The Hindu Business Line : Not power hungry

Energy efficiency, an integral part of green IT initiatives, is perhaps today synonymous with technology itself, and it would be difficult to spot stakeholders who have no low-power strategy in place.

The semiconductor ecosystem comprising electronic design automation companies, chip design companies and chipmakers have, over the years, played an important role in developing products or solutions that reduce energy consumption.

Today, most have low-power solutions or methodologies in place, though R&D is an ongoing process; and there have been various initiatives to bring together all the stakeholders in the semiconductor industry to jointly address the issue.

One such was the Power Forward Initiative, which was begun in 2006 by Cadence, a provider of chip designing tools and methodologies, to address the absence of a common power specification for the ecosystem to work together. It brought together EDA companies, IP providers, foundries and the semiconductor players to help create the Common Power Format.

“With the Common Power Format (CPF) we are at least speaking the same language so that it becomes seamless when we are transferring data from one stage to another,” says Rahul Arya, Marketing Director, Cadence Design Systems India.

Earlier, because there was no common exchange of power specification, the power intent did not get transferred. If one was designing at the architecture level, the power specifications did not get transferred to the next level because there was no common format. Also, the design methodology was not uniform. With the CPF, a common low-power methodology has come into place, says Arya.

For ARM Embedded Technologies, which provides the IP for microprocessors that form the core of chips used in electronic devices, low power is fundamentally being able to do things more efficiently, while maintaining the level of performance.

One of the ways the company does this is through its Intelligent Energy Manager, which can put a certain part of the processor into sleep mode when not needed, says Anil Gupta, Managing Director, ARM - India Operations. In the first-generation processors, all the circuits consumed power.

Explaining with an example, Gupta says that if a chip handles voice calls and emails, some sections of the chip would be dedicated to voice and others to data. When there is a call, the circuit handling the call is alive. Suddenly, if one wants to use email, the other circuit becomes active and the call circuit is switched off.

But the challenge is to ensure that when the circuit is switched off no calls get missed. So the circuit needs to be put in a mode where it conserves as much energy as possible, but quickly wakes up when required. This is called Interrupt Handling, and ARM’s focus is to ensure this is very good. “These things need to be handled very efficiently. We have created an architecture from that perspective, and we are refining that,” says Gupta.

ARM also has the Dynamic Voltage and Frequency Scale technology, which helps to regulate the voltage and frequency, thereby helping save power. “Dynamically we should be able to change the voltage. When you are working, you need to have a relatively high voltage so that everything works fine. When you are not, there should be low voltage,” says Gupta. Similarly, one needs to change the frequency as well. Higher the frequency, higher is the energy consumed, he adds.

Texas Instruments has tried to address the issue at the applications end and also through power management, says Ram Anant, Systems Engineering Manager, Portable Power Management, Texas Instruments. The company has worked on active power management within the chips to help devices conserve power, as also render power converters more efficient.

Giving an example, he says the company has green mode controllers that reduce power consumption in devices like television, which when plugged to the socket draws power even after it is turned off. “What our controller does is to see that instead of the TV consuming say 3 watts, it consumes just 0.5 watts,” says Anant.

He says Texas Instruments has also focused on developing capability for power conversion with minimum losses. The company has converters that are 96 per cent efficient, which means only four per cent of energy gets lost as heat.

Power converters provide the power required for cell phones, digital cameras, televisions and other consumer appliances. It converts the battery voltage to the usable voltage inside the device, or it can take AC mains and convert it to DC.

Talking of mobile phones, he points out that various applications like the speakers, display, backlight, GPS, radio, modem and camera require different voltages. “The actual conversion happens between the battery and the applications and that’s where we do a majority of our work. If the converters can themselves consume less, you are saving more power,” Anant adds.

Advanced Micro Devices, too, has various techniques to make its products more power efficient.

“The first and foremost technique we use to bring the power down is shrinking the manufacturing technology. When you bring down the manufacturing technology, the power consumed by those transistors will come down,” says Vansi Krishna, Senior Manager, Technical, AMD India Engineering Centre.

As far as server processors are concerned, another important measure is to switch off the processor, bring down the frequency and voltage consumed during non-peak hours. This reduces overall power consumption, and the moment the load increases, it will increase immediately, says Krishna.

He says the company also has other techniques that allow some of the CPU cores to run at less power or even completely switch off when not in use.

Freescale Semiconductor, which makes embedded semiconductor for the industrial, consumer, automotive and telecommunication sectors, says reducing the size of the manufacturing and VLSI designs have helped reduce power consumption.

Very-large-scale-integration is the process of creating integrated circuits by combining many transistor-based circuits on to a single chip.

“VLSI chip design integrates the peripheral components on to a chip and helps reduce power usage. Individual components will have their circuit. Integration on a chip lowers power consumption,” says Sanjeev Keskar, Country Sales Manager, Freescale Semiconductor India.

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