Secure lighting circuit for discharge lamp used in motor vehicle headlamp, uses controller monitoring for anomalies and monitoring circuit for controller, both switching in alternative illumination source if there is a fault

摘要

The lighting circuit has a control circuit (7) that detects any anomalies in the discharge lamp (8) or the lighting circuit and if an anomaly is detected stops the operation of the lighting circuit and activates an alternative light source. Another circuit (26) monitors the state of the control circuit, and if anomaly is detected activates the alternate light source and alerts the driver.