TLE4953

TLE4953C

Data Sheet

3

V 4.0, 2010-04

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 (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 3

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

V

Direction of rotation right = DR-R

DR-R information is issued in the output pulse length when the active target wheel in

front of the Hall Effect IC moves from the pin GND to the pin

V

AED03189

Pulse

Length

MagneticSignal

Output Signal