Power resistor

• US 7,843,309 B2
• Filed: 09/27/2007
• Issued: 11/30/2010
• Est. Priority Date: 09/27/2007
• Status: Expired due to Fees

• Current Assignee: Vishay Dale Electronics (Vishay Intertechnology Incorporated)
• Original Assignee: Vishay Dale Electronics (Vishay Intertechnology Incorporated)
• Inventors: Zandman, Felix, Smith, Clark L., Bertsch, Thomas L., Veik, Thomas L., Wyatt, Todd L.
• Primary Examiner(s): LEE, KYUNG S
• Application Number:
  US11/862,572
• Publication Number:
  US 20090085715A1
• Time in Patent Office: 1,160 Days
• Field of Search: 338/195, 338/48, 338/51, 338/260, 338/283, 338/293, 338/307, 338/309, 338/325, 338/332
• US Class Current: 338/195
• CPC Class Codes: H01C 1/014 the resistor being suspended between and being supported by two supporting sections H01C1/016 takes precedence
• CPC Class Codes: H01C 1/08 Cooling, heating or ventilating arrangements
• CPC Class Codes: H01C 13/02 Structural combinations of resistors impedance networks per se H03H
• CPC Class Codes: H01C 17/23 by opening or closing resistor geometric tracks of predetermined resistive values, e.g. snapistors
• CPC Class Codes: Y10T 29/49087 with envelope or housing
• CPC Class Codes: Y10T 29/49098 Applying terminal
• CPC Class Codes: Y10T 29/49101 Applying terminal

Abstract

A resistor includes first and second opposite terminations, a resistive element formed from a plurality of resistive element segments between the first and second opposite terminations, at least one segmenting conductive strip separating two of the resistive element segments, and at least one open area between the first and second opposite terminations and separating at least two resistive element segments. Separation of the plurality of resistive element segments assists in spreading heat throughout the resistor. The resistor or other electronic component may be packaged by bonding to a heat sink tab with a thermally conductive and electrically insulative material. The resistive element may be a metal strip, a foil, or film material.

Claims

1. A resistor, comprising:

first and second opposite terminations;

a resistive element formed from a plurality of resistive element segments between the first and second opposite terminations;

at least one segmenting conductive strip separating two of the resistive element segments;

at least one open area between the first and second opposite terminations and separating at least two resistive element segments;

wherein separation of the plurality of resistive element segments assists in spreading heat throughout the power resistor.

2. The resistor of claim 1 wherein the first termination is formed from a first outer metal strip, the resistive element is formed from a middle strip, and the second opposite termination is from a second opposite outer metal strip, the three strips joined together.

3. The resistor of claim 2 wherein the middle strip comprises a resistive material clad with a conductive material, with a portion of the conductive material etched away.

4. The resistor of claim 1 further comprising:

a heat sink tab, the resistive element bonded to the heat sink tab with a thermally conductive and electrically insulative material to thereby mechanically connect the heat sink tab and the resistive element without short circuiting the heat sink tab to the resistive element; and

a molded body encasing the resistive element.

5. The resistor of claim 1 wherein the resistive element is a thin film resistive element.

6. The resistor of claim 1 wherein the plurality of resistive element segments comprises at least four resistive element segments.

7. The resistor of claim 1 wherein the resistive element is a metal strip resistive element.

8. A method of manufacturing a power resistor, comprising:

forming a joined metal strip providing first and second opposite terminations and a resistive element between the first and second opposite terminations wherein the first termination is formed from a first outer metal strip, the resistive element is formed from a middle strip, and the second opposite termination is formed from a second opposite outer metal strip, the three strips joined together to form the joined metal strip;

segmenting the resistive element into a plurality of resistive element segments between the first and second opposite terminations by providing at least one segmenting conductive strip separating two of the resistive element segments and at least one open area between the first and second opposite terminations and separating at least two resistive element segments;

wherein separation of the plurality of resistive element segments assists in spreading heat throughout the power resistor.

9. The method of claim 8 further comprising bonding the resistive element to a heat sink tab with a thermally conductive and electrically insulative material to thereby mechanically connect the heat sink tab and the resistive element without short circuiting the heat sink tab to the resistive element.

10. The method of claim 9 further comprising connecting at least two terminals to the resistive element.

11. The method of claim 10 further comprising encasing the resistive element within a molded body.

12. A method of manufacturing a power resistor, comprising:

forming a joined metal strip providing first and second opposite terminations and a resistive element between the first and second opposite terminations wherein the first termination is formed from a first outer metal strip, the resistive element is formed from a middle strip, and the second opposite termination is formed from a second opposite outer metal strip, the three strips joined together to form the joined metal strip;

segmenting the resistive element into a plurality of resistive element segments between the first and second opposite terminations;

trimming one or more of the resistive element segments to provide a current path configured to assist in spreading heat throughout the power resistor.

13. The resistor of claim 12 wherein the resistive element is a thin film resistive element.

14. The resistor of claim 12 wherein the trimming pattern includes at least one slot with first and second opposite ends removed from edges of the resistive element.