×

Method and device for remote monitoring of led lamps.

  • US 20030067302A1
  • Filed: 10/02/2002
  • Published: 04/10/2003
  • Est. Priority Date: 11/19/1999
  • Status: Active Grant
First Claim
Patent Images

1. A cold filament detection circuit connected between first and second lines through which a voltage and current supply source supplies voltage and current to a light-emitting load, the voltage and current supply source having a set up time during which no current is supplied to the light-emitting load, said cold filament detection circuit comprising:

  • a) a resistor;

    b) a controllable switch member connected in series with the resistor between the first and second lines;

    responsive to the voltage on said first and second lines; and

    having a current-conductive junction established in response to the voltage on the first and second lines to thereby establish through said resistor a current path between said first and second lines; and

    c) a switch control unit responsive to the current supplied to the light-emitting load, connected to the first controllable switch member, and having a switch-disabling circuit which prevents the current-conductive junction to establish as long as current is supplied to the light-emitting load;

    whereby, during the set up time no current is supplied to the light-emitting load and the current path is established through said resistor to emulate the impedance of an incandescent lamp, and when current is supplied to the light-emitting load, said switch-disabling circuit prevents said current-conductive junction to establish whereby said resistor is disconnected from between said first and second lines.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×