TLE4942-2 Просмотр технического описания (PDF) - Infineon Technologies
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TLE4942-2 Datasheet PDF : 9 Pages
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TLE4942-2, TLE4942-2C Supplement
Example: The 14th row describes the behaviour shown in Fig. 1: The standstill pulse length
can be cut by the first detected speed pulse, therefore the minimum distance between the
rising edges will be 45µs. The distance between the first and second detected speed pulse is
determined by the initial signal phase and amplitude and a possible first PGA switching. As
the first pulse length also can theoretically be cut off by the following pulse, the minimum
distance could be 45µs. The rising edge between the first signal minimum and the first signal
maximum can cause the PGA switching into a lower gain range. As a result the digital noise
constant value can increase in relation to the signal amplitude. That typically leads to an
increased delay between the second and the third pulse, its maximum value is 260°. The
following minimum and maximum are necessary for peak detection. After offset correction,
the delay between the 5th and the 6th pulse can have a maximum value 270°. As this marks
the transition from uncalibrated to calibrated mode, the following consecutive pulses (4, 5, 6
...) will be spaced 180° nominally.
Same example with numbers: ∆B = 10mT sin (ωt + ϕ). ϕ = 30°
Typical startup-behaviour at a sinusoidal input signal of 10mT amplitude, initial phase= 30°.
1
2
3
4
5
6
7
8
9
10
ϕ 43,6° 133,9° 333,2° 513,2° 693,2° 900° 1080° 1260° 1440° ...
90,3°
∆ϕ (PGA,
uncal)
199,3°
(PGA,
uncal)
180°
(uncal)
180°
(uncal)
206,8°
(Offset-
correction)
180°
(cal)
180°
(cal)
180°
(cal)
180°
(cal)
→ This corresponds to row 14 in the table, behaviour similar to Fig. 1
As a special (and rare) case instead of an offset correction after edge number 5, a further
(extra) PGA switching could occur before edge number 5. PGA switching inhibits an
immediate offset update. It can happen if one of the signal peaks is exactly at a PGA
switching threshold (speed-ADC overflow). In this case the offset update (switching from
uncalibrated mode to calibrated mode) would be delayed by two to three further edges. The
referring phase shifts of the example would then be as follows:
1
2
3
ϕ 43,6° 133,9° 333,2°
4
513,2°
5
727,5°
6
7
907,5° 1087,5°
8
1260°
9
10
1440° ...
90,3°
∆ϕ (PGA,
uncal)
199,3°
(PGA,
uncal)
180°
214,3°
180°
(uncal) (extra PGA) (uncal)
180°
(uncal)
172,5°
(Offset-
correction)
180°
(cal)
180°
(cal)
→ This corresponds to row 13 of the table.
TLE4942-2 - TLE4942-2C Data sheet supplement 5
February 2002
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