According to San Jose, Calif.-based Power Integrations, the LinkSwitch-II family of power-conversion ICs enables manufacturers of cell-phone chargers to achieve the recently announced five-star rating for no-load energy consumption.
The new rating system, launched by the world's top-five cell-phone makers last November, 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, cell-phone 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. Cell-phone manufacturers estimate that if the 3 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 employs Power Integrations' EcoSmart technology to automatically adjust power consumption when the charger enters a no-load condition. Furthermore, 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%, but also improves energy efficiency because secondary-side components consume power.