Electronic ballast with two transistors and two transformers
First Claim
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1. A circuit for powering a gas discharge lamp from a source of AC power comprising:
- a first rectifier coupled to the source of AC power;
a half bridge inverter having a pair of series connected transistors, each transistor having a control electrode, the pair of transistors having a shared terminal;
a series connected inductor and resonant capacitor connected between a circuit common and the shared terminal;
the inductor having a winding, the winding inductively coupled to a power factor correction winding, the power factor correction winding providing a signal used for power factor correction, the power factor correction winding also coupled to the input of a high frequency rectifier bridge, the output of the high frequency rectifier bridge coupled to the first rectifier;
the control electrodes of the transistors inductively coupled to the inductor; and
a lamp circuit having the lamp and a series connected current limiting capacitor, the lamp circuit coupled to the inductor.
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Abstract
A power factor corrected electronic ballast circuit uses two transformer components. An inductively coupled charge pump technique is used for power factor correction while the gates of the transistor switches are driven directly from a resonant inductor.
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Citations
7 Claims
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1. A circuit for powering a gas discharge lamp from a source of AC power comprising:
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a first rectifier coupled to the source of AC power; a half bridge inverter having a pair of series connected transistors, each transistor having a control electrode, the pair of transistors having a shared terminal; a series connected inductor and resonant capacitor connected between a circuit common and the shared terminal; the inductor having a winding, the winding inductively coupled to a power factor correction winding, the power factor correction winding providing a signal used for power factor correction, the power factor correction winding also coupled to the input of a high frequency rectifier bridge, the output of the high frequency rectifier bridge coupled to the first rectifier; the control electrodes of the transistors inductively coupled to the inductor; and a lamp circuit having the lamp and a series connected current limiting capacitor, the lamp circuit coupled to the inductor. - View Dependent Claims (2, 3, 4)
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5. A circuit for powering a gas discharge lamp from a source of AC power comprising:
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a first rectifier coupled to the source of AC power; a half bridge inverter having a pair of series connected transistors, each transistor having a control electrode, the pair of transistors having a shared terminal; a series connected inductor and resonant capacitor connected between a circuit common and the shared terminal; the inductor having a winding, the winding inductively coupled to a power factor correction winding, the power factor correction winding providing a signal, the signal used for power factor correction, to the input of a high frequency rectifier bridge, the output of the high frequency rectifier bridge coupled to the first rectifier; the control electrodes of the transistors inductively coupled to the inductor; a lamp circuit having the lamp and a series connected current limiting capacitor, the lamp circuit coupled to the resonant capacitor. - View Dependent Claims (6, 7)
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Specification