Ultra-Miniature Linear Motion for Mobile and Handheld Devices

DN Staff

February 4, 2010

3 Min Read
Ultra-Miniature Linear Motion for Mobile and Handheld Devices

Atiny ultrasonic piezo motor (2.8 x 2.8 x 6 mm) and drive ASIC (1.8 x 1.8 mm)creates a miniature linear motion system that offers performance comparable tomuch larger electromechanical systems using 40 percent lower power and lessthan one-fourth the size. Targetapplications are battery-operated hand-held devices, mobile phone cameras,digital still and video cameras and miniature medical actuators used forminimally invasive surgery.

TheSQUIGGLE RV motor from New ScaleTechnologies is a new "reduced voltage" piezo micro motor that usesmulti-layer piezo technology from TDK-EPC(formerly Epcos) to reduce the input voltage requirements. A NSD-2101 driver developedin partnership with austriamicrosystemscontrols the motor using a standard IA 2C interface.

Thedrive IC accepts direct 2.3 to 5.5V dc battery power and uses patentedfull-bridge switching technology to create the ultrasonic motor drivefrequency. The IC has patent-pending smart drive features built-in thatoptimize motor performance while minimizing power consumption over a broadrange of operating and environmental conditions. A built in oscillatoreliminates the need for an external master clock.

"Allof the drive circuitry is on the IC," says Ralph Weber, product manager for NewScale Technologies. "Using multilayer piezo technology, we have IP and patentpending concepts like hybrid controls and frequency tracking on the chip. As aresult we almost double the force of our previous SQUIGGLE motor using half thepower. It really performs like an electromagnetic linear system at about one-quarterof the size."

Webersays that the multilayer piezo technology provides an interleaving of piezolayers, and combining the layers in the piezo stack creates the same deflectionat a lower voltage than a full single layer, piezo stack. The drive IC alsouses a proprietary design to actively manage low power consumption. It offers apower-down mode for minimal power consumption in stand-by and an idle mode forreduced power consumption while maintaining frequency calibration.

"Thisis a tremendous milestone for the piezo motor industry," says Weber. "Weare the first company to commercialize a piezoelectric motor system thatmatches the low voltage operation of stepper motors while at the same timeusing radically less space and power."

TheSQL-RV-1.8 motor achieves forces in excess of 50 gm and high resolution to 0.5micrometer. It can run at speeds greater than 7 mm/sec with power consumptionof less than 350 mW when moving under typical loading conditions whichcorresponds to a dc current of only 120 mA for a typical 3V dc battery. Itsunique self-locking design means that zero power is required to hold the motorposition.

NewScale's TRACKER NSE-5310 linear encoder can be integrated with the SQUIGGLE RVsystem for high system repeatability with submicron resolution. Its small sizeprovides an ability for designers to create tiny, high resolution integratedclosed-loop motion systems.

Reduced voltage SQUIGGLE motor and drive IC offer high performance and direct 3V input to driver for integration into advanced miniature OEM products. Photo:  New Scale Technologies.

Ultra-Miniature Linear Motion A

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