Magnetic electronic fluorescent lamp ballast

• US 5,256,939 A
• Filed: 03/18/1992
• Issued: 10/26/1993
• Est. Priority Date: 10/24/1985
• Status: Expired due to Fees

• Current Assignee: Ole K Nilssen
• Original Assignee: Ole K Nilssen
• Inventors: Nilssen, Ole K.
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): Neyzari, Ali
• Application Number:
  US07/853,876
• Time in Patent Office: 587 Days
• Field of Search: 315/97, 315/102, 315/103, 315/105, 315/106, 315/107, 315/DIG. 2, 315/242, 315/247, 315/DIG. 5
• US Class Current: 315/244
• CPC Class Codes: H05B 41/295 with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
• CPC Class Codes: Y10S 315/05 Starting and operating circuit for fluorescent lamp

Abstract

A magnetic-type ballast powers an F40/T12 four foot fluorescent lamp from a regular 120 Volt/60 Hz power line by way of a main inductor. A power factor correction capacitor is connected in series with an auxiliary inductor of relatively small inductance value, thereby forming a series-combination; which series-combination is connected across the power line. A 30 Volt/60 Hz voltage is established across this auxiliary inductor. The phasing of this 30 Volt/60 Hz voltage is opposite that of the 120 Volt/60 Hz power line voltage. Thus, by adding the 30 Volt/αHz voltage to the 120 Volt/60 Hz voltage, a 150 Volt/60 Hz voltage is obtained; which 150 Volt/60 Hz voltage is of magnitude adequate to properly power the F40/T12 four foot fluorescent lamp, although it is not of magnitude adequate to provide proper lamp ignition in a rapid-start mode.

A small inverter-type power supply is used for providing cathode heating power to the lamp'"'"'s thermionic cathodes as well as for providing lamp ignition voltage by way of a relatively high-magnitude (250 Volt) high-frequency (30 kHz) voltage supplied to the lamp through a high-pass filter and operative to rapid-start the lamp. After the lamp has been rapid-started by this 250 Volt/30 kHz ignition voltage, it is ready to be properly powered by the 150 Volt/60 Hz voltage.

After lamp ignition, power output from the power supply is halted, thereby removing both cathode heating power as well as lamp ignition voltage.

Claims

1. An arrangement characterized by comprising:

inductor means connected with an ordinary electric utility power line and operative to provide a manifestly current-limited AC voltage at a pair of output terminals;

the frequency of the AC voltage being substantially equal to the frequency of the voltage normally present on said power line;

gas discharge lamp connected with these output terminals and operative, but only after having been ignited, to be properly powered by the current-limited AC voltage provided therefrom, the lamp having thermionic cathodes;

cathode power supply means connected in circuit with the power line and operative to provide low-voltage heating power for the thermionic cathodes; and

ignition power supply means connected in circuit with the power line and operative to provide an ignition voltage across the lamp, this ignition voltage being;

i) of frequency substantially higher than that of the AC voltage, ii) capable, but only after the cathodes have become hot, of causing lamp ignition, and iii) provided independently of any current flowing through the inductor means;

thereby causing the lamp to ignite by way of the ignition voltage and, after having been ignited, to be properly powered from the AC voltage.

2. The arrangement of claim 1 wherein the ignition voltage is removed after the lamp has ignited.

3. The arrangement of claim 1 wherein the cathode heating power is removed after the lamp has ignited.

4. The arrangement of claim 1 wherein lamp ignition is accomplished in rapid-start manner.

5. The arrangement of claim 1 wherein the cathode power supply means is at least partly combined with the ignition power supply means, thereby having a number of components in common.

6. The arrangement of claim 1 wherein the magnitude of the AC voltage before lamp ignition is about fifty percent larger than it is after lamp ignition.

7. The arrangement of claim 1 wherein the magnitude of the ignition voltage before lamp ignition is about two to three times larger than it is after lamp ignition.

8. In an arrangement characterized by:

a) having inductor means connected in circuit with an ordinary electric utility power line and operative to provide a manifestly current-limited AC voltage at a pair of output terminals, the AC voltage being of relatively low frequency; and

b) having a gas discharge lamp connected with these output terminals and operative, but only after having been ignited, to be fully powered by the current-limited AC voltage provided therefrom, the lamp having thermionic cathodes;

the improvement comprising;

auxiliary power supply connected in circuit with the power line and operative to provide low-voltage cathode heating power for the cathodes and a high-frequency ignition voltage across the lamp, this ignition voltage being;

i) of relatively high frequency, ii) productive of causing lamp ignition, but only after the cathodes have become hot, iii) inoperative to provide enough current to fully power the lamp, and iv) provided independently of any current flowing through the inductor means;

thereby causing the lamp to ignite by way of the high frequency ignition voltage and, after having been ignited, to be fully powered from the low frequency AC voltage.

9. The improvement of claim 8 wherein the ignition voltage is removed after the lamp has ignited.

10. The improvement of claim 8 wherein the cathode heating power is removed after the lamp has ignited.

11. An arrangement comprising:

an ordinary electric utility power line operative to provide a substantially non-current-limited AC voltage between a live and a reference power line terminal;

a capacitor means connected between the live power line terminal and an auxiliary junction;

an auxiliary inductor means connected between the auxiliary junction and the reference power line terminal, thereby causing an auxiliary voltage to be present at this auxiliary junction, the phasing of this auxiliary voltage being substantially opposite to that of the voltage present at the live power line terminal; and

a gas discharge lamp connected at a cathode junction with a main current-limiting inductor to form a series-combination, this series-combination being connected between the live power line terminal and the auxiliary junction;

such that a current-limited AC voltage is provided across this series-combination, where the magnitude of this current-limited AC voltage is larger than that of the non-current-limited AC voltage, thereby permitting proper operation of the gas discharge lamp even though the magnitude of the voltage required for its proper operation may be higher than that of the voltage available directly from the power line.

12. The arrangement of claim 11 and lamp ignition means connected in circuit between the power line and the cathode junction and operative to cause the lamp to ignite even though the magnitude of the current-limited AC voltage may by itself be inadequate to cause lamp ignition.

13. The arrangement of claim 12 wherein:

i) the gas discharge lamp means comprises thermionic cathodes, and ii) the ignition means is operative to provide low-voltage heating power for these cathodes.

14. The arrangement of claim 11 wherein, at the fundamental frequency of the voltage on the power line, the net impedance of the series-combination of the capacitor means and the auxiliary inductor means is predominantly capacitive.

15. The arrangement of claim 11 wherein the series-combination of the capacitor means and the auxiliary inductor means is non-resonant at any of the harmonics of the voltage present on the power line.