Ayman Fayed, assistant professor of electrical and computer engineering, has been working with more energy efficient regulators, which can increase the battery life of portable devices.

“The problem with battery technology, or the technology that leads to the idea of storing more energy in the same volume, is that it has not advanced in the past 10 years as significantly as we would like to see,” Fayed said.

“[Because batteries haven’t advanced in the past 10 years] with your portable systems now, you’re jamming more and more functionality that requires more and more energy but your battery energy and energy stored is the same it was ten years ago.”

His focus is on the electrical industry, coming up with ways to reduce the amount of electricity consumed by portable devices such as cell phones, media players and laptops.

Fayed said this technology hasn’t been advancing, it’s been “saturating” and people have been coming up with many different kinds of circuit techniques to consume less power.

“We can’t design stuff at lower power anymore and the battery’s energy is not increasing anymore,” Fayed said.

Fayed has been concentrating on the regulators for these devices, which operate similarly to the adapters in cell phones.

“What we focus on is the process … of power conversion. This has a very low efficiency,” Fayed said. “It can be as low as 50 percent, which means if your load requires a certain amount of energy, you actually have to consume double that amount through the battery to be able to deliver the energy to the load.”

One solution to this over consumption would be the use of a switching regulator, which is highly energy efficient. Switching regulators send up to 95 percent of a battery’s power to the device’s circuits. However, these regulators produce noise that harms noise sensitive circuitry inside the devices.

Linear regulators can be implemented within devices to reduce the noise. These regulators can waste up to half the battery’s life in the process.

“What we came up with is a new controlled technique to design switching regulators, using the 95 percent efficiency from the switching regulators but the regulator noise performance is made friendly toward radio frequencies that ride off sensitive loads,” Fayed said.

“This way you can power these loads directly from these types of converters, enjoy the efficiency that you get while not compromising the performance of your sensitive circuits in your system and you can end up with a significant increase in how long you can run the system with a single charge of your battery.”

Haluk Sasmazer, an engineer for Rockwell Collins, a company that specializes in aviation electronics, information management and communications, has worked with Fayed and stressed the potential of these regulators.

“The linear regulators that are used typically to reduce noise are less efficient than the switching regulators,” Sasmazer said.

“A switching regulator can work up to 95 percent efficiency but they have the switching noise that volts up the circuitry would not like and the idea to using the switching regulators but with the efficiency coming from the switching regulators but the noise levels coming in from linear regulators, it’s getting the best of both approaches.”

Fayed said the switching regulators work in the same way as water regulators.

“Imagine you have a water pipe that has a wide side and a narrow side, you have a flow of water coming in from the wide side, the wide side represents higher voltage in an electric circuit, then you have a lot of water … coming in because that opening is very wide,” Fayed said. “At the other side of the pipe the opening is much narrower, which represents a lower voltage in an electric circuit.”

“The water coming in from one side is trying to exceed the water coming out from the other side. What’s going to happen if you try to use a system like that is the pipe is going to explode, so the efficient way of regulation is essentially saying, ‘I’m going to poke a hole in the pipe from the side so that the extra water coming in will be dumped to the floor and wasted.’ So the water runs smoothly from the wide opening to the narrow opening.”

Having the water run smoothly between both ends of the pipe is an example of a linear regulator. The linear regulator regulates the flow of water by throwing away the extra energy and waste.

A more efficient way is switching power regulators, which work by using a gate at the wide opening, allowing water to open the gate only for a brief period of time and then shut it off periodically, Fayed said.

“Now the water comes in bursts instead of a continuous flow and what I do, I take control of the average rate of the water flow which is how much water that comes in for a long period of time and I take the average,” Fayed said. “I can control this average to anything I want by controlling a rate between how long do I leave the gate open and how long do I shut it off in a given period of time.”

This, as Fayed suggests, is an efficient way to regulate the water but it also means it’s coming out in bursts, which is a very noisy process. What Fayed focuses on is how he can effectively control the opening and closing of the gate in such a way that the noise won’t affect the circuitry.

With these regulators in progress, Fayed hopes to take some of the strain off of those who deal with portable devices with low battery life. By doing so, these regulators will decrease electrical consumption significantly.

“Many of those portable applications, they contain significant noise sensitive circuitry that consumes a significant portion of the energy consumed by the system and for any improvement in the efficiency can result in significant improvements in effective battery life,” Fayed said.