The present technology provides a high-pressure sodium lamp lighting device that reduces occurrence of the acoustic resonance phenomenon. A high-pressure sodium lamp lighting device of one aspect of the present invention comprises a high-pressure sodium lamp of arc length AL within the scope of 142.8 mmAL167 mm. The lighting device also includes an electronic ballast configured to supply a high frequency AC voltage to the high-pressure sodium lamp. A lighting frequency of the electronic ballast is a frequency that avoids a first and a second acoustic resonance occurrence bands f1 kHz and f2 kHz determined based on equations from an arc tube inner diameter D mm of the high-pressure sodium lamp. The equation for f1 is a range of f1min to f1max=(7.4D+130) to (8.3D+156). The equation for f2 is a range of f2 min to f2max=(11.5D+200) to (10.0D+197).

The present disclosure relates to a starting device for a CDM lamp, comprising: a full-bridge inverter, which at least provides an output as a starting power source to initiate the CDM lamp to work normally; a driving circuit for driving the full-bridge inverter; a single-chip microcomputer, which is connected to the driving circuit; an ignition determining module, one end of which is connected to the full-bridge inverter to sense whether the output of the full-bridge inverter has powered on the CDM lamp, so as to determine whether ignition of the CDM lamp succeeds and then output a result of the determining to the single-chip microcomputer via the other end. The present disclosure provides a novel starting device for a CDM lamp, which facilitates determining whether starting of the CDM lamp succeeds and also facilitates enhancement of successful rate of starting the CDM lamp subsequently.

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.