Considering the widespread application of magnetic sensors in the Internet of Things (IoT), a Hall sensor readout interface circuit with low offset voltage and low-temperature drift characteristics based on a 180 nm CMOS process is designed in this work. In response to the temperature drift characteristic of the Hall sensor sensitivity, a temperature sensing circuit that is combined with the table lookup method to adjust the gain of the Programmable Gain Amplifier (PGA) is designed, which effectively reduces the Temperature Coefficient (TC) of the Hall sensor. On this basis, the offset voltage of the Hall sensor is greatly eliminated by the use of Correlated Double Sampling (CDS) technology in the main signal channel. The simulation results show that the TC of the Hall sensor is decreased from 966.4 ppm/°C to 58.1 ppm/°C in the temperature range of –40°C～125°C. The chip measurement results of the main signal channel show that the offset voltage of the Hall sensor is reduced from about 25 mV to about 4 mV and the nonlinear error of the Hall sensor is 0.50％, which occupies an active area of 0.69 mm2.
关键词
霍尔传感器/接口电路/温度补偿/低失调电压
Key words
Hall sensor/Readout interface circuit/Temperature compensation/Low offset voltage
维普
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