Interference-free light-emitting means control

Controller (1) for a lighting device (5), where the controller (1) is equipped with an interface circuit (2) and with a drive circuit (3),

• where the interface circuit (2) generates an interface signal (21, 31, 41, 41) depending on a control signal (Vn, 10), and
• where the drive circuit (3) controls the lighting device (5) depending on the interface signal (21, 31, 41, 51),
• where the control signal (Vn, 10) is an alternating voltage signal generated outside of the controller (1), wherein the interface circuit (2) detects when a lower threshold value has been exceeded for at least the majority of the duration of one of two half-waves of the control signal (Vn, 10), and
• the interface circuit (2) generated for each detection of the case when the lower threshold value has been exceeded, a signal pulse with a low level (24) in the interface signal (21, 31, 41, 51), and with a repeated succession of a plurality of such signal pulses having a low level (24), the application of the control signal (Vn, 10) is detected.