Oscillating driver circuit with power factor correction, electronic lamp ballast employing same and driver method
First Claim
1. A circuit for driving a gas discharge illumination device comprising:
- a pair of electronic switches arranged in a half bridge configuration;
a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device; and
a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and being responsive to said dc bus voltage for preventing said dc bus voltage from exceeding said preset range if said illumination device is removed or becomes substantially an open circuit by regulating said dc bus voltage in comparison to a preset reference level.
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Accused Products
Abstract
A circuit and method for driving a load such as a gas discharge illumination device from an ac main supply with a high power factor. The circuit includes a pair of electronic switches arranged in a half bridge configuration and a self oscillating driver circuit having two outputs for driving respective ones of the electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the load. The circuit further includes a voltage regulator circuit coupled across the dc bus voltage and coupled to the self oscillating driver circuit, the voltage regulator circuit maintaining the dc bus voltage within a preset range and preventing the dc bus voltage from exceeding the range if the load is removed or becomes an open circuit. The voltage regulator preferably is a boost regulator switching an inductance. The circuit is particularly suitable for driving gas discharge illumination devices, e.g., fluorescent lamps, at a high power factor with minimum instability of the dc bus.
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Citations
72 Claims
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1. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and being responsive to said dc bus voltage for preventing said dc bus voltage from exceeding said preset range if said illumination device is removed or becomes substantially an open circuit by regulating said dc bus voltage in comparison to a preset reference level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said illumination device is removed or becomes substantially an open circuit, the voltage regulator circuit comprising; a comparator having a reference input and an input coupled to said dc bus voltage and for producing an output when the dc bus voltage exceeds a preset level; and an electronic switch coupled across the dc bus and having a control input coupled to the output of the comparator, said electronic switch providing a shunt across the dc bus to control the dc bus voltage. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across adc bus voltage and having a switched output coupled to the illumination device, said self oscillating driver circuit comprising a timing circuit and wherein a component of said timing circuit comprises a dimming control; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said illumination device is removed or becomes substantially an open circuit by regulating said dc bus voltage in comparison to a preset reference level. - View Dependent Claims (21, 22)
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23. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device; a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and being responsive to said dc bus voltage for preventing said dc bus voltage from exceeding said preset range if said illumination device is removed or becomes substantially an open circuit;
wherein the illumination device comprises a high intensity discharge lamp; anda trigger device coupled to said high intensity discharge lamp. - View Dependent Claims (24)
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25. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device, said self oscillating driver circuit comprising a timing circuit and wherein a component of said timing circuit comprises a dimming control; a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said illumination device is removed or becomes substantially an open circuit; and a synchronization circuit coupled to said illumination device and to said timing circuit for synchronizing the timing circuit to the illumination device current until the illumination device strikes. - View Dependent Claims (26, 27)
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28. A circuit for driving a gas discharge illumination device comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage and having a switched output coupled to the illumination device; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said illumination device is removed or becomes substantially an open circuit by regulating said dc bus voltage in comparison to a present reference level, wherein the power factor of power provided from an ac mains supply for powering the illumination device is controlled by the voltage regulator circuit so that it exceeds 0.95 lagging.
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29. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and being responsive to said dc bus voltage for preventing said dc bus voltage from exceeding said preset range if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising;
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said load is removed or becomes an open circuit, the voltage regulator circuit comprising; a comparator having a reference input and an input coupled to said dc bus voltage and for producing an output when the dc bus voltage exceeds a preset level; and an electronic switch coupled across the dc bus and having a control input coupled to the output of the comparator, said electronic switch providing a shunt across the dc bus to control the dc bus voltage. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load, said self oscillating driver circuit comprising a timing circuit and wherein a component of said timing circuit comprises a dimming control; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level. - View Dependent Claims (51)
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52. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and being responsive to said dc bus voltage for preventing said dc bus voltage from exceeding said preset range if said load is removed or becomes an open circuit;
wherein the load comprises a high intensity discharge lamp; anda trigger device coupled to said high intensity discharge lamp. - View Dependent Claims (53)
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54. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load, said self oscillating driver circuit comprising a timing circuit and wherein a component of said timing circuit comprises a dimming control; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said load is removed or becomes an open circuit;
wherein said load comprises a gas discharge illumination device; anda synchronization circuit coupled to said illumination device and to said timing circuit for synchronizing the timing circuit to the illumination device current until the illumination device strikes. - View Dependent Claims (55, 56)
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57. A circuit for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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a pair of electronic switches arranged in a half bridge configuration; a self oscillating driver circuit having two outputs for driving respective ones of said electronic switches, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; and a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit, said voltage regulator circuit maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level, wherein the power factor of power provided from the ac mains supply for powering the load is controlled by the voltage regulator circuit so that it exceeds 0.95 lagging.
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58. A method for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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arranging a pair of electronic switches in a half bridge configuration; driving respective ones of said electronic switches with a self oscillating driver circuit having two outputs, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; providing a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit; and maintaining said dc bus voltage within a preset range and preventing, in response to said dc bus voltage, said dc bus voltage from exceeding said preset range with said voltage regulator circuit if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level. - View Dependent Claims (59, 60)
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61. A method for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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arranging a pair of electronic switches in a half bridge configuration; driving respective ones of said electronic switches with a self oscillating driver circuit having two outputs, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; providing a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit; and maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range with said voltage regulator circuit if said load is removed or becomes an open circuit; wherein the step of providing a voltage regulator circuit comprises; providing a comparator having a reference input and an input coupled to said dc bus voltage and producing an output when the dc bus voltage exceeds a preset level determined by said reference input; and arranging an electronic switch across the dc bus and having a control input coupled to the output of the comparator, said electronic switch providing a shunt across the dc bus to control the dc bus voltage. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68)
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69. A method for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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arranging a pair of electronic switches in a half bridge configuration; driving respective ones of said electronic switches with a self oscillating driver circuit having two outputs, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load, wherein said self oscillating driver circuit comprises a timing circuit and further comprising using a component of said timing circuit as a dimming control; providing a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit; and maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range with said voltage regulator circuit if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level. - View Dependent Claims (70)
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71. A method for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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arranging a pair of electronic switches in a half bridge configuration; driving respective ones of said electronic switches with a self oscillating driver circuit having two outputs, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load, wherein said self oscillating driver circuit comprises a timing circuit and further comprising using a component of said timing circuit as a dimming control; providing a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit; maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range with said voltage regulator circuit if said load is removed or becomes an open circuit;
wherein said load comprises a gas discharge illumination device; andcoupling a synchronization circuit to said illuminating device and to said timing circuit and synchronizing the timing circuit to the illumination device current until the illumination device strikes.
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72. A method for driving a load from an ac main supply at a high power factor approaching unity, comprising:
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arranging a pair of electronic switches in a half bridge configuration; driving respective ones of said electronic switches with a self oscillating driver circuit having two outputs, the electronic switches being coupled across a dc bus voltage supplied by a rectifier from the ac main supply and the electronic switches having a switched output coupled to the load; providing a voltage regulator circuit coupled across said dc bus voltage and coupled to said self oscillating driver circuit; and maintaining said dc bus voltage within a preset range and preventing said dc bus voltage from exceeding said range with said voltage regulator circuit if said load is removed or becomes an open circuit by regulating said dc bus voltage in comparison to a present reference level;
wherein the power factor of power provided from the ac mains supply for powering the load is controlled by the voltage regulator circuit so that it exceeds 0.95 lagging.
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Specification