Emi mitigation of power converters by modulation of switch control signals

Abstract

The present invention provides for EMI mitigation in switching circuitry, such as power converters, by implementing a controlled, non-random change in frequency in every cycle of switch control signals based on a static or dynamically changing modulation cycle. This permits frequency spreading across a wide range while avoiding excessive jitter between cycles and voltage dropouts common to randomized EMI control circuitry. Further, since it may be implemented digitally, some embodiments may avoid performance, size and power consumption problems experienced by mixed signal or analog switch control circuitry and EMI control circuitry. Further still, implementations of the present invention may mitigate EMI from a constant frequency source without the necessity of a variable frequency source, such as one generated by a VCO, to realize frequency variation. By eliminating the need for analog and mixed signal circuitry, and additional corrective circuitry, some embodiments may also reduce design, testing and production costs.