Motor control is becoming a huge market, driven by energy saving demands in
consumer products and the growing use of small motors in autos. Microchip Inc.
is the latest company to jump on this bandwagon, unveiling a microcontroller
with peripherals tailored to motor control.
Automotive engineers are using motors in fuel pumps, to position seats, and
improve ventilation, while consumer product engineers are striving to reduce
power consumption to meet Energy Star requirements. In both environments,
quieter operation is one of many factors fueling a boom for chipmakers.
"With motor control, there are many ways to reduce power, and you can
eliminate belts and gears to lower costs. You can also eliminate clunky starts
by ramping up slowly to reduce noise," says Cheri Keller, product marketing
manager at Microchip's Advanced Microcontroller and Automotive Division in
Chandler, AZ (http://asp.microchip.com/wwwParamChart/chart.aspx?branchID=104&mid=&gdir=1010).
Appliances are the key target market, followed by automotive and industrial
applications, she adds.
Other chipmakers are responding with products that typically cost less than
$10. Philips Semiconductors of San Jose, CA, targeted motor control when it
introduced its LPC21xx, a$5 Arm 7 processor core, last fall (www.semiconductors.philips.com/markets/mms/products/microcontrollers/support/development_tools/lpc2100/index.html).
Motorola unveiled its approach at about the same time, coming out with the
56F8300, a microcontroller with DSP that includes components needed for motor at
pricing below $10.†
The Microchip device, the PIC18F, costs from $4.50 to $5 in OEM quantities
dropping to around $2 in very high volumes. The line offers three peripherals
used in many motor control systems. Its power control module has a three-phase
pulse width modulation structure, handling up to eight PWM channels with 14-bit
resolution and center alignment. A quadrature encoder interface is included in
the motion feedback module, while a 200 ksamples per second analog-to-digital
converter rounds out the motor control features.
INTEGRATING CONTROL: Microchip adds
functions that simplify motor control for high volume
"The 200 k sample rate is one of the fastest in the industry," Keller says.
She adds that the device has low power consumption, in the nanowatt range,
addressing another need for both portables and hardware that operates while
plugged in. A clock monitor provides fail safe operation in the event of clock
These motor control chips also handle some motion control functions, but they
typically only handle one axis of motion. Therefore, the ICs aren't expected to
have much of an impact on the many firms that sell motion control systems, which
are typically far more complex. "We have many axes of motion that require 32-bit
processors. Our customers typically don't want to build their own systems," says
Lisa Wade, spokeswoman at Galil Motion Control Inc. of Rocklin, CA (www.galilmc.com/products/index.html).
Motion control companies typically design boards for complex, comparatively
low volume products such as semiconductor processing equipment. Chipmakers are
addressing a vastly different market.† "The chips are a great solution for
high volume designs that are comparatively simple," Wade adds.
Though the chips are at the low end of this marketplace, they're not aimed at
extremely simple applications. In simple tasks like moving vehicle windows or
mirrors, motors can be controlled by very inexpensive, 8-pin processor chips
that are often mounted directly on the motors. The more powerful devices now
entering the marketplace are aimed at applications with greater demands. "These
devices have 28-40 pins. Often, they will be communicating with other chips,"
Keller says. For example, an auto's fuel pump needs to communicate with other
power train controllers. These chips may also handle other tasks such as
measuring temperature, she adds.