Current synchronous zero voltage switching resonant topology
DCFirst Claim
1. A power converter for converting an input power signal to an output power signal, said power converter comprising:
- a controller having an oscillator circuit, a synchronous detector and a plurality of control signal outputs for providing transistor control signals dependent upon the oscillator frequency;
a plurality of transistors coupled to receive said input power signal and provide a square wave voltage signal, each transistor being associated with one of said control signal outputs and having a control input coupled to receive a control signal from the associated control signal output of said controller;
a resonant circuit controlled by said square wave voltage signal from said plurality of transistors to produce a resonant current and provide a high frequency sine wave output voltage signal;
wherein said synchronous detector includes a circuit coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit.
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Abstract
A power converter circuit provides low conversion losses, low generated noise and output power controllability. The circuit includes a controller, at least two transistors and an output network that provides impedance matching and operating point stabilization functions. The output network also enables zero voltage switching of the transistors, thus reducing radiated noise and minimizing (and possibly eliminating almost completely) switching losses. The controller circuitry includes an oscillator which is capable of self synchronizing to the resonant frequency of the components of the output network. Power modulation (e.g., for dimming of a lamp) is accomplished simply by desynchronizing and increasing the oscillator frequency. Thus, the control architecture allows the use of external parts of lower precision and cost while providing dimming capability in a single stage.
349 Citations
25 Claims
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1. A power converter for converting an input power signal to an output power signal, said power converter comprising:
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a controller having an oscillator circuit, a synchronous detector and a plurality of control signal outputs for providing transistor control signals dependent upon the oscillator frequency; a plurality of transistors coupled to receive said input power signal and provide a square wave voltage signal, each transistor being associated with one of said control signal outputs and having a control input coupled to receive a control signal from the associated control signal output of said controller; a resonant circuit controlled by said square wave voltage signal from said plurality of transistors to produce a resonant current and provide a high frequency sine wave output voltage signal; wherein said synchronous detector includes a circuit coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A controller for a power converter operable with a resonant circuit having a resonant frequency, for converting an input power signal to an output power signal, said controller comprising:
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an oscillator circuit having a controllable oscillation frequency and adapted to be coupled to control the operating frequency of the resonant circuit; a synchronous detect circuit coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the oscillation frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit. - View Dependent Claims (10, 11)
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12. A method of converting an input power signal to an output power signal with a resonant circuit and a control circuit for controlling the operating frequency of the resonant circuit, said power converter method comprising:
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sensing the resonant frequency of the resonant circuit; controlling the oscillation frequency of an oscillator dependent upon the resonant frequency of the resonant circuit; and controlling the operating frequency of the resonant circuit dependent upon the oscillation frequency of the oscillator. - View Dependent Claims (13, 14, 15)
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16. A fluorescent lamp system comprising:
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a controller having an oscillator circuit, a synchronous detect circuit and a plurality of control signal outputs for providing transistor control signals dependent upon the oscillator frequency; a plurality of transistors coupled to receive said input power signal and provide a square wave voltage signal, each transistor being associated with one of said control signal outputs and having a control input coupled to receive a control signal from the associated control signal output of said controller; a resonant circuit controlled by said square wave voltage signal from said plurality of transistors to produce a resonant current and provide a high frequency sine wave output voltage signal; at least one fluorescent lamp coupled to receive said high frequency sine wave output voltage signal; wherein said synchronous detect circuit includes a frequency detector coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit. - View Dependent Claims (17)
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18. A fluorescent lamp system comprising:
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a resonant circuit having a resonant frequency and controlled to produce a resonant current signal and provide a high frequency sine wave output voltage signal; and a controller having an oscillator circuit and a synchronous detect circuit, wherein; the oscillator circuit has a controllable oscillation frequency and adapted to be coupled to control the operating frequency of the resonant circuit; and the synchronous detect circuit is coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the oscillation frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit. - View Dependent Claims (19, 20, 21, 22)
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23. A power supply device for providing an output sine wave power signal, said power supply device comprising:
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a controller having an oscillator circuit, a synchronous detector and a plurality of control signal outputs for providing transistor control signals dependent upon the oscillator frequency; a plurality of transistors coupled to receive an input power signal, each transistor being associated with one of said control signal outputs and having a control input coupled to receive a control signal from the associated control signal output of said controller, the control signals controlling the transistors to turn on at a frequency dependent upon the oscillator frequency to provide a square wave voltage signal; an output network including a resonant circuit controlled by said square wave voltage signal from said plurality of transistors for producing a resonant current and providing a sine wave output power signal; wherein said synchronous detector includes a circuit coupled to detect the resonant frequency of the resonant circuit and to provide an oscillator control signal to control the frequency of the oscillator circuit dependent upon the resonant frequency of the resonant circuit. - View Dependent Claims (24, 25)
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Specification