here is an ongoing push for power supply manufacturers to develop smaller, more feature-rich products,” explains Andy Skinner, Chief Technology Officer at TDK-Lambda UK. “Since the use of an EMC filter can represent a significant percent of the overall volume of the unit, reduction of the common-mode noise flowing back into the power source is a key criterion for a more compact design.”
In essence, the ZVSC topology uses a half-bridge switching circuit with additional noise cancelling circuitry to reduce conducted common-mode noise. Since noise is reduced, a much smaller EMC filter is needed for the power supply to comply with EMC regulations, thus achieving a compact, high power density unit. TDK-Lambda’s NV300 uses such a topology, achieving a power density of 8.3W/in3.