Abstract
Recently, piezoresistive-type (PRT) pressure sensors have been gaining attention in variety of applications due to their simplicity, low cost, miniature size and ruggedness. The electrical behavior of a pressure sensor is highly dependent on the temperature gradient which seriously degrades its reliability and reduces measurement accuracy. In this paper, polynomial-based adaptive digital temperature compensation is presented for automotive piezoresistive pressure sensor applications. The non-linear temperature dependency of a pressure sensor is accurately compensated for by incorporating opposite characteristics of the pressure sensor as a function of temperature. The compensation polynomial is fully implemented in a digital system and a scaling technique is introduced to enhance its accuracy. The resource sharing technique is adopted for minimizing controller area and power consumption. The negative temperature coefficient (NTC) instead of proportional to absolute temperature (PTAT) or complementary to absolute temperature (CTAT) is used as the temperature-sensing element since it offers the best temperature characteristics for grade 0 ambient temperature operating range according to the automotive electronics council (AEC) test qualification ACE-Q100. The shared structure approach uses an existing analog signal conditioning path, composed of a programmable gain amplifier (PGA) and an analog-to-digital converter (ADC). For improving the accuracy over wide range of temperature, a high-resolution sigma-delta ADC is integrated. The measured temperature compensation accuracy is within ±0.068% with full scale when temperature varies from −40 °C to 150 °C according to ACE-Q100. It takes 37 µs to compute the temperature compensation with a clock frequency of 10 MHz. The proposed technique is integrated in an automotive pressure sensor signal conditioning chip using a 180 nm complementary metal–oxide–semiconductor (CMOS) process.
Highlights
Research on pressure sensors and transducers has been gaining significant attention.These sensors are being adapted widely in variety of applications such as the automotive industry, biomedical systems, petrochemicals, energy and electric power systems, aerospace, process control and humidity sensing systems [1,2,3,4]
The PRT sensor exhibits non-linear temperature the temperature increases up to 150 ◦ C and consistency in sensor accuracy and performance are dependency and its output voltage is influenced by temperature significantly
The PRT sensor input-out and temperature dependent characteristics are output voltage is influenced by temperature significantly
Summary
Research on pressure sensors and transducers has been gaining significant attention.These sensors are being adapted widely in variety of applications such as the automotive industry, biomedical systems, petrochemicals, energy and electric power systems, aerospace, process control and humidity sensing systems [1,2,3,4]. The PRT sensor exhibits non-linear temperature the temperature increases up to 150 ◦ C and consistency in sensor accuracy and performance are dependency and its output voltage is influenced by temperature significantly. For automotive applications, according to AEC-Q100 grade 0, the ambient temperature temperature-dependent nature adversely affects the accuracy, reliability, precision and performance range is −40 ◦ C to 150 ◦ C [5]. Other than non-linear behavior, gain and offset errors, depicted in Figure adversely affects the accuracy, reliability, precision and performance of piezoresistive sensors.
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