KMI15/4 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

KMI15/4

Rotational speed sensor

Philips Electronics 

Philips Semiconductors

Rotational speed sensor

Product specification

KMI15/4

FUNCTIONAL DESCRIPTION

The KMI15/4 sensor is sensitive to the motion of ferrous

gear wheels or reference marks. The functional principle is

shown in Fig.3. Due to the effect of flux bending, the

different directions of magnetic field lines in the

magnetoresistive sensor element will cause an electrical

signal. Because of the chosen sensor orientation and the

direction of ferrite magnetization, the KMI15/4 is sensitive

to movement in the ‘y’ direction in front of the sensor only

(see Fig.2).

The magnetoresistive sensor element signal is amplified,

temperature compensated and passed to a Schmitt-trigger

in the conditioning integrated circuit (Figs 4 and 5).

The digital output signal level (see Fig.6) is at a fixed level

independent of the sensing distance. A (2-wire) output

current enables safe sensor signal transport to the

detecting circuit (see Fig.7). The integrated circuit housing

is separated from the sensor element housing to optimize

the sensor behaviour at high temperatures.

The strength of the magnetic field caused by the

Ferroxdure 100 magnet in the different sensor directions,

measured at the centre of the magnetoresistive bridge, is

typically: Hx = 7 kA/m (auxiliary field) and Hz = 17 kA/m

(perpendicular to the sensor surface). Hy is zero due to the

trimming process.

handbook, halfpage x

y

magnet with

direction of

magnetization

x

z

sensor

IC

MBH779

Fig.2 Component detail of the KMI15/4.

handbook, full pagewigdethar wheel

z

magnet

sensor y

(a)

2000 Sep 05

magnetic

field lines

direction

of

motion

(b)

(c)

Fig.3 Functional principle.

4

MRA957

(d)

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