Voltage Controlled Ring Oscillator for Low Phase Noise Application

Gupta, Nisha

doi:10.5120/1840-2484

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…They report a jitter between 16.1ps and 19.3ps, which is close to our cycle-to-cycle jitter of 20ps. With respect to references [3], [9] and [27], the VCRO reported in this paper presents better phase noise and FoM_VCRO with less area. This achievement in terms of power is explained as follows: the references [3] and [9] have the same voltage supply and transistors channel length, but use transistors 10 times larger.…”

Section: ) Measurements On the Vcro Operationmentioning

confidence: 66%

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Arrayable Voltage-Controlled Ring-Oscillator for Direct Time-of-Flight Image Sensors

Vornicu

Carmona-Galán

Rodríguez-Vázquez

2017

IEEE Trans. Circuits Syst. I

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Direct time-of-flight (d-ToF) estimation with high frame rate requires the incorporation of a time-to-digital converter (TDC) at pixel level. A feasible approach to a compact implementation of the TDC is to use the multiple phases of a voltage-controlled ring-oscillator (VCRO) for the finest bits. The VCRO becomes central in determining the performance parameters of a d-ToF image sensor. In this paper we are covering the modeling, design and measurement of a CMOS pseudo-differential VCRO. The oscillation frequency, the jitter due to mismatches and noise and the power consumption are analytically evaluated. This design has been incorporated into a 64×64-pixel array. It has been fabricated in a 0.18µm standard CMOS technology. Occupation area is 28×29μm 2 and power consumption is 1.17mW at 850MHz. The measured gain of the VCRO is of 477MHz/V with a frequency tuning range of 53%. Moreover it features a linearity of 99.4% over a wide range of control frequencies, namely from 400MHz to 850MHz. The phase noise is of-102dBc/Hz at 2MHz offset frequency from 850MHz. The influence of these parameters in the performance of the TDC has been measured. The minimum time bin of the TDC is 147ps with a RMS DNL/ INL of 0.13/ 1.7LSB.

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Section: ) Measurements On the Vcro Operationmentioning

confidence: 66%

“…Frequency control is another relevant feature for TDC implementation. It can be achieved either by using current starved techniques [7], [8] or by resistive tuning of the delay cell [9]. Another widely used technique is based on tuning the voltage supply or the load capacitor of the delay cell [10], [11].…”

Section: Introductionmentioning

confidence: 99%

Arrayable Voltage-Controlled Ring-Oscillator for Direct Time-of-Flight Image Sensors

Vornicu

Carmona-Galán

Rodríguez-Vázquez

2017

IEEE Trans. Circuits Syst. I

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“…The advantage for this configuration is that the oscillation frequency can be tuned for a wide range by varying the control voltage [7], [8]. are assumed to be equal, the delay (τ ) of each inverter stage will be approximately given by Equation (6) as:…”

Section: Existing Current Starved Ring Vcomentioning

confidence: 99%

Design of Improved Performance Voltage Controlled Ring Oscillator

Kinger

Suman

Sharma

et al. 2015

2015 Fifth International Conference on Advanced Computing &Amp; Communication Technologies

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Voltage Controlled Oscillator is one of the most important basic building block for analog, digital as well as in mixed signal circuits. This paper presents a new technique to improve the performance of ring oscillator. The VCO is based on single ended ring oscillator. The circuit is designed using 0.13 m μ CMOS technology with supply voltage of 3.3 V. A VCO with high frequency range from 2.26GHz to 3.50 GHz is achieved by using this technique. Simulation results reveal the better performance of the proposed design as compared to existing current staved ring VCO in terms of oscillation frequency and power consumption.

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“…The large signal oscillation frequency can be written as [ 15 ]:

where

is the propagation delay and M is the number of delay cells. It is defined as the time lapse between the ideal input step and the moment when the output ramp crosses the trip point of the next delay cell.…”

Section: In-pixel Time-to-digital Convertermentioning

confidence: 99%

Compensation of PVT Variations in ToF Imagers with In-Pixel TDC

Vornicu

Carmona-Galán

Rodríguez-Vázquez

2017

Sensors

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The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact of process parameters, voltage supply, and temperature (PVT) variations on the time bin of the TDC array. Moreover, the design and characterization of a global compensation loop is presented. It is based on a phase locked loop (PLL) that is integrated on-chip. The main building block of the PLL is a voltage-controlled ring-oscillator (VCRO) that is identical to the ones employed for the in-pixel TDCs. The reference voltage that drives the master VCRO is distributed to the voltage control inputs of the slave VCROs such that their multiphase outputs become invariant to PVT changes. These outputs act as time interpolators for the TDCs. Therefore the compensation scheme prevents the time bin of the TDCs from drifting over time due to the aforementioned factors. Moreover, the same scheme is used to program different time resolutions of the direct time-of-flight (ToF) imager aimed at 3D ranging or depth map imaging. Experimental results that validate the analysis are provided as well. The compensation loop proves to be remarkably effective. The spreading of the TDCs time bin is lowered from: (i) 20% down to 2.4% while the temperature ranges from 0 °C to 100 °C; (ii) 27% down to 0.27%, when the voltage supply changes within ±10% of the nominal value; (iii) 5.2 ps to 2 ps standard deviation over 30 sample chips, due to process parameters’ variation.

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Voltage Controlled Ring Oscillator for Low Phase Noise Application

Cited by 13 publications

References 8 publications

Arrayable Voltage-Controlled Ring-Oscillator for Direct Time-of-Flight Image Sensors

Arrayable Voltage-Controlled Ring-Oscillator for Direct Time-of-Flight Image Sensors

Design of Improved Performance Voltage Controlled Ring Oscillator

Compensation of PVT Variations in ToF Imagers with In-Pixel TDC

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