Interface Circuitry and Microsystems

Abstract

Sensing physical or chemical quantities is a fundamental task in information processing and control systems. A sensing element or transducer converts the quantity to be measured into an electrical signal, such as a voltage, a current, or a resistive or capacitive variation. The data obtained from the transducers then have to be translated into a form understandable by humans, computers, or measurement systems. An electronic circuit called a sensor interface usually performs this task. The functions implemented by a sensor interface can range from simple amplification or filtering to A/D conversion, calibration, digital signal processing, interfacing with other electronic devices or displays, and data transmission (through a bus or, recently, through a wireless connection, such as Bluetooth).Very-large-scale integration (VLSI) technologies have been extensively used to make sensor interface circuits since the appearance of the first integrated circuit (IC) in the early 1960s. Most of the sensor systems realized so far consist of discrete sensors combined with one or more application-specific integrated circuits (ASICs) or commercial components on a printed circuit board (PCB) or hybrid board. Over the past few years, however, progress in silicon planar technologies has allowed miniaturized sensors (microsensors) to be realized by exploiting the sensing properties of IC materials (silicon, polysilicon, aluminum, silicon oxide, and nitride) or additional deposited materials (such as piezoelectric zinc oxide, sensitive polymers, or additional metallization layers).When microsensors are realized using IC technologies and materials, it is possible to integrate the interface circuit and several sensors on the same chip or in the same package, leading to microsystems or micromodules. [1][2][3][4][5][6] The potential advantages of this approach are numerous: The cost of the measurement system is greatly reduced due to batch fabrication of both the sensors and the interface circuits; its size and interconnections are minimized; and its reliability is improved.

The simulation of influence of main components’ parameters of reference voltage sources on output voltage

“…The influence of voltage gain, bandwidth, output resistance of the operational amplifier, input bias voltage on the nominal output voltage and the temperature coefficient are investigated. A regression analysis was performed to display in a polynomial of the 4th order form like 𝐼 = 𝑏 0 + 𝑏 1 𝑇 + 𝑏 2 𝑇 2 + 𝑏 3 𝑇 3 + 𝑏 4 𝑇 4 , temperature dependence of the currents generated in the circuit. This allows you to choose the correct values of current transfer coefficients in the current mirrors to reduce the temperature dependence of the output voltage.…”

“…Але одним із недоліків таких схем є неможливість працювати з напругою живлення нижче 1 В [2], [3]. Це викликано тим, що принцип роботи базується на ширині забороненої зони кремнію рівною 1,25 В, що вже перевищує 1 В живлення [2], [4].…”

System in package of bandgap voltage reference circuit with sub-1-V operation in CMOS for communication control and BioMedical applications

“…However, as devices are scaling down so as their supply voltage, low voltage reference is needed and then researches on sub-l V BGR become important, it is not suitable. Furthermore, there are aspects to improve bandgap voltage reference, such as using a fraction of the original reference voltage in [2,3], and studying low-voltage for supply in [4,5]. In [5], its supply voltage is 1.2 V at the expense of higher TC of 350 PPMfC and higher output voltage reference of 1.01 V. A low supply voltage of 0.6 V is used and obtains good results of both TC and output BGR, but only simulation data is found.…”

The Evolution of Integrated Interfaces for MEMS Microphones

“…Thanks to the use of advanced fabrication technologies, MEMS microphones offer several advantages with respect to ECMs: better performance, smaller size, compatibility with high-temperature automated printed circuit board (PCB) mounting processes, and lower sensitivity to mechanical shocks. Moreover, MEMS microphones can be integrated together with the CMOS electronics on the same chip or, more commonly, within the same package [ 2 ], thus reducing area, complexity, and costs, while increasing efficiency, reliability, and performance. As a result, around 2014 MEMS microphones overcame ECMs in terms of sold units, with an annual market size increase of more than 11%, as shown in Figure 1 .…”