photo: Freescale
Freescale Semiconductor on Monday is unveiling a new power conversion technology that the chipmaker says will dramatically enhance the efficiency of solar cells and other devices by allowing them to operate at low voltages.
That means a single solar cell attached to a mobile phone or other handheld device could charge the gadget. The bigger potential is to maximize the electricity generated from rooftop solar panels. which typically contain a dozen or more solar cells each. When a cloud or a tree shades part of a solar panel, power output from all the solar cells drops because they are linked together. By integrating Freescale’s power converter
into each solar cell, those that aren’t shaded can still produce electricity, according to Arman Naghavi, general manager of Freesale’s Analog, Mixed-Signal & Power Division.
That’s because each solar cell can operate at much lower voltages when Freescale’s (FSL) converter is used. While most electronics need a jolt of 700 millivolts to begin working, Freescale’s technology allows them to operate on as little as 320 millivolts. (See video below.)
Sounds geeky but the consequences could be far-ranging, reducing electricity consumption and opening the door to a new generation of solar-powered devices. One big hurdle to using solar cells to power everything from laptops to street lights is that it takes too many of them to produce enough power to be practicable. After all, who’s going to carry around a solar panel to charge their MacBook.
Freescale’s technology could change that equation. “For instance, you wouldn’t have to put a battery in a garage door opener – just add a solar strip on the remote control,” Kevin Parmenter, a Freescale applications engineering manager, told Green Wombat. (Samsung last week announced it would start selling a mobile phone (photo above) equipped with a solar panel but it’s unclear just how much talk or texting time it would allow.)
Other uses are more sci-fi: self-powered nanosensors that tap the technology to harvest ambient heat or friction in the environment.
The converter will hit the market in the second half of 2009. Potential customers include solar cell makers like SunPower (SPWRA) and Suntech (STP) as well as biomedical companies and defense contractors. Freescale, headquartered in Austin, Texas, was spun out of Motorola (MOT) in 2004.
“It really helps the entire green movement,” says Naghavi. “We are seeing a tremendous interest from lots of areas historically we have never touched or played in.”
Green Wombat 
I waited for such decive because I have some single solar cells among my electronic devices. Now there is the answer on the question: “how can I get 5 volts from 0.5 volts?”. I am waiting for apllication notes.
This is great from a user standpoint… not having to plug into a wall, or replace, or charge batteries, but consumer electronics (especially cell phones) have an average lifespan of only a few years. The latest data I’ve heard is that it takes 4 years of standard use for a solar cell to produce as much energy as was required to make the solar cell. As these will be more efficient that will be lower, but I think you need to get to the 1-2 month level to make it worth it for a solar cell with a capacity factor less than 1% in order to call consumer electronic solar cells green (except for those rare folks who keep their phones in the sun all day long).
Lothar:
Apologies in advance if you already know this – other readers may not…
The DC power (voltage * current) is the conserved quantity.
So if you increase the voltage, you have to “pay for it” with current.
In the picture the left two meters show the input power from the cells is 488mW (1.27A*0.384V) – high current, low voltage.
The output power to the load is 399mW (0.099A*4.03V) – low current, high voltage).
The efficiency of the converter is (basically) the ratio of the output power to the input power – in this case 399/488 = 0.81 = 81%.
Hopes this helps.
-Don
Scott — In cases where you are far from being able to plug in, it’s not just the cost of the electricity that is important, but the access. A handsfree speakerphone in your car is an example — if you can use a solar cell instead of having to wire it up to your car, then there is a benefit.