High-resolution sensorless position estimation using delta-sigma-modulated current measurement

The accuracy of current measurements can be increased by appropriate amplification of the signal to within the measurement range. Accurate current measurement is important for energy monitoring and in power converter control systems. Resistance and inductive current transducers are used to measure the major current in AC/DC power converters. The output value of the current transducer depends on the load motor, and changes across the whole measurement range. Modern current measurement circuits are equipped with operational amplifiers with constant or programmable gain. These circuits are not able to measure small input currents with high resolution. This article proposes a precise loop gain system that can be implemented with various algorithms. Computer analysis of various automatic gain control (AGC) systems proved the effectiveness of the Mamdani controller, which was implemented in an MCU (microprocessor). The proposed fuzzy controller continuously determines the value of the conversion factor. The system also enables high resolution measurements of the current emitted from small electric loads (≥1 A) when the electric motor is stationary.

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A High-Resolution and Low Offset Delta-Sigma Analog to Digital Converter for Detecting Photoplethysmography Signal

ASME 2021 30th Conference on Information Storage and Processing Systems ◽

10.1115/isps2021-65248 ◽

2021 ◽

Author(s):

Eka Fitrah Pribadi ◽

Rajeev Kumar Pandey ◽

Paul C.-P. Chao

Keyword(s):

High Resolution ◽

Continuous Time ◽

Operational Amplifier ◽

High Frequency ◽

Analog To Digital Converter ◽

Digital Converter ◽

Analog To Digital ◽

Delta Sigma Modulator ◽

Delta Sigma ◽

Low Offset

Abstract A high-resolution, low offset delta-sigma analog to digital converter for detecting photoplethysmography (PPG) signal is presented in this study. The PPG signal is a bio-optical signal incorporated with heart functionality and located in the range of 0.1–10 Hz. The location to get PPG signal is on a pulsating artery. Thus the delta-sigma analog-to-digital (DS ADC) converter is designed specifically in that range. However, the DS ADC circuitry suffers from 1/f noise under 10 Hz frequency range. A chopper based operational amplifier is implemented in DS ADC to push the 1/f noise into high-frequency noise. The dc offset of the operational amplifier is also pushed to the high-frequency region. The DS ADC circuitry consists of a second-order continuous-time delta-sigma modulator. The delta-sigma modulator circuitry is designed and simulated using TSMC 180 nm technology. The continuous-time delta-sigma modulator active area layout is 746μm × 399 μm and fabricated using TSMC 180 nm technology. It operates in 100 Hz bandwidth and 4096 over-sampling ratios. The SFDR of the circuit is above 70 dB. The power consumption of the delta-sigma modulator is 35.61μW. The simulation is performed in three different kinds of corner, SS, TT, and FF corner, to guarantee the circuitry works in different conditions.

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A/D Conversion Applications

Multirate Systems ◽

10.4018/978-1-930708-30-3.ch005 ◽

2002 ◽

pp. 143-173 ◽

Cited By ~ 1

Author(s):

Godi Fischer

Keyword(s):

High Resolution ◽

Data Conversion ◽

Practical Implementation ◽

Trade Offs ◽

Delta Sigma ◽

Physical Level ◽

Delta Sigma Modulation ◽

The Way

We begin our excursion into the field of data conversion by reviewing the most frequently applied conversion principles. The next section explains the fundamentals of delta-sigma modulation. This paves the way for the section which provides a case study of a delta-sigma based high-resolution ADC system intended for a sonar application. This design example not only illustrates the various trade-offs on the architectural level but also addresses practical implementation issues on the physical level. Finally, the last section summarizes our findings and contains some concluding remarks.

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