Methods for Increasing the Speed of the Analog Interfaces for Physical Quantity Sensors Based on Radiation-Hardened and Low-Temperature Technologies

Abstract

The main circuitry methods for improving dynamic parameters in the large signal operation of the analog sensor interfaces (ASI) used in the instrumentation and automatic control systems are compared in the article. It is shown that the existing methods for increasing the slew rate (SR) of the ASI based on the operational amplifier (OA) are associated with the increase in the gain-crossover frequency of the OA due to the higher-frequency technologies (i.e., SiGe), or with the expansion of the range of active operation of the input subcircuit included before the integrating capacitor of the OA. A method for increasing the SR of the inverting ASI with an OA input stage of the dual-input class is proposed. The basis of the method lies in the introduction of two differentiating correction circuits (DCC) into the classical OA circuit, which in the large signal operation form additional overcharge currents of the integrating capacitance of the OA correction. In this case, the DCCs practically do not affect the low-signal amplitude-frequency characteristic of the OA. Such OAs have low current consumption in static mode and can be performed on the basis of standard processes, including radiation-hardened and low-temperature ones (CMOS, SOI, SOS, BiJFet, BJT, SiGe and others). The BJT OA computer simulation results show that the inverting ASI SR increases from 170 to 1800 V/μs. We consider the promising architectures of the high-speed OAs with the DCCs providing an increase in the SR in both inverting and non-inverting ASIs. The proposed ASI circuitry is designed to be used in automation devices and control systems, including nuclear and energy facilities.