Power supply reference design targets Ecodesign specs

San Jose, Calif. — Power Integrations recently released a new Design Engineering Report (DER-227) that details the design of a 3-watt power-supply circuit that consumes just 10 mW during no-load operation. The low-power consumption allows for much more power available for use by electronic systems designed to comply with the standby power limits mandated by regulations such as the European Union’s Ecodesign Directive for Energy-Using Products (EuP).

The EuP standard will limit standby power consumption to 500 mW, although many manufacturers of consumer products and appliances are choosing even lower standby power budgets of 100 mW, 50 mW, or 30 mW, according to Power Integrations. A standby power supply that consumes only 10 mW at zero load allows a greater margin for other leaky circuit components such as input filters, capacitors, and bias components, while still providing the power required to support system standby activities.

These include functions such as powering circuits to monitor an infrared remote control in consumer entertainment equipment, as well as hardware to sense a key-press to activate appliances or send automated wake-up signals such as those provided to a LCD monitor by a PC, according to the company.

The power circuit described in the DER-227 design is based on Power Integrations’ LNK363DN, a member of the LinkSwitch-XT offline switcher IC family in an SO-8 package. This 3-watt, single-output, isolated power supply operates from a universal 85 to 265 VAC input, delivering 5 V at up to 0.6 A. It meets EN55022B/CISPR22B limits without the need for a Y capacitor, and meets the efficiency requirements of the European EuP Ecodesign Directive and ENERGY STAR EPS v 2.0.

Based on Power Integration’s EcoSmart technology that reduces power consumption in no-load or light-load conditions, the company says the power-supply design also features careful transformer design and circuit bias component selection, together with algorithms that switch only when required to maintain output voltage regulation. Click here for other company resources.