An Ultra-Low-Power, 16 Bits CT Delta-Sigma Modulator Using 4-Bit Asynchronous SAR Quantizer for Medical Applications

2019 ◽  
Vol 29 (04) ◽  
pp. 2050056
Author(s):  
Sahel Javahernia ◽  
Esmaeil Najafi Aghdam ◽  
Pooya Torkzadeh
Keyword(s):  
Low Power ◽  
Cmos Technology ◽  
Digital To Analog Converter ◽  
Ultra Low Power ◽  
Feed Forward ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Summing Amplifier ◽  
Capacitor Structure ◽  
Asynchronous Sar

In this paper, a low-power second-order feed-forward capacitor-structure continuous-time [Formula: see text] modulator with a 4-bit asynchronous successive approximation register (SAR) quantizer is presented. Through the utilization capacitor structure in the proposed modulator, first, the summation node of the integrators’ outputs and the feed-forward signals is implemented within the second integrator to reduce power consumption by eliminating an active summing amplifier. Second, the proposed architecture can compensate for the quantizer delay without using any excess inner digital to analog converter (DAC). In this design, the modulator applies two different low-power operational amplifiers. These advantages cause the modulator to consume very low power and achieve a favorable figure of merit (FOM) value. In fact, in this paper, the combination of the previously reported methods and designs and doing required reforms has led to a new design with better performance, especially in power reduction. The designed modulator which is simulated using 0.18[Formula: see text][Formula: see text]m CMOS technology achieves 95.98[Formula: see text]dB peak signal-to-noise and distortion (SNDR) for 10[Formula: see text]KHz signal bandwidth and dissipates 44[Formula: see text][Formula: see text]w while its FOM is obtained about 43 fJ/conv.-step.

scholarly journals A Low-Power Opamp-Less Second-Order Delta-Sigma Modulator for Bioelectrical Signals in 0.18 µm CMOS

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6456
Author(s):  
Fernando Cardes ◽  
Nikhita Baladari ◽  
Jihyun Lee ◽  
Andreas Hierlemann
Keyword(s):  
Low Power ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Second Order ◽  
Frequency Noise ◽  
Voltage Controlled Oscillator ◽  
Noise Shaping ◽  
Delta Sigma Modulator ◽  
Delta Sigma

This article reports on a compact and low-power CMOS readout circuit for bioelectrical signals based on a second-order delta-sigma modulator. The converter uses a voltage-controlled, oscillator-based quantizer, achieving second-order noise shaping with a single opamp-less integrator and minimal analog circuitry. A prototype has been implemented using 0.18 μm CMOS technology and includes two different variants of the same modulator topology. The main modulator has been optimized for low-noise, neural-action-potential detection in the 300 Hz–6 kHz band, with an input-referred noise of 5.0 μVrms, and occupies an area of 0.0045 mm2. An alternative configuration features a larger input stage to reduce low-frequency noise, achieving 8.7 μVrms in the 1 Hz–10 kHz band, and occupies an area of 0.006 mm2. The modulator is powered at 1.8 V with an estimated power consumption of 3.5 μW.

A low-power 2nd-order CT delta–sigma modulator with an asynchronous SAR quantizer

2015 ◽  
Vol 84 (3) ◽  
pp. 409-420 ◽  
Author(s):  
Dejan Radjen ◽  
Martin Anderson ◽  
Lars Sundström ◽  
Pietro Andreani
Keyword(s):  
Low Power ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Asynchronous Sar

scholarly journals Ultra low power design approach of asynchronous delta sigma modulator

2017 ◽  
Vol 7 (1.1) ◽  
pp. 84
Author(s):  
Anil Kumar Sahu ◽  
Rashid Sheikh ◽  
A. Surendar
Keyword(s):  
Low Power ◽  
Low Power Design ◽  
Design Approach ◽  
Ultra Low Power ◽  
Vital Part ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Inverse Operation

Asynchronous Delta Sigma Modulator (ADSM) is assuming an extremely vital part in the majority of conveying device  and information convertor and in this manner requires the exceptional consideration in outlining. The execution of the vast majority of the device having DSM as an essential segment is described by the execution of the DSM hardware. This paper introduces the audit of work performed in planning of Asynchronous Delta Sigma Modulator. Latest trends are about the utilization of ADSM for various applications. Contrasting the execution of various ADSM circuits, an execution paradigm is settled for ADSM plan. The execution criteria basically think about the Low working voltages, low power utilization, high SNDR and better focus recurrence. At that point a strategy is suggested that characterizes the High execution ADSM that influence joined utilization of various methods to like inverse operation and mass driven MOS for ultra low power outline and enhancing the execution of an Asynchronous Delta Sigma Modulator.

A LOW POWER CASCADED FEED-FORWARD DELTA-SIGMA MODULATOR FOR RF WIRELESS APPLICATIONS

2009 ◽  
Vol 18 (02) ◽  
pp. 407-429 ◽  
Author(s):  
SHAILESH B. NERURKAR ◽  
KHALID H. ABED
Keyword(s):  
Power Consumption ◽  
Cmos Technology ◽  
Third Order ◽  
Feed Forward ◽  
Analog To Digital ◽  
Wireless Applications ◽  
Fully Differential ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Rf Wireless

This paper presents a design of a novel cascaded third-order feed-forward delta-sigma analog-to-digital converter (ADC). This ADC is realized using fully differential switched capacitor architecture and produces a 12-bit resolution at a data output rate (DOR) of 2.5 MS/s for RF wireless applications. The delta-sigma modulator consists of a second-order single-bit feed-forward modulator cascaded with a multi-bit first-order modulator. The cascaded feed-forward third-order (2-1) ADC is simulated using Matlab and Simulink. The delta-sigma modulator was designed using Cadence Virtuoso in TSMC 0.18 μm CMOS technology. The power consumption of the designed modulator is 12.74 mW, and the resolution is 11.85 bits for an over-sampling ratio (M = 32). The figure of merit is 1.38 pJ at a sample rate of 80 MS/s. The proposed delta-sigma modulator is compared with other state-of-the-art low-pass delta-sigma modulators in terms of their speed, power, DOR, and the proposed modulator has one of the lowest power consumption.

A Wideband Continuous Time Quadrature Delta Sigma Modulator Based on a Real DSM for Low Power WLAN Receiver

2017 ◽  
Vol 27 (03) ◽  
pp. 1850044 ◽  
Author(s):  
Alireza Shamsi ◽  
Esmaeil Najafi Aghdam
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Continuous Time ◽  
Signal To Noise Ratio ◽  
System Level ◽  
Complex Coefficient ◽  
Loop Filter ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Excess Loop Delay

Power consumption and bandwidth are two of the most important parameters in design of low power wideband modulators as power consumption is growing with the increase in bandwidth. In this study, a multi bit wideband low-power continuous time feed forward quadrature delta sigma modulator (CT-FF-QDSM) is designed for WLAN receiver applications by eliminating adders from modulator structure. In this method, a real modulator is designed and its excess loop delay (ELD) is compensated, then, it is converted into a quadrature structure by applying the complex coefficient to loop filter. Complex coefficients are extracted by the aid of a genetic algorithm to further improve signal to noise ratio (SNR) for bandwidth. One of the disadvantages of CT-FF-QDSM is the adders of loop filters which are power hungry and reduce the effective loop gain. Therefore, the adders have been eliminated while the transfer function is intact in the final modulator. The system level SNR of the proposed modulator is 62.53[Formula: see text]dB using OSR of 12. The circuit is implemented in CMOSTSMC180nm technology. The circuit levels SNR and power consumption are 54[Formula: see text]dB and 13.5[Formula: see text]mW, respectively. Figure of Merit (FOM) obtained from the proposed modulator is about 0.824 (pj/conv) which is improved (by more than 40%) compared to the previous designs.

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