Method and device for remote monitoring of led lamps

• US 6,608,485 B2
• Filed: 10/02/2002
• Issued: 08/19/2003
• Est. Priority Date: 11/19/1999
• Status: Expired due to Term

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: Gelcore (General Electric Company)
• Inventors: St-Germain, Nicolas
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Nguyen, Vincent Q.
• Application Number:
  US10/263,327
• Publication Number:
  US 20030042908A1
• Time in Patent Office: 321 Days
• Field of Search: 340/638, 340/641, 340/661, 340/664, 340/907, 340/912, 315/291, 315/302, 315/307, 315/308, 315/119, 315/169.3, 368/89, 361/57, 361/56, 361/104, 361/119, 361/124, 361/125, 361/127, 324/500, 324/522, 324/537, 324/550, 324/424, 324/769
• US Class Current: 324/500
• CPC Class Codes: B61L 2207/02 using light-emitting diodes [LEDs]
• CPC Class Codes: B61L 5/1881 Wiring diagrams for power supply, control or testing
• CPC Class Codes: G01R 31/44 Testing lamps
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/44 with an active control inside an LED matrix
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits

Abstract

LED lamp circuitry that emulates an incandescent lamp'"'"'s behavior upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Claims

1. A voltage control circuit for controlling the amplitude of a voltage signal on a control terminal of a power controller unit itself controlling a voltage and current supply source which supplies a current to a light-emitting load through first and second voltage and current supply lines, said voltage control circuit comprising:

a) a voltage divider circuit connected between said first and second lines and comprising resistors which divide the voltage on the first and second lines to produce a first trigger voltage signal;

b) a first controllable switch member connected in series with a high impedance element between said control terminal and one of said first and second lines to define a high impedance current path between said control terminal and said one line, said first controllable switch member being responsive to the first trigger voltage signal and having a first current-conductive junction established when the first trigger voltage reaches a give amplitude, wherein the high impedance current path produces a second trigger voltage having a first amplitude when the first current-conductive junction is not established and a second amplitude when the first current-conductive junction is established; and

c) a second controllable switch member connected in series with a low impedance element between said control terminal and said one line to define a low impedance current path between said control terminal and said one line, and second controllable switch member being responsive to the second trigger voltage and having a second current-conductive junction established when the second trigger voltage has the first amplitude and non established when the second trigger voltage signal has the second amplitude;

whereby, when said first trigger voltage has an amplitude lower than said given amplitude, the first current-conductive junction is not established to produce in the high impedance current path a second trigger voltage of first amplitude which establishes both the second current-conductive junction and the low impedance current path to result in a voltage signal amplitude on said control terminal which disables said power controller unit and, when the amplitude of the first trigger voltage reaches said given amplitude, both the first current-conductive junction and the high impedance current path are a second trigger voltage of second amplitude whereby both the second current-conductive junction and the low impedance current path are not established to result in a voltage signal amplitude on said control terminal which enables said power controller unit.

2. A voltage control circuit as in claim 1, wherein said light-emitting load comprises a light-emitting diode.

3. A voltage control circuit as in claim 2, wherein said high impedance current path comprises a first resistor and said low impedance current path comprises a second resistor.

4. A voltage control circuit as in claim 3, wherein said first controllable switch member comprises a first transistor having a control electrode responsive to said first trigger voltage.

5. A voltage control circuit as in claim 4, wherein said second controllable switch/member comprises a second transistor having a control electrode responsive to said second trigger voltage signal.

6. A voltage and current supply source as in claim 3, wherein said first controllable switch member comprises a first transistor having a control electrode responsive to said first trigger voltage.

7. A voltage and current supply source as in claim 4, wherein said second controllable switch member comprises a second transistor having a control electrode responsive to said second trigger voltage signal.

8. A voltage and current supply source responsive to alternating voltage and current from an ac source for supplying dc voltage and current to a light-emitting load, comprising:

a) a rectifier unit rectifying the alternating voltage and current from the ac source and supplying the rectified voltage and current to first and second voltage and current supply lines;

b) a converter of the rectified voltage and current into the dc voltage and current supplied to the light-emitting load;

c) a power controller unit having a control terminal and controlling the converter in response to the rectified voltage on the first and second lines; and

d) a voltage control circuit as in claim 1, for controlling the amplitude of a voltage signal on the control terminal of the power controller unit.

9. A voltage and current supply source as in claim 8, wherein said high impedance current path comprises a first resistor and said low impedance current path comprises a second resistor.

10. A voltage control circuit for controlling the amplitude of a voltage signal on a control terminal of a power controller unit itself controlling a voltage and current supply source which supplies a current to a light-emitting load through first and second voltage and current supply lines, said voltage control circuit comprising:

a) means for producing a first trigger voltage in response to the voltage across the first and second lines, said first trigger voltage having an amplitude representative of the amplitude of the voltage across the first and second lines;

b) first switch means, connected in series with a high impedance element between said control terminal and one of said first and second lines, for establishing a high impedance current path between said control terminal and one of said lines when the first trigger voltage reaches a given amplitude, wherein said first switch means comprises means for producing a second trigger voltage having a first amplitude when the high impedance current path is not established and a second amplitude when the high impedance current path is established; and

c) second switch means, connected in series with a low impedance element between said control terminal and one of said lines, for establishing a low impedance current path between said control terminal and one of said lines when the second trigger voltage has the first amplitude;

whereby, when said first trigger voltage has an amplitude lower than said given amplitude, the high impedance current path is not established, a second trigger voltage of first amplitude is produced, and the low impedance current path is established to result in a voltage signal amplitude on said control terminal which disables said power controller unit and, when the amplitude of the first trigger voltage reaches said given amplitude, the high impedance current path is established, a second trigger voltage of second amplitude is produced, and the low impedance current path is not established to result in a voltage signal amplitude on said control terminal which enables said power controller unit.