Switching power supply for discharge lamp and method for powering a lamp

• US 20030184242A1
• Filed: 05/30/2003
• Published: 10/02/2003
• Est. Priority Date: 06/08/1999
• Status: Active Grant

• Current Assignee: Lempi SA
• Original Assignee: Lempi SA
• Inventors: Denes, Alain
• Granted Patent: US 6,888,320 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H01R 33/945 Holders with built-in electrical component
• CPC Class Codes: H01R 33/9453 for screw type coupling devices
• CPC Class Codes: H05B 41/2851 for protecting the circuit against abnormal operating conditions
• CPC Class Codes: H05B 41/36 Controlling

Abstract

The invention concerns a method for powering a discharge lamp with a switching power supply. Said method is characterised in that it consists in: applying a voltage firing the lamp, then after the lamp has been energized, applying a lower service voltage to the firing voltage. The firing and service voltages ages can be generated by using a resonant circuit at the terminals of which a chopped voltage is applied with different frequencies. The invention also concerns a light source comprising a discharge lamp and a switching power supply. Said light source can be equipped with devices for measuring several parameters, such as power, light intensity or the amplitude of vibrations. The invention is useful for producing public lighting.

Claims

1. A method for powering a discharge lamp with a switch mode power supply, comprising the steps:

of applying a lamp startup voltage to the lamp;

after starting the lamp, of applying a service voltage lower than the startup voltage.

2. The power supply method as claimed in claim 1, wherein:

the switch mode power supply comprises a resonant circuit supplying the lamp;

the resonant circuit provides the startup voltage to the lamp when a voltage chopped at a first frequency is applied thereto and provides the service voltage to the lamp when a voltage chopped at another frequency is applied thereto.

3. The power supply method as claimed in claim 1 or 2, wherein the service voltage is applied to the lamp after a specific duration of startup voltage application or when a threshold of current flowing through the lamp is reached or when a threshold of light intensity of the lamp is reached.

4. A light source comprising:

a discharge lamp;

a switch mode power supply powering the discharge lamp.

5. The light source of claim 4, wherein the switch mode power supply supplies the lamp selectively with at least one startup voltage and with a service voltage lower than the startup voltage.

6. The light source of claim 5, wherein the switch mode power supply supplies the lamp with the service voltage after startup.

7. The light source of claim 6, wherein the switch mode power supply comprises means for determining the end of startup as a function of the duration of startup voltage application, as a function of the current flowing through the lamp or as a function of the light intensity emitted by the lamp.

8. The light source according to claim 5, wherein the switch mode power supply further comprises:

a resonant circuit providing the startup voltage to the lamp when a voltage chopped at a first frequency is applied thereto and providing the service voltage to the lamp when a voltage chopped at another frequency is applied thereto.

9. The light source according to claim 8, wherein the resonant circuit is an LC circuit.

10. The light source of claim 5, wherein the switch mode power supply further comprises:

voltage chopping means;

a transformer supplied by the chopping means and having;

a first output providing the startup voltage;

a second output supplying the service voltage;

means for selectively applying the startup voltage and the service voltage to the lamp.

11. The light source of claim 4, wherein the switch mode power supply further comprises a transceiver controlling the ignition/extinction of the lamp.

12. The light source as claimed in claim 4, wherein the switch mode power supply further comprises a control circuit carrying out at least one of the following measurements:

measurement of the electric current consumed by the lamp;

measurement of the external temperature or of the control circuit;

measurement of the external brightness;

measurement of the phase shift between current and voltage supplying the lamp;

measurement of external vibration;

measurement of external shock;

the control circuit preferably comprising a memory for storing one or more of the measurements carried out.

13. The light source as claimed in claim 11, wherein the switch mode power supply further comprises a control circuit carrying out at least one of the following measurements:

measurement of the electric current consumed by the lamp;

measurement of the external temperature or of the control circuit;

measurement of the external brightness;

measurement of the phase shift between current and voltage supplying the lamp;

measurement of external vibration;

measurement of external shock;

the control circuit preferably comprising a memory for storing one or more of the measurements carried out.

14. The light source of claim 13, wherein the transceiver transmits the measurements from the control circuit.