Circuit Solution for Sensitivity Increasing of Piezoresistive Pressure Sensors

The topic of this thesis is devoted to the use of various solutions for electrical circuits of pressure sensor (PS) chips. The piezoresistive differential amplifier (PDA) with 4 piezoresistors (PR) and piezoresistive differential amplifier with negative feedback loop (PDA-NFL) with 8 PRs used as electrical circuit. The use of deformable and non-deformable bipolar junction transistors (BjT) with vertical structure npn-type (V-NPN) and lateral structure pnp-type (L-PNP) is considered. The first, the output characteristics of developed piezoresistive PDA chip are researched in the comparative analysis relative to analog TMU18 with Wheatstone bridge (WB) circuit for 60 kPa pressure range. The analysis confirmed the possibility of sensitivity increasing by 2.2 times while maintaining the input conditions for geometry of mechanical structure and supply voltage. The second, the output characteristics of the developed piezoresistive PDA-NFL chip are researched in the comparative analysis relative to analog IPD60 with WB circuit for 60, 160 and 600 kPa pressure ranges. The analysis confirmed the possibility of sensitivity increasing by 3.5 times while maintaining the input conditions for geometry of mechanical structure, supply voltage and low errors; or minimization of chip area by 2.4 times while maintaining sensitivity. The possibility of reducing the noise of zero output signal by 20 times and the errors of temperature characteristics by more than an order relative to the parameters of piezoresistive PDA chip has been confirmed. The third, the output characteristics of ultra-highly sensitive small-sized PDA-NFL chip confirmed the possibility of simultaneously sensitivity increasing by 5.8 times and reducing chip area by 2.4 times relative to the analog IPD52 with WB circuit for 10 kPa range and while maintaining supply voltage and low errors.