TLE4953x

Functional Description

Data Sheet

8

Version 4.1, 2018-01-02

2

Functional Description

Figure 2-1 Block Diagram

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 (remark: rear side may contain data matrix code) of the IC package.

Magnetic offsets of up to ± 20 mT and mechanical offsets are cancelled out through a self-calibration algorithm.

Only 2 transitions are necessary for the self-calibration procedure. After the initial self-calibration sequence

switching occurs when the input signal crosses the adaptive threshold on the rising magnetic edge.

The ON and OFF state of the IC are indicated by High and Low current consumption. Each rising magnetic edge

of the magnetic input signal triggers an output pulse.

Figure 2-2 Output Pulses on magnetic rising edge

In addition to the speed signal, the following information is provided by varying the length of the output pulses

(PWM modulation):

Speed signal = S

The speed signal is issued at the first output pulse after start up and when the magnetic frequency is above 1kHz.

Direction of rotation left = DR-L

DR-L information is issued in the output pulse length when the active target wheel in front of the Hall Effect IC

moves from the pin VCC to the pin GND.

Direction of rotation right = DR-R

-

+

-

+

L

eft

R

ight

C

entr

PGA

A/D

slope/peak

detection

offset

calc.

-

(R+L)/2-C

output

protocol

system control

& watchdog

-

D/A

supply

generator

clock

gen.

Hall probes:

LP

comp

D/A

Tracking

algor.

+ noise

shaper

Dig.

Filter

Direction

algorithm

-

Pulse

Length

Output Signal

Magnetic Signal