Multiple die industrial process control transmitter

Abstract

A two-wire industrial process control transmitter includes a sensor (14), at least two integrated circuits (70, 72), and a level shift circuit (48). The first integrated circuit (70) contains the analog measurement circuit that includes a sensor detection circuit (16) and the analog portion (44) of a digital-to-analog convertor. The second integrated circuit (72) contains the digital system circuit that includes a modem (78) and the digital portion (46) of the analog-to-digital convertor. The first and second Ics may be powered at different voltage levels (Vdda, Vddd) to maximize the power of the analog circuit and improve resolution. Alternatively, the Ics may be powered at the same voltage level (Vddd), but the digital circuits are divided among several stacked dies (120, 122) to minimize the voltage for each digital circuit. In either case, the level shifting circuit (48) shifts the voltage level between the analog and digital circuits.

Description

technical field

[0001] The present invention relates to the process control industry, in particular to second-wire industrial process control transmitters having improved resolution without increasing power requirements. Background technique

[0002] An industrial process control transmitter is a transducer that responds to a process variable and provides a standard transmit signal as a function of the measured variable. The term "process variable" refers to a physical or chemical state of matter, or transformation of energy. Examples of process variables include pressure, temperature, flow, conductivity, pH, and other properties. Pressure can be considered a fundamental process variable since it can be used for measurement of flow (difference between two pressures), level (head or backpressure), and temperature (fluid pressure in thermal systems). Industrial Process Pressure Transmitters are used in industrial processes such as slurry, liquid, vapor, and gas processing in...

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