EMI Cancellation with Balance Technique
Conventionally, common mode (CM) EMI noise is difficult to control since it is caused by the parasitic capacitance between the power circuit and the ground. CPES has developed a balance technique, which employs Wheatstone bridge theory, to balance common mode (CM) noise for any given converter topology. With this proposed balance technique, most of the CM noise is canceled before it flows to power lines. There is 20-30dB reduction in measured CM EMI noise compared with the case without using balance technique. As a direct benefit, CM EMI filter can be reduced from 2-stage to one stage.