Control device configured to be employed in a switched electrical power supply system to control a DC/DC converter of said switched electrical power supply system, said control device comprising: - a first input terminal and a second input terminal, - a first transistor connected to the second input terminal and provided with a gate intended to be connected to a control unit designed to deliver control signals to its gate, - a second transistor in series with the first transistor, and provided with a gate, - a control assembly designed to control the second transistor, connected to the gate of the second transistor and to the second input terminal and comprising a voltage source (Vdc) and a Zener diode connected in series with the voltage source (Vdc), - several identical patterns, each pattern comprising: - a first connection point and a second connection point, - a capacitor (Cb) connected to the first connection point, - a first Zener diode connected in series with said capacitor (Cb), - a third transistor (T3_i) provided with a gate connected to said first Zener diode and with a source connected to the second connection point, - a second Zener diode connected between the gate and the source of the third transistor (T3_i), - the first added pattern being connected up by its second connection point to the drain of the second transistor and by its first connection point to the gate of the second transistor, - each additional pattern being connected up by its second connection point to the drain of the third transistor (T3_n-1) of the previous pattern and by its first connection point to the gate of the third transistor (T3_n-1) of the previous pattern, the drain of the third transistor of the last pattern being connected to the first input terminal. - a first input terminal and a second input terminal, - a first transistor connected to the second input terminal and provided with a gate intended to be connected to a control unit designed to deliver control signals to its gate, - a second transistor in series with the first transistor, and provided with a gate, - a control assembly designed to control the second transistor, connected to the gate of the second transistor and to the second input terminal and comprising a voltage source (Vdc) and a Zener diode connected in series with the voltage source (Vdc), - several identical patterns, each pattern comprising: - a first connection point and a second connection point, - a capacitor (Cb) connected to the first connection point, - a first Zener diode connected in series with said capacitor (Cb), - a third transistor (T3_i) provided with a gate connected to said first Zener diode and with a source connected to the second connection point, - a second Zener diode connected between the gate and the source of the third transistor (T3_i), - the first added pattern being connected up by its second connection point to the drain of the second transistor and by its first connection point to the gate of the second transistor, - each additional pattern being connected up by its second connection point to the drain of the third transistor (T3_n-1) of the previous pattern and by its first connection point to the gate of the third transistor (T3_n-1) of the previous pattern, the drain of the third transistor of the last pattern being connected to the first input terminal.