HALL-EFFECT-BASED MAGNETIC FIELD SENSOR HAVING AN IMPROVED OUTPUT BANDWIDTH

摘要

A magnetic field sensor formed by a Hall cell having a first, second, third and fourth conduction nodes electrically coupled together by resistive paths. Flowing between the first and second conduction nodes is a control current. In the presence of a magnetic field, a difference of potential due to the Hall effect is generated between the third and fourth conduction nodes. An operational amplifier has an inverting input terminal coupled to the fourth conduction node, a non-inverting input terminal biased at the voltage at the third conduction node, and an output terminal coupled in feedback mode to the inverting input by a feedback resistor. The current generated in feedback through the feedback resistor generates a voltage indicating unbalancing, due to the Hall effect, between the third and fourth conductive nodes, and consequently indicates the intensity of the magnetic field that acts upon the Hall cell.

主权项

1. A circuit, comprising:
a resistive bridge circuit having first, second, third and fourth nodes; a first circuit having an input coupled to the third node and an output coupled to the first node, said first circuit configured to bias the first node at a first voltage and bias the second node at a second voltage and further provide a bias current flowing through the resistive bridge from the first node to the second node; and a second circuit having an input coupled to the fourth node and an output coupled by a feedback circuit to the fourth node to maintain the fourth node at a third voltage and generate at said output a fourth voltage having a magnitude corresponding to a degree to which the resistive bridge circuit is unbalanced.