CIRCUIT ARRANGEMENT FOR THE IGNITION AND ALTERNATING CURRENT SUPPLY OF A GAS AND/OR VAPOR DISCHARGE LAMP

• US 3,679,936 A
• Filed: 03/11/1970
• Issued: 07/25/1972
• Est. Priority Date: 03/22/1969
• Status: Expired due to Term

• Current Assignee: Jozef Cornelis Moerkens
• Original Assignee: Jozef Cornelis Moerkens
• Inventors: Moerkens, Jozef Cornelis
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Dahl, Lawrence J.
• Application Number:
  US05/018,546
• Time in Patent Office: 867 Days
• Field of Search: 315/1U,243,362,258,283,289,205
• US Class Current: 315/205
• CPC Class Codes: H05B 41/042 using semiconductor devices
• CPC Class Codes: Y10S 315/05 Starting and operating circuit for fluorescent lamp

Abstract

An ignition circuit for a discharge lamp comprising a ballast impedance in series with the lamp across the AC supply terminals. A capacitor and an SCR connected in series across the lamp electrodes. A diode connected anti-parallel to the SCR. A zener diode between the SCR anode and gate electrodes. The series circuit, including the ballast impedance, the capacitor, and the SCR and diode connected in anti-parallel, is under critically damped.

Claims

1. A circuit arrangement for the ignition of and supply of alternating current to a gas discharge lamp comprising, a pair of input terminals adapted to be connected to a source of AC supply current, a ballast impedance including an inductance connected in a first series arrangement with said lamp to the input terminals, a capacitor, a controlled semiconductor rectifier, means for shunting a part of said first series arrangement comprising the lamp with a second series arrangement which at least includes said capacitor and said controlled semiconductor rectifier, said controlled semiconductor rectifier being shunted by a branch circuit which includes an uncontrolled rectifier connected parallel to the controlled semiconductor rectifier but oppositely polarized, an electric voltage breakdown circuit element connected between the anode and the control electrode of the controlled semiconductor rectifier so that the controlled semiconductor rectifier becomes conducting when a given threshold voltage appears between its anode and cathode, and wherein the circuit including the input terminals, the second series arrangement and the uncontrolled rectifier is less than critically damped.

2. A circuit arrangement as claimed in claim 1, wherein the voltage breakdown element comprises a zener diode connected with its pass direction opposite to the pass direction of the controlled semiconductor rectifier.

3. A circuit arrangement as claimed in claim 1 wherein the second series arrangement shunts the lamp and a part of the ballast impedance, said arrangement further comprising a transformer with a primary winding in series with the lamp and the ballast impedance, means connecting a secondary winding of said transformer to the control electrode of the controlled semiconductor rectifier and to the cathode of the controlled rectifier such that the controlled semiconductor rectifier becomes conducting when a current flows at least in one direction through the primary winding of the transformer.

4. A circuit arrangement as claimed in claim 3, wherein said means connecting the secondary winding of the transformer to the control electrode includes a rectifier.

5. A circuit arrangement as claimed in claim 2, further comprising means connecting the uncontrolled rectifier and the zener diode in series with each other in said branch circuit.

6. A starter particularly suitable for a circuit arrangement as claimed in claim 1 provided with a capacitor in series with a controlled semiconductor rectifier, characterized in that the controlled semiconductor rectifier is shunted by a branch including an uncontrolled rectifier which is connected anti-parallel to the controlled semiconductor rectifier, an electric circuit element being provided between the anode and the control electrode of the controlled semiconductor rectifier such that the controlled semiconductor rectifier becomes conducting when a threshold voltage between its anode and cathode is exceeded.

7. An ignition circuit for a discharge lamp comprising, input terminals for connection to a source of alternating current, a ballast impedance including an inductance connected in series with said lamp across said terminals, a capacitor and a semicOnductor controlled rectifier connected in series, means connecting the series arrangement of the capacitor and controlled rectifier in shunt with the lamp, a rectifier element connected parallel to the semiconductor controlled rectifier and with reverse polarity, an electric circuit element having a given breakdown voltage connected between the anode and the control electrode of the semiconductor controlled rectifier so that the controlled rectifier is triggered into conduction when the voltage between its anode and cathode exceeds a predetermined threshold level, the circuit including at least a part of the ballast impedance, the capacitor, the semiconductor controlled rectifier and said rectifier element being less than critically damped.

8. A circuit as claimed in claim 7 wherein the electric circuit element between the control electrode and the anode of the semiconductor controlled rectifier comprises a zener diode connected with a polarity which is opposite to that of the controlled rectifier.

9. A circuit as claimed in claim 7 wherein said series arrangement shunts the lamp and a part of the ballast impedance, a transformer, means connecting a primary winding of the transformer in series with the lamp and the ballast impedance, means connecting one terminal of a secondary winding of said transformer to the control electrode of the controlled rectifier and another terminal of said secondary winding to the cathode of the controlled rectifier so that the controlled rectifier begins to conduct when a current flows at least in one direction through the primary winding of the transformer.

10. A circuit as claimed in claim 9 further comprising a second rectifier connected between said control electrode and said one terminal of the transformer secondary winding.

11. A circuit as claimed in claim 7 further comprising means connecting said breakdown element in series with said rectifier element and with the rectifier element connected between the cathode and the control electrode of the semiconductor controlled rectifier.

12. A circuit as claimed in claim 7 wherein the amplitude of the AC supply voltage to which said input terminals are to be connected is lower than the ignition voltage of the discharge lamp, said capacitor and rectifier element being operative together with the supply voltage at said input terminals to develop a voltage across the lamp terminals that is greater than the lamp ignition voltage during given half cycles of the AC supply voltage.