A Chopper Stabilization Audio Instrumentation Amplifier for IoT Applications

Internet of Things: Development Intelligent Programmable IoT Controller for Emerging Industry Applications

The Internet of Things (IoT) has become critical to the implementation of Industry 4.0. The successful operation of smart manufacturing depends on the ability to connect everything together. In this research, we applied the TOC (Theory of Constraints) to develop a wireless Wi-Fi intelligent programmable IoT controller that can be connected to and easily control PLCs. By applying the TOC-focused thinking steps to break through their original limitations, the development process guides the user to use the powerful and simple flow language process control syntax to efficiently connect to PLCs and realize the full range of IoT applications. Finally, this research uses oil–water mixer equipment as the target of continuous improvement and verification. The verification results meet the requirements of the default function. The IoT controller developed in this research uses a marine boiler to illustrate the application. The successful development of flow control language by TOC in this research will enable academic research on PLC-derivative applications. The results of this research will help more SMEs to move into smart manufacturing and the new realm of Industry 4.0.

A 5-nV/√Hz Chopper Negative-R Stabilization Preamplifier for Audio Applications

This paper presents a low-noise and low-power audio preamplifier. The proposed low-noise preamplifier employs a delay-time chopper stabilization (CHS) technique and a negative-R circuit, both in the auxiliary amplifier to cancel the non-idealities of the main amplifier. The proposed technique makes it possible to mitigate the preamplifier 1/f noise and thermal noise and improve its linearity. The low-noise preamplifier is implemented in 65 nm complementary metal-oxide semiconductor (CMOS) technology. The supply voltage is 1.2 V, while the power consumption is 159 µW, and the core area is 192 µm². The proposed circuit of the preamplifier was fabricated and measured. From the measurement results over a signal bandwidth of 20 kHz, it achieves a signal-to-noise ratio (SNR) of 80 dB, an equivalent-input referred noise of 5 nV/√Hz and a noise efficiency factor (NEF) of 1.9 within the frequency range from 1 Hz to 20 kHz.