Research on Switching Noise Cancellation of Switching DC Power Converter

• Main Authors: Jui-Sheng Chen, 陳瑞昇
• Other Authors: Huang-Jen Chiu
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/f29ucx

碩士 === 國立臺灣科技大學 === 電子工程系 === 105 === Although an adequate filter design helps reduce the noise level of switching power supplies and satisfy the electromagnetic interference requirement; the parasitic elements within the passive components affects the filtering performance and fail to suppress the switching noise. This thesis presents the research on switching noise cancellation especially on DC-DC switching power supplies. The mechanism that induces switching noise is analyzed by considering the parasitics of the circuit components, such as the equivalent series inductance (ESL) of capacitors and equivalent parallel capacitance (EPC) of inductors. The results show that the parasitics indeed induce noise currents as the active switch is switching on and off. The noise current imposes on the output voltage to present as output switching noise. In this research, an ESL cancellation method that can effectively reduce switching noise by canceling the parasitics of output capacitor is studied. At last, this method is implemented and tested on a 130 W hard-switching synchronous rectified (SR) Buck converter. In comparison, about 86.9 % of noise reduction can be obtained in high voltage and low voltage output. The theoretical analysis is agreed with the experimental results.