UCLA scientists working to create smaller, faster integrated circuits

Dec 19, 2007

Integrated circuits are the "brain" in computers, cell phones, DVD players, iPhones, personal digital assistants, automobiles' navigation systems and anti-lock brakes, and many other electronic devices.

A team of UCLA scientists has now demonstrated substantial improvements in integrated circuits, achieved not by costly improvements in manufacturing but by improved computer-aided design software based on better mathematical algorithms.

"We can get circuits designed with 30 percent less wire length using improved optimization than what we had demonstrated three years ago, based on circuits that were samples from industry," said Jason Cong, UCLA professor and chair of computer science. "We believe that when you apply these methods to current industry circuits, you will see similar gains. Industry says even 5 percent is very significant.

"We are showing there is another way to make major improvements, with better design and better architecture," added Cong, who has collaborated for nearly a decade with Tony Chan, UCLA professor of mathematics and the National Science Foundation's assistant director for mathematics and physical sciences.

The traditional way to achieve smaller, faster integrated circuits — also known as silicon chips — is by building smaller and smaller transistors and thinner wires. While the computer industry has made smaller, improved devices, Cong, Chan and their colleagues are improving the design of the chip itself.

A goal of the collaboration is the development of silicon chips that are faster and cheaper and consume less power than the current generation of chips, said Cong, who is also a member of the California NanoSystems Institute at UCLA.

"We think optimizing chip design is an exciting direction," he said.

Integrated circuits have a series of interconnected, nanosize nodes; the locations of the nodes on the chip's surface are very important because they can minimize the wire length on which the signal travels.

Nodes include tiny "logic gates," as well as much larger memory blocks and other functional blocks. There are tens of millions of nodes on a chip.

"We have found there is a huge amount of room for improvement in the physical design of the chip itself, including where nodes are placed," said UCLA mathematics graduate student Eric Radke, who works with Chan and Cong. "We want to minimize the wire length in each node."

A challenge, Cong said, is "how do you place the nodes on a two-dimensional surface with big pieces and small pieces that are all connected to one another" It's like a jigsaw puzzle with millions of pieces. How do you place them to minimize the total interconnections (wires) among them""

"It's fairly easy to model this problem mathematically," Radke said. "You can think of the nodes as points on a giant graph, and you can think of the interconnects as hyper-edges that connect more than two nodes. We can use mathematics to determine how the placement problem should be solved. We use a mathematical technique called multiscale methods, in which we group nodes together until we get a mathematical problem that is small enough to solve."

Chan and Radke design algorithms for computer software to improve the placement of the nodes and are using differential equations that they build into the algorithms. The scientists expect that the research will lead to improved software for enhanced chip design. Cong's laboratory has found strong evidence that existing computer-aided programs for integrated circuit design are far from optimal.

Chan and Radke are now working to minimize the amount of time it takes a signal to get through a processor.

Research by Chan, Cong and their graduate students won the 2005 award for best paper at the International Symposium of Physical Design (ISPD). Their placement software, developed together with their former students Kenton Sze and Min Xie, also produced the best wire-length results in the 2006 Circuit Placement Contest organized by ISPD.

Chan and Cong are also working with Lieven Vandenberghe, UCLA professor and vice chair of electrical engineering, as well as computer science graduate student Guojie Luo and electrical engineering graduate student John Lee.

"It's great to come to the meetings and hear everybody's ideas because everybody comes from a different background," Radke said.

Source: University of California - Los Angeles

Explore further: 'Deep web search' may help scientists

Related Stories

The monopoly of aluminium is broken

8 hours ago

Discovering Majorana's was only the first step, but utilizing it as a quantum bit (qubit) still remains a major challenge. An important step towards this goal has just been taken, as shown by researchers ...

Yik Yak's frat-bro founders shrug off growing pains

8 hours ago

The most popular post of all time on Yik Yak is a dirty joke. Less than 2 years old, the Atlanta-based social network is geared mostly toward college students who access and post unsigned announcements through an app on their ...

Fears for pink iguanas as Galapagos volcano erupts

8 hours ago

A volcano in the Galapagos islands erupted for the first time in more than 30 years Monday, sending streams of lava flowing down its slopes and potentially threatening the world's only colony of pink iguanas.

Recommended for you

'Deep web search' may help scientists

May 25, 2015

When you do a simple Web search on a topic, the results that pop up aren't the whole story. The Internet contains a vast trove of information—sometimes called the "Deep Web"—that isn't indexed by search ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.