Magnetic field feedback delta-sigma modulator sensor circuit

A magnetic field sensor and sensor technology, applied in the field of magnetic field sensors, can solve problems such as increasing complexity

Active Publication Date: 2009-12-23
CIRRUS LOGIC INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, such a circuit adds significant complexity because the source and detector need to be calibrated, and the calibration must be periodic or outside the ideal detection distance of the sensor circuit, which often also requires additional filtering circuitry

Method used

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  • Magnetic field feedback delta-sigma modulator sensor circuit
  • Magnetic field feedback delta-sigma modulator sensor circuit
  • Magnetic field feedback delta-sigma modulator sensor circuit

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Embodiment Construction

[0014] The present invention includes a semiconductor magnetic field sensor circuit and method using the noise-shaping loop of a delta-sigma regulator analog-to-digital converter (ADC) to provide a calibration signal for the semiconductor magnetic field sensor. This allows the circuit to calibrate itself to compensate for low-frequency variations in the offset voltage and sensor output signal. The analog-to-digital sensor output provides the digital output of the sensor circuit and also has high noise immunity.

[0015] now as figure 1 As shown, it is a semiconductor magnetic field sensor circuit according to an embodiment of the present invention. A Hall-effect sensor H, which can also be replaced by another type of magnetic field sensor, such as a magneto-resistive device, is supplied with a bias current I B , and the output is connected to the differential input of amplifier A, which can be a chopper amplifier to reduce offset and 1 / f noise that would otherwise be introdu...

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Abstract

A magnetic field feedback delta-sigma modulator sensor circuit, provides accurate magnetic field measurements without requiring complex additional calibration circuitry. The output of the semiconductor magnetic field sensor, which may be a Hall effect sensor, is coupled to the input of the delta-sigma modulator loop filter. The output of the quantizer of the delta-sigma modulator is magnetically coupled to the magnetic field sensor, producing a field that causes the output of the sensor to be canceled for frequencies in the band of the modulator loop filter. The output of the quantizer is provided to a current output digital-to-analog converter, which feeds a current loop that is inductively coupled to the sensor body. A chopper amplifier can be provided between the output of the sensor and the modulator loop filter input to reduce 1 / f noise and bias current and output terminals can be rotated to further reduce 1 / f noise and offset.

Description

technical field [0001] The present invention relates to a magnetic field sensor, and more particularly to a converter circuit providing a digital output from a semiconductor magnetic field sensor. Background technique [0002] Hall effect sensors and other semiconductor magnetic field sensors are widely used to provide measurements of direct current (DC) magnetic fields and related low frequency alternating current (AC) magnetic fields that cannot easily be induced with coils or other antennas. Such applications include fixed position and moving position sensors, used in linear and rotary motion, power supply and motor control, detection of transformers or motors, use in audio speakers, detection of signal containment strength in speakers, and for high frequency Energy Driven etc. provide lighting controllers such as sodium lamps. [0003] Semiconductor magnetic field sensors typically exhibit large variations in their output voltage versus magnetic field strength as a sens...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R33/07
CPCG01R33/12G01R33/07H03M3/34H03M3/422G01D5/145
Inventor 约翰·L.·梅安森
Owner CIRRUS LOGIC INC
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