Abstract: A control unit has an input with a positive and negative connectors. The control unit also includes an output and with an electronic switch. The switch has a first connector, a second connector and a control connector, and has an on-state resistance between its first and second connector that depends on a control voltage at the control connector of the switch. The first connector is connected to the connector for the positive potential of the input, the second connector is connected to the connector for the positive potential of the output, and the control connector is connected to a trigger circuit. A second controllable switch is also included with a first connector connected to the second connector of the first switch, a second connector connected to the control connector of the first switch, and a control connector connected to the connector for the negative potential of the input.