TLE4917 Datasheet, PDF (3/13 Pages) Infineon Technologies AG – Low Power Hall Switch

V_S
1
Bias and
Com pensation
Circuits
Active Error
Com pensation
Hall
Probe
Chopped
A m plifier
Oscillator
&
Sequencer
Threshold
Generator
Com p arator
w ith
Hysteresis
Decision
Logic
Latch
2, 4, 5 _GND
3Q
6
PRG
AEB02800_C
Figure 2 Block Diagram
Circuit Description
The Low Power Hall IC Switch comprises a Hall probe, bias generator, compensation
circuits, oscillator, output latch and an n-channel open drain output transistor.
The bias generator provides currents for the Hall probe and the active circuits.
Compensation circuits stabilize the temperature behavior and reduce technology variations.
The Active Error Compensation rejects offsets in signal stages and the influence of
mechanical stress to the Hall probe caused by molding and soldering processes and other
thermal stresses in the package. This chopper technique together with the threshold
generator and the comparator ensures high accurate magnetic switching points.
Very low power consumption is achieved with a timing scheme controlled by an oscillator
and a sequencer. This circuitry activates the sensor for 50 µs (typical operating time) sets
the output state after sequential questioning of the switch points and latches it with the
beginning of the following standby phase (typ. 130 ms). In the standby phase the average
current is reduced to typical 3.5 µA. Because of the long standby time compared to the
operating time the overall averaged current is only slightly higher than the standby current.
By connecting the programming pin to GND (normal to V_S) the Output State can be inverted
to further reduce the current consumption in applications where a high magnetic field is the
Data Sheet
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