Electronics & Connectivity - November 28, 2012 - 6

Integration opens the door
and draw less power than brushed motors. The trade-off for these gains is that more powerful microcontrollers and sensors are needed to monitor motor movement. Sensor suppliers are helping lower the size and cost of motors by making sensors rugged enough to live inside the motors. They’re also letting motor makers use less expensive materials. “Anisotropic magnetroresistive (AMR) sensors provide an alternative to Hall sensors,” said Lars Reger, Vice President of Automotive Strategy for NXP Semiconductors. “AMRs don’t require rare-earth magnets used with Hall-effect sensors, so their brushless motors can be cheaper.” Controllers must constantly gather data from all modules. Many chipmakers are integrating sensors into power devices so one chip can monitor actuators while controlling components. “We’re integrating sensing functions like current and temperature sensing into MOSFETs,” said Gary Wagner, Director of Automotive High Voltage at Fairchild Semiconductors. “We’re also integrating driver and diagnostic circuitry in these smart MOSFETs. This integration helps with time-to-market and ensures that everything will operate with the correct heat dissipation.” These components are likely to remain separate from the microcontrollers. It’s possible to put everything on one piece of silicon, but most chipmakers say it’s more efficient to put logic circuits on the microcontroller and power, sensing, and communications on another. “The integration of power devices onto a logic circuit will not work because microprocessor technology is based on a 5-V or lower power source, while the power devices are connected to the battery at 12-40 V,” said Dietmar Menden, Technical Marketing Engineer for STMicroelectronics’ Automotive Group. This focus on power consumption is rising rapidly. A single component may save only a few milliamps, but that becomes important as the number of electronic components soars. Saving 10% on each module’s power consumption can add up to a significant contribution to CO2 reduction. Power handling devices can make big contributions, especially given the big changes that often occur in power supply levels. “When you manage power with dc-dc converters instead of low-dropout regulators, you’re replacing a component

Losing power

Power components from Fairchild are integrating more functions to trim space requirements.

November 28, 2012

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Electronics & Connectivity - November 28, 2012

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