Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] The invention is related to a device for reducing an effect of electromagnetic compatibility (EMC) on a control unit .

Background of the invention

[0002]Electronics devices trend of reduced channel length has the adverse effect in its immunity level that brings the challenges in meeting the EMC regulatory requirement and also raising the risk in undefined field failures. The same semiconductor technology trend of increasing the operating frequency results in higher radiative emission level. The high operating frequency operating devices dissipates the correspondent heat. The above-mentioned issues are critical when it comes to product compliance and the robustness of the control unit. The present invention provides one such solution for this.

[0003] A US patent application 2012050985 discloses an electronic device having a heat dissipating component is provided. The electronic device includes a circuit board, a heat pipe which is disposed on a first side of the circuit board, a heat generating device which is disposed on a second side of the circuit board opposite to the first side, a heat sink placed which is disposed on a surface of the heat generating device and absorbs heat of the heat generating device, and a connecting member which penetrates through the circuit board and thermal conductivity connects the heat pipe and the heat sink.

Brief description of the accompanying drawings
[0004] Figure 1 illustrates a device for reducing an effect of electromagnetic compatibility (EMC) on a control unit according to one embodiment of the invention.

Detailed description of the embodiments
[0005] Figure 1 illustrates a device for reducing an effect of electromagnetic compatibility (EMC) on a control unit in accordance with one embodiment of the invention. The control unit 12 comprises a microcontroller 14 having a case 16 and mounted on a printed circuit board (PCB) 18 and a LC circuit 20 positioned in proximity to the microcontroller 14, in an enclosure 22. The control unit 12 further comprises a thermal insulating material (TIM) 24 positioned between the enclosure 22 and the microcontroller 14. The device 10 comprises at least one metal plate 26 fitted between a bottom surface of the enclosure 22 and a top surface of the case 16 of the microcontroller 14 through the TIM 24, such that, the at least one metal plate 26 reduces the effect of the EMC on the microcontroller 14 by reducing a radiative emission of the control unit 12.

[0006] Further the construction of the different components of the control unit along with their working is explained in detail. The control unit is chosen from a group of control units comprising a microcontroller, a microprocessor, a digital circuit, an integrated chip, and the like. The control unit 12 as mentioned in the present invention can be used in any kind of applications like in vehicles, in home appliances, in health care devices and the like as known to a person skilled in the art. For ease of understanding, according to one embodiment of the invention, the control unit 12 is a vehicle control unit that emits a radiative emission when high frequency signals are passed by. The construction of the control unit 12 as in the present invention comprises the PCB 18 on which the microcontroller 14 and the LC circuit 20 (comprising at least one inductance and a capacitance 20(a) is connected as shown in the figure 1) are soldered. The microcontroller 14 is enclosed with a case and above the case along the length of the microcontroller , the TIM 24 is placed to absorb the heat dissipated during the operating mode of the microcontroller 14.

[0007] However, due to the high frequency signals and the ESD pulses (which are large amplitude pulses generated in shorter time intervals), the immunity level of the microcontroller 14 will be reduced. The EMC/ESD behavior on the microcontroller 14 worsens during the operating mode , as there is no short return path and due to additional coupling from the microcontroller 14 and the enclosure 22. In order to avoid this, the present invention uses one or more metal plates 26 along the length of microcontroller 14. The metal plate 26 is fabricated to the bottom surface of the enclosure 22 and is made to pass through the TIM 24. The at least one metal plate 26 is fabricated to the enclosure 22 at one end and is positioned to be in contact with the microcontroller 14 via the case 16 and the TIM 24.

[0008] The at least one metal plate 26 reduces an electrostatic discharge (ESD) on the microcontroller 14 by absorbing the high frequency signal generating from the capacitor (20(a)) of the control unit 12. The path of the high frequency signal is determined and due to the presence of the one or more metal plate below the enclosure, helps in reducing the radiative emission levels. The device 10 comprises one metal plate or multiple metal plates 26 positioned in parallel to each other and in the space between the enclosure 22 and the case of the microcontroller 22 via the TIM 24. The metal plates 26 are positioned along the length of the microcontroller 14 case 16 for reducing the EMC/ESD effect. The metal plates 26 reduces the conduction of the heat and limits the radiative emission levels of the control unit 12.

[0009] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We Claim:
1. A device(10) for reducing an effect of electromagnetic compatibility (EMC) on a control unit (12), said control unit (12) comprising :
- a microcontroller (14) having a case (16) and mounted on a printed circuit board (PCB) (18);
- a LC circuit (20) positioned in proximity to said microcontroller (14) , in an enclosure (22);
- a thermal insulating material (TIM) (24) positioned between said enclosure (22) and said microcontroller (14);
characterized in that :
said device (10) comprising :
- at least one metal plate (26) fitted between a bottom surface of said enclosure (22) and a top surface said case (16) of said microcontroller (14) through said TIM (24), such that, said at least one metal plate (26) reduces said effect of said EMC on said microcontroller (14) by reducing a radiative emission of said control unit (12).

2. The device (10) as claimed in claim 1, wherein said at least one metal plate (26) is fabricated to said enclosure (22) at one end and is positioned to be in contact with the microcontroller (14) via the case (16) and the TIM (24).

3. The device (10) as claimed in claim 1, wherein the at least one metal plate (26) reduces a electrostatic discharge (ESD) on the microcontroller (14) by absorbing the high frequency signal generating from the capacitor (20(a) of the control unit (12).

4. The device (10) as claimed in claim 1, wherein the device (10) comprises one metal plate (26) or multiple metal plates (26) positioned in parallel to each other and in the space between the enclosure (22) and the case of the microcontroller (14).

5. The device (10) as claimed in claim 1, wherein the metal plates (26) are positioned along the length of the microcontroller (14) case for reducing the EMC/ESD effect.

6. The device (10) as claimed in claim 1, wherein the metal plates (26) reduces the conduction of the heat and limits the radiative emission levels of the control unit (12).