ams AG (SIX: AMS), a leading provider of high performance analog ICs and
sensors, today introduced a new series of magnetic position sensors
featuring a breakthrough technology capable of producing extremely
accurate angle measurements of rotors spinning at high speed.
The new “47 series” position sensors include the AS5047D, AS5147 and
AS5247 with DAEC™ (Dynamic Angle Error Compensation), a patent-pending
technology developed by ams that eliminates the measurement error
attributable to propagation delay.
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The AS5047D is ideally suited for industrial applications including
robots and encoder modules.
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The AS5147 is an AEC-Q100 qualified part for automotive applications
such as electronic power steering and pumps.
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The dual-die AS5247 (also AEC-Q100 qualified) is well suited for
automotive applications requiring the highest level of functional
safety compliance.
All three parts are specified with a maximum ±0.17° angle error
(excluding integral non-linearity).
This precision measurement performance is the result of implementing
DAEC, an algorithm which performs error compensation internally and
responds automatically to changes in the speed of rotation. Traditional
magnetic rotary position sensor ICs suffer from a propagation delay
(typically 100-200µs) as they convert raw measurements of magnetic field
strength at their embedded magnetic elements into digital angle
measurements. During this delay, a spinning rotor’s angular displacement
changes, so that its actual position when the digital output leaves the
sensor differs from its measured position.
The resulting error increases in a linear fashion with increases in the
speed of rotation: for a propagation delay of 100µs, at 1,000rpm the
dynamic angle error is 1.2° and at 10,000rpm it is 12°.
DAEC almost completely eliminates this source of error, dynamically
compensating every measurement sample for the speed of rotation at the
time the sample is captured. The 47 series sensors provide angle
measurements accurate to ±0.08° at 7,000rpm, to ±0.14° at 12,000rpm and
to ±0.17° at 14,500rpm.
With its extreme accuracy, the ams 47 Series is ideally suited to all
motor control and angle measurement applications. In high-speed
brushless DC (BLDC) motors and permanent magnet synchronous motors
(PMSM) the sensor’s high accuracy enables better execution of the
commutation scheme, resulting in higher torque and efficiency, lower
torque ripple and smoother operation.
All three devices provide absolute position measurements as a digital
PWM output, and UVW outputs for use in field-oriented commutation
schemes. They also provide an incremental ABI output equivalent to the
output of an optical encoder. This means an AS5047D IC can replace an
optical encoder without requiring the user to change the software
interface in the host system’s microcontroller or DSP.
The 47 Series devices offer high 14-bit resolution (to 0.022°) in their
digital SPI output, and maximum resolution of 2,000 steps per revolution
in decimal mode and 2,048 steps per revolution in binary ABI mode.
Like all ams magnetic position sensors, the new 47 Series benefits from
a proven differential sensing technique, which offers immunity to stray
magnetic fields and enables the devices to be used in electrically noisy
environments without any requirement for shielding.
“The introduction of the 47 series marks a radical step forward in
magnetic position sensor technology,” said Bernd Gessner, Vice President
and General Manager of the Automotive Business Unit at ams. “For the
first time, designers of high-speed motors can use robust, compact
magnetic position sensors without the need to implement a complex error
compensation scheme in an external microcontroller or DSP.”
The AS5047D, AS5147 and AS5247 will be displayed in the ams booth (stand
909) at the Sensors Expo, Chicago, 24-26 June 2014.
The AS5047D is available for sampling in a 14-pin TSSOP package. It is
priced at $4.21 in 1,000-piece quantities.
The AS5147, priced at $4.84, is also in a 14-pin TSSOP package.
The AS5247, priced on request, is in an MLF-40, 7mm x 7mm package
General product availability end of July 2014. For more information on
the 47 series please visit our website at www.ams.com/Magnetic-Rotary-Position-Sensors/
Download Press Pictures or Block Diagram at
http://www.ams.com/eng/Press/Press-Releases/
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