TLE4943C datasheet(6/48 Pages) INFINEON

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TLE4943C

Data Sheet

V 1.2, July 2018

Functional Description

2.1

General

The basic operation of the TLE4943C is to measure the differential magnetic field of ferromagnetic or permanent

magnet target wheels and generate an output signal which represents the motion of these objects. Additionally

the direction of rotation of a rotating target wheel and the quality (strength) of the magnetic signal are detected.

For the applications with ferromagnetic toothed wheels a back bias magnet is required. The magnetic

measurement is based on three equally spaced Hall elements, integrated on the IC. The two outer Hall elements

have a distance of 2.5mm, the third Hall element is placed in the middle between the outer Hall elements. The

outer Hall elements generate a differential signal which corresponds to the speed of the detected object. All three

Hall elements are used for the information of direction detection. The IC has a three-level current interface which

corresponds to the AK-protocol described below in this data sheet.

Magnetic offsets of up to +/-30mT are cancelled by a self-calibration algorithm. Only a few magnetic edges after

start-up (uncalibrated mode) are necessary to finish the self-calibration and providing offset corrected signals in

calibrated mode. Independent of the mode every increment of the encoder triggers a signal output. The output

signal frequency represents the increment frequency, e.g. 100 increments per second are equal to 100Hz. The

frequency of the magnetic signal is half of the output signal frequency.

Figure 1

Definition of increment

Increment n

Increment n+1

Increment n+2

Zero

Crossing

Sensor output

current Is

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