Laptop power supply maker follows green trend

Marvell has announced new digital power technology to lower PC and notebook power consumption. The company supplies OEMS making PC and notebook power supplies.

The new chips are digital signal processors (DSPs) which dynamically adapt power characteristics in real time for power supplies and power adapters for PCs and notebook computers by better controlling the AC-DC current switching needed.

The digitalization of power supplies has been talked about for some time.

Digital signal processing involves digitizing an input analogue signal, such as a sound stream, modifying its digital profile in real time to produce a desired characteristic, such as enhanced bass notes, and then feeding the modified sound stream to a device, such as a loudspeaker, and producing a better outcome.

With Marvell’s power factor correction (PFC) technology, incoming electric current to a PC or notebook has its profile modified through a DSP chip. It determines the amount of power required for users’ applications that keeps the peak current at the lowest level, improving energy efficiency.

It does this with an adaptive drive capability which intelligently adjusts the electricity supply profile to reduce power supply switching losses and also reduces electromagnetic interference.

Incoming power can suffer from harmonic distortion; multiples of the power frequency superimposed on the power waveform which causes heating in wiring. With current technology the total harmonic distortion can average 80 percent. The Marvell technology claims to reduce it to around one percent or less.

Voltage and current are brought into phase, wasting less energy than present technology. Adaptive current limits are also automatically adjusted for varying current threshold limits world-wide, which adds system protection and reliability.

Marvell-based notebook adapters are approximately one-third smaller and lighter than current notebook adapters. This is because the new components can replace up to 20 individual parts used currently and so simplify power supply design as well as increasing power efficiency.

Larry Qua, Chairman and CEO at Ionics EMS, a supplier of IT power equipment to computer manufacturers, said: “With more functionality integrated onto a single chip, we can build our power supplies with fewer components thus saving cost and reducing design and manufacturing complexity. We are using Marvell’s chips to build energy-efficient notebook adapters as well as power supplies for applications such as flat-screen TVs and printers.”

The U.S. Environmental Protection Agency (EPA) estimates that there are more than 10 billion AC-DC power supplies used in computing, telecommunications, and consumer electronics world-wide. According to the EPA, more efficient power supply designs could significantly reduce U.S energy use, saving nearly US$3 billion and about 24 million tons of carbon dioxide emissions per year.

The U.S. Energy Star rating system for PCs mandates that AC power efficiency has to reach 80 percent. By reducing the proportion of wasted energy at the power input stage the rest of a computer’s components have less individual work to do to increase the computer’s overall power efficiency.

Marvell’s 88EM8041 controller chip for notebook adapters and 88EM8011 controller chip for desktop power supplies are in production now with volume ramp anticipated for Q1’08.