Introduction to CAPZero

When AC voltage is applied, CAPZero blocks current flow in the X capacitor safety discharge resistors, reducing the power loss to less than 5 mW at 230 VAC. When AC voltage is disconnected, CAPZero automatically discharges the X capacitor by connecting the bleed resistors in parallel. By eliminating the bleed-resistor power loss, significant power (often in excess of 100 mW) can be saved, which is very significant reduction that allows the designer to meet increasingly strict no-load and standby power consumption targets. CAPZero also allows flexibility in the choice of the X capacitor - to optimize differential mode EMI filtering and reduce inductor costs, with no power consumption penalty.