Vehicle circuit arrangement for the electrical supply of a first electrical load of a vehicle with a voltage which is down-converted with respect to a vehicle on-board voltage and for the supplementary reverse-polarity protected supply of at least one second electrical load with an unconverted vehicle on-board voltage, the second electrical load comprising a control device for controlling a vehicle function, the vehicle circuit arrangement comprising the following: - a vehicle on-board voltage input for supplying the vehicle on-board voltage, - a linear regulator, which can be electrically connected to the vehicle on-board voltage input, for outputting the voltage, which has been converted downwards with respect to the vehicle on-board voltage, for the electrical supply of the first load, characterized in that the vehicle circuit arrangement further comprises - has a DCDC voltage converter which is connected to the vehicle on-board voltage input and is separate from the linear regulator and has a voltage output, the voltage output being connected to the linear regulator for the electrical supply of the linear regulator, the DCDC voltage converter being set up for outputting a basic voltage which is lower than the supplyable vehicle on-board voltage and a voltage which is higher than the supplyable vehicle on-board voltage to the same voltage output, the increased voltage and the basic voltage being output in a clocked manner in a time-duration ratio, the lowered basic voltage being greater than or equal to the down-converted voltage of the linear regulator, wherein the second load is connected to the vehicle on-board voltage input via a series-connected n-channel mosfet, which is provided as reverse polarity protection, wherein the source terminal of the n-channel mosfet is connected to the vehicle on-board voltage input, the drain terminal of the n-channel mosfet is connected to the second load and the gate of the n-channel mosfet can be permanently supplied and controlled via the DCDC converter by the voltage, which is higher than the vehicle on-board voltage, if the polarity of the vehicle on-board voltage is correct, in that a diode is connected between the voltage output of the DCDC converter and the gate of the n-channel mosfet for the directional supply of the gate, and the gate is also connected to a capacitor, which smoothes the increased voltage supplied by the diode and thus enables the n-channel mosfet to be permanently switched through when the polarity is correct, whereby in the event of reverse polarity of the vehicle on-board voltage at the vehicle on-board voltage input, the n-channel mosfet automatically blocks in the absence of through-control of the gate and thus electrically isolates the second load from the vehicle on-board voltage input and thus from the reverse-polarity vehicle on-board voltage. - a vehicle on-board voltage input for supplying the vehicle on-board voltage, - a linear regulator, which can be electrically connected to the vehicle on-board voltage input, for outputting the voltage, which has been converted downwards with respect to the vehicle on-board voltage, for the electrical supply of the first load, the vehicle circuit arrangement further comprises - has a DCDC voltage converter which is connected to the vehicle on-board voltage input and is separate from the linear regulator and has a voltage output, the voltage output being connected to the linear regulator for the electrical supply of the linear regulator, - has a DCDC voltage converter which is connected to the vehicle on-board voltage input and is separate from the linear regulator and has a voltage output, the voltage output being connected to the linear regulator for the electrical supply of the linear regulator, the DCDC voltage converter being set up for outputting a basic voltage which is lower than the supplyable vehicle on-board voltage and a voltage which is higher than the supplyable vehicle on-board voltage to the same voltage output, the increased voltage and the basic voltage being output in a clocked manner in a time-duration ratio, the lowered basic voltage being greater than or equal to the down-converted voltage of the linear regulator, wherein the second load is connected to the vehicle on-board voltage input via a series-connected n-channel mosfet, which is provided as reverse polarity protection, wherein the source terminal of the n-channel mosfet is connected to the vehicle on-board voltage input, the drain terminal of the n-channel mosfet is connected to the second load and the gate of the n-channel mosfet can be permanently supplied and controlled via the DCDC converter by the voltage, which is higher than the vehicle on-board voltage, if the polarity of the vehicle on-board voltage is correct, in that a diode is connected between the voltage output of the DCDC converter and the gate of the n-channel mosfet for the directional supply of the gate, and the gate is also connected to a capacitor, which smoothes the increased voltage supplied by the diode and thus enables the n-channel mosfet to be permanently switched through when the polarity is correct, whereby in the event of reverse polarity of the vehicle on-board voltage at the vehicle on-board voltage input, the n-channel mosfet automatically blocks in the absence of through-control of the gate and thus electrically isolates the second load from the vehicle on-board voltage input and thus from the reverse-polarity vehicle on-board voltage.