System awareness improves SOC power management

Satish Sathe, Senior Systems Architect, Applied Micro Circuits Corp.
EETimes (3/18/2011 9:38 AM EDT)

Reducing the power consumption of SOCs (system on chip) has become increasingly important in electronic system designs, even when there are no batteries involved. Improvements in device-level methods are one step in the enhancement of SOC power management. Adding system and application awareness, however, can amplify the effectiveness of those efforts significantly.

The benefits of power management in battery-operated systems are obvious. The lower the average power consumption, the smaller, lighter, or cheaper the battery can be. When using stock commercial batteries, lower power means longer operating life. Either way, lower power translates to greater customer satisfaction.

Increasingly, however, power management is becoming critical in line-powered systems as well. Managing system power consumption yields multiple benefits. In data centers, for instance, the server farms are seldom fully loaded, yet never completely off. As a result, they can consume nearly half their total power simply idling.

Most consumer electronics systems also dissipate power when nominally “off” because they must remain active enough to respond to remote controls, and similar functions. Such “vampire” systems are estimated to account for nearly 10% of household energy use in the US, wasting some $3 billion worth of energy. System power management can reduce such waste considerably. Power management can also remove performance constraints on system designs, especially in systems such as Power over Ethernet (PoE) that have limited power available.

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