the storage capacitor to the internal voltage output wherein the storage capacitor is charged and a first current flows in a first direction through the primary winding, a second switch that, when ON, permits the charged storage capacitor to discharge, wherein a second current flows in a second direction opposite to the first direction through the primary winding, and duty cycle control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and the second switch being ON when the first switch is OFF, the duty cycle control circuitry alternately switching the first and second switches at a constant duty cycle, and such that the ON and OFF times of each switch are substantially equal, whereby, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch; and
a clock coupled to the plurality of the alternating current tanks, wherein the first switches are switched synchronously with each other and the second switches are switched synchronously with each other. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36)
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37. A power converter, comprising:
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a first circuit stage including a modulated switching power converter having a power switch for regulating an internal voltage output; and
a second circuit stage including an alternating current tank coupled to the internal voltage output, the alternating current tank having a storage capacitor and a transformer having a primary winding, a first switch that, when ON, couples the storage capacitor to the internal voltage output wherein the storage capacitor is charged and a first current flows in a first direction through the primary winding, a second switch that, when ON, permits the charged storage capacitor to discharge, wherein a second current flows in a second direction opposite to the first direction through the primary winding, and duty cycle control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and the second switch being ON when the first switch is OFF, the duty cycle control circuitry alternately switching the first and second switches it a constant duty cycle, and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch.
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38. A circuit for use in a power supply, comprising
a first circuitry stage including: -
a power switch coupled to a voltage input;
a pulse width modulator for controlling a duty cycle of the power switch;
a diode having its anode coupled to the voltage input; and
a second circuitry stage coupled to the first circuitry stage, said second circuitry stage including;
a first switch coupled to the cathode of the diode and to a voltage output;
a second switch coupled to the voltage output; and
control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and vice versa, the control circuitry alternately switching the first and second switches at a constant duty cycle, and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch.
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39. A power converter, comprising:
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a first circuitry stage including a modulated switching power converter having a power switch for regulating an internal voltage output;
a second circuitry stage including a plurality of alternating current tanks coupled to the internal voltage output, each alternating current tank in the plurality of alternating current tanks having a storage capacitor and a transformer having a primary winding, a first switch that, when ON, couples the storage capacitor to the internal voltage output wherein the storage capacitor is charged and a first current flows in a first direction through the primary winding, a second switch that, when ON, permits the charged storage capacitor to discharge, wherein a second current flows in a second direction opposite to the first direction through the primary winding, and duty cycle control circuitry for alternately switching ON and OFF the first and second switches, the first switch being ON when the second switch is OFF and the second switch being ON when the first switch is OFF, the duty cycle control circuitry alternately switching the first and second switches at a constant duty cycle, and such that the ON and OFF times of each switch are substantially equal, whereby a voltage produced across a secondary winding of the transformer is regulated by modulating the power switch; and
a clock circuit coupled to the plurality of the alternating current tanks, wherein the first switches are switched synchronously with each other and the second switches are switched synchronously with each other.
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40. A dual stage power converter, comprising:
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a first stage modulated switching power converter having a regulated output; and
a second stage alternating current tank coupled to said output of said first stage, said second stage having a first switch and second switch that are actuated by alternately switching ON and OFF the first and second switches, the first switch being ON at approximately the same time the second switch is OFF and vice versa, and said first and second switches being actuated at a constant duty cycle.
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Specification