Long life, fail safe traffic light
AssigneeDialight Corporation
InventorsKevin A. Hebborn, Glenn J. Zingler
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Abstract
The present disclosure is directed to a method for detecting a failure in a signal light. In one embodiment, the method includes monitoring operation of one or more light emitting diodes (LEDs) of the signal light coupled to a constant current driver, detecting a short circuit in at least one of the one or more LEDs and signaling a failure in the signal light when the short circuit is detected.
Claims20
A method for detecting a failure in a signal light, comprising:
- monitoring operation of one or more light emitting diodes (LEDs) of the signal light coupled to a constant current driver;
- detecting a short circuit in at least one of the one or more LEDs;
- and
- signaling the failure in the signal light when the short circuit is detected.
A light signal circuit comprising:
- an AC to direct current (AC-DC) converter for coupling to an AC power supply;
- a controller in communication with the AC-DC converter;
- one or more LEDs coupled to the AC-DC converter;
- an under-current and under voltage sensing circuit coupled to the one or more LEDs;
- and
- a failed state impedance circuit coupled to the under current and under voltage sensing circuit and the control circuit.
An alternating current to direct current (AC-DC) converter for driving one or more light emitting diodes (LEDs) of a signal light, comprising:
- a first diode;
- a first inductor coupled to the first diode;
- a first capacitor coupled to the first inductor, wherein the first capacitor comprises a non-electrolytic capacitor;
- a second diode coupled to the first capacitor and the first diode, wherein the first diode, the first inductor, the first capacitor and the second diode comprise a first loop;
- and
- a switch coupled to the first loop.
Dependencies are inferred from the claim text.