A patent application titled “Control Unit and Method for Designing a Circuit Board of a Control Unit” has been made available on the U.S. Patent and Trademark website.
Background information supplied by the inventors states, “modern motor vehicles include a multitude of electronic control units, which are installed at different locations in order to assume control or regulation functions. Control units are also used as embedded systems for the control and regulation of machinery, plants and other technical processes. In order to allow a safe operation of a control unit in installation locations where discharges of static electricity (ESD) and other potentially interfering electromagnetic effects are to be expected, adequate electromagnetic compatibility (EMC) of the control unit must be ensured.”
“Industry standards such as ISO 10605:2008 prescribe specific test methods by which the electromagnetic compatibility of a control unit must be checked, in particular with regard to electrostatic discharges. For this purpose, the running control unit is selectively exposed to the effects of an air discharge in close proximity to its housing, and it is monitored whether malfunctions arise in the electronics of the control unit. The mechanism that leads to the malfunction in the electronics system is that the high electrostatic field affects the voltage level of high Ohmic circuit components (e.g., oscillator circuits, inputs of analog-digital converters and open-circuited pins on ICs with weak pullup sources such as test pins, programming pins, sensors). If the voltage level of a circuit experiencing such interference is outside its function range, the electronic system may malfunction.”
“The present invention is based on the idea of placing a conductive protection element, which is connected to ground, in close proximity to the high-impedance circuit component on the circuit board such that the characteristic of an electric field produced by an electrostatic discharge outside the control unit is deflected toward the protection element.”