The electronic ballast (E) ignites the inert gas mixture in the bulb with a high-voltage pulse of up to 30 kV (4th generation). It causes a spark to flash over between the electrodes of the bulb. The electronic ballast controls the start-up of the bulb so the bulb reaches its operating phase quickly, and then controls the bulb power to a constant 35 W.
A DC converter generates the required voltage for the electronics and the bulb from the vehicle electrical system. The bridge circuit supplies a 300-Hz alternating voltage to operate the xenon bulbs. Several control and safety circuits are integrated in the device.
Several control and safety circuits are integrated in the device.
The system is switched off within 0.2 seconds in the event of:
- A missing or faulty burner
- Damaged wiring harness or bulb part
- Differential current (fault current) greater than 30 mA; the switch-off time becomes shorter the greater the differential current
To protect the ballast electronics, a counting circuit ensures that a faulty bulb is only ignited seven times. After this, it is switched off.
If the cable connector is removed during operation, the voltage connections are practically voltage-free (< 34 V) after < 0.5 seconds, meaning that there is no immediate danger of electric shock should the warning notice not be complied with.