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High-Performance Motor Control at an Affordable Price
Built-in motor control peripherals and floating-point math accelerator key
Karen Field, Editor-in-Chief -- Design News, September 10, 2009
Designed for high-performance motor control applications,
TI's F2802x/2803x Piccolo Microcontroller is worth a look from design engineers
who want the perks of 32-bit, real-time control but at more affordable cost.
The device is priced at less than $2 in volume.
TI announced the device in September 2008 and is now
releasing the part to mass production.
Loaded with specialized, built-in peripherals to enhance motor control applications,
noteworthy features include the on-chip, 12-bit, 13/16-channel ADC that offers
up to 4.6 MSPS. ADCs on competitive devices typically offer in the neighborhood
of 1 MSPS, says Keith Ogboenyiya, TI Product Manager for C2000 32-bit microcontrollers.
"Our ADC t allows designers to significantly reduce latency, which is a key benefit
in motor control applications since the speed at which you can grab the voltage
and current data ultimately affects your control precision."
The device also features TI's patented pulse width modulators (PWMs) that provide frequency modulation down to 150 ps for better harmonics control.
The most unique feature is the on-chip, floating-point math accelerator (or Control Law Accelerator. It runs a high-speed control loop, thereby freeing up the main CPU to handle I/O and feedback loop metrics. Running two loops in parallel in this way, says Ogboenyiya, allows designers to build additional functionality into their motor control application without adding more devices. For example, one Piccolo could provide precise control of two three-phase motors and a power factor correction without running out of headroom.
Not wanting to trade-off functionality, Piccolo's designers made a slight trade-off in power consumption. "We chose a more high performance ADC and though while it is still very good with respect to power consumption, it's not the lowest- power device we offer," says Ogboenyiya.
The Piccolo is code compatible with TI's family of C2000 devices. TI also offers a complete set of 3-phase motor control libraries and training material, and has announced two new Piccolo F28035 development kits with one or two motors.
