EMI reduction device and assembly
AssigneeHewlett-Packard Company
InventorsHans T. Mellberg, Bertram Kim Cheong Chan, Susannah Gardner
Life of this patent
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Abstract
An EMI reduction device is coupled between a printed circuit board (PCB) assembly and a heat sink. The PCB assembly includes a processor core that is the source of unintentional electromagnetic interference (EMI). The EMI reduction device is attached to a heat sink which is positioned over the processor core such that it capacitively couples emissions from the processor core to a grounding plane resident in the PCB assembly, thereby reducing the unintentional EMI. Simultaneously, the EMI reduction device is able to maintain thermal contact with the heat sink.
Claims20
An electronic assembly, comprising:
- a circuit board having a top surface and a bottom surface, the circuit board including an electronic device mounted on the top surface thereof;
- a thermal dissipation device positioned over the top surface of the circuit board and thermally contacting the electronic device;
- and
- an Electromagnetic Interference (EMI) reduction device interposed between the circuit board and the thermal dissipation device, the EMI reduction device having top surface and a bottom surface, the EMI reduction device including a plurality of mounting tabs projecting from the top surface thereof and a plurality of spring fingers projecting from the bottom surface thereof,
- wherein the EMI reduction device is attached to the thermal dissipation device via the mounting tabs, and wherein the EMI reduction device contacts the circuit board via the spring fingers.
An Electromagnetic Interference (EMI) reduction device capable of reducing electromagnetic emissions emanating from an electronic device of a circuit board, the EMI reduction device comprising:
- a frame having a top surface and a bottom surface;
- a plurality of mounting tabs projecting from the top surface of the frame, the mounting tabs adapted to couple the EMI reduction device to a thermal dissipation device;
- and
- a plurality of spring fingers projecting from the bottom surface of the frame, the spring fingers adapted to contact the circuit board at points surrounding the electronic device and position the frame relative to the circuit board.
A method of reducing Electromagnetic Interference (EMI) emissions emanating from and dissipating heat generated by an electronic device mounted on a circuit board, the method comprising the steps of:
- providing an EMI reduction device having a top surface and a bottom surface and having an aperture defined therein, the aperture communicating with the top surface and the bottom surface;
- attaching the EMI reduction device to a thermal dissipation device with a plurality of mounting tabs projecting from the top surface of the EMI reduction device;
- contacting the circuit board with a plurality of spring fingers projecting from the bottom surface of the EMI reduction device;
- and
- contacting the electronic device with the thermal dissipation device through the aperture of the EMI reduction device.
Dependencies are inferred from the claim text.