Programmable universal lighting system

• US 6,040,661 A
• Filed: 05/12/1998
• Issued: 03/21/2000
• Est. Priority Date: 02/27/1998
• Status: Expired due to Fees

• Current Assignee: Lumion Corporation
• Original Assignee: Lumion Corporation
• Inventors: Bogdan, Alexei
• Primary Examiner(s): VU, DAVID HUNG
• Application Number:
  US09/075,841
• Time in Patent Office: 679 Days
• Field of Search: 315/244, 315/307, 315/291, 315/219, 315/200 R, 315/224, 315/DIG. 4, 315/DIG. 5
• US Class Current: 315/224
• 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: H05B 41/36 Controlling
• CPC Class Codes: H05B 41/3925 by frequency variation H05B41/3922 takes precedence
• CPC Class Codes: H05B 41/3927 by pulse width modulation H05B41/3922 takes precedence
• CPC Class Codes: Y10S 315/04 Dimming circuit for fluorescent lamps

Abstract

A programmable universal ballast can be programmed to accommodate a gas discharge lamp within a relatively wide wattage range. The ballast uses a microprocessor to store and execute various routines to start, run and dim a particular lamp type. A host computer produces customized routines which are downloaded into a microprocessor located within the ballast. These routines output signals to the MOSFET transistors of the inverter which effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. By selectively changing simultaneously both the frequency and duty cycle of the inverter signal, the energy spectrum of the resonance network is altered and circuit voltages and currents can be controlled to accurately match required lamp characteristics and operational requirements. The ballast may include an inductive element in parallel with the lamp allowing dimming to 1% of full light output. The use of this inductive element also results in a simplified and reliable lamp starting procedure and power factor correction.

Claims

1. A universal lamp system comprising:

(a) a lamp having a predetermined set of lamp operating characteristics, said operating characteristics including a lamp running voltage and a filament voltage, said lamp running voltage having a value between a first value and a second value and said lamp filament voltage having a value between a third value and a fourth value;

(b) a universal ballast having;

(i) a first power circuit for outputting a high frequency AC signal;

(ii) a coupling circuit coupled to the power circuit for applying the AC signal to the lamp to provide said lamp running voltage and said filament voltage at said lamp; and

(iii) a control circuit adapted to vary the duty cycle of the AC signal in a range of between about a 50/50 ratio and about a 2/98 ratio and the frequency of the AC signal in a range of between about 20 and about at least 47 kilohertz but not greater than about 55 kilohertz and therefore to vary said lamp running voltage between said first and second values and said filament voltage between said third and fourth values, said first and second values having a difference between them of about 77 percent and said third and fourth values having a difference between them of about 58 percent.

2. The universal lamp system of claim 1 wherein the AC signal is a square wave.

3. The universal lamp system of claim 1 wherein the control circuit includes a controller and a host computer.

4. The universal lamp system of claim 3 wherein said controller includes a microprocessor having a memory.

5. The universal lamp system of claim 3 wherein said host computer is connected to the controller through a port such that a program can be downloaded to the controller to appropriately vary the frequency and duty cycle of the AC signal in accordance with the set of lamp characteristics.

6. The universal lamp system of claim 1, 2, 3, 4 or 5 wherein the coupling circuit includes a capacitor and an inductor in series with the lamp.

7. The universal lamp system of claim 1, 2, 3, 4 or 5 wherein the coupling circuit includes an inductive element across the lamp.

8. The universal lamp system of claim 1, 2, 3, 4, or 5 wherein the lamp has two filaments and wherein three inductors are connected in series across the lamp such that one inductor is connected across each filament.

9. The universal lamp system of claim 1, 2, 3, 4, or 5 wherein the lamp has two filaments and wherein a three winding inductor is connected across the lamp such that a winding is connected across each filament.

10. The universal lamp system according to claim 1, wherein the universal ballast includes an impedance in series with the first power circuit for limiting the current supplied thereto and a controllable switch connected across the impedance, said switch having open and closed states so that when the switch is in the open state the impedance limits the current to the first power circuit, and when the switch is in the closed state current to the first power circuit is not limited by said impedance, and wherein said control circuit is coupled to the controllable switch for maintaining the switch in the open state for a predetermined period of time after the lamp is started and then closing the switch.

11. The lamp system according to claim 10 wherein the circuit includes a second power circuit in series with the first power circuit for supplying a DC voltage to the first power circuit and wherein the impedance comprises a resistance coupled in series between first and second power circuits.

12. The lamp system according to claim 11 wherein the controller includes a microprocessor having a memory.

13. The lamp system according to any one of claims 10, 11 and 12 wherein the lamp includes at least one filament and wherein the current provided by the first power circuit when the switch in the open state is insufficient to strike the lamp but sufficient to preheat the at least one filament when applied for the predetermined period of time.

14. A method of powering any one of a plurality of gas discharge lamp types, each lamp type having a predetermined set of lamp operating characteristics, said method comprising the steps of:

(a) producing a high frequency AC signal;

(b) applying the AC signal to the lamp; and

(c) varying the duty cycle of the AC signal within the range of from about a 50/50 ratio to about a 2/98 ratio and the frequency of the AC signal within the range of from about 20 to about at least 47 kilohertz but not greater than about 55 kilohertz such that the predetermined set of lamp operating characteristics are produced.

15. The method of claim 14 and including storing information about the lamp characteristics in a microprocessor having memory and using said microprocessor to control the step of varying the duty cycle and frequency of the AC signal.

16. A method of dimming a gas discharge lamp, comprising:

(a) establishing an inductance across the lamp;

(b) producing a high frequency AC signal;

(c) applying the AC signal to the lamp;

(d) varying the duty cycle of the AC signal within a range of from about a 50/50 ratio to about a 2/98 ratio and the frequency of the AC signal within the range of from about 20 to at least about 47 kilohertz but not greater than about 55 kilohertz to dim the lamp.