US6011360A — High efficiency dimmable cold cathode fluorescent…

Claim 1

Independent Claim 47 words

A ballast, comprising: a switching stage having an output; and a circuit having a resonant frequency and coupled to the output of the switching stage; wherein the only type of discrete element within the circuit substantially affecting the resonant frequency thereof is substantially inductive in electrical character.

Claim 2

Dependent Claim 47 words

A ballast, comprising: a switching stage having an output; and a circuit having a resonant frequency and coupled to the output of the switching stage; wherein the only type of discrete element within the circuit substantially affecting the resonant frequency thereof is substantially inductive in electrical character.

Claim 3

Dependent Claim 23 words

The ballast of claim 1, wherein the circuit further includes a transformer having leakage inductance and parasitic capacitances which affect the resonant frequency.

Claim 4

Dependent Claim 48 words

The ballast of claim 1, wherein the circuit is coupled to a lamp load having at least one lamp and a shield and characterized by a parasitic capacitance between the at least one lamp and shield; the resonant frequency being affected by the parasitic capacitance of the lamp.

Claim 5

Dependent Claim 48 words

The ballast of claim 2, wherein the circuit is coupled to a lamp load having at least one lamp and a shield and characterized by a parasitic capacitance between the at least one lamp and shield; the resonant frequency being affected by the parasitic capacitance of the lamp.

Claim 6

Dependent Claim 20 words

The ballast of claim 2, wherein the transformer is connected without an intervening discrete ballasting element to a lamp load.

Claim 7

Dependent Claim 20 words

The ballast of claim 4, wherein the transformer is connected without an intervening discrete ballasting element to a lamp load.

Claim 8

Dependent Claim 44 words

The ballast of claim 1, wherein the switching stage is of the half bridge type comprising first and second controlled switches each of which is active to convert DC input power into AC power for a discharge lamp to be coupled to the circuit.

Claim 9

Dependent Claim 15 words

The ballast of claim 6, wherein the switching stage is of the half bridge type.

Claim 10

Dependent Claim 50 words

The ballast as claimed in claim 1 wherein the switching stage includes at least one switching transistor having equal on and off periods which are determined by said resonant frequency, and wherein a discharge lamp load is coupled to the circuit via connection means free of any discrete ballast elements.

Claim 11

Dependent Claim 40 words

The ballast as claimed in claim 1 wherein the circuit further includes a transformer having leakage inductance and parasitic capacitance, wherein only the discrete inductive element, the leakage inductance and parasitic capacitance significantly affect the resonant frequency of the circuit.

Claim 12

Dependent Claim 57 words

The ballast as claimed in claim 1 wherein the switching stage comprises at least one switching transistor that is switched on and off as a function of said resonant frequency and in a manner so as to deliver power during both the on and off periods of the switching transistor to a load coupled to the circuit.

Claim 13

Dependent Claim 61 words

The ballast as claimed in claim 1 wherein the switching stage comprises at least one switching transistor that is switched on and off at said resonant frequency and wherein both the on and off periods of the switching transistor are variable, and the switching stage and circuit have only a single resonant frequency which is the resonant frequency of said circuit.

Claim 14

Dependent Claim 66 words

The ballast as claimed in claim 11 wherein the switching stage further comprises a second switching transistor connected in series circuit with said at least one switching transistor to a pair of DC supply voltage terminals, and control means for switching said transistors on and off at said resonant frequency whereby a sinusoidal AC current is supplied to a discharge lamp when coupled to said circuit.

Claim 15

Dependent Claim 40 words

The ballast as claimed in claim 2 wherein the circuit is adapted for coupling to a discharge lamp load and the circuit resonant frequency is the frequency of power delivered to a discharge lamp load when coupled to said circuit.

Claim 16

Dependent Claim 87 words

A ballast, comprising: a switching stage; a circuit coupled to the switching stage, having a resonant frequency and including a serial combination of an inductor, a first capacitor and a primary winding of a transformer, that portion of the serial combination formed by the first capacitor and primary winding being in parallel with a second capacitor; and a lamp load coupled to a secondary winding of the transformer; wherein the only discrete elements of the circuit substantially affecting the resonant frequency are the inductor and second capacitor.

Claim 17

Dependent Claim 87 words

A ballast, comprising: a switching stage; a circuit coupled to the switching stage, having a resonant frequency and including a serial combination of an inductor, a first capacitor and a primary winding of a transformer, that portion of the serial combination formed by the first capacitor and primary winding being in parallel with a second capacitor; and a lamp load coupled to a secondary winding of the transformer; wherein the only discrete elements of the circuit substantially affecting the resonant frequency are the inductor and second capacitor.

Claim 18

Dependent Claim 30 words

The ballast as claimed in claim 9 wherein the lamp load is coupled to the secondary winding of the transformer via a further circuit devoid of any discrete capacitor element.

Claim 19

Independent Claim 50 words

A method of ballasting a lamp load, comprising the steps of: generating a varying DC voltage; and applying the varying DC voltage to a circuit having a resonant frequency wherein the only type of discrete element within the circuit substantially affecting the resonant frequency is substantially inductive in electrical character.

Claim 20

Independent Claim 50 words

A method of ballasting a lamp load, comprising the steps of: generating a varying DC voltage; and applying the varying DC voltage to a circuit having a resonant frequency wherein the only type of discrete element within the circuit substantially affecting the resonant frequency is substantially inductive in electrical character.

Claim 21

Dependent Claim 31 words

The method of claim 17, further including the step of controlling the resonant frequency based on the discrete element and a parasitic capacitance associated with a transformer included in the circuit.

Claim 22

Dependent Claim 27 words

The method of claim 17, further including the step of controlling the resonant frequency based on a leakage inductance associated with a transformer included in the circuit.

Claim 23

Dependent Claim 44 words

The method of claim 18, wherein the lamp load has at least one lamp and a shield and characterized by parasitic lamp capacitance between the at least one lamp and shield, and further including controlling the resonant frequency based on the parasitic lamp capacitance.

Claim 24

Dependent Claim 44 words

The method of claim 19, wherein the lamp load has at least one lamp and a shield and characterized by parasitic lamp capacitance between the at least one lamp and shield, and further including controlling the resonant frequency based on the parasitic lamp capacitance.

Claim 25

Dependent Claim 25 words

The method of claim 18, further including the step of controlling the resonant frequency based in part on a leakage inductance associated with the transformer.

Claim 26

Dependent Claim 86 words

A ballast circuit for a discharge lamp comprising: input terminals for supplying an operating voltage to the ballast circuit, a transistor switching stage coupled to the input terminals and operative at a high frequency, a circuit having a resonant frequency corresponding to the switching stage high frequency and coupled to an output of the switching stage, said circuit including a transformer having leakage inductance and parasitic capacitance, wherein the resonant frequency of the circuit is determined substantially only by said leakage inductance and said parasitic capacitance.

Claim 27

Dependent Claim 86 words

A ballast circuit for a discharge lamp comprising: input terminals for supplying an operating voltage to the ballast circuit, a transistor switching stage coupled to the input terminals and operative at a high frequency, a circuit having a resonant frequency corresponding to the switching stage high frequency and coupled to an output of the switching stage, said circuit including a transformer having leakage inductance and parasitic capacitance, wherein the resonant frequency of the circuit is determined substantially only by said leakage inductance and said parasitic capacitance.

Claim 28

Dependent Claim 47 words

The ballast circuit as claimed in claim 23 wherein the circuit further comprises a discrete inductor coupling the transformer to the output of the switching stage, wherein the discrete inductor, along with the leakage inductance and parasitic capacitance, together substantially determine the resonant frequency of the circuit.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-01-03	2003-07-05	2004-01-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-01-03	2007-07-05	2008-01-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-01-03	2011-07-05	2012-01-04	$7700.00	Window Closed / Lapsed

High efficiency dimmable cold cathode fluorescent lamp ballast

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag