The Experts below are selected from a list of 3843 Experts worldwide ranked by ideXlab platform

M. Laguna - One of the best experts on this subject based on the ideXlab platform.

  • Continuous-Time Sigma–Delta Modulator With an Embedded Pulsewidth Modulation
    IEEE Transactions on Circuits and Systems I: Regular Papers, 2008
    Co-Authors: F. Colodro, Antonio Torralba, M. Laguna
    Abstract:

    A new Continuous-Time (CT) sigma-delta modulator (SDM) based on the well-known asynchronous SDM is proposed in this paper. To this end, the flash quantizer and the digital-to-analog converter (DAC) in a multibit (MB) CT-SDM clocked at a rate fmax are replaced by a single-bit (SB) Comparator with hysteresis clocked at a higher rate fs and a SB-DAC, respectively. By proper selection of the hysteresis in the Comparator and the ratio F = fs/fmax, the performances of both modulators are shown to be equivalent. The Comparator with hysteresis and the loop filter produce, in the modulator Output, a limit cycle of frequency /max which is modulated by the input signal. Therefore, the modulator Output can be considered to be a pulsewidth (PW) modulated signal with a frequency approximately equal to /max, and the proposed modulator is called a PW-SDM. Despite the high sampling rate of the Comparator Output, the integrators and the SB-DAC of the proposed modulator have the same speed requirements as those of the equivalent conventional MB-SDM. On the other hand, in the proposed modulator there are not MB (analog-to-digital or digital-to-analog) converters. Therefore, for a given set of specifications, the proposed PW-SDM is expected to consume less power and area than its equivalent conventional MB modulator.

Rajesh Kumar - One of the best experts on this subject based on the ideXlab platform.

  • Design of a Low Power and High Speed Wallace Tree Encoder for Flash ADC
    SSRN Electronic Journal, 2020
    Co-Authors: Sarfraz Hussain, Rajesh Kumar
    Abstract:

    An improved design of Wallace tree encoder is presented in this paper. Wallace tree encodes a thermometer code into binary code in a Flash ADC. It has the advantage of correcting bubble errors without the need of an extra bubble error correcting (BEC) block. It consists of full adder circuits and adds the number of 1’s generated through the Comparator Output in a Flash ADC. The new Wallace tree encoder is compared with the previously designed traditional Wallace tree encoder in 45nm technology. The results show that new design is efficient than the previous design. The proposed encoder dissipates 9.61μW power and has a delay of 29.5ps. The PDP and EDP is calculated to be 0.28 fJ and 0.83x10-26 Js.

R Menaka - One of the best experts on this subject based on the ideXlab platform.

  • VLSI Architecture for High Performance Wallace Tree Encoder
    2020 6th International Conference on Advanced Computing and Communication Systems (ICACCS), 2020
    Co-Authors: J.m. Mathana, R. Dhanagopal, R Menaka
    Abstract:

    In the research, the VLSI architecture design for Wallace tree encoder with modified full adder is proposed. In analog to digital conversion process, Wallace tree encoder is utilized in the process of converting the thermometer code to binary. This can be termed to be a high speed application and a flash type of flash ADC, which is a resistor ladder, encoder and Comparator circuit. A suitable encoder is required for getting binary code from Comparator Output. Reducing energy of the encoder is a vital concern whereas designing the minimal power flash form ADC. Wallace tree encoders diminishes the mistake due to the availability of zeroes in the sequence of the once presence to the series of zeroes in a Comparator Output, but it consumes more power. Hence in the proposed work, a low power Wallace tree encoder is designed using pass transistor logic (PTL) full adder. The proposed design dissipates only 74.15nW power and delay also reduced to 0.0495ns. The circuit is designed using CADENCE 5.1.0 EDA equipped and simulated with the application of spectre virtuoso.

Shouri Chatterjee - One of the best experts on this subject based on the ideXlab platform.

  • An 18 nA, 87% Efficient Solar, Vibration and RF Energy-Harvesting Power Management System With a Single Shared Inductor
    IEEE Journal of Solid-State Circuits, 2016
    Co-Authors: Gajendranath Chowdary, Arun Kumar Singh, Shouri Chatterjee
    Abstract:

    We present a modular power management system that can harvest energy from three sources simultaneously, with available power levels of 25 nW to $100~\mu \text {W}$ , with one inductor. The DC-DC converter is clocked with energize and dump pulses, and the pulse-widths are generated for constant peak inductor current and for no reversal, without current sensing. We use a Comparator to reach the open-circuit-voltage (OCV)-based maximum power point (MPP), and train an oscillator to mimic the Comparator Output. The oscillator frequency is tuned through a successive-approximation algorithm within 11 Comparator cycles. The 180 nm chip has a maximum efficiency of 87% at an input available power of $20~\mu \text {W}$ (input voltage of 0.6 V), and has an Output voltage of 1.5 V.

Terukazu Sato - One of the best experts on this subject based on the ideXlab platform.

  • hysteretic pwm control method for all types of dc to dc converters
    International Telecommunications Energy Conference, 2007
    Co-Authors: Takashi Nabeshima, Terukazu Sato, Kimihiro Nishijima, K Onda
    Abstract:

    A new control method of a hysteretic PWM controller for all types of DC-to-DC converters are proposed. The triangular voltage obtained from a simple RC network connected between hysteretic Comparator Output and converter Output is superimposed to the Output voltage and fed to the hysteretic Comparator as a feedback signal. Since the hysteretic PWM controller essentially has derivative characteristics and has no error amplifier, the presented method provides no steady-state error voltage on the Output and excellent dynamic performances for the load current transient by choosing proper values of time constants in the RC network. Performances of the proposed controller are experimentally verified for the buck, buck-boost and boost converters.

  • Design ofa New Hysteretic PWM Controller forAll Types ofDC-to-DCConverters
    2007
    Co-Authors: Takashi Nabeshima, Terukazu Sato
    Abstract:

    A newcontrol methodusinga hysteretic PWM controller foralltypesofconverters anditsproper designmethodarepresented. The triangular voltage obtained froma simple RC networkconnected between Comparator Output andconverter Output issuperimposed to theOutput voltage andasafeedback signal toahysteretic Comparator. Since thehysteretic PWM controller essentially hasderivative characteristics andhasnoerror amplifier, the presented methodprovides nosteady-state error voltage on theOutput andexcellent dynamic performances fortheload currenttransient by choosing propervaluesoftime constants intheRC network. Performances oftheproposed controller areexperimentally verified forthebuck, buck-boost andboost converters IndexTerms--DC-DC converter, Hysteretic PWM control, Transfer function, Transient response

  • Design of a New Hysteretic PWM Controller for All Types of DC-to-DC Converters
    2007 7th International Conference on Power Electronics and Drive Systems, 2007
    Co-Authors: Min Lin, Takashi Nabeshima, Terukazu Sato, Kimihiro Nishijima
    Abstract:

    A new control method using a hysteretic PWM controller for all types of converters and its proper design method are presented. The triangular voltage obtained from a simple RC network connected between Comparator Output and converter Output is superimposed to the Output voltage and as a feedback signal to a hysteretic Comparator. Since the hysteretic PWM controller essentially has derivative characteristics and has no error amplifier, the presented method provides no steady-state error voltage on the Output and excellent dynamic performances for the load current transient by choosing proper values of time constants in the RC network. Performances of the proposed controller are experimentally verified for the buck, buck-boost and boost converters.