Home | Links | Contact Us | More About Intellectual Property | Bookmark

Search patents:

Home

Light Fixtures

Circuit-for-interfacing-between-a-conventional-traffic-signal-conflict-monitor-and-light-emitting-diodes-replacing-a-conventional-incandescent-bulb-in-the-signal

Stripline flexible cable to printed circuit board attachment system

In accordance with the foregoing objects, a method of solder attaching an insulated electrical lead ...

Lighting entertainment system

The structure and operation of various methods and systems that are embodiments of the invention ...

Systems and methods for providing illumination in machine vision systems

OF THE ILLUSTRATIVE EMBODIMENTS(S) The description below pertains to several illustrative ...

Vehicular headlamp

Therefore, it is an object of the present invention to provide a vehicular headlamp, which is ...

Draping type decorative light assembly

In accordance with two embodiments of the invention each of three light strings is used to provide ...

Soft light fixture

The present invention is a soft light fixture. In particular, it is an LED soft light fixture. The ...

Counterbalanced lamp having a resiliently bowed spring lever

The main purpose of this invention is "to provide a structure of lighting decoration support that ...

Device and process for measuring and analysing spectral radiation, in particular for measuring and analysing color characteristics

The invention provides a colourimeter which, on the one hand, is simply constructed, but on the ...

Method and apparatus for sensing the color point of an RGB LED white luminary using photodiodes

It is an object of the present invention to overcome disadvantages of the prior art systems and ...

Ring illuminator

This invention provides a ring illuminator having a reduced size. This invention separately ...

Circuit for interfacing between a conventional traffic signal conflict monitor and light emitting diodes replacing a conventional incandescent bulb in the signal

Details

Inventors: Perry, Bradford J.;
Assignee: Precision Solar Controls Inc. (Garland, TX)
Primary Examiner: Vu; David H.
Assistant Examiner:
Attorney, Agent or Firm: Nixon & Vanderhye P.C.

A circuit for interfacing between a conventional traffic signal's control monitor and a plurality of light emitting diodes (LEDs) replacing an incandescent lamp of the traffic signal is disclosed. The interface circuit includes a current source for driving the LEDs with a regulated power factor corrected current. Compatibility with traditional conflict monitors is achieved through a circuit that short circuits incoming current to indicate full turn off of the signal and opens up to indicate full turn on of the signal, and through an "OFC" circuit which presents an open circuit to the conflict monitor upon failure of the traffic signal LEDs. Quick turn-off of the traffic signal LEDs is accomplished with a switching circuit that reduces current flowing through the LEDs below the range for visible turn-off. To minimize light reduction in case of LED failure, the traffic signal LEDs are arranged in either multiple strings of LEDs connected in parallel though multiple substring connections between groups of LEDs, or in a single string of LEDs with reverse biased zener diodes connected in parallel with groups of LEDs.

DETAILED DESCRIPTION Accordingly, it is an object of the present invention to provide an LED traffic signal which presents the type of electrical load that is desirable to utility companies.
It is also an object of the present invention to provide an LED traffic signal in which the LEDs are powered by a regulated current source that maximizes the consistency of output intensity of the traffic signal as a whole.
Another object of the present invention is to provide an LED traffic signal which sufficiently turns off LED arrays so as to eliminate any undesirable glow of LEDs due to residual current flow through the LEDs.
A further object of the present invention is to provide an LED traffic signal which is compatible with conventional incandescent conflict monitors that verify that two signal lights in the traffic signal are not on at the same time, or that a catastrophic failure might have occurred.
Yet another object of the present invention is to arrange the replacement LEDs in a manner that will minimize a reduction in light output in case of a catastrophic LED failure.
The present invention is directed to a circuit for interfacing between a conventional traffic signal's control circuitry and a plurality of light emitting diodes (LEDs) replacing one or more incandescent lamps of the traffic signal.
The interface circuit uses a power factor corrected current source for driving the LEDs.
The current source switches an input current so that input current has an envelope that is substantially the same as the input voltage.
The current source is also regulated by a feedback current so as to control the LEDs' light intensity.
The LED traffic signal interface circuit of the present invention achieves compatibility with the conflict monitors used in conventional traffic signals through the use of a circuit that short circuits incoming current that is below a certain value, indicating signal light turn off, and that opens up when the incoming current exceeds this value, indicating signal light turn on

Related patents

	Lighting apparatus In order to overcome the problems of the prior art described above, the present inventor carried out experiments to determine the relationship between the illuminating ...
	Power-saving lamp The present invention has been accomplished to provide a power-saving lamp, which eliminates the aforesaid drawbacks. It is the main object of the present invention to ...
	Light-emitting diode (LED) package and packaging method for shaping the external light intensity distribution With reference to FIGS. 1 and 2, a preferred embodiment of the invention will be described. The light-emitting diode (LED) package or capsule 10 includes an LED die 12 ...
	Flexible led backlighting circuit What is claimed is: 1. A light emitting diode (LED) device, comprising: a light emitting diode; a light emitting diode drive circuit; a flexible circuit board having a ...
	LED nightlight I claim: 1. A nightlight, comprising: a. a base unit having a front surface, a rear surface, and at least two spaced-apart electric prongs mounted on said rear surface ...
	Method of manufacturing image forming apparatus OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the drawings, preferred embodiments of this invention will be explained in an illustrating manner and in ...
	Display and method for driving the same 1. A display device for selectively discharging a plurality of discharge cells to display an image, comprising: a display panel that includes said plurality of discharge ...
	Light emitting diode display having heat sinking circuit rails OF THE INVENTION FIG. 3 shows a first embodiment of the present invention. A number corrugated metallic partitions 21 are lined up in parallel. The grooves 25 of the ...
	Bicycle lighting system What is claimed is: 1. A lighting system for a vehicle comprising: a) a central housing having an electrical power source therein, said central housing secured to and ...
	Microstrip flexible printed wiring board interconnect line OF THE PREFERRED EMBODIMENT The invention is a class of RF flexible PWB transmission lines used to connect strip transmission line microwave PWB assemblies without the ...

0.004
Archive: All patents - Links Copyright (c)2006 Eipa-patents.org - All rights reserved