Power Integrations Launches CAPZero-4 X-Capacitor Discharge ICs for Lower Standby Power

Power Integrations has introduced CAPZero-4, the fourth generation of its X-capacitor discharge IC family for reducing no-load and standby power consumption in AC-DC power supplies.

X-capacitors connected across the AC input require a discharge path so that stored energy can be safely dissipated when equipment is unplugged. A conventional approach uses bleed resistors across the capacitor, but these continue to consume power while the equipment is connected to the AC supply.

CAPZero-4 disengages the discharge resistor during normal operation and makes it available when the equipment is unplugged and the X-capacitor needs to discharge. Power Integrations says the new IC consumes less than 0.75 mW at 230 VAC and can reduce system no-load and standby input power by up to 1000 mW by eliminating losses associated with the bleed resistors.

Reducing X-Capacitor Bleed Resistor Losses

The reduction in continuous power loss is particularly relevant to AC-DC supplies operating within tight standby budgets. Power Integrations is targeting appliances requiring ErP Lot 6 compliance and adapters with no-load consumption below 300 mW, as well as displays and industrial equipment.

CAPZero-4 supports AC-DC converters with line-to-neutral input capacitance from 100 nF to 6 µF. Rather than using part of the available standby power budget in the X-capacitor discharge network, the device keeps the bleed resistor out of circuit until it is required.

The operating temperature range has also been extended to -40°C to +125°C, covering industrial and outdoor equipment that may encounter wider ambient temperature conditions.

Pin-Compatible Upgrade from CAPZero-3

CAPZero-4 retains package and pin compatibility with the previous CAPZero-3 generation. For existing designs, Power Integrations says adoption involves selecting the appropriate external resistor values to achieve the required X-capacitor discharge time rather than redesigning the discharge circuit.

Designs using CAPZero-4 can meet IEC 60335 requirements for appliances, as well as EN/IEC 62368-1, UL 62368-1 and GB 4943.1 safety standards.

The CAPZero-4 family is in production and shipping to customers now.

Learn more and read the original announcement at power.com.

Technology Overview

Power Integrations CAPZero-4 is an X-capacitor discharge IC family for AC-DC power supplies. It disconnects the X-capacitor bleed resistor during normal operation to reduce continuous power loss, consuming less than 0.75 mW at 230 VAC while supporting input capacitances from 100 nF to 6 µF.

FAQs

What does CAPZero-4 do?

CAPZero-4 disengages the X-capacitor discharge resistor while equipment is connected to AC power and makes the resistor available when the equipment is unplugged and the capacitor needs to discharge.

How much power does CAPZero-4 consume?

Power Integrations specifies consumption below 0.75 mW at 230 VAC and says eliminating bleed-resistor losses can reduce system no-load and standby input power by up to 1000 mW.

Can CAPZero-4 replace CAPZero-3?

CAPZero-4 is package- and pin-compatible with CAPZero-3. Power Integrations says designers select the appropriate external resistor values to meet the required X-capacitor discharge time.