| 1. |
- Hassanli, Kourosh, et al.
(författare)
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A highly sensitive, low-power, and wide dynamic range CMOS digital pixel sensor
- 2015
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Ingår i: Sensors and Actuators A-Physical. - : ELSEVIER SCIENCE SA. - 0924-4247 .- 1873-3069. ; 236, s. 82-91
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a new pixel-level light-to-frequency converter (LFC) that operates at a low supply voltage, and also offers low power consumption, low area, wide dynamic range, and high sensitivity. By using the proposed LFC, a digital pixel sensor (DPS) based on a pulse-frequency-modulation (PFM) scheme has been designed and fabricated. The prototype chip, including an array of 16 x 16 DPS with pixel size of 23 x 23 mu m(2) and 33.5% fill factor, was fabricated in a standard 180-nm CMOS technology. Experimental results show that the pixel operates with maintained output characteristics at supply voltages down to 1 V. The pixel sensor achieves an overall dynamic range of more than 142 dB and consumes 103 nW per pixel at a supply voltage of 1V at room light intensity. The sensitivity of the LFC is very high at the lower end of the light intensity compared to the higher end which enables the ability to capture clear images. (C) 2015 Elsevier B.V. All rights reserved.
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| 2. |
- Hassanli, Kourosh, et al.
(författare)
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A low-power wide tuning-range CMOS current-controlled oscillator
- 2016
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Ingår i: Integration. - : ELSEVIER SCIENCE BV. - 0167-9260 .- 1872-7522. ; 55, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a low-power, small-size, wide tuning-range, and low supply voltage CMOS current controlled oscillator (CCO) for current converter applications. The proposed oscillator is designed and fabricated in a standard 180-nm, single-poly, six-metal CMOS technology. Experimental results show that the oscillation frequency of the CCO is tunable from 30 Hz to 970 MHz by adjusting the control current in the range of 100 fA to 10 mu A, giving an overall dynamic range of over 160 dB. The operation of the circuit is nearly independent of the power supply voltage and the circuit operates at supply voltages as low as 800 my. Also, at this voltage, with control currents in the range of sub-nano-amperes, the power consumption is about 30 nW. These features are promising in sensory and biomedical applications. The chip area is only 8.8 x 11.5 mu m(2). (C) 2016 Elsevier B.V. All rights reserved.
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| 3. |
- Jalili, Armin, et al.
(författare)
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A nonlinearity error calibration technique for pipelined ADCs
- 2011
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Ingår i: Integration. - Amsterdam, The Netherlands : Elsevier. - 0167-9260 .- 1872-7522. ; 44:3, s. 229-241
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a digital background calibration technique that measures and cancels offset, linear and nonlinear errors in each stage of a pipelined analog to digital converter (ADC) using a single algorithm. A simple two-step subranging ADC architecture is used as an extra ADC in order to extract the data points of the stage-under-calibration and perform correction process without imposing any changes on the main ADC architecture which is the main trend of the current work. Contrary to the conventional calibration methods that use high resolution reference ADCs, averaging and chopping concepts are used in this work to allow the resolution of the extra ADC to be lower than that of the main ADC.
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| 4. |
- Jalili, Armin, et al.
(författare)
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Calibration of high-resolution flash ADCS based on histogram test methods
- 2010
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Ingår i: Electronics, Circuits, and Systems (ICECS), 2010 17th IEEE International Conference on. - : IEEE. - 9781424481552 ; , s. 114-117
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a calibration technique for high-resolution, flash analog- to-digital converters (ADCs) based on histogram test methods is proposed. A probability density function, PDF, generator circuit is utilized to generate a triangular signal with a constant PDF, i.e., uniform distribution, as a test signal. In the proposed technique both offset estimation and trimming are performed without imposing any changes on the comparator structure in the ADC. The proposed algorithm estimates the offset values and stores them in a RAM. The trimming circuit uses the stored values and performs the trimming by adjusting the reference voltages to the comparators. An 8-bit flash ADC with a 1-V reference voltage, a comparator offset distribution with σos ≈ 30 mV, and a 10-bit test signal with about 3% nonlinearity are used in the simulations. The results show that the calibration improves the DNL and INL from about 3.6/3.9 LSB to about 0.9/0.75 LSB, respectively.
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| 5. |
- Jalili, Armin, et al.
(författare)
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Calibration of sigma-delta analog-to-digital converters based on histogram test methods
- 2010
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Ingår i: NORCHIP, 2010. - : IEEE. - 9781424489725 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a calibration technique for sigma-delta analog-to-digital converters (ΣΔADC) in which highspeed, low-resolution flash subADCs are used. The calibration technique as such is mainly targeting calibration of the flash subADC, but we also study how the correction depends on where in the ΣΔ modulator the calibration signals are applied. It is shown that the calibration technique can cope with errors that occur in the feedback digital-to-analog converter (DAC) and the input accumulator. Behavioral-level simulation results show an improvement of in effective number of bits (ENOB) from 6.6 to 11.3. Fairly large offset and gain errors have been introduced which illustrates a robust calibration technique.
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| 6. |
- Jalili, Armin, et al.
(författare)
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Inter-channel offset and gain mismatch correction for time-interleaved pipelined ADCs
- 2011
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Ingår i: Microelectronics Journal. - Oxford, UK : Elsevier. - 0959-8324 .- 0026-2692. ; 42:1, s. 158-164
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a digital background calibration technique to compensate inter-channel gain and offset errors in parallel, pipelined analog-to-digital converters (ADCs). By using an extra analog path, calibration of each ADC channel is done without imposing any changes on the digitizing structure, i.e., keeping each channel completely intact. The extra analog path is simplified using averaging and chopping concepts, and it is realized in a standard 0.18‐μm CMOS technology. The complexity of the analog part of the proposed calibration system is same for a different number of channels.Simulation results of a behavioral 12-bit, dual channel, pipelined ADC show that offset and gain error tones are improved from −56.5 and −58.3 dB before calibration to about −86.7 and −103 dB after calibration, respectively.
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| 7. |
- Wikner, Jacob, et al.
(författare)
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Aiming for the cloud - a study of implanted battery-free temperature sensors using NFC
- 2016
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Ingår i: 2016 INTERNATIONAL SYMPOSIUM ON INTEGRATED CIRCUITS (ISIC). - : IEEE. - 9781467390194
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Konferensbidrag (refereegranskat)abstract
- In this paper we present results based on measurements of implantable devices which can be powered externally and communicated with using the near-field communication (NFC) infrastructure. NFC allows us to not have a dedicated gateway and intra-body communication to bridge the data from sensors to phone. In our trials, we have used commercially available sub-components and mounted them on a thin plastic with printed interconnections and coated them for bio-compatibility. Devices were implanted in porcine models during one week. We could during this time measure the in-vivo body temperature through skin and subcutaneous tissue ranging in thickness from some mm to a couple of cm. The implanted sensor devices are mounted on thin, printed-electronics plastic sheets where the coils and conductors are designed with different types of materials. The choice of materials is done in order to offer a low-cost solution to read out data from in-vivo sensors. We compile measured data, practical results and guidelines, together with theoretical results referring to the design of the implanted inductive NFC coil as well as the energy transfer from one mobile device to another.
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