摘要 |
A driver (1) for driving a gas discharge lamp (2) comprises:—a current source (3) generating lamp current, having a setpoint input (4) for receiving a setpoint signal;—a controller (10) generating a current setpoint signal (SM);—a controllable noise signal source (20) generating a pseudo random noise signal (SPRNS);—an adder (22) adding the current setpoint signal (SM) from the controller and the pseudo random noise signal (SPRNS) from the noise signal source, and providing the result to the setpoint input of the current source;—measuring means (40) measuring a characteristic lamp response of the lamp in response to the pseudo random noise signal (SPRNS), and providing to the controller a sense signal;—a memory (30) associated with the controller, having stored therein at least one reference signal. The controller compares the measured lamp response with said predetermined reference signal in the memory, and may switch off the lamp. |