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.

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.

A FULLY INTEGRATED MULTI-BAND LCVCO BASED ON CMOS TECHNOLOGY

2010 ◽  
Vol 19 (06) ◽  
pp. 1299-1305 ◽  
Author(s):  
XUEPO MA ◽  
WEI ZHANG ◽  
YANG LIU
Keyword(s):  
Phase Noise ◽  
Tuning Range ◽  
Low Frequency ◽  
Cmos Technology ◽  
Frequency Noise ◽  
Voltage Controlled Oscillator ◽  
Worst Case ◽  
Fully Integrated ◽  
Phase Noise Performance ◽  
Multi Band

In this paper, a cross-coupled complementary inductance–capacitance voltage controlled oscillator (LCVCO) with low phase noise and wide tuning range is presented. It has a multi-band topology and was fabricated with RF CMOS technology. For the purpose of lowering the K VCO and reducing the nonlinearities of varactors, the sizes of the varactors are set small. Also noise filtering technique is adopted to minimize up-conversion of the low frequency noise as well as down-conversion of the high frequency noise, thus the phase noise performance of the VCO is greatly improved. Simulation and experimental results indicate that the LCVCO displays a phase noise of -126.1 dBc at 900 kHz offset in worst case with a tuning range from 1.76 to 1.96 GHz.

scholarly journals Design of a very low-power, low-cost 60 GHz receiver front-end implemented in 65 nm CMOS technology

2011 ◽  
Vol 3 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Michael Kraemer ◽  
Daniela Dragomirescu ◽  
Robert Plana
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Noise Figure ◽  
Low Cost ◽  
Cmos Technology ◽  
Low Noise ◽  
Oxide Semiconductor ◽  
Voltage Controlled Oscillator ◽  
60 Ghz ◽  
Front End

The research on the design of receiver front-ends for very high data-rate communication in the 60 GHz band in nanoscale Complementary Metal Oxide Semiconductor (CMOS) technologies is going on for some time now. Although a multitude of 60 GHz front-ends have been published in recent years, they are not consequently optimized for low power consumption. Thus, these front-ends dissipate too much power for battery-powered applications like handheld devices, mobile phones, and wireless sensor networks. This article describes the design of a direct conversion receiver front-end that addresses the issue of power consumption, while at the same time permitting low cost (due to area minimization by the use of spiral inductors). It is implemented in a 65 nm CMOS technology. The realized front-end achieves a record power consumption of only 43 mW including low-noise amplifier (LNA), mixer, a voltage controlled oscillator (VCO), a local oscillator (LO) buffer, and a baseband buffer (without this latter buffer the power consumption is even lower, only 29 mW). Its pad-limited size is 0.55 × 1 mm2. At the same time, the front-end achieves state-of-the-art performance with respect to its other properties: Its maximum measured power conversion gain is 30 dB, the RF and IF bandwidths are 56.5–61.5 and 0–1.5 GHz, respectively, its measured minimum noise figure is 9.2 dB, and its measured IP−1 dB is −36 dBm.

scholarly journals Delta-Sigma Modulator-Based Step-Up DC–DC Converter with Dynamic Output Voltage Scaling

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 498 ◽  
Author(s):  
Young-Kyun Cho ◽  
Bong Hyuk Park ◽  
Seok-Bong Hyun
Keyword(s):  
Conversion Efficiency ◽  
Output Voltage ◽  
Input Voltage ◽  
Low Noise ◽  
Mode Switching ◽  
Noise Shaping ◽  
Delta Sigma Modulator ◽  
Delta Sigma ◽  
Spurious Peak ◽  
Wide Range

The switching noise and conversion efficiency of step-up DC-DC converters need to be improved to meet increasing demand. The delta-sigma modulation (DSM) technique is typically used to improve the performance of buck converters; however, this control scheme is not directly applicable for boost converters. This paper presents a boost DC–DC converter using a continuous-time delta-sigma modulator (DSM) controller for battery-powered and noise-sensitive applications. The proposed converter can adjust a wide range of output voltages dynamically by clamping the maximum duty cycle of the DSM, thus enabling stable and robust transient responses of the converter. The switching harmonics in the converter output are reduced effectively by the noise shaping property of the modulator. Moreover, the converter does not suffer from instability of mode switching due to the use of a fixed third-order DSM. Fabricated in a 180 nm CMOS, the converter occupies an active area of 0.76 mm2. It produced an output voltage ranging from 2.5 V to 5.0 V at an input voltage of 2.0 V and achieved a peak conversion efficiency of 95.5%. The output voltage ripples were maintained under 25 mV for all load conditions. A low noise output spectrum with a first spurious peak located −91 dBc from the signal was achieved.

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