The present invention discloses a device and a method for the redundant voltage supply of safety-relevant systems, in particular in motor vehicles. Both a failure of a voltage supply to safety-relevant systems is detected and a switchover to another voltage supply is initiated in response to this, and it is also ensured that even if one or two drive devices for switching over the voltage fail, a fallback level is available which then switches over the voltage. This ensures, both if a voltage supply to safety-relevant systems fails and if drive devices fail, that voltage is nevertheless switched over and in this way the availability of safety-relevant systems is considerably improved.