Abstract: In a circuit arrangement for switching on a power output stage, in particular for electric motors with a high current draw, the output stage and at least one buffer capacitor connected in parallel with it are connected to an operating voltage source via a relay. A current source which supplies a limited current is connected to the at least one capacitor, bypassing the relay. A delay device is provided, which does not switch on the relay until the at least one capacitor is charged to approximately the operating voltage by the current source.

Abstract: In a method and in a circuit arrangement for transmitting signals from an output of a first circuit to an input of a second circuit, where the circuits have a first and a second operating voltage and a first and a second ground potential applied to them, and where variable potential differences can arise between the ground potentials. A current controlled by the signal which is to be transmitted flows from the output of the first circuit to a circuit point having a further potential applied to it and controls a further current, which emanates from the circuit point and is supplied to the input of the second circuit, and the further potential is chosen such that a respective voltage enabling the current and the further current is present between the output of the first circuit and the further potential, on the one hand, and between the further potential and the input of the second circuit, on the other hand, for the potential differences which arise.

Abstract: In a power supply device to which a DC voltage can be fed and which outputs a stabilized voltage for operating an electronic circuit in a motor vehicle, a step-up converter is arranged between an input for the operating voltage and an output of a voltage regulator, which step-up converter is activated when a battery voltage is below a predefined threshold voltage, and raises the battery voltage to at least the threshold value.

Abstract: A invention relates to a method for monitoring the operating state of a load which is driven cyclically by a control signal, especially for an electric motor in a motor vehicle, the cyclic drive being provided by a pulse-width-modulated drive signal. In a method which permits the detection of the operating state of the load as well as driving the load in accordance with the situation on the basis of the operating state, the drive signal, whose pulse width is varied in order to limit the current flow through the load, is evaluated in order to determine the operating state of the load.

Abstract: In a circuit arrangement for switching on a power output stage, in particular for electric motors with a high current draw, the output stage and at least one buffer capacitor connected in parallel with it are connected to an operating voltage source via a relay. A current source which supplies a limited current is connected to the at least one capacitor, bypassing the relay. A delay device is provided, which does not switch on the relay until the at least one capacitor is charged to approximately the operating voltage by means of the current source.