Electromagnetic Compatibility Noise Research Articles

Switching converter EMI conduction modelling and verification

Switching converters are widely used. Electromagnetic compatibility (EMC) is an important index in the design process. At present, there are three problems: (i) EMC noise test is usually carried out after the prototype design is completed. This method, which is not tested at the design stage, increases the design cost to some extent; (ii) the complexity and limitations of the test environment lead to low confidence of test results; (iii) traditional modelling methods ignore many factors such as power supply feeders. To solve the above problems, an electromagnetic interference conduction model is proposed in this Letter. After experimental verification, it is found that the test results of this model have a high matching degree with the measurement results of standard EMC equipment.

Modelling and measurement of high‐frequency conducted electromagnetic interference in DC–DC converters

Conducted electromagnetic compatibility (EMC) noise qualification tests are normally carried out after a prototype has been designed, built and tested and the process is repeated in the event of non-compliance. The ability to determine compliance with electromagnetic interference (EMI) standards at the design stage is therefore desirable. This study will present conducted EMC noise modelling and measurement techniques, yielding simulated and measurement noise results accurate enough to serve as a prequalification test at the design and prototyping stages, respectively. Accurate models of the power feed line connecting the line impedance stabilisation network to the device under test (converter), including the load are developed. Predictive conducted EMC modelling is accomplished using detailed active level 3 SPICE-based models, creating a real-time circuit model consisting of a complete converter in its operational state, without the need to separate into equivalent models. Effects of the power feed-line length on EMI noise measurements are investigated as currently available literature has not dealt adequately with this issue. The modelling and measurements are performed using software and instruments available in a development laboratory..

EMC Optimized Design of Linear Regulators Including a Charge Pump

The charge pump belongs to the most critical blocks for electromagnetic compatibility (EMC) of low dropout linear regulators (LDO) because of its switching nature. The goal of this paper is to contribute charge pump design practice and a prediction method for the LDO EMC performance already in an early design phase. LDO noise coupling mechanisms are analyzed. EMC aware circuit design includes the choice of low-noise architectures, the right switching frequency, and noise filtering. The derived simulation method shows very good matching with EMC test results for an LDO with two different charge pumps fabricated in 350 nm high-voltage BiCMOS technology. For a realistic prediction of the EMC noise magnitude, a relative simple simulation setup gives results with less than 3 dB μV accuracy. A tripler current mode charge pump turned out to be well suitable for EMC. Conducted emissions could be predicted and confirmed to be improved by ~50 dBμV versus a conventional voltage-mode charge pump.