A Hall signal amplify circuit

Abstract

A Hall signal amplify circuit includes a Hall sensor module connected to a power supply, first amplifier, second amplifier, third amplifier, compensation module, a first output of the Hall sensor module is connected to a non-inverting input of the first amplifier, a second output of the Hall sensor module is connected to an inverting input of the first amplifier, the non-inverting output terminalof the first amplifier is respectively connected with the non-inverting output terminal of the second amplifier and the non-inverting input terminal of the third amplifier. The inverting output terminal of the first amplifier is respectively connected with the inverting output terminal of the second amplifier and the inverting input terminal of the third amplifier, the first output terminal of thecompensation module is connected with the non-inverting input terminal of the second amplifier, and the second output terminal of the compensation module is connected with the inverting input terminal of the second amplifier. The invention generates the equivalent input offset voltage related to the thermal voltage through the compensation module, and has good temperature compensation function while eliminating the operational amplifier offset voltage.

Description

technical field [0001] The invention relates to the field of amplifiers, in particular to a Hall signal amplifying circuit. Background technique [0002] In the process of amplifying the Hall signal, affected by the offset voltage of the operational amplifier, the static output voltage (in the case of zero magnetic field) is not at the midpoint potential, which affects its application in high-precision speed detection sensors and position detection sensors. In order to reduce the influence of the offset voltage of the operational amplifier, the traditional Hall signal amplifier circuit generally adopts the reference figure 1 The instrumentation amplifier structure shown includes the Hall sensor module 01 for outputting the Hall signal, the first operational amplifier OPA 1 , the second operational amplifier OPA 2 , the third operational amplifier OPA 3 , the first resistor, the second resistor until the seventh resistor, where the first resistor is denoted as R 0 , the s...

AI Technical Summary

Problems solved by technology

[0002] In the process of amplifying the Hall signal, affected by the offset voltage of the operational amplifier, the static output voltage (in the case of zero magnetic field) is not at the midpoint potential, which affects its application in high-precision speed detection sensors and position detection sensors

In order to reduce the influence of the offset voltage of the operational amplifier, the traditional Hall signal amplifier circuit generally adopts the reference figure 1 The instrumentation amplifier structure shown includes the Hall sensor module 01 for outputting the Hall signal, the first operational amplifier OPA 1 , the second operational amplifier OPA 2 , the third operational amplifier OPA 3 , the first resistor, the second resistor until the seventh resistor, where the first resistor is denoted as R 0 , the second resistor is the same as the third resistor, both are denoted as R 01 , the fourth resistor and the fifth resistor are the same, both are denoted as R 02 , the sixth resistor and the seventh resistor are the same, both are denoted as R 03 , although this symmetrical structure can reduce the influence of the offset voltage of the op amp to a certain extent, it cannot completely eliminate the offset voltage of the op amp.

In order to achieve the effect of offsetting the offset voltage of the operational amplifier, the Hall signal amplifying circuit also includes an adjustment module 02 on the basis of this structure, which is used to adjust the reference voltage V REF , so as to offset the influence of the offset voltage of the op amp, but the offset voltage of the op amp in the Hall signal amplifying circuit will also change with the temperature, considering the temperature coefficient of the offset voltage of the op amp and the thermal voltage V in the amplifying circuit T It is difficult to offset by the temperature coefficient of a single resistor. Therefore, the solution in the prior art does not have a good temperature compensation effect on the offset voltage of the op amp in the Hall amplifier circuit, and cannot guarantee that the static output voltage is in the full temperature operating range. high precision in

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