The present invention relates to a driver device (30) for driving a load (32), in particular an LED unit (32) having one or more LEDs, comprising input terminals (45) for receiving an input voltage (V14) from an external power source (12) for powering the load (32), a current path (46) including a controllable switch (50) for connecting the input terminals (45) to each other, a measurement path (48) including a resistor (56, 58, 84, 86) connecting the input terminals (45) to each other for providing an alternating voltage corresponding to the input voltage (V14) and including a measuring device (64, 70) for measuring the alternating voltage (V15) at the measurement path (48), and a controller (54, 62) for controlling the controllable switch (50) on the basis of the measured alternating voltage.