The invention relates to a circuit arrangement, in particular for driving an electrical machine, comprising at least one high-voltage semiconductor bridge circuit having a low-side semiconductor switch and a high-side semiconductor switch, wherein a low-side gate driver is assigned to the low-side semiconductor switch and a high-side gate driver is assigned to the high-side semiconductor switch.
Circuit arrangements of the type mentioned in the introduction are known from the prior art. Semiconductor bridge circuits are often used in inverters in order to switch the phases of an electrical machine during operation. Gate drivers suitable for fast and optimum switching of the phases are generally provided for switching the individual semiconductor switches. In modern vehicles that also have one or more electrical machines as drive machines, it is known to provide voltage systems having different voltage levels. An on-board electrical system having a low voltage level is usually provided, which is used for example for the operation of a radio, interior luminaires or the like. By contrast, a subsystem having a higher voltage level, the so-called high-voltage system, is used for operating an electrical drive machine having a very much higher energy demand than components of the on-board electrical system. Usually, therefore, the semiconductor bridge circuits of an inverter for an electrical drive machine are also assigned to the high-voltage system since they have to switch the high voltages. However, the driving of the gate drivers themselves is usually carried out by the low-voltage on-board electrical system of the vehicle using forward or flyback converters that have to overcome a required isolation barrier between low-voltage and high-voltage systems. The flyback converters, also called boost or buck converters, form a galvanic isolation between the two systems, such that in particular a voltage overloading of the low-voltage system is avoided.