US5027040A — EL operating power supply circuit

Claim 1

Independent Claim 108 words

An EL operating power supply circuit comprising a DC power supply, a first inverter connected across the power supply for producing an AC voltage at an output thereof, an electroluminescent (EL) means, and an inductor, said electroluminescent means and said inductor being serially connected to said first inverter wherein the AC voltage is applied from the inverter to the electroluminescent means to emit light; wherein the inverter has a switching frequency f given by the following equation: ##EQU1## wherein L is an inductance of the inductor, C is a capacitance of the EL means, and the resistance component and resistance equivalent component of the circuit are negligibly small.

Claim 2

Dependent Claim 108 words

An EL operating power supply circuit comprising a DC power supply, a first inverter connected across the power supply for producing an AC voltage at an output thereof, an electroluminescent (EL) means, and an inductor, said electroluminescent means and said inductor being serially connected to said first inverter wherein the AC voltage is applied from the inverter to the electroluminescent means to emit light; wherein the inverter has a switching frequency f given by the following equation: ##EQU1## wherein L is an inductance of the inductor, C is a capacitance of the EL means, and the resistance component and resistance equivalent component of the circuit are negligibly small.

Claim 3

Dependent Claim 21 words

The EL operating circuit of claim 1 wherein said electroluminescent means comprises an electroluminescent element or an array of electroluminescent elements.

Claim 4

Dependent Claim 19 words

The EL operating circuit of claim 1 which further comprises a bipolar capacitor connected parallel to the electroluminescent means.

Claim 5

Dependent Claim 50 words

The EL operating circuit of claim 1 wherein the inductance of said inductor reduces the current during switching operation of said first inverter and a charge accumulated in the electroluminescent means through said first inverter and said inductor is recovered to the power supply side as a reverse current flow.

Claim 6

Dependent Claim 51 words

The EL operating circuit of claim 3 wherein the inductance of said inductor reduces the current during switching operation of said first inverter and a charge accumulated in the electroluminescent means and/or the bipolar capacitor through said first inverter is recovered to the power supply side as a reverse current flow.

Claim 7

Dependent Claim 22 words

The EL operating circuit of claim 1 which further comprises a buffering capacitor between said DC power supply and said first inverter.

Claim 8

Dependent Claim 33 words

The EL operating circuit of claim 1 which further comprises a second inverter between said DC power supply and said first inverter, said second inverter performing opposite switching operation to said first inverter.

Claim 9

Dependent Claim 32 words

The EL operating circuit of claim 7 which further comprises a phase controlling coil between said DC power supply and said second inverter and/or between said first inverter and said second inverter.

Claim 10

Dependent Claim 42 words

The EL operating circuit of any one of claims 1 to 8 wherein the first inverter is adapted to receive a switching signal wherein the frequency and/or pulse duration duty ratio of the switching signal can be set in a variable manner.

Claim 11

Dependent Claim 63 words

The EL operating circuit of any one of claims 1 to 8 wherein the first inverter includes a charging inverter section and a feedback inverter section, said charging and said feedback inverter sections being driven by a switching signal having the same frequency and the same rise, said feedback inverter section having a larger pulse duration duty ratio than said charging inverter section.

Claim 12

Dependent Claim 52 words

The EL operating circuit of any one of claims 1 to 8 wherein said first inverter includes at least a pair of switching elements and said power supply circuit further includes first diodes respectively connected in parallel with the switching elements for forming bypass channels for feeding back the reverse current flows.

Claim 13

Dependent Claim 33 words

The EL operating circuit of claim 11 which further includes second diodes respectively in forward series connection with the switching elements inside the inverter channels bypassed by said reverse current flow bypass channels.

Claim 14

Dependent Claim 129 words

An EL operating power supply circuit comprising: a DC power supply, a first inverter connected across the power supply for changing the DC power into an AC power at an output thereof, and a transformer having primary and secondary windings, a bipolar capacitor, said transformer and said bipolar capacitor being serially connected to the first inverter, and electroluminescent (EL) means connected to the transformer such that an AC output power available on the transformer secondary winding is applied to the electroluminescent means to emit light; wherein the inverter has a switching frequency f given by the following equation: ##EQU2## wherein L is an inductance of the inductor, C is a capacitance of the EL means, and the resistance component and resistance equivalent component of the circuit are negligibly small.

Claim 15

Dependent Claim 129 words

An EL operating power supply circuit comprising: a DC power supply, a first inverter connected across the power supply for changing the DC power into an AC power at an output thereof, and a transformer having primary and secondary windings, a bipolar capacitor, said transformer and said bipolar capacitor being serially connected to the first inverter, and electroluminescent (EL) means connected to the transformer such that an AC output power available on the transformer secondary winding is applied to the electroluminescent means to emit light; wherein the inverter has a switching frequency f given by the following equation: ##EQU2## wherein L is an inductance of the inductor, C is a capacitance of the EL means, and the resistance component and resistance equivalent component of the circuit are negligibly small.

Claim 16

Dependent Claim 21 words

The EL operating circuit of claim 13 wherein said electroluminescent means comprises an electroluminescent element or an array of electroluminescent elements.

Claim 17

Dependent Claim 47 words

The EL supply circuit of claim 13 wherein the inductance of said transformer reduces the current during switching operation of said first inverter and a charge accumulated in the electroluminescent means through said first inverter is recovered to the power supply side as a reverse current flow.

Claim 18

Dependent Claim 54 words

The EL operating circuit of claim 13 wherein the inductance of said transformer reduces the current during switching operation of said first inverter and a charge accumulated in the electroluminescent means and/or the bipolar capacitor through said first inverter and said transformer is recovered to the power supply side as a reverse current flow.

Claim 19

Dependent Claim 22 words

The EL operating circuit of claim 13 which further comprises a buffering capacitor between said DC power supply and said first inverter.

Claim 20

Dependent Claim 33 words

The EL operating circuit of claim 13 which further comprises a second inverter between said DC power supply and said first inverter, said second inverter performing opposite switching operation to said first inverter.

Claim 21

Dependent Claim 32 words

The EL operating circuit of claim 18 which further comprises a phase controlling coil between said DC power supply and said second inverter and/or between said first inverter and said second inverter.

Claim 22

Dependent Claim 42 words

The EL operating circuit of any one of claims 13, 14, 15-19 wherein the first inverter is adapted to receive a switching signal wherein the frequency and/or pulse duration duty ratio of the switching signal can be set in a variable manner.

Claim 23

Dependent Claim 63 words

The EL operating circuit of any one of claims 13, 14, 15-19 wherein the first inverter includes a charging inverter section and a feedback inverter section, said charging and said feedback inverter sections being driven by a switching signal having the same frequency and the same rise, said feedback inverter section having a larger pulse duration duty ratio than said charging inverter section.

Claim 24

Dependent Claim 52 words

The EL operating circuit of any one of claims 13, 14, 15-20 wherein said inverter includes at least a pair of switching elements and said first power supply circuit further includes first diodes respectively connected in parallel with the switching elements for forming bypass channels for feeding back the reverse current flows.

Claim 25

Dependent Claim 33 words

The EL operating circuit of claim 22 which further includes second diodes respectively in forward series connection with the switching elements inside the inverter channels bypassed by said reverse current flow bypass channels.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-06-24	1994-12-24	1995-06-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-06-24	1998-12-24	1999-06-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-06-24	2002-12-24	2003-06-25	$7700.00	Window Closed / Lapsed

EL operating power supply circuit

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