Research And Design Of High Precision Hall Sensor

Hall sensors can sense magnetic field,position or current without contact,which is especially suitable for applications such as electric vehicles,autonomous driving,smart meters,power inverters,etc.As a result,Hall sensors are widely applied as magnetometers,position sensors,and current sensors in automotive,industrial,and consumer products.However,the influence of temperature and offset voltage will reduce the precision of the Hall sensor,thereby limiting its range of use.Low-precision Hall sensors cannot meet the needs of users at all,so improving measurement precision has become a research hotspot of Hall sensors.In this paper,based on the theoretical research of the principle of Hall element,offset voltage cancellation and temperature compensation,a high precision Hall sensor chip is designed by using 0.18?m 1P6 M BCD process.The main research contents and results are as follows: 1.Combine the differential array Hall element,Dynamic-offset cancellation technology,Switched-capacitor notch filter and Low-offset operational amplifier to eliminate the offset voltage.The differential array Hall element effectively suppresses the common mode magnetic field.The Dynamic-offset cancellation technology is based on the modulation-demodulation principle,which separates the magnetic field signal and the offset voltage in the frequency domain.Switched-capacitor notch filter effectively filter out high-frequency offset voltage.Low-offset and Low-noise programmable gain amplifier and output stage amplifier reduce the introduction of offset voltage in the signal path.2.Combining current compensation technology and piecewise linear interpolation temperature compensation technology to compensate sensitivity temperature drift and quiescent output voltage temperature drift.The current compensation technology compensates the first-order sensitivity temperature drift through the temperature drift of the power supply current.The piecewise linear interpolation temperature compensation technology adjusts sensitivity and quiescent output voltage by detecting real-time temperature values,thereby reducing temperature drift.The test results show that the temperature drift of the sensitivity is ± 1.2%,and the temperature drift of the quiescent output voltage is ± 7m V,and the compensation effect is obvious.3.Designed a programmable gain amplifier and a programmable current source(VQ adjustment circuit).The user can program the EEPROM through the VP and VOUT pins to control the gain of the programmable gain amplifier and the current of the programmable current source,thereby adjusting the sensitivity and quiescent output voltage of the Hall sensor.The test results show that the sensitivity adjustment range is 0.5?15 m V/G,and the quiescent output voltage adjustment range is-0.26V?0.3V.4.Designed the bandgap reference circuit and voltage regulator circuit.The bandgap reference circuit has the characteristics of low offset and high power supply rejection ratio.It generates a reference voltage of 1.209 V and its temperature drift is 8.70ppm/?.The voltage regulator module generates a constant voltage of ± 2.5V and supplies power to other circuit modules.The high-precision Hall sensor designed in this paper is powered by positive and negative power supply.It achieves a power supply voltage range up to ± 18 V and an output voltage swing of ± 12 V,and the operating temperature range is-40? to 150?.The circuit design,simulation verification and layout design were carried out with the aid of the Cadence software platform.The chip area was 2.5mm × 2mm.Finally,the chip samples produced by tape-out were tested and verified.The actual measurement results show that the Hall sensor functions normally,and various parameters meet the design requirements.