Fixed operating frequency inverter for cold cathode fluorescent lamp having strike frequency adjusted by voltage to current phase relationship
First Claim
1. A method of driving a lamp that uses a DC to AC inverter that is connected to a winding of a transformer comprising:
- (a) monitoring a phase relationship between a voltage across said winding of said transformer and a current through said winding of said transformer; and
(b) keeping said phase relationship between said voltage across said winding of said transformer and said current through said winding of said transformer at substantially a predetermined relationship.
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Accused Products
Abstract
A method of driving a lamp that uses a DC to AC inverter that is connected to a primary winding of a transformer is disclosed. The inverter frequency is variable, and in one embodiment, may be controlled by a voltage controlled oscillator. Circuitry is included that monitors the phase relationship between a voltage across a secondary of the transformer and a current through the primary of the transformer. The circuitry monitors the phase relationship and adjusts the inverter frequency, such as by adjusting voltage controlled oscillator, so that the phase relationship is maintained at a predetermined relationship.
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Citations
42 Claims
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1. A method of driving a lamp that uses a DC to AC inverter that is connected to a winding of a transformer comprising:
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(a) monitoring a phase relationship between a voltage across said winding of said transformer and a current through said winding of said transformer; and (b) keeping said phase relationship between said voltage across said winding of said transformer and said current through said winding of said transformer at substantially a predetermined relationship. - View Dependent Claims (2, 3, 4)
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5. An apparatus for driving a lamp comprising
a transformer having a primary and a secondary; -
means for convertinga circuit configured to convert a DC power into AC power and operating at a frequency, the means for converting driving the primary, wherein the circuit is configured to operate at a frequency and drive the primary of said transformer; means for monitoring phase comparison that monitors a phase relationship between a voltage across said primary of said transformer and a current through said primary of said transformer; and
means for adjusting frequency control that adjusts the frequency of said means for converting circuit such that said a phase relationship between said voltage across said primary of said transformer and said current through said primary of said transformer is maintained at substantially a predetermined relationship. - View Dependent Claims (6, 7, 8)
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9. A method of driving a lamp that uses a DC to AC inverter that is coupled to a transformer having a primary and a secondary, the method comprising:
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(a) determining a phase relationship between a voltage across either the primary or the secondary of the transformer and a current through either the primary or the secondary of the transformer; and (b) keeping the phase relationship between the voltage across either the primary or the secondary of the transformer and the current through either the primary or the secondary of the transformer at a substantially predetermined relationship. - View Dependent Claims (10, 11, 12, 13)
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14. A method of striking a lamp comprising:
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determining a phase relationship between a voltage across a transformer and a current through the transformer; and sweeping a frequency of a signal applied to the transformer to a strike frequency based on the phase relationship between the voltage across the transformer and the current through the transformer. - View Dependent Claims (15, 16, 17, 18)
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19. A method of converting a DC input voltage to an AC signal for driving a lamp, comprising:
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controllably switching the DC input voltage ON and OFF to generate an AC signal; monitoring two or more signals, wherein the two or more signals comprise at least a drive voltage signal and a drive current signal; determining a phase relationship between the drive voltage signal and the drive current signal to generate a control signal; and controlling a frequency of the AC signal based on the control signal. - View Dependent Claims (20, 21, 22)
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23. A method comprising:
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receiving a DC voltage; generating one or more switching signals; generating an AC signal from the DC voltage based on the switching signals; monitoring two or more signals, wherein the two or more signals comprise at least a drive voltage signal and a drive current signal; determining a phase relationship between the drive voltage signal and the drive current signal to generate a control signal; and sweeping a frequency of the AC signal based on the control signal. - View Dependent Claims (24, 25, 26)
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27. An inverter circuit for driving a lamp, the circuit comprising:
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one or more switches to controllably switch an input voltage ON and OFF to generate an AC signal; and a control circuit configured to; monitor a drive voltage signal and a drive current signal, determine a phase relationship between the drive voltage signal and the drive current signal to generate a control signal, and control a frequency of the AC signal based on the control signal. - View Dependent Claims (28, 29, 30)
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31. An integrated inverter controller comprising:
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a first circuit configured to monitor at least two or more signals, wherein the two or more signals comprise at least a drive voltage signal and a drive current signal; a second circuit configured to determine a phase relationship between the drive voltage signal and the drive current signal to generate a control signal; a third circuit configured to control the frequency of an AC signal based on the control signal. - View Dependent Claims (32, 33, 34, 35, 36)
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37. An inverter controller for driving a lamp, the controller comprising:
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a first circuit configured to monitor at least two or more signals, wherein the two or more signals comprise at least a drive voltage signal and a drive current signal; a second circuit configured to determine a phase relationship between the drive voltage signal and the drive current signal to generate a control signal; a third circuit configured to control the frequency of an AC signal based on the control signal. - View Dependent Claims (38, 39, 40, 41, 42)
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Specification