Abstract: A dimmer interface (110, 300) for a dimmable lighting driver (100) for a lighting unit (20) includes: a pulse width modulator (320, 420, 500) configured to generate a pulse width modulated signal (V2) from a dimming control input (Vdim), where the dimming control input (Vdim) is variable to adjust the brightness of the lighting unit (20); a low-pass filter (444) configured to output a dimming control voltage (Vo); and an optocoupler (330, 4300 configured to galvanically couple the pulse width modulated signal (V2) from an output of the pulse width modulator (320, 420, 500) to an input of the low-pass filter (444).