Control unit and method for designing a circuit board of a control unit

• US 8,943,460 B2
• Filed: 07/12/2011
• Issued: 01/27/2015
• Est. Priority Date: 09/10/2010
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Huebl, Jochen, Keicher, Michael
• Primary Examiner(s): DO, THUAN V
• Application Number:
  US13/820,561
• Publication Number:
  US 20130223024A1
• Time in Patent Office: 1,295 Days
• Field of Search: 716/137, 716/139
• US Class Current: 716/137
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement
• CPC Class Codes: H05K 1/02 Details
• CPC Class Codes: H05K 1/0213 Electrical arrangements not otherwise provided for
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 2201/10295 Metallic connector elements partly mounted in a hole of the PCB
• CPC Class Codes: H05K 9/0067 Devices for protecting against damage from electrostatic discharge
• CPC Class Codes: Y02T 10/82 Elements for improving aerodynamics

Abstract

A control unit, e.g., for a motor vehicle, includes a circuit board, a high-impedance circuit component situated on the circuit board and having an impedance of 1 kΩ or higher in relation to ground of the control unit, and at least one conductive protection element electrically connected to ground and situated adjacent to the high-impedance circuit component. The protection element has a height within a protective distance from the high-impedance circuit component that is at least equal to the protective distance. A method for designing a circuit board of a control unit, and a computer program product for executing the method, include the steps of specifying a position of the high-impedance circuit component, and specifying a position of the protection element such that the protection element has a height within a protective distance from the high-impedance circuit component that is at least equal to the protective distance.

Claims

1. A control unit, comprising:

a circuit board;

a high-impedance circuit component situated on the circuit board and having an impedance of 1 kΩ

or higher in relation to ground of the control unit; and

at least one conductive protection element;

that is electrically connected to ground;

that is situated, adjacent to the high-impedance circuit component on the circuit board, to, within a protective distance from the at least one conductive protection element, deflect electric field components produced outside the control unit away from the high-impedance circuit component; and

a height of which is at least equal in length to the protective distance.

2. The control unit according to claim 1, further comprising:

a housing made of an essentially non-conductive material.

3. The control unit according to claim 2, wherein a conductivity of the housing is less than 1 mS.

4. The control unit according to claim 1, wherein the high-impedance circuit component includes at least one of an oscillator, a sensor, an input of an analog-digital converter and an open-circuited connection terminal of an integrated circuit.

5. The control unit according to claim 1, wherein a base area of the high-impedance circuit component on the circuit board essentially lies inside the protective distance about a section of the circuit board above which the at least one protection element has the height.

6. The control unit according to claim 5, wherein the high-impedance circuit component essentially lies within a protection region around the at least one protection element, the protection region being formed by superimposing a multitude of right circular cones, each having an opening angle of 90°

, a cone apex on the at least one protection element, and a base circular plane on the circuit board.

7. The control unit according to claim 1, wherein the at least one protection element is developed essentially in a shape of a rod or plate projecting perpendicularly from the circuit board.

8. The control unit according to claim 1, wherein the at least one protection element includes a pressfit pin which is retained in an opening of the circuit board and fixates the circuit board in the control unit.

9. The control unit according to claim 8, wherein the pressfit pin fixes the circuit board in place in the control unit.

10. The control unit according to claim 1, wherein the at least one protection element includes a circuit component which is connected to ground at at least one connection terminal.

11. The control unit according to claim 10, wherein the at least one protection element is a capacitor, a transistor, or a diode.

12. The control unit according to claim 1, wherein the arrangement of the at least one conductive protection element is such that the electric field components produced outside the control unit are deflected towards the at least one conductive element, away from the high-impedance circuit component.

13. The control unit according to claim 12, wherein the electric field components that are deflected are ones produced by an electrostatic discharge occurring outside the control unit and above the high-impedance circuit component.

14. The control unit according to claim 13, wherein the electric field components are field lines of an electric field produced by the electrostatic discharge.

15. A computer-implemented method for designing a circuit board of a control unit, comprising:

specifying, by a computer processor, a position of a high-impedance circuit component, which has an impedance of 1 kΩ

or higher in relation to ground of the control unit, on the circuit board;

specifying, by the processor, a position, adjacent to the high-impedance circuit component on the circuit board, of at least one conductive protection element electrically connected to ground, such that the at least one protection element, within a protective distance from the at least one protection element, deflects electric field components produced outside the control unit away from the high-impedance circuit component;

wherein a height of the at least one protection element is at least equal in length to the protective distance.

16. A non-transitory computer readable storage device storing a computer program that is executable by a computer processor, the program which, when executed by the processor, causes the processor to perform a method for designing a circuit board of a control unit, the method comprising:

specifying a position of a high-impedance circuit component, which has an impedance of 1 kΩ

or higher in relation to ground of the control unit, on the circuit board;

specifying a position, adjacent to the high-impedance circuit component on the circuit board, of at least one conductive protection element electrically connected to ground, such that the at least one protection element, within a protective distance from the at least one protection element, deflects electric field components produced outside the control unit away from the high-impedance circuit component;

wherein a height of the at least one protection element is at least equal in length to the protective distance.