Solar-powered mobile phone in stores this year
Electronic component manufacturer TI has confirmed to IET Engineering & Technology magazine that it is working to bring the world's first solar-powered mobile phone to production with one of the main mobile phone makers as early as this year (2008)
The device will have the ability to harvest energy from a single solar cell to maintain its charge, thus enabling smaller arrays of cells to be placed directly on the device rather than receive it from a separate portable source with a larger footprint.
Such a device would require its voltage boosted to an appropriate level using a step-up converter (a power converter with an output DC voltage greater than its input DC Voltage). TI Claims that this is now possible as would the ability to charge a mobile phone with artificial ambient lighting when placed indoors.
"TI has hundreds of customers that have sampled the TPS61200 boost converter since the announcement, and it will be used in a variety of applications ̵1; one of which will be solar/ambient charging to help sustain the battery charge in a mobile phone," claims a TI spokesperson.
Although prototype devices have been demonstrated, no devices are available on general sale ̵1; making this device the world's first.
In April, the company introduced a low input voltage DC/DC boost converter, which enables devices to draw power from variable energy sources such as solar. The tiny power circuit operates with input voltages lower than 0.3 V - which would allow designers to overcome the low voltage design barrier.
The device's ability to operate from a single solar cell would eliminate the need for multiple solar cells in series, and also eliminates the required protection circuitry associated with series connection.
"You can use multiple cells to boost the voltage, but if you do so, the portable device and its complexity get bigger," claims Alexander Friebe, product marketing engineer at TI.
In contrast, today's best step-up converters can only support an input voltage beginning at 0.7V with start-up at 0.9V ̵1; good for primary re-chargeable battery cells or main supplies, but not low enough to support a single solar cell.
Image: The device eliminate the need for multiple solar cells in series (©IMEC)