Inverter power supply circuit

Claim 2

An arrangement comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; the absolute magnitude of the DC voltage being substantially higher than the peak absolute magnitude of the power line voltage; inverter means connected with the DC terminals and operative to provide an inverter voltage at a pair of inverter terminals; the inverter voltage having a fundamental period; the inverter means having a first periodically conducting transistor operative to conduct in its forward direction only during a first conduction period; the first conduction period having a duration substantially shorter than half the duration of the fundamental period; and load means connected with the inverter terminals and operative to draw a load current therefrom; the load means including energy-storing inductor means and a gas discharge lamp.

Claim 3

The arrangement of claim 1 wherein the inverter means has a second alternatingly conducting transistor operative to conduct in its forward direction only during a second conduction period; the second conduction period having a duration substantially shorter than half the duration of the fundamental period.

Claim 4

The arrangement of claim 1 wherein the first conduction period has a duration shorter than one-quarter of the duration of the fundamental period.

Claim 5

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period.

Claim 6

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period.

Claim 7

The electronic ballast of claim 4 wherein the duration of the second period is about equal to, or longer than, one-tenth the duration of the first period.

Claim 8

The electronic ballast of claim 4 wherein the absolute magnitude of the DC voltage is substantially higher than the peak absolute magnitude of the power line voltage.

Claim 9

The electronic ballast of claim 4 wherein the inverter is characterized by including an inductor and a capacitor connected together and being resonant at or near the fundamental frequency of the alternating inverter voltage.

Claim 10

The electronic ballast of claim 4 wherein the inverter includes means or controlling the frequency of the alternating inverter voltage.

Claim 11

The electronic ballast of claim 4 wherein the inverter is characterized by including: (i) a periodically conducting transistor having control input terminals; and (ii) a control signal source providing an alternating control signal to the control input terminals, the peak-to-peak magnitude of the control signal being substantially larger than twice the forward voltage drop of an ordinary semiconductor diode junction.

Claim 12

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; the absolute magnitude of the DC voltage being substantially higher than the peak absolute magnitude of the power line voltage; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period.

Claim 13

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; the absolute magnitude of the DC voltage being substantially higher than the peak absolute magnitude of the power line voltage; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period.

Claim 14

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period; the inverter means being further characterized by including means for controlling the frequency of the alternating inverter voltage.

Claim 15

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period; the inverter means being further characterized by including means for controlling the frequency of the alternating inverter voltage.

Claim 16

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period; the inverter means being further characterized by including: (i) a periodically conducting transistor having control input terminals; and (ii) a control signal source providing an alternating control signal to the control input terminals; the peak-to-peak magnitude of the control signal being substantially larger than twice the forward voltage drop of an ordinary semiconductor diode junction.

Claim 17

An electronic ballast for a gas discharge lamp, comprising: a source operative to provide a power line voltage at a set of power line terminals; rectifier means connected with the power line terminals and operative to provide a DC voltage at a set of DC terminals; and inverter means connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the alternating inverter voltage having a fundamental period and an instantaneous magnitude that (i) during a first period, remains substantially constant at a negative level, (ii) during a second period, increases at a substantially constant rate, (iii) during a third period, remains substantially constant at a positive level, and (iv) during a fourth period, decreases at a substantially constant rate; the sum of the durations of the four periods being equal to the duration of the fundamental period; the duration of the first period being approximately equal to that of the third period; the duration of the first period being distinctly shorter than half the duration of the fundamental period; the inverter means being further characterized by including: (i) a periodically conducting transistor having control input terminals; and (ii) a control signal source providing an alternating control signal to the control input terminals; the peak-to-peak magnitude of the control signal being substantially larger than twice the forward voltage drop of an ordinary semiconductor diode junction.

Claim 18

An arrangement comprising: a source operative to provide a DC voltage at a pair of DC terminals; an inverter connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the inverter voltage having a fundamental period characterized by including: (i) a first relatively long period during which the instantaneous magnitude of the inverter voltage remains at a first substantially constant level, (ii) a first relatively short period during which the instantaneous magnitude of the inverter voltage gradually changes between the first substantially constant level and a second substantially constant level, (iii) a second relatively long period during which the instantaneous magnitude of the inverter voltage remains at the second substantially constant level, and (iv) a second relatively short period during which the instantaneous magnitude of the inverter voltage gradually changes between the second and the first substantially constant levels; the duration of the first relatively long period being substantially equal to that of the second relatively long period; the duration of the first relatively short period being substantially shorter than the duration of the first relatively long period; the inverter being characterized by including a first periodically conducting transistor conducting current in its forward direction for a substantial part of the first relatively long period, but not during any substantial part of the first relatively short period, nor during the second relatively short period; and a load connected with the inverter terminals and operative to draw a load current therefrom; the load including an energy-storing inductor and a gas discharge lamp.

Claim 19

An arrangement comprising: a source operative to provide a DC voltage at a pair of DC terminals; an inverter connected with the DC terminals and operative to provide an alternating inverter voltage at a pair of inverter terminals; the inverter voltage having a fundamental period characterized by including: (i) a first relatively long period during which the instantaneous magnitude of the inverter voltage remains at a first substantially constant level, (ii) a first relatively short period during which the instantaneous magnitude of the inverter voltage gradually changes between the first substantially constant level and a second substantially constant level, (iii) a second relatively long period during which the instantaneous magnitude of the inverter voltage remains at the second substantially constant level, and (iv) a second relatively short period during which the instantaneous magnitude of the inverter voltage gradually changes between the second and the first substantially constant levels; the duration of the first relatively long period being substantially equal to that of the second relatively long period; the duration of the first relatively short period being substantially shorter than the duration of the first relatively long period; the inverter being characterized by including a first periodically conducting transistor conducting current in its forward direction for a substantial part of the first relatively long period, but not during any substantial part of the first relatively short period, nor during the second relatively short period; and a load connected with the inverter terminals and operative to draw a load current therefrom; the load including an energy-storing inductor and a gas discharge lamp.

Claim 20

The arrangement of claim 13 wherein the transistor: (i) has an emitter and a collector; and (ii) when it indeed conducts current in its forward direction, it conducts current directly between its emitter and collector without causing any substantial voltage drop thereacross.