Design Of A Switch Type Hall Chip

With the development of information technology, sensor technology has been widely used. It is favored with small size, low cost and simple structure. This paper studies a switch type hall circuit chip based on the existing hall circuit chip. It can convert the magnetic signal into electric signal and through the analysis of the hall potential to detect the presence of magnetic field. The switch type hall chip is small and strong anti-interference ability.Based on the depth analysis of working principle of the Hall-effect and combined with the domestic existing process conditions, a switch type hall circuit chip is designed. This chip mainly contains: voltage regulator circuit, the Hall element, a differential amplifier, Schmitt trigger circuit, open collector output circuit. Analysis and comparison of several eliminate the offset voltage of the Hall element methods, the final rotary current method is adopted. And the Hall element is placed in the middle position of the entire chip to reduce the impact of the piezoresistive effect. In order to facilitate simulation and improve the simulation accuracy, using Verilog-A language build a model for the Hall element under the deep analysis. Applying schmitt trigger to realize the hysteresis characteristics of the hall switch chip, analysis and calculation of their two-point reversal. When the magnetic field increases to the open point, the output is a low level. And continue to increase the magnetic field, the output unchanged. If the magnetic field is reduced only to the release point, the output voltage will be from low to high. When the magnitude of the magnetic field is in the hysteresis range, the output status remains unchanged, and thus ensure that the circuit is reliable and stable working.On the basis of the composition and working principle of each module circuit, the Hall circuit chip is worked out and the simulation results to verify the feasibility of the circuit. Finally,the layout of the chip is designed by the 2μm 36 V Bipolar process and the correctness of the layout is verified by the DRC and LVS. Meanwhile, the layout has been taped, and the chip testing results show that each performance index meets the design requirements.