A device and method are disclosed for driving an electromagnet for operating a pump. The electromagnet includes a primary winding and a moving element that is attracted within the primary winding when an energizing current is higher than a first threshold value. The moving element lets a liquid dose into an external hydraulic circuit depending on the a travel of the moving element. A control logic unit detects an energizing current to provide the energizing current to the primary winding until the energizing current assumes a second threshold value, depending on a value of the liquid dose to let into the external hydraulic circuit. The second threshold value is higher than the first threshold value and not higher than a third threshold value in correspondence of which the moving element arrives at a stop.