A 24.88 nV/√Hz Wheatstone Bridge Readout Integrated Circuit with Chopper-Stabilized Multipath Operational Amplifier

Abstract

This paper proposes a low noise readout integrated circuit (IC) with a chopper-stabilized multipath operational amplifier suitable for a Wheatstone bridge sensor. The input voltage of the readout IC changes due to a change in input resistance, and is efficiently amplified using a three-operational amplifier instrumentation amplifier (IA) structure with high input impedance and adjustable gain. Furthermore, a chopper-stabilized multipath structure is applied to the operational amplifier, and a ripple reduction loop (RRL) in the low frequency path (LFP) is employed to attenuate the ripple generated by the chopper stabilization technique. A 12-bit successive approximation register (SAR) analog-to-digital converter (ADC) is employed to convert the output voltage of the three-operational amplifier IA into digital code. The Wheatstone bridge readout IC is manufactured using a standard 0.18 µm complementary metal-oxide-semiconductor (CMOS) technology, drawing 833 µA current from a 1.8 V supply. The input range and the input referred noise are ±20 mV and 24.88 nV/ √ Hz, respectively.

An Autonomous Low-Power LoRa-Based Flood-Monitoring System

“…The key advantage of this solution is the simplicity and the reduced lumped elements count, which significantly lowers the overall costs for the system implementation. Besides the fact that voltage mode or current mode bridge-based solutions, like those proposed in [61][62][63][64][65], could be more effective for noise reduction, increased sensitivity and accuracy, they need a higher number of discrete components to be implemented. Moreover, the high resistance variation of the fork sensor in presence/absence of water leads to an ON/OFF behavior which can be clearly detected by a simple voltage divider architecture.…”

Simulation Analysis and Experimental Verification of the Locking Torque of the Microgravity Platform of the Chinese Space Station

“…The locations of each sensor are shown in Figure 12. The pressure signals collected by the force sensor were converted by Wheatstone Bridge Circuit [17,18], and then acquired by the data acquisition system, so as to obtain the real-time locking force value. Through data feedback, the relationship between torques and locking forces is shown in Figure 13.…”

Development of Inverter Circuits with Dual Control Subchannel Areas of Integral CMOS Sensor Element

“…The information signal of the resistive sensor is processed in analog or digital electrical circuits. Analog circuits use bridge circuits that are connected to analog-to-digital converters (ADCs) [8], interface circuits [9], or microcontrollers [10]. Digital circuits use various techniques for digitizing the information signal [11,12].…”