TMR Sensor

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TMR Technologies Brief

TMR (Tunnel Magneto Resistance) is a new technology, using magneto resistance effect sensors for industrial applications in recent years. It's tunnel magneto resistance effect is induced by magnetic multilayer film material, the rate of resistance change of TMR performs better than AMR's and GMR's. We usually refer TMR to Magnetic Tunnel Junction (MTJ). Comparing with the Hall element, the MTJ element has better thermal stability, higher sensitivity, lower power consumption, better linearity, no additional polyethylene magnetic circular structure. Relative to AMR, TMR has better temperature stability, higher sensitivity, wider linear range and no additional set / reset coil structure; Relative to the GMR, TMR has higher stability in temperature, higher sensitivity, lower power consumption and wider linear range.

Our target customers are the top supplier of automotive components and systems

TMR Angle Sensors

There is a growing demand for high-accuracy angle detection in the fields of vehicle electrical components, industrial equipment, and consumer electronics.

TDK has applied TMR technology, which has shown excellent performance in HDD heads, to develop sensors that have high-output, resistant to noise and have high angle accuracy. TDK offers angle sensors with high stability in temperature and compact package that are fit into automobiles.

They have already been under mass production, and used in a wide range of applications which require high accuracy and stability, namely EPS motors.

Features

360° absolute angle measurement
Analogue output which can be interpolated for higher resolution
Differential output to reduce common mode noise
Redundancy or embedded Amp is available
Larger operating air gap
ISO26262

Application

EPS Motors
Steering angles
Pedal opening, throttle valve opening
Brushless Motors
Motors for wipers, etc

Gear Tooth Sensors

TDK commercializes gear tooth sensors as rotation sensors. TDK’s gear tooth sensors are highly sensitive rotation sensors that help purifying emission from four-wheeled and two-wheeled vehicles,and improve fuel efficiency, and improve engine performance.

Features

Multi pole magnet type/Back Bias Magnet Type
Stray magnetic field compensation
Rotary speed/direction detection
IF: Standard, PWM, AK, ABZ
Lower jitter (1%)

Application

ABS speed sensor
Cam-Crank shaft sensor
Motor rotator speed/position sensor

Engine Velocity (Crankshaft) Sensor

Measuring the speed of engine and determine the crankshaft position (position of the pistons) for the engine management system.

Reference Mark is used to defined crankshaft position and synchronize the control unit.

Engine Phase (Camshaft) Sensor

Indicate the piston (compression or exhaust) stroke to trigger the ignition and fuel injection.

Electrical connection (plug)
Sensor housing
Crankcase
Sealing ring
Permangent magnet
Sensors
Pulse wheel with tooth/segment (Z) and space (L)

b: Output signal

Speed Sensors for Transmission

Detect the speed of the turbine/output shaft in AT, the primary and secondary pulleys in CVT, input/driving shift in DKG, rotation direction is necessary for high-end products.

Customized design including ASIC, package,mechanical and magnetic interface due to diversity of the transmissions.

Trigger Wheel Type

Multipole Wheel Type

Differential signal btw R/C

Differential signal btw C/L

Output signal for CW

Output signal for CCW

Wheel Speed Sensors

Measure the vehicle wheels speed to controls the braking force individually at each wheel to prevents the wheels from locking up (with ABS) or from spinning (with TCS or ESP), and to calculate the speed/traveled distance.

CCW Signal

CW Signal

Stationary Signal

Self-diagnosis Signal

Acceleration Pedal Sensor

Recording the travel or the angular position of the accelerator pedal for the electronic throttle control (ETC).

E-Throttle Sensor

Responding the angle position information of the throttle valve to ECU to regulate the intake air mass for a specific air-fuel mixture.

Steering Angle Sensor

Monitor the driver’s input by continuously measuring the position and turning rate of the steering wheel and report the information to ECU, in order to control various driver-assist systems such as ESP, EPS and Active Steering together with the information from other sensors.

The passenger-car steering wheel turns through ±720° (a total of 4 complete turns), conventional angular position sensors can only measure maximum 360°, so 2 angle sensors are needed.

Axle Sensor

Two angle sensors on front/end axle record the bodywork’s tilt angle resulting from the vehicle loading, braking/acceleration for adjusting the vehicle’s headlamp range automatically, or adjusting the chassis height via active suspension.