Electric discharge protection for surface mounted and embedded components

• US 9,320,135 B2
• Filed: 02/25/2011
• Issued: 04/19/2016
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Littelfuse Incorporated
• Inventors: Kosowsky, Lex, Fleming, Robert, Graydon, Bhret, Vasquez, Daniel
• Primary Examiner(s): Semenenko, Yuriy
• Application Number:
  US13/035,791
• Publication Number:
  US 20110211319A1
• Time in Patent Office: 1,880 Days
• Field of Search: 174250-268, 361/56, 361/191.1, 361/111, 361/127, 361760-764
• US Class Current: 1/1
• CPC Class Codes: H05K 1/0254 High voltage adaptations; Electrical insulation details; Overvoltage or electrostatic discharge protection electrostatic discharge protection for electric apparatus in general H05K9/0067, H05K9/0079; Arrangements for regulating voltages or for using plural voltages
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/0738 Use of voltage responsive materials, e.g. voltage switchable dielectric or varistor materials
• CPC Class Codes: H05K 2203/304 Protecting a component during manufacturing

Abstract

Printed circuit boards including voltage switchable dielectric materials (VSDM) are disclosed. The VSDMs are used to protect electronic components, arranged on or embedded in printed circuit boards, against electric discharges, such as electrostatic discharges or electric overstresses. During an overvoltage event, a VSDM layer shunts excess currents to ground, thereby preventing electronic components from destruction or damage.

Claims

1. A printed circuit board, comprising:

at least one conductor;

a voltage switchable dielectric material (VSDM) layer applied to the at least one conductor;

an electronic component having at least one lead and disposed on the VSDM layer, wherein the at least one lead is electrically coupled to the VSDM layer;

a via; and

a conductive pad connected to the conductor by the via,

wherein the VSDM layer comprises an active volume defined by a gap between the at least one lead and the conductive pad, wherein the active volume to pass current through to a ground during an overvoltage event.

2. The printed circuit board of claim 1, wherein the electronic component is a surface mounted component.

3. The printed circuit board of claim 2, wherein the surface mounted component includes one or more of a resistor, an inductor, and a capacitor.

4. The printed circuit board of claim 2, wherein the surface mounted component includes one or more of a diode, a transistor, a semiconductor device, a circuit, a chip, and an integrated circuit.

5. The printed circuit board of claim 1, wherein the VSDM layer is incorporated within a non-conductive layer.

6. The printed circuit board of claim 1, wherein the VSDM layer is disposed between at least two non-conductive layers.

7. The printed circuit board of claim 1, wherein the electronic component comprises a thin film resistive layer.

8. A printed circuit board, comprising:

at least one non-conductive layer;

at least one conductor;

a voltage switchable dielectric material (VSDM) layer applied to one of the at least one non-conductive layer;

an electronic component having at least one lead and is mounted to the VSDM layer, wherein the at least one lead is electrically coupled to the VSDM layer; and

a via; and

a conductive pad connected to the conductor by the via,

wherein the VSDM layer comprises an active volume defined by a gap between the at least one lead and the conductive pad, wherein the active volume to pass current through to a ground during an overvoltage event.

9. The printed circuit board of claim 8, wherein the electronic component is a surface mounted component.

10. The printed circuit board of claim 9, wherein the surface mounted component includes one or more of a resistor, an inductor, and a capacitor.

11. The printed circuit board of claim 9, wherein the surface mounted component includes one or more of a diode, a transistor, a semiconductor device, a circuit, a chip, and an integrated circuit.

13. The printed circuit board of claim 8, wherein the VSDM layer is disposed between at least two non-conductive layers.

14. The printed circuit board of claim 8, wherein the electronic component comprises a thin film resistive layer.

12. The printed circuit board of 8, wherein the VSDM layer is incorporated within the at least one non-conductive layer.