High-frequency lamp operating circuit

Claim 2

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, and integrating network means connected between said first induction device and said triggering means for providing stability to the load current.

Claim 3

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induCtion device controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including a transformer having a primary and a secondary and connected in series with said load means, a second capacitor connected to the primary of said transformer and to said controlled switch means and forming therewith a high-frequency discharge loop for discharging energy from said capacitor through said transformer primary upon closing of said controlled switch means, said transformer stepping up the voltage on said primary for applying high-frequency high-voltage pulses to said load means for starting the same.

Claim 4

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induCtion device controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including a transformer having a primary and a secondary and connected in series with said load means, a second capacitor connected to the primary of said transformer and to said controlled switch means and forming therewith a high-frequency discharge loop for discharging energy from said capacitor through said transformer primary upon closing of said controlled switch means, said transformer stepping up the voltage on said primary for applying high-frequency high-voltage pulses to said load means for starting the same.

Claim 5

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, and feedback means for compensating for variations in supply current and load current comprising impedance means in series with said controlled switch means and across said load means.

Claim 6

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, and feedback means for compensating for variations in supply current and load current comprising impedance means in series with said controlled switch means and across said load means.

Claim 7

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source end across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, and voltage-limiting means connected across said charging capacitor for providing a constant driving potential for said triggering means.

Claim 8

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source end across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, and voltage-limiting means connected across said charging capacitor for providing a constant driving potential for said triggering means.

Claim 9

A circuit for starting and controlling the operation of a load comprising, in combination, A source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including control means for reducing the starting pulse frequency applied to said load means.

Claim 10

A circuit for starting and controlling the operation of a load comprising, in combination, A source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including control means for reducing the starting pulse frequency applied to said load means.

Claim 11

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction n device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said conduction induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, said triggering means comprising a capacitance and resistance connected together in series, and voltage-sensitive switch means connected to said controlled switch means and across said capacitance, and control means for reducing the starting pulse frequency applied to said load means, said control means comprising an auxiliary capacitance and a normally closed thermal switch arranged in series across said first-mentioned capacitance, and heating impedance means connected in circuit with said triggering means and thermally coupled to said thermal switch for opening the same upon reaching a predetermined heat level during the operation of said triggering means, whereby the triggering frequency is reduced during the starting interval.

Claim 12

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction n device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said conduction induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, said triggering means comprising a capacitance and resistance connected together in series, and voltage-sensitive switch means connected to said controlled switch means and across said capacitance, and control means for reducing the starting pulse frequency applied to said load means, said control means comprising an auxiliary capacitance and a normally closed thermal switch arranged in series across said first-mentioned capacitance, and heating impedance means connected in circuit with said triggering means and thermally coupled to said thermal switch for opening the same upon reaching a predetermined heat level during the operation of said triggering means, whereby the triggering frequency is reduced during the starting interval.

Claim 13

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forMing with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, said triggering means comprising a capacitance and resistance connected together in series, and voltage sensitive switch means connected to said controlled switch means and across said capacitance, and feedback means for regulating operation of said load means while compensating for supply voltage variations comprising variable resistor means connected to said current source in series with said capacitance, and a storage capacitor connected across said capacitance and connected at its output side to said variable resistor means.

Claim 14

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forMing with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, said triggering means comprising a capacitance and resistance connected together in series, and voltage sensitive switch means connected to said controlled switch means and across said capacitance, and feedback means for regulating operation of said load means while compensating for supply voltage variations comprising variable resistor means connected to said current source in series with said capacitance, and a storage capacitor connected across said capacitance and connected at its output side to said variable resistor means.

Claim 15

A circuit as defined in claim 7, including means connected in series with said storage capacitor for providing a linear feedback voltage output.

Claim 16

A circuit as defined in claim 7, including voltage-limiting means connected across said storage capacitor for limiting feedback voltage across the same.

Claim 17

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including transformer means in series with said load means, current-limiting impedance means in series with said controlled switch means and across said load means, and load-current-sensing means for protecting said controlled switch means in the absence of load current, said sensing means comprising normally open thermal switch means connected in series with said controlled switch means and across said current limiting impedance means and arranged in the path of magnetic flux generated by said transformer means during passage of load current therethrough, said thermal switch means closing when heated by said magnetic flux and providing a bypass around said current limiting impedance means during operation of said load means.

Claim 18

A circuit for starting and controlling the operation of a load comprising, in combination, a source of electrical current, a first induction device in series with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, controlled switch means and a second induction device in series with said first induction device and across said capacitor, load means connected to said electrical source and across said capacitor, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronism with the voltage of said charging capacitor, said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said capacitor to again reverse and raise the voltage across said capacitor for applying to said load means, including transformer means in series with said load means, current-limiting impedance means in series with said controlled switch means and across said load means, and load-current-sensing means for protecting said controlled switch means in the absence of load current, said sensing means comprising normally open thermal switch means connected in series with said controlled switch means and across said current limiting impedance means and arranged in the path of magnetic flux generated by said transformer means during passage of load current therethrough, said thermal switch means closing when heated by said magnetic flux and providing a bypass around said current limiting impedance means during operation of said load means.

Claim 19

A circuit for starting and controlling the operation of a gaseous discharge lamp load comprising, in combination, a source of electrical current, a first induction device in series wit with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, load means comprising a gaseous discharge lamp connected to said electrical source and across said charging capacitor, controlled switch means and a second induction device connected in series with said first induction device across said charging capacitor and across said load means, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronIsm with the voltage of said charging capacitor, said with said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said charging capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said charging capacitor to again reverse and raise the voltage across said charging capacitor for applying to said load means, said first induction device having a larger inductance than said second induction device, said triggering means comprising an RC network comprising a capacitance and a resistance in series connected across said controlled switch means, and voltage-sensitive switch means connected to said controlled switch means and across said capacitance.

Claim 20

A circuit for starting and controlling the operation of a gaseous discharge lamp load comprising, in combination, a source of electrical current, a first induction device in series wit with said source of electrical current, a charging capacitor connected across said current source at the output of said first induction device, load means comprising a gaseous discharge lamp connected to said electrical source and across said charging capacitor, controlled switch means and a second induction device connected in series with said first induction device across said charging capacitor and across said load means, and triggering means connected to said charging capacitor for operating said controlled switch means at predetermined intervals in synchronIsm with the voltage of said charging capacitor, said with said capacitor forming with said second induction device a first resonant circuit when said controlled switch means is closed for reversing the voltage across said charging capacitor for opening said controlled switch means, and forming with said first induction device a second resonant circuit when said controlled switch means is opened for transferring energy stored in said first induction device to said charging capacitor to again reverse and raise the voltage across said charging capacitor for applying to said load means, said first induction device having a larger inductance than said second induction device, said triggering means comprising an RC network comprising a capacitance and a resistance in series connected across said controlled switch means, and voltage-sensitive switch means connected to said controlled switch means and across said capacitance.

Claim 21

A circuit as defined in claim 11, said source of electrical current being a source of alternating current, said controlled switch means being a high-frequency triac, and said voltage sensitive switch being a bidirectional conducting switch.