High Efficiency Power Supply controllers first to use Smart Technology

Date: 9/6/2009

High Efficiency Power Supply controllers first to use Smart Technology

Marvell is first to market with devices destined to significantly cut PC energy usage and thereby help reduce the carbon footprint and the need to build more power stations. The 88EM8011 and 88EM8041 DSP-based power factor correction (PFC) controllers for AC-DC power supplies use ‘smart technology’ that changes from Pulse-Width Modulation (PWM) to Pulse-Frequency Mode (PFM) to keep the peak current at the lowest level, thereby improving energy efficiency and reducing overall system size.

The new devices integrate the functionality of the 20 or so discrete components conventionally used to build notebook adapters and desktop PC power supplies, allowing OEMs to improve product reliability while reducing size and cost. Put into perspective, plug-top power adapters built with the new controller technology are significantly lighter and approximately thirty-three percent smaller than current plug-top adapters.

According to the U.S. Environmental Protection Agency (EPA), there are more than 10 billion AC-DC power supplies used in computing, telecommunications, and consumer electronics worldwide. More efficient power supply designs could cut energy usage in half, saving about 24 million tons of carbon dioxide emissions per year in the US alone. PSU destined for the European market will soon have to ‘harmonise’ with the current American EISA 2007 EPS standard and in less than two years, conform to the tighter ENERGY STAR EPS version 2.0 specification.

88EM8011 and 88EM8041 
Power supplies based on Marvell’s 88EM8011 (for desktop PSUs) and 88EM8041 (for plug-top power adapters) DSP-based power factor correction (PFC) controllers delver enhanced efficiency by bringing the voltage and current into phase, wasting less energy than present technology. In contrast to conventional approaches which deliver Total Harmonic Distortion (THD) at an average of 80 percent, the 88EM8011/88EM8041 controllers delivers THD figures of one percent or less.

The 88EM8011/88EM8041 are also designed to comply with the US EPA Energy Star specification, which requires that 80 percent of the power consumed is actually used by the PC.

Smart Technology
With Marvell’s ‘smart technology’ for power supplies, the DSP determines the amount of power required for users’ applications. Its mixed-mode technology optimises operation throughout the cycle by changing from Pulse-Width Modulation (PWM) to Pulse-Frequency Mode (PFM). This keeps the peak current at the lowest level, improving energy efficiency as well as reducing overall system size. The adaptive drive capability of the DSP intelligently adjusts the driving level to the switch; reducing switching loses, while adaptive adjustments also reduce electromagnetic interference (EMI) for a wide range of switches. Adaptive current limits are automatically adjusted for varying current threshold limits worldwide, which adds system protection and reliability.

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