Circuit structure for reading orthogonal rotating current of Hall sensor

Abstract

The invention discloses a circuit structure for reading the orthogonal rotating current of a Hall sensor. The circuit structure comprises a constant current source, six N-channel metal oxide semiconductor (NMOS) switches, two P-channel metal oxide semiconductor (PMOS) switches, an amplifier and a square Hall disk, wherein the eight MOS switches can perform on / off selecting operation by providing two clocks which are not overlapped with each other; the square Hall disk leads out a terminal from four corners respectively; the terminals are connected with two PMOS switches and two NMOS switches respectively; the constant current source is connected with the other end of each of the two PMOS switches respectively; two ends of the residual four NMOS switches are connected with the four terminals of the Hall disk and two input ends of the amplifier respectively; and the generated Hall voltage signal is amplified by the amplifier. By the circuit structure, the offset voltage and noise can be combined with input offset and noise of the back-end amplifier, so that the next level of signal processing circuit can eliminate the offset voltage and the noise conveniently.

Description

technical field [0001] The invention relates to a circuit structure for Hall sensor current readout, more specifically a circuit structure for Hall sensor orthogonal rotation current readout. Background technique [0002] For the CMOS Hall sensor integrated circuit using the Hall plate structure, the influence of non-ideal factors such as the offset voltage of the Hall plate itself, temperature drift, and the noise of the CMOS process itself (such as 1 / f noise) will greatly reduce the impact of the sensor itself on the sensor. Sensitivity to magnetic field. Among them, the offset voltage of the Hall plate itself plays a major role. A common solution is to connect two or more Hall plates in parallel, but let the current directions injected into each other be perpendicular to each other. The offset voltage is canceled because changing the direction of the current only affects the polarity of the Hall plate's offset voltage, not the output signal voltage. But the disadvantag...

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Problems solved by technology

But the disadvantage of this method is that when mass production is carried out, due to the discreteness of the process, even if the consistency of shape and position is paid attention to, the characteristics of each Hall plate will be different, so the offset voltage cannot be completely determined. offset

In addition, since the signals of CMOS Hall sensors are generally weak, only on the order of tens to hundreds of microvolts, in order for the back-end circuit to recognize such a weak voltage, it needs to be amplified first, and the amplifier itself is also There will be offset and noise effects, which also interfere with the sensor signal

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