Patent ID: 6392563
Filing Date: 2002-05-21
Classification: G08G

Abstract:
A traffic light backup system for use with a traffic light, the traffic light comprising at least one enclosure housing a bulb, said traffic light having a primary lead for each of said at least one enclosure and a neutral lead, said bulb being electrically connected to the corresponding primary lead and the neutral lead, the traffic light backup system comprising:an auxiliary light source associated with at least one of said at least one enclosure; rechargeable backup power means associated with said auxiliary light source; at least one primary power supply and power failure detection circuit, for providing power to said rechargeable backup power means during a normal operating condition and for sensing a voltage across said bulb of said at least one enclosure and providing an output related to said voltage; an electronic control module operatively connected to said auxiliary light source, said rechargeable backup power means and said primary power supply and power failure detection circuit, for receiving power from said primary power supply and power failure detection circuit during the normal operating condition in order to recharge said rechargeable backup power means, for receiving said output related to said voltage and for activating said auxiliary light source with said rechargeable backup power means when said electronic control module determines that a power failure has occurred; and a secondary power failure detection circuit for sensing a current in said neutral lead.