IC supporting environment and money saving mobile phone charging adapters

For an environment conscious person throwing away a nice but old mobile phone charger just because it doesn't have pin and voltage compatibility for a phone from a different vendor is lot irritating. Added to this, user has to shell out extra money in buying a new charger. Simple decision by the industry to have a common i/p voltage or a device to take care of range of i/p voltages is nothing but a common sense. Finally, here is one such common sense solution from STMicroelectronics.

STMicroelectronics introduced a new IC for cellphones and mobile devices offering choice of four threshold voltage suitable for chargers upto 6.8V including both USB and main power chargers that will help combat the environmental impact of large numbers of battery chargers discarded when their owners upgrade to newer equipment. With about one billion handsets now shipping each year, this could save over 500 million scrap chargers, worldwide.

Chinese government and the GSM Association have proposed, standard battery-charger connectors and voltages to allow universal chargers for mobile phones. These efforts are focusing on USB standards as a convenient, cost-effective solution. In addition to reducing discarded chargers, standard chargers will also allow charging from a PC or laptop USB port. In fact, any type of mobile device, marketed in any territory, can improve environmental performance and increase convenience for users by providing a standardized charger interface.

ST's new IC, the STBP120, protects the charging-control circuitry inside cellphones and other battery-powered portable equipment in case the external charger applies an excessive voltage. A number of variants are available, suitable for a range of charging-voltage levels including the USB voltages recommended by the current best-known proposals. These include YD/T 1591-2006 put forward by China's Minister for Information and Industry (MII).

When implemented inside a battery-powered product, the STBP120 monitors the voltage from the connected charger. If the detected voltage exceeds a preset threshold, an internal solid-state switch is opened, thereby preventing the over-voltage from damaging the internal circuitry. There are four variants spanning threshold values from 5.375V to 6.02V, allowing engineers to optimize for USB chargers at up to 5.25V or other chargers at higher voltages up to 6.8V. Each device will protect against over-voltages as high as 28V. In normal operation the internal switch, an N-channel MOSFET, has very low resistance of 90 milliohms to promote efficiency and minimize heat dissipation.

Other features include a fault-indicator output, soft-start capability to limit inrush current to the charging circuitry, and a thermal shutdown to protect against excessive temperature. The device can save pc-board space and component count in many other types of products where over-voltage protection is normally implemented using a discrete transient-voltage suppressor and a fuse. The over-voltage threshold can also be set more accurately than when using discrete devices.

Package: STBP120: ultra-small 2 x 2.5mm, 10-lead TDFN package.
Price: Each $0.37 for 1k pieces.

For further information visit www.st.com/powerpath.

We call this a green semiconductor product.