SEMI RESONANT SWITCHING REGULATOR, POWER FACTOR CONTROL AND LED LIGHTING
First Claim
1. A method of zero voltage switching for power factor control, the method comprising the steps of:
- (a) providing a capacitor in parallel with a switching device;
(b) detecting the polarity of the current through the capacitor; and
(c) operating the switch responsive to a change in the polarity of the current through the capacitor.
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Abstract
Described are improvements in power factor control and systems embodying said improved power factor control. Improvements lie in a method of zero voltage switching in which a capacitor is placed in parallel with a switching device, and the switching device is operated responsive to a change in the polarity of the current through the capacitor. Switching therefore occurs at zero or close to zero voltage across the switching device in both on and off modes resulting in very low switching losses and electromagnetic interference. Systems employing the method include a power factor controller, LED light source, boost converter and a power source comprising one or more photovoltaic cells.
85 Citations
28 Claims
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1. A method of zero voltage switching for power factor control, the method comprising the steps of:
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(a) providing a capacitor in parallel with a switching device; (b) detecting the polarity of the current through the capacitor; and (c) operating the switch responsive to a change in the polarity of the current through the capacitor. - View Dependent Claims (2)
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3. A power factor controller comprising:
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a capacitor in parallel with a switching device; and a level sensing device configured to sense the polarity of current passing through the capacitor; wherein the switching device is operated responsive to a change in the polarity of the current through the capacitor. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 21, 22, 23, 24, 25, 26, 27, 28)
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17. A boost converter comprising;
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a capacitor in parallel with a switching device; and a level sensing device configured to sense the polarity of current passing through the capacitor; wherein the switching device is operated responsive to a change in the polarity of the current through the capacitor. - View Dependent Claims (18, 19, 20)
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Specification