oki tri-axis accelerometer module ml8952 · short-range development plan of oki...
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CONFIDENTIAL
OKI TRI-AXIS ACCELEROMETER MODULEML8952
OKI Electric Industry Co., Ltd.WP Business Development WP Business division
Silicon Manufacturing Company
CONFIDENTIAL
CONTENTS
What’s tri-axis accelerometer ?
Typical applications
Outline of ML8952
Specification
Roadmap of OKI motion sensor
Demonstration of free fall detection
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It can detect….
ACCELERATION
SHOCK
VIBRATION3D MOTION
What’s tri-axis accelerometer?What’s tri-axis accelerometer?
TILT
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PERSONAL MOBILE
COMUNICATION DEVICES
Electric Compass Correction
Safeguard Protection of HDD (freefall detection)
Pedometer
3D Mouse Control
Car Navigation System
Emerging Potential forMEMS-based Tri-Axis Accelerometers
SECURITY
Anti-theft alarms- motorcycles - ATM (automatic teller machines) etc.
Burglary alarms
Typical ApplicationsTypical Applications
Fault Vibration Detector
Seismograph (Earthquake sensor)
Tilt Angle Compensationfor Projector
Electric Level
INDUSTRIALGAMES
Display Controller
Input Controller
Robot Posture Controller
(Cell phones, PDA, Watch)
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Application to electronic compass correctionApplication to electronic compass correction• Introduction of a mobile phone with GPS and electronic compass in 2002
The mobile phone had to remainat an even level with the ground *
Tri-axis accelerometer (tilt sensor) clears this problem
tri-axis accelerometer
tri-axis accelerometer signal
processing unitsignal
processing unit
earth’s magneticfield sensor
earth’s magneticfield sensor
Electronic CompassElectronic CompassCell phones , PDAOKI
Drawing up a road map !
GPS +
* Existing earth’s magnetic field sensors have compass error depending on an operating tilt-angle.
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Package Feature of ML8952 (Commercial Device)
Package Feature of ML8952 (Commercial Device)
LCC 18 pin packageSize: 6.3 mm(W) x 6.2 mm(D) x 1.2 mm(H) (world's thinnest)Pb Free & Halogen Free
14
13
123
4
5
6
7
8
9 11 12
15
16
17
18
10
6.2
6.3
ML8
952
2.0 x 2.0
1.90.8
0.8
R 0.15
1 x 0.45
1.55
1.5 x 0.45
TOP VIEW BOTTOM VIEW
SIDE VIEW
1.0
(mm)
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Feature ML8950 (Type A) (Tech. Eval. Purpose) ML8952 (Type B’) (Commercial Device)
Package Size 5.0 x 5.0 x 1.4 (mm) 14-pin LCC 6.3 x 6.2x 1.2 (mm) 18-pin LCC
Calibration No internal EEPROM for calibration data Calibration data is stored on internal EEPROM (factory stored)
SPI and I2C SPI
3-wire serial I/F (SIOCLK, SIODT, SIOST)
4-wire serial I/F (SIOCLK, SIDT, SODT, SIOST)
CLK Frequency CLK Frequency
~ 1.53 MHz (SPI), ~ 400KHz (I2C) ~12MHz (EEPROM: ~ 1MHz)
<Automatic Compensation> <Automatic Compensation>
No automatic temperature compensationAutomatic temperature compensation for its sensitivity and offset value using a built-in temperature sensor and the calibration data.
<Automatic Measurement > <Automatic Measurement >
Only measurement controlled by external MPUIncluding automatic measurement mode, controlled by an internal CLK. When a G variation is detected, a interrupt signal is triggered to host CPU.
<Automatic Interrupt> <Automatic Interrupt>
No interrupt functionIncluding a programmable level-interrupt that can be triggered by freefall detection (0G), shock detection (G over threshold setting) or by sensing motion depending on the G variation.
<Time Averaging> <Time Averaging>
No time-averaging function
Including time-averaging function that can minimize the output data spread by time-averaging measured data per unit time. The given measurement times are 4, 16 and 64, which can be chosen suitable for customers applications.
Logic Control Circuit
CPU Interface
Feature Differences between Type A and Type B’Feature Differences between Type A and Type B’
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☆Our accelerometer is useful for HDD damage protection systems・No gravity (static acceleration) detection (~ 0G)→ offers retraction of a HDD’s head to safe position by detecting no
gravity during falling・ Collision/vibration (dynamic acceleration) detection→ features fast response time upon collision (<10msec). Possible to
stop the access safely resulting in avoidance of structive damage.
Automatic detection mode issues Automatic detection mode issues automatic interrupt signal to HOST CPUautomatic interrupt signal to HOST CPUwhen set value is exceeded.when set value is exceeded.
落下時の加速度イメージ
0.0
1.0
2.0
経過時間
加速度(絶対値表示)
1G+α
-α
Steady state
Falling
After collision
0G+α
Sample waveform
Elapsed time
Acc
eler
atio
n (A
bsol
ute
valu
e)An example of applications
- HDD damage protection -An example of applications
- HDD damage protection -
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Static Output Characteristic of AccelerometerStatic Output Characteristic of Accelerometer
-200.0-150.0-100.0-50.00.0050.0
100.0150.0200.0
0 30 60 90 120 150 180 210 240 270 300 330 360Angle [deg]
Out
put [
bit]
Vy
< y-axis Rotation >Y
X
Z
Vz
Vx
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Structure of OKI’s Piezoresistivity AccelerometerStructure of OKI’s Piezoresistivity Accelerometer
X
Z
Y
AL Pad
SiO2 (BOX)SOI
Piezoresistance
Beam
Overview
Cross-section
SOI Waf.Si Sub.Weight
AccelerationOn Weight
Strain/tensionOn Beams
ResistanceChange
Change in resistance can be read as proportional to acceleration
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Rx2Rx1
Rx3Rx4
Rz1Rz2
Ry1
Ry3Ry4
Ry2 Rz3 Rz4
Bridge CircuitsRx1- Rx4
X direction Ry1 - Ry4
Y direction Rz1 - Rz4
Z direction
<Top View >
X(Y) axis acceleration Z axis acceleration
R1 R2
R3R4E
R1 R2
R3 R4E Vout
Resistance Change due to mechanical Stress
stretch strainresistance increase(+)
compression strainresistance decrease(-)
+ +
Fx(y)
R4R3+
Fz
Vout
R2R1R3 R4R1 R2beam beam beambeam
Basic Principle of Acceleration DetectionBasic Principle of Acceleration Detection
- - - - <Piezoresistive Effect>+
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AdvantagesAdvantagesWorld’s Thinnest Package --- LCC:1.2 mm TypicalEasy of Use--- Serial Digital Interface (SPI)--- Application Development Tool available (I/F board and Software)Software)Environment --- Available in Pb Free & Halogen FreeA lot of functions -- Logic control supports several operational modes
Type
5 x 5.6 x2.0
4.8 x 4.8 x 1.3
6.3 x 6.2 x 1.2
PKG Size(mm3)
0~ +60AnalogHokuriku Electric Ind.
Hitachi Metal -25~ +75 +/- 2gAnalog
-20~ +70+/- 2gDigitalOKI
Operating Temp.
Range( C)
Detection RangeInterfacecompetitors
7 x 7 x 1.8 -40~ +85DigitalST Micron
+/- 2g
+/- 2gcapacitance
PiezoresistPiezoresist..
PiezoresistPiezoresist..
PiezoresistPiezoresist..
5.0x 5.0 x2.0 0~ +70AnalogADI
5.0 x 5.0 x 2.0 -40~ +70MEMSIC
+/- 2g
+/- 2g
capacitancecapacitance
Thermal Analog
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ML8952 SpecificationML8952 Specification
serial Digital I/F (SPI)Interface
mm6.3 (W) x 6.2 (D) x 1.2 (H)PKG Size (Typical)10.0 (Max)
2.5 (Max)
0.5 (Average)10
mA @RTCurrent consumption
Stand-by Current
(Acceleration)
Supply Voltage
CHARACTERISTICS SPECIFICATION (typ.) UNIT
+2.5 to +3.3 (analog)+1.8 to +3.3 (Digital) V
Detection range +/- 2 g
Detection Resolution (Angle)
mg/bit
/bit
Non linearity +/- 5 %FS
%FSOff-axial sensitivity +/- 10Response frequency DC~100 Hz
Shock survivability > 5000 g
Operating Temp. Range -20 to +70( -4 to + 158 ) C (deg F)
uA @70 C
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Short-range Development Plan of OKI AccelerometerShort-range Development Plan of OKI Accelerometer
2005 2006Target
ES: Jun. 2005~ MP: Dec. 2005~
Fall Model
ES: Winter 2005~ MP: Summer 2006~
Type B (1.0mm-thick-PKG)- 6.3 x 6.2 x 1.0mm- Built-in EEPROM- 4-wire-SPI- Freefall detection/ wake-up function- Time-averaging function
Type-C (Small size version)- 4.8 x 4.8 x 1.2mm- Built-in EEPROM- 4-wire-SPI- Freefall detection/wake-up function- Time-averaging function
Spring Model
ES: Winter 2006~ MP: Summer 2007~
Spring ModelFall Model
- Major target: Mobile-phone -- Major target: Mobile-phone -
** To be Sequentially Developed for the futureTo be Sequentially Developed for the future
year 2007
Type B’ (1.2mm-thick PKG, High shock-resistance version)- 6.3 x 6.2 x 1.2mm
Type-D (Electronic Compass)- 3D Earth Magnetic Field Sensor+ 3D Accelerometer- 6.3 x 6.2 x 1.2mm(preliminary)
ES: Summer 2006~ MP: Winter 2006~
ES: Apr. 2005~ MP: Sep. 2005~
Type-E (5D Motion Sensor)- 2D Gyro sensor +3D Accelerometer
<ML8951>
<ML8952>
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Roadmap of OKI Motion Sensor (Long-range)Roadmap of OKI Motion Sensor (Long-range)
Teak
FERAM 3-axis angular velocity sensor3-axis angular velocity sensor
3-axis accelerometer3-axis accelerometer
6-axis motion sensor6-axis motion sensor
- DSC , Video camera: correction of distortion with hand motion
- Toy robot
- DSC , Video camera: correction of distortion with hand motion
- Toy robot
- Detection of a bicycle turn over- Game controller- Electronic compass correction
- Detection of a bicycle turn over- Game controller- Electronic compass correction
- High-end posture controller
(robot, vehicle)Flash
EEPROM
U8
ARM
Sensor Correction, Signal Processing Technology
AMP, LPF
- More highly functional MEMS sensors plus ICs -- More highly functional MEMS sensors plus ICs -
CONFIDENTIAL
Oki Provides Total Silicon Solutions for Customer’s NeedsLong Term Partnership with Customers
Oki Provides Total Silicon Solutions for Customer’s NeedsLong Term Partnership with Customers
THANK YOU