Power Integrations Introduces Family of Two-Terminal Automatic X Capacitor Discharge ICs

Power Integrations launched CAPZero, a family of two-terminal, automatic X capacitor discharge ICs that eliminate power losses while allowing power supplies to comply with safety standards.

CAPZero acts as a smart high-voltage switch when placed in series with discharge resistors. When ac voltage is applied, CAPZero blocks current flow in the X capacitor safety discharge resistors, reducing the power wasted in these components to zero at 230Vac. When the ac voltage is disconnected, CAPZero automatically and safely discharges the X capacitor by closing the circuit through the bleed resistors and directing the energy away from the exposed ac plug. This approach is said to provide engineers with total flexibility in their choice of the X capacitor used to optimize differential-mode EMI filtering without worrying about the effect of the required bleed resistors on system no-load and standby power budget. The two-terminal design inherently meets international safety standards for all open and short-circuit fault tests, allowing CAPZero to be used before or after the system input fuse.

David New, Product Marketing Manager at Power Integrations, commented, "New energy-efficiency requirements have highlighted X capacitor discharge resistors as a significant source of power loss, especially in applications over 50 watts. CAPZero is a simple, cost-effective solution that eliminates this loss and requires virtually no change to system or PCB layout. It is easy to design-in and requires minimal effort to retrofit into existing designs, easily bringing them into compliance with new standards."

CAPZero is suitable for all ac-dc converters with X capacitors that require very low standby power, and is offered with 825 or 1000V MOSFETs to support a variety of power supply design needs. It is well suited for a wide range of applications, including PCs, servers/workstations, monitors and TVs, printers and notebooks, as well as appliances requiring EuP Lot 6 compliance and adapters requiring ultra-low no-load consumption.

CAPZero devices are available now in an SO-8 package at $0.40 each for 10,000-piece quantities.