POWER SUPPLY DEVICE FOR TRAFFIC SIGNAL LIGHT USING PIEZOELECTRIC DEVICE

摘要

PURPOSE: A power supply device for a traffic signal light is provided, which employs a piezoelectric device to use the driving force generated at the piezoelectric device by the loading of vehicles as an electric power of the signal light. CONSTITUTION: The power supply device comprises an illuminance sensor(46); a piezoelectric device(4a, 4b, ..., 4n) which is buried in the inside of outside of a road, and generates high voltage when the outside is pressed; a transformer(38) which converts the high voltage generated at the piezoelectric device into a certain size of voltage; a conductor unit(40) which accumulates the electricity; a switching unit(42) which is connected with the conductor unit and a load(44); and a control unit(48) receives the sensing signal from the illuminance sensor and sends the control signal to the switching unit to control whether a power is turned on or off into the load, and senses the voltage value of the transformer and controls the switching unit for allow the AC power to be supplied to the load if the voltage value is reduced below a certain value.