The Design Of LED Railway Signals

Railway Signal is a display equipment that commands railway and ensues traffic safety. In this paper, a LED railway signal is designed, which attaches to the railway standards, by deeply analyzing the railway standards.The LED railway signal consists of lighting unit and LED luminous board. The lighting unit mainly completes power converter, power detecting and failure alarm, and supplies energy for the LED luminous board with dual DC/DC Supply Standby. LED luminous board consists of one hundred and three LEDs in series-parallel, which are delivered constant current by LED driver circuit. To not change the existing interlocking equipments, the design offers full backwards compatibility with current signaling systems.This work presents the circuit of lighting unit, which includes supply converter circuit, dual power detect circuit, LED detect and alarm circuit; meantime, by introducing the selection of LED configurations and LED driver modes, proposes the circuit of LED luminous board, which contains the series-parallel LED matrix and low drop out linear LED driver offering constant current.According to the design in this paper, a model machine of LED railway signal is developed. To verify the performance, related qualifications and failure-safety are tested, moreover a field testing is held. The testing and experimental results show the design in this paper is correct and achieves the design goals.