Circuit board with thermal control

• US 9,693,446 B2
• Filed: 12/10/2014
• Issued: 06/27/2017
• Est. Priority Date: 12/13/2013
• Status: Active Grant

• Current Assignee: Endress+Hauser Conducta Gesellschaft FUER Mess- und Regeltechnik mbH+Company KG
• Original Assignee: Endress+Hauser Conducta Gesellschaft FUER Mess- und Regeltechnik mbH+Company KG
• Inventors: Ragg, Thomas
• Primary Examiner(s): Smith, Courtney
• Assistant Examiner(s): Matey, Michael
• Application Number:
  US14/566,126
• Publication Number:
  US 20150173173A1
• Time in Patent Office: 930 Days
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 1/0212 Printed circuits or mounted components having integral heating means
• CPC Class Codes: H05K 2203/1115 Resistance heating, e.g. by current through the PCB conductors or through a metallic mask
• CPC Class Codes: H05K 7/205 Heat-dissipating body thermally connected to heat generating element via thermal paths through printed circuit board [PCB] details of PCBs relating to heat transfer H05K1/0201

Abstract

A printed circuit board comprises a base material containing at least one conductor path and at least one heat-conducting path forming a heating layer embedded in the base material for generating and conducting heat. The circuit board is characterized in that the heat-conducting path comprises a PTC thermistor with a constant voltage applied thereto. The invention further relates to a plug-in module comprising such a circuit board, and additionally to a field device comprising such a circuit board and/or such a plug-in module.

Claims

1. A printed circuit board (PCB), comprising:

a base material including at least one electrically conductive path adapted to connect through an electrical contact to an electronic component on a component layer;

at least one heat-conducting path forming a heating layer embedded in the base material for generating and conducting heat;

wherein each heat-conducting path forms a positive temperature coefficient (PTC) thermistor or resistor;

wherein a constant voltage is applied to each heat-conducting path; and

wherein the applied constant voltage results in a corresponding flow of electrical current that heats the PCB to a temperature specific to the applied constant voltage, until a balance is reached between the amount of heat generated and dissipated, resulting in a self-control of the PCB temperature.

2. The printed circuit board according to claim 1, including at least two, separately controlled heat-conducting paths.

3. The printed circuit board according to claim 1, including heat-conducting paths positioned below and/or above the component layer.

4. The printed circuit board according to claim 1, including a thermal via connecting at least one of the heat-conducting paths to the component layer.

5. The printed circuit board according to claim 4, including the thermal via that is thermally conductive but not electrically conductive.

6. The printed circuit board according to claim 4, including the thermal via that directly connects a heat-conducting path to the electrical contact.

7. The printed circuit board according to claim 4, including the thermal via that connects a heat-conducting path to a conductive surface that makes contact with the electronic component.

8. The printed circuit board according to claim 1, wherein the heat-conducting path heats the electronic component to its lowest operating temperature.

9. The printed circuit board according to claim 1, wherein the heat-conducting path heats the electronic component to an operating temperature of −

40°

C.

10. The printed circuit board according to claim 1, further comprising a heatsink for radiating the heat produced by the printed circuit board.

11. A field device, comprising:

at least one plug-in module including a printed circuit board (PCB) composed of a base material including at least one electrically conductive path adapted to connect through an electrical contact to an electronic component on a component layer;

at least one heat-conducting path forming a heating layer embedded in the base material of the PCB for generating and conducting heat;

wherein each heat-conducting path forms a positive temperature coefficient (PTC) thermistor or resistor; and

wherein a constant voltage is applied to each heat-conducting path; and

wherein the applied constant voltage results in a corresponding flow of electrical current that heats the PCB to a temperature specific to the applied constant voltage, until a balance is reached between the amount of heat generated and dissipated, resulting in a self-control of the PCB temperature.

12. The field device according to claim 11, wherein the PCB includes at least two, separately controlled heat-conducting paths.

13. The field device according to claim 11, wherein the PCB includes heat-conducting paths positioned below and/or above the component layer.

14. The field device according to claim 11, wherein the PCB includes a thermal via connecting at least one of the heat-conducting paths to the component layer.

15. The field device according to claim 14, wherein the PCB includes the thermal via that is thermally conductive but not electrically conductive.

16. The field device according to claim 14, wherein the PCB includes the thermal via that directly connects a heat-conducting path to the electrical contact.

17. The field device according to claim 14, wherein the PCB includes the thermal via that connects a heat-conducting path to a conductive surface that makes contact with the electronic component.

18. The field device according to claim 11, wherein the heat-conducting path of the PCB heats the electronic component to its lowest operating temperature.

19. The field device according to claim 11, wherein the heat-conducting path of the PCB heats the electronic component to an operating temperature of −

40°

C.

20. The field device according to claim 11, wherein the PCB a heatsink for radiating the heat produced by the PCB in to the field device.

21. The field device according to claim 11, further comprising one or more of the following:

a data processing unit;

a transmitter; and

a sensor.