Power Integrations Delivers Five-Star Rating for Cellphone-Charger Power Consumption

The new rating system, launched by the world's top five cellphone makers earlier this month (see Nokia press release), covers all chargers currently sold by Nokia, Samsung, Sony Ericsson, Motorola and LG Electronics. Efficiency ratings range from five stars for the most efficient chargers down to zero stars for units consuming the most energy.

If left plugged into an electrical outlet, cellphone chargers continue to use electricity even when disconnected from the phone. To achieve the coveted five-star rating, chargers may not exceed 0.03 W (30 mW) power consumption in no-load mode. This no-load power consumption is believed to account for up to two-thirds of the electricity used by mobile phones. Cellphone manufacturers estimate that if the three billion mobile devices in service today were using four- or five-star chargers, the world would save an amount of energy equal to the yearly output of two mid-sized power stations.

Power Integrations’ LinkSwitch-II power conversion ICs enable manufacturers to achieve the five-star rating—and meet other efficiency specifications such as ENERGY STAR 2.0—without increasing the cost of their chargers. LinkSwitch-II utilizes Power Integrations’ EcoSmart technology to automatically adjust power consumption when the charger enters a no-load condition. Further, LinkSwitch-II eliminates the need for optocouplers and secondary-side CV/CC control circuitry, as well as all control-loop compensation circuitry. This not only reduces component count by as much as 30 percent, but also improves energy efficiency since secondary-side components consume power.

Comments Doug Bailey, vice president of marketing at Power Integrations: “People may not realize that if they leave their cellphone charger plugged in – which most people do – it may consume up to 0.5 watts even when disconnected from the phone. The new star rating system makes it easy for consumers to compare and choose the most energy-efficient chargers.”

Bailey continues: “LinkSwitch-II enables designers to slash overall component count and eliminate lossy components such as the sense resistor. Chargers using LinkSwitch-II with PI’s proprietary EcoSmart technology can easily meet the most aggressive five-star rating at no additional cost to the manufacturer.”