Patent ID: 6999292

Claim:
Method for supplying circuit units with an overvoltage present on a high voltage circuit, in which connected items of low voltage equipment are protected from damage due to the applied overvoltage, the method comprising: a) provisioning the high voltage circuit for the application of the overvoltage, which supplies the circuit units; b) provisioning at least one item of low voltage equipment with at least one low voltage circuit for carrying out low voltage circuit functions and with at least one protection voltage source for the provision of at least one protection voltage; c) connecting a protection device for the protection of the items of low voltage equipment from damage due to the overvoltage present on the high voltage circuit in such a way that the protection device is connected in series between the high voltage circuit and the items of low voltage equipment; d) feeding a reference voltage potential in the form of the protection voltage to the protection device via a connection unit, the protection voltage being present between the connection unit and ground, wherein the protection device is a serial protection device that ensures that a maximum voltage value of a low voltaae present at a circuit module is not exceeded; e) clamping, by means of the protection device, of the low voltage, which is applied to a low voltage node, which is arranged between the protection device and the items of low voltage equipment, and which is made available to the items of low voltage equipment, to a voltage value, which does not exceed a definable voltage value of the protection voltage, in such a way that the items of low voltage equipment are protected from damage due to overvoltages; and f) providing a protection current by a protection current source, wherein the protection current prevents the potential present at the low voltage node from varying when a main current flowing into the items of low voltage eguipment becomes zero.