Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
EE Times-Asia > Power/Alternative Energy
Power/Alternative Energy??

Integrated voltage regulators cut power by 20%

Posted: 24 Feb 2012 ?? ?Print Version ?Bookmark and Share

Keywords:TSV? 3D chip stack? IVR?

Researchers at IBM and Columbia University have demonstrated at the International Solid-State Circuits Conference (ISSCC) a silicon interposer containing the necessary magnetic inductors in a study funded by Semiconductor Research Corp. (SRC) and the U.S. Department of Energy.

By locating the magnetic inductors on the bottom of a 3D chip stack, the demonstration showed how a voltage regulator's ordinarily bulky discrete components can be integrated into an otherwise CMOS design flow.

image name

By fabricating the bulky components such as power inductors (center) on a silicon interposer, future CMOS chips will integrate their own voltage regulators on the bottom of a 3D chip stack.

"What we have done at this point, is integrate the power inductors on a silicon interposer in what we call a 2.5D stacknot true 3D since we don't yet have TSVs," said Ken Shepard, a professor at Columbia University. "The next step, which we are already fabbing, is a full 3D stack where the silicon interposers contain not only the power inductors, but also the power trainthe transistors that switch those power inductorsenabling power to flow from the package up through the interposer, where it is converted down in voltage then sent up through TSVs to power the CMOS chip itself on top."

Today voltage regulators are located on separate chips combined with discrete components that must feed PCB traces connected to chip pins, requiring large currents to be pushed through extensive power distribution networks, presenting problems with both loss and power supply integrity. However, by switching the industry to voltage regulators located at the bottom on 3D chip stacks, future self-regulating 3D CMOS chip stacks will allow these high current levels at low supply voltages to be generated right at the load, improving overall energy efficiency by up to 20 percent, according to SRC.

Future voltage regulators on silicon interposers also promise to provide all the various voltages required by modern processors and memory chips, as well as manage smart energy conservation techniques, such as scaling the voltage and frequency to match the current workload. The researchers claim that integrated voltage regulation (IVR) will be able to respond to the energy needs of future CMOS chips in nanoseconds, compared to microseconds with off-chip voltage regulators, enhancing the ability to balance workloads on multicore processors with its switched-inductor voltage converters.

The Columbia University effort, in partnership with IBM where the fabrication is being performed, claims that IVR could shave up to $270 million off the electricity bills of data centers nationwide.

All the details are available in an ISSCC paper entitled: "A 2.5D integrated voltage regulator using coupled magnetic core inductors on silicon interposer delivering 10.8A/mm2.

- R. Colin Johnson
??EE Times

Article Comments - Integrated voltage regulators cut po...
*? You can enter [0] more charecters.
*Verify code:


Visit Asia Webinars to learn about the latest in technology and get practical design tips.

Back to Top