Philips Semiconductors
Magnetoresistive sensors for
magnetic field measurement
General
The simplest form of temperature compensation is to use a current source to supply to the sensor instead of a voltage source. In this case, the resulting reduction in sensitivity due to temperature is partially compensated by a corresponding increase in bridge resistance.
Thus a current source not only improves the stability of the
output voltage ‘Vo’, and reduces the variation in sensitivity to a factor of approximately 1.5 (compared to a factor of three using the voltage source). However, this method requires a higher supply voltage, due to the voltage drop of the current source.
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| T | = | 25oC | ||
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| H y (kA/m) | ||
Fig.32 Output voltage ‘Vo’ of a KMZ10B sensor as a function of transverse field ‘Hy’ using a current source, for several temperatures.
2000 Sep 06 | 27 |