TLE4942 Datasheet, PDF (3/18 Pages) Infineon Technologies AG – Differential Two-Wire Hall Effect Sensor IC

TLE4942, TLE4942C
Functional Description
The differential Hall Effect IC detects the motion of ferromagnetic or permanent
magnet structures by measuring the differential flux density of the magnetic field. To
detect the motion of ferromagnetic objects the magnetic field must be provided by a
backbiasing permanent magnet. Either the South or North pole of the magnet can be
attached to the rear, unmarked side of the IC package.
Magnetic offsets of up to ± 20mT and mechanical offsets are cancelled out through a
self-calibration algorithm. Only a few transitions are necessary for the self-calibration
procedure. After the initial self-calibration sequence switching occurs when the input
signal crosses the arithmetic mean of its max. and min. values (e.g. zero-crossing for
sinusoidal signals).
The ON and OFF state of the IC are indicated by High and Low current
consumption. Each zero crossing of the magnetic input signal triggers an output
pulse.
Magnetic signal
Pulse length
Output Signal
I
Figure 3 Zero-crossing principle and corresponding output pulses
Differential
Magnetic Flux
Density
∆B
Range for EL pulse: ∆B_EL
Range for warning pulse: ∆B_Warning
∆B_Limit
(max .airgap
exceeded)
t
Figure 4 Definition of differential magnetic flux density ranges
TLE4942 - TLE4942C Data Sheet
3
February 2002