Data Sheet

15

1.10

2018-09-13

TLE4929C Crankshaft Sensor

Fully Programmable Crankshaft Sensor

3.3.5

Averaging Algorithm

To calculate the threshold within the running phase, valid maxima and minima are averaged to reduce

possible offset-updates. Each offset-update gives an increased jitter, which has to be avoided.

3.3.6

Direction Detection

Direction is calculated from the amplitude-value of direction-signal sampled at zero-crossing of speed-

channel. For each pole-pair or pair of tooth and notch two digital values are generated for detecting the

direction. Subtracting the second value from the first value the direction is determined by its sign. According

to EEPROM-setting a positive sign is either direction forward or direction backward.

Figure 6

Direction Detection Principle: TLE4929C-XAN-M28 issues forward-pulses at each middle of

tooth

Table 6

EEPROM-options for polarity and direction

EEPROM

EDGE_POLAR

EEPROM

FORWARD_DE

F

Function

0

0

Forward-pulse is issued when wheel rotates from pin 1 to pin 3.

Falling edge of output-pulse occurs at middle of the notch.

0

1

Forward-pulse is issued when wheel rotates from pin 3 to pin 1.

Falling edge of output-pulse occurs at middle of the tooth.

(as in TLE4929C-XAN-M28)

1

0

Forward-pulse is issued when wheel rotates from pin 1 to pin 3.

Falling edge of output-pulse occurs at middle of the tooth.

1

1

Forward-pulse is issued when wheel rotates from pin 3 to pin 1.

Falling edge of output-pulse occurs at middle of the notch.

B z,left

B z,right

B z,center

B z,left –B z,right

Monocell

speed

signal

direction

signal

Branded

side

1 2 3

N

S