ats643 Allegro MicroSystems, Inc., ats643 Datasheet - Page 11

• Manufacturer Part Number: ats643
• Description: Ats643lsh Self-calibrating Zero-speed Differential Gear Tooth Sensors With Continuous Update
• Manufacturer: Allegro MicroSystems, Inc.

ATS643LSH
Power-On State Operation. The ATS643 is guaranteed to
power-on in the high current state, I
Initial Edge Detection. The device self-calibrates using the
initial teeth sensed, and then enters Running mode. This results
in reduced accuracy for a brief period (less than four teeth),
Figure 5. Power-on initial edge detection. This figure demonstrates four typical power-on scenarios. All of these examples assume that the target is
moving relative to the sensor in the direction indicated. The length of time required to overcome Start Mode Hysteresis, as well as the combined effect
of whether it is overcome in a positive or negative direction plus whether the next edge is in that same or opposite polarity, affect the point in time when
AGC calibration begins. Three high peaks are always required for AGC calibration.
Sensor Position
Target
(Gear)
Power-on
over valley
Start Mode
Power-on
at rising edge
Overcome
Hysteresis
Start Mode
Overcome
Hysteresis
Power-on
over tooth
Power-on
at falling edge
Start Mode
1
1
Overcome
Hysteresis
2
2
Start Mode
Overcome
Hysteresis
CC(High)
3
3
4
4
.
Gear Tooth Sensor with Continuous Update
AGC Calibration
Output
Output
Output
Self-Calibrating, Zero-Speed Differential
V
V
V
V
PROC
PROC
PROC
PROC
AGC Calibration
AGC Calibration
AGC Calibration
Output
however, it allows the device to optimize for continuous update
yielding adaptive sensing during Running mode. As shown in
figure 5, the first three high peak signals are used to calibrate
AGC. However, there is a slight variance in the duration of ini-
tialization, depending on what target feature is nearest the sensor
when power-on occurs.
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
Running Mode
Running Mode
Running Mode
Running Mode
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