Control device

Control device for controlling an inductive load connected to an output, in particular a radiator fan motor of a motor vehicle, comprising a control circuit generating in accordance with a set value a pulse duration modulation signal having successive switch-on and switch-off intervals, an FET final stage switch for connecting a supply current for the load in accordance with the switch-on and switch-off intervals, said supply current flowing to the output from a voltage supply connection, a switch-on state and a switch-off stage for the switching on and off of a gate voltage of the final stage switch, said stages being controlled by the control circuit in accordance with the switch-on and switch-off interval of the pulse duration modulation signal, and a gate voltage supply for the switch-on stage for generating a gate supply voltage for the through-connection of the final stage switch during the switch-on interval, characterized in that the gate voltage supply (GSV) has a charge pump circuit, comprising a diode (D2) located between a plus connection (PLA) and a center tap (MA) in forward direction and a capacitor (C1) located between the center tap (MA) and a minus connection (MIA), that the center tap (MA) is connected to the switch-on stage (ES) and that a potential at the minus connection (MIA) of the charge pump circuit alters in accordance with a potential at the output (A) and thus a current flowing via the diode (D2) charges the capacitor (C1) during the switch-off interval (AIV) and blocks the diode (D2) during the entire switch-on interval (EIV) and the capacitor (C1) supplies at the center tap (MA) a gate supply voltage (U.sub.GV) corresponding at least to a voltage at the connection (D) of the final stage switch (T1) on the supply side.