scholarly journals A Novel Highly Linear Voltage-To-Time Converter (VTC) Circuit for Time-Based Analog-To-Digital Converters (ADC) Using Body Biasing

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2033
Author(s):  
Ahmed Elgreatly ◽  
Ahmed Dessouki ◽  
Hassan Mostafa ◽  
Rania Abdalla ◽  
El-sayed El-Rabaie

Time-based analog-to-digital converter is considered a crucial part in the design of software-defined radio receivers for its higher performance than other analog-to-digital converters in terms of operation speed, input dynamic range and power consumption. In this paper, two novel voltage-to-time converters are proposed at which the input voltage signal is connected to the body terminal of the starving transistor rather than its gate terminal. These novel converters exhibit better linearity, which is analytically proven in this paper. The maximum linearity error is reduced to 0.4%. In addition, the input dynamic range of these converters is increased to 800 mV for a supply voltage of 1.2 V by using industrial hardware-calibrated TSMC 65 nm CMOS technology. These novel designs consist of only a single inverter stage, which results in reducing the layout area and the power consumption. The overall power consumption is 18 μW for the first proposed circuit and 15 μW for the second proposed circuit. The novel converter circuits have a resolution of 5 bits and operate at a maximum clock frequency of 500 MHz.

2019 ◽  
Vol 29 (10) ◽  
pp. 2020005
Author(s):  
Hao Wang ◽  
Wenming Xie ◽  
Zhixin Chen

A novel area-efficient switching scheme is proposed for the successive approximation register (SAR) analog-to-digital converters (ADCs). The capacitor-splitting structure, charge-average switching technique, and [Formula: see text] (equal to [Formula: see text]/4) are combined together and optimized to realize the proposed switching scheme. [Formula: see text] is only used in the last two bit cycles, which affects the ADC accuracy little and reduces capacitor area by half. It achieves a 98% less switching energy and an 87.5% less capacitor area compared with the conventional switching method. In addition, the DAC output common-mode voltage is approximately constant. Thus, the proposed switching method is a good tradeoff among power consumption, capacitor area, DAC output common-mode voltage, and ADC accuracy. The proposed SAR ADC is simulated in 0.18[Formula: see text][Formula: see text]m CMOS technology with a supply voltage of 0.6[Formula: see text]V and at a sampling rate of 20[Formula: see text]kS/s. The signal-to-noise-distortion ratio (SNDR) and spurious free dynamic range (SFDR) are 58.2 and 73.7[Formula: see text]dB, respectively. The effective number of bits (ENOB) is 9.4. It consumes 42[Formula: see text]nW, resulting in a figure-of-merit (FoM) of 3.11 fJ/conversion-step.


2012 ◽  
Vol 433-440 ◽  
pp. 5727-5732
Author(s):  
Jun Han ◽  
Wei Dong Wang

This paper presents the design and implementation of a single-loop three-order switched-capacitor sigma-delta modulator(SDM) with a standard 0.18um CMOS technology. A current optimization technique is utilized in proposed design to reduce the power of operational transconductance amplifier(OTA).Using a chain of Integrators with weighted feed-forward summation(CIFF) structure and optimized single-stage class-A OTA with positive feed-back to minimize the power consumption. The SDM has been presented with an over-sampling ratio of 128,clock frequency 6.144MHz,24kHz band- width, and achieves a peak SNR of 100dB,103dB dynamic range. The whole circuits consume 2.87mW from a single 1.8V supply voltage.


2014 ◽  
Vol 23 (02) ◽  
pp. 1450020 ◽  
Author(s):  
JIANGTAO XU ◽  
WEISONG JIN ◽  
KAIMING NIE ◽  
SUYING YAO

In this paper, a CMOS digital pixel sensor (DPS) with pixel-level ADC based on pulse width modulation (PWM) scheme is proposed to overcome the restriction of low supply voltage imposed by device scaling trend. The pixel operates with a dynamic current comparison scheme to avoid using complex in-pixel comparator and achieve a high dynamic range (DR). By adjusting clock frequency for different illumination, DR is further extended due to increasing the maximum detectable photocurrent and lowering the minimum detectable photocurrent. The pixel contains a photodiode (PD), an 11-bit in-pixel SRAM and other 11 transistors, and occupies an area of 7 μm × 7 μm, with a fill factor of 31.3% using a standard 65 nm CMOS technology. Simulation results show that this pixel can work at a supply voltage as low as 0.5 V with 120 dB DR and 80 dB linear DR (LDR). The properties of high DR and logarithmic response make the proposed digital pixel be capable of human eye. Frame rate achieves 246 fps with 640 × 480 pixel array by using in-pixel ADC and SRAM. This makes the digital pixel very suitable for high-speed snap shot digital camera application.


2019 ◽  
Vol 28 (10) ◽  
pp. 1950172
Author(s):  
Mehdi Bandali ◽  
Alireza Hassanzadeh ◽  
Masoume Ghashghaie ◽  
Omid Hashemipour

In this paper, an 8-bit ultra-low-power, low-voltage current steering digital-to-analog converter (DAC) is presented. The proposed DAC employs a new segmented structure that results in low integral nonlinearity (INL) and high spurious-free dynamic range (SFDR). Moreover, this DAC utilizes a low-voltage current cell. The low-voltage characteristic of the current cell is achieved by connecting the body of MOSFET switches to their sources. Utilizing a low supply voltage along with a low bias current in the current cells results in about 623.81-[Formula: see text]W power consumption in 140-MS/s sample rate, which is very small compared to previous reports. The post-layout simulation results in 180-nm CMOS technology and [Formula: see text]-V supply voltage with the sample rate of 140[Formula: see text]MS/s show SFDR [Formula: see text] 64.37[Formula: see text]dB in the Nyquist range. The differential nonlinearity (DNL) and INL of the presented DAC are 0.1254 LSB and 0.1491 LSB, respectively.


2017 ◽  
Vol 26 (05) ◽  
pp. 1750073
Author(s):  
Abdullah El-Bayoumi ◽  
Hassan Mostafa ◽  
Ahmed M. Soliman

Time-based Analog-to-Digital Converter (TADC), plays a major role in designing Software-Defined Radio (SDR) receivers, at scaled CMOS technologies, as it manifests lower area and power than conventional ADCs. TADC consists of 2 major blocks. The input voltage is converted into a pulse delay using a Voltage-to-Time Converter (VTC). In additions, the pulse delay is converted into a digital word using a Time-to-Digital Converter (TDC). In this paper, a novel fully-differential VTC based on a new methodology is presented which reports a highly-linear design. A metal-insulator-metal (MIM) capacitor as well as a dynamic calibration technique based on a set of large-sized capacitor-based voltage dividers circuits are utilized to automatically compensate the Process-Voltage-Temperature (PVT) variations. Moreover, the layout design is introduced. The proposed design operates on a 1[Formula: see text]GS/s sampling frequency with a supply voltage of 1.2[Formula: see text]V. After calibration, simulation results, using TSMC 65[Formula: see text]nm CMOS technology, report a 1.42[Formula: see text]V wider dynamic range due to the differential mechanism with a 3% linearity error. This design achieves a resolution up to 14 bits, a 0.07 fJ/conversion FOM, a 229[Formula: see text][Formula: see text]m2 area and a 0.25[Formula: see text]mW power. The simulation results are compared to the single-ended VTC results and the state-of-the-art analog-part ADCs results to show the strength of the proposed design.


2014 ◽  
Vol 23 (06) ◽  
pp. 1450090 ◽  
Author(s):  
ARASH ESMAILI ◽  
HADISEH BABAZADEH ◽  
KHAYROLLAH HADIDI ◽  
ABDOLLAH KHOEI

A 13-bit analog-to-digital converter (ADC) is designed in 0.35 μm CMOS technology that reduces the power consumption through sharing the resources between pipeline stages. Using a dummy sample-and-hold (S/H) and recirculating concept the requirements for the first stage are relaxed and the design restrictions are resolved. This ADC does not use a dedicated S/H and reaches a speed of 50 MS/s. The design is tested with TSMC mixed-signal 0.35 μm technology and post layout simulations shows over 75 dB Signal-to-Noise and Distortion-Ratio (SNDR) and over 85 dB Spurious Free Dynamic Range (SFDR) at the Nyquist frequency. The designed chip occupies an area of 1.3 mm–0.7 mm and consumes 164 mW power at Nyquist from a 3.3 V supply.


2009 ◽  
Vol 18 (05) ◽  
pp. 933-945
Author(s):  
CHIA-CHUN TSAI ◽  
KAI-WEI HONG ◽  
TRONG-YEN LEE

In this paper, we present a bisection-based power reduction design for CMOS flash analog-to-digital converters (ADCs). A comparator-based inverter is employed along with two switches of an NMOS and a PMOS, the bisection method can let only half of comparators in a flash ADC work in every clock cycle for reducing power consumption. A practical example of 6-bit flash ADC operates at 200 MHz sampling rate and 3.3 V supply voltage is demonstrated. The power consumption of proposed circuit is only 40.75 mW with HSPICE simulation. Compared with the traditional flash ADC, our bisection method can reduce up to 43.18% in terms of power dissipation.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Thi Thuy Pham ◽  
Dongmin Kim ◽  
Seo-Hyeong Jeong ◽  
Junghyup Lee ◽  
Donggu Im

This work presents a high efficiency RF-to-DC conversion circuit composed of an LC-CL balun-based Gm-boosting envelope detector, a low noise baseband amplifier, and an offset canceled latch comparator. It was designed to have high sensitivity with low power consumption for wake-up receiver (WuRx) applications. The proposed envelope detector is based on a fully integrated inductively degenerated common-source amplifier with a series gate inductor. The LC-CL balun circuit is merged with the core of the envelope detector by sharing the on-chip gate and source inductors. The proposed technique doubles the transconductance of the input transistor of the envelope detector without any extra power consumption because the gate and source voltage on the input transistor operates in a differential mode. This results in a higher RF-to-DC conversion gain. In order to improve the sensitivity of the wake-up radio, the DC offset of the latch comparator circuit is canceled by controlling the body bias voltage of a pair of differential input transistors through a binary-weighted current source cell. In addition, the hysteresis characteristic is implemented in order to avoid unstable operation by the large noise at the compared signal. The hysteresis window is programmable by changing the channel width of the latch transistor. The low noise baseband amplifier amplifies the output signal of the envelope detector and transfers it into the comparator circuit with low noise. For the 2.4 GHz WuRx, the proposed envelope detector with no external matching components shows the simulated conversion gain of about 16.79 V/V when the input power is around the sensitivity of −60 dBm, and this is 1.7 times higher than that of the conventional envelope detector with the same current and load. The proposed RF-to-DC conversion circuit (WuRx) achieves a sensitivity of about −65.4 dBm based on 45% to 55% duty, dissipating a power of 22 μW from a 1.2 V supply voltage.


Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 563
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano

This paper presents a new approach based on the use of a Current Steering (CS) technique for the design of fully integrated Gm–C Low Pass Filters (LPF) with sub-Hz to kHz tunable cut-off frequencies and an enhanced power-area-dynamic range trade-off. The proposed approach has been experimentally validated by two different first-order single-ended LPFs designed in a 0.18 µm CMOS technology powered by a 1.0 V single supply: a folded-OTA based LPF and a mirrored-OTA based LPF. The first one exhibits a constant power consumption of 180 nW at 100 nA bias current with an active area of 0.00135 mm2 and a tunable cutoff frequency that spans over 4 orders of magnitude (~100 mHz–152 Hz @ CL = 50 pF) preserving dynamic figures greater than 78 dB. The second one exhibits a power consumption of 1.75 µW at 500 nA with an active area of 0.0137 mm2 and a tunable cutoff frequency that spans over 5 orders of magnitude (~80 mHz–~1.2 kHz @ CL = 50 pF) preserving a dynamic range greater than 73 dB. Compared with previously reported filters, this proposal is a competitive solution while satisfying the low-voltage low-power on-chip constraints, becoming a preferable choice for general-purpose reconfigurable front-end sensor interfaces.


2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
A. K. Pandey ◽  
R. A. Mishra ◽  
R. K. Nagaria

We proposed footless domino logic buffer circuit. It minimizes redundant switching at the dynamic and the output nodes. The proposed circuit avoids propagation of precharge pulse to the output node and allows the dynamic node which saves power consumption. Simulation is done using 0.18 µm CMOS technology. We have calculated the power consumption, delay, and power delay product of the proposed circuit and compared the results with the existing circuits for different logic function, loading condition, clock frequency, temperature, and power supply. Our proposed circuit reduces power consumption and power delay product as compared to the existing circuits.


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