| 摘要 |
An electronic circuit for powering an LED (light emitting diode) signal lamp, in particular a railway signal lamp, adapted for detecting a failure of the LED signal lamp, comprises
- an LED unit (1), comprising a plurality of LEDs (LED1-LED4) connected in series,
- a first transistor (FET1), connected in series with the LED unit (1), wherein the first transistor (FET1) has a first control input (3), in particular a base or a gate,
- a photo detection subcircuit (PDS) comprising at least one photo detection unit (PDU, PDU1-PDU4), wherein the photo detection subcircuit (PDS) provides a voltage to the first control input (3) in dependence of the illumination of the at least one photo detection unit (PDU, PDU1-PDU4) by the LEDs (LED1-LED4) of the LED unit (1),
- a start capacity (CST) connected in parallel to the first transistor (FET1),
- a signalling unit (SU) comprising a signalling means (SM) connected in series with a second transistor (FET2), wherein the second transistor (FET2) has a second control input (4), in particular a base or a gate, connected to the start capacity (CST). The inventive electronic circuit allows reliable protection of LED failures and offers good protection of the electronic circuit in case of failure of one of the LEDs. |
