| Title |
EMI Reduction Filter Design using Heat Sink |
| Authors |
최병인(Byeong-In Choi) ; 좌성훈(Sung-Hoon Choa) |
| DOI |
https://doi.org/10.5573/ieie.2020.57.12.3 |
| Keywords |
Electromagnetic interference; Heat sink; Filter; MLCC |
| Abstract |
Recently, radiated electromagnetic interference (EMI) is increasing due to an increase in data rates and high-frequency noise with the commercialization of 5G and 10 Gbps Ethernet technologies. The generation of EMI will influence the performance of nearby electronic devices and lead to malfunction of devices. The use of a heat sink also became essential as high heat is generated due to an increase in the load on the CPU and communication devices. However, the heat sink can act as an antenna that radiates electromagnetic waves generated from the inside of the devices, which may cause electromagnetic interference problem. In this study, we applied EMI filters between the heat sink and PCB to reduce the radiated EMI. The multi-layer ceramic capacitor (MLCC) was used for EMI filter, which has advantages in miniaturization and packaging. MLCCs of 1, 33, and 100 pF were used, respectively. The EMI test was conducted in an electromagnetic anechoic chamber according to international and domestic standards at a distance of 3 m between the device and the antenna. If MLCC was not applied, the radiated EMI generated exceeded the allowable limit. When MLCCs of 1 and 33 pF were applied, respectively, radiated EMI was reduced, but exceeded the allowable limit at the specific frequencies. In the case of applying MLCC of 100 pF, the radiated EMI was improved overall from 30 MHz to 1 GHz and satisfied the allowable limit of EMI standard. In addition, it was confirmed that the application of the EMI filter did not affect the conducted EMI. In conclusion, we successfully applied the MLCC filters to reduce radiated EMI and presented a design of the EMI filter using the heat sink. |