scholarly journals A CMOS Integrator-Based Clock-Free Time-to-Digital Converter for Home-Monitoring LiDAR Sensors

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 554
Author(s):  
Ying He ◽  
Sung Min Park

This paper presents a nine-bit integrator-based time-to-digital converter (I-TDC) realized in a 180 nm CMOS technology for the applications of indoor home-monitoring light detection and ranging (LiDAR) sensors. The proposed I-TDC exploits a clock-free configuration so as to discard clock-related dynamic power consumption and some notorious issues such as skew, glitch, and synchronization. It consists of a one-dimensional (1D) flash TDC to generate coarse-control codes and an integrator with a peak detection and hold (PDH) circuit to produce fine-control codes. A thermometer-to-binary converter is added to the 1D flash TDC, yielding four-bit coarse codes so that the measured detection range can be represented by nine-bit digital codes in total. Test chips of the proposed I-TDC demonstrate the measured results of the 53 dB dynamic range, i.e., the maximum detection range of 33.6 m and the minimum range of 7.5 cm. The chip core occupies the area of 0.14 × 1.4 mm2, with the power dissipation of 1.6 mW from a single 1.2-V supply.

2018 ◽  
Vol 28 (02) ◽  
pp. 1950021
Author(s):  
B. Ghanavati ◽  
E. Abiri ◽  
M. R. Salehi ◽  
N. Azhdari

In this paper, a two-stage time interpolation time-to-digital converter (TDC) is proposed to achieve adequate resolution and wide dynamic range for measuring R-R intervals in QRS detection. The architecture is based on a coarse counter and a couple of two-stage interpolator circuit in order to improve the conversion linearity. The proposed TDC is modeled with the neural network, while the teacher–learner-based optimization algorithm (TLBO) is used to optimize the integral nonlinearity (INL) of the proposed TDC. The proposed optimization method shows a characteristic close to the ideal output of the TDC behavior over a wide input range. Using the achieved results of the TLBO algorithm simulation results using CADENCE VIRTUOSO and standard 180[Formula: see text]nm CMOS technology shows 1.2[Formula: see text]s dynamic range, 100[Formula: see text]ns resolution, 0.19[Formula: see text]mW power consumption and area of 0.16[Formula: see text]mm2. The proposed circuit can find application in biomedical engineering systems and other fields where long and accurate time interval measurement is needed.


2019 ◽  
Vol 29 (08) ◽  
pp. 2050124
Author(s):  
Farshad Goodarzi ◽  
Siroos Toofan

This paper describes a 9-bit time-to-digital converter (TDC) with 3.6 ps resolution. The resolution of 3.6 ps is achieved using coarse and fine structure. The structure of the proposed two-step pipeline TDC is composed of a 4-bit coarse TDC (CTDC) based on delay line and a 5-bit fine TDC (FTDC) based on an SAR-CD algorithm where a Time Amplifier (TA) is used between them. Since TA amplifies the time intervals in different stages of delay line to achieve accurate gain with wide linear range. Therefore, the TDC has good linearity. The proposed TDC has Differential Non-Linearity (DNL) and Integral Non-Linearity (INL) errors of 1.6 and 2.6 LSB, respectively. This TDC was designed in 0.18[Formula: see text][Formula: see text]m CMOS technology. Using a supply voltage of 1.8[Formula: see text]V, the proposed TDC consumes 1.88[Formula: see text]mW at 25 MS/s throughput.


Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 558 ◽  
Author(s):  
Bjorn Van Bockel ◽  
Jeffrey Prinzie ◽  
Paul Leroux

This article presents a radiation tolerant single-shot time-to-digital converter (TDC) with a resolution of 15.6 ps, fabricated in a 65 nm complementary metal oxide semiconductor (CMOS) technology. The TDC is based on a multipath pseudo differential ring oscillator with reduced phase delay, without the need for calibration or interpolation. The ring oscillator is placed inside a Phase Locked Loop (PLL) to compensate for Process, Voltage and Temperature (PVT) variations- and variations due to ionizing radiation. Measurements to evaluate the performance of the TDC in terms of the total ionizing dose (TID) were done. Two different samples were irradiated up to a dose of 2.2 MGy SiO 2 while still maintaining a resolution of 15.6 ps. The TDC has a differential non-linearity (DNL) and integral non-linearity (INL) of 0.22 LSB rms and 0.34 LSB rms respectively.


2021 ◽  
Author(s):  
Parth Parekh

This report presents a low-power time integrator and its applications in an all-digital first-order ΔΣ time-to-digital converter (TDC). Time-to-Digital Converter (TDC) that map a time variable to a digital code is the most important building blocks of time-mode circuits. The time integrator is realized using a bi-directional gated delay line (BD-GDL) with time variable to be integrated as the gating signal. The integration of the time variable is obtained via the accumulation of the charge of the load capacitor and the logic state of gated delay stages. Issues affecting the performance of the time integrator and TDC are examined. The all-digital first-order ΔΣ TDC utilizing the time integrator was designed in using IBM 130 nm 1.2 V CMOS technology and analysed using Spectre ASP from Cadence Design Systems with BSIM4 models. A sinusoid time input of 333 ps amplitude and 231 kHz frequency with an oversampling ratio 68 was digitized by the modulator. The TDC provides first-order noise-shaping and a SNR of 34.64 dB over the signal band 48.27 ~ 231 kHz while consuming 293.8 μW.


2021 ◽  
Author(s):  
Parth Parekh

This report presents a low-power time integrator and its applications in an all-digital first-order ΔΣ time-to-digital converter (TDC). Time-to-Digital Converter (TDC) that map a time variable to a digital code is the most important building blocks of time-mode circuits. The time integrator is realized using a bi-directional gated delay line (BD-GDL) with time variable to be integrated as the gating signal. The integration of the time variable is obtained via the accumulation of the charge of the load capacitor and the logic state of gated delay stages. Issues affecting the performance of the time integrator and TDC are examined. The all-digital first-order ΔΣ TDC utilizing the time integrator was designed in using IBM 130 nm 1.2 V CMOS technology and analysed using Spectre ASP from Cadence Design Systems with BSIM4 models. A sinusoid time input of 333 ps amplitude and 231 kHz frequency with an oversampling ratio 68 was digitized by the modulator. The TDC provides first-order noise-shaping and a SNR of 34.64 dB over the signal band 48.27 ~ 231 kHz while consuming 293.8 μW.


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