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A novel approach to the design of high-performance operational-amplifier-based differential charge and transresistance amplifiers is proposed. It is based on a two-stage topology: The first stage performs a differential measurement to single-ended signal conversion, providing a common-mode rejection that only depends on the matching between two resistors; the second stage filters the signal. Three novel topologies that are based on this technique are presented, analyzed, and measured, and design criteria are finally given. Their performance is compared with that of a state-of-the-art topology that is used as the benchmark, and it results in a better common-mode rejection ratio (CMRR).

The performance of a feedback-controlled piezoelectric tube scanner is limited by its inherent nonlinear properties such as hysteresis and creep, its mechanical resonance modes and its displacement sensor bandwidth and associated noise properties. Capacitive sensors have emerged as the displacement sensor of choice in piezoelectric tube scanners. Resolution of a capacitive sensor is largely determined by its bandwidth and noise density which is typically in the order of 20 pm/√Hz for a ±100 µm range. Consequently, to achieve sub-nanometer resolution, the sensor's bandwidth needs to be made small. Achieving satisfactory tracking performance using a low-bandwidth displacement sensor is a challenging task. To improve the bandwidth, the piezoelectric strain voltage induced in the electrode opposite to the actuating electrode is used as a secondary measurement. A two-sensor-based H∞ controller is designed and implemented on a prototype piezoelectric tube nanopositioning system. The tube is driven by a charge amplifier to reduce the hysteresis. Experimental results demonstrate a significant increase in the tracking bandwidth due to the use of the additional sensor.

This paper presents the development of a micro-machined dual-backplate capacitive microphone for aeroacoustic measurements. The device theory, fabrication, and characterization are discussed. The microphone is fabricated using the five-layer planarized-polysilicon SUMMiT V process at Sandia National Laboratories. The microphone consists of a 0.46-mm-diameter 2.25-mum-thick circular diaphragm and two circular backplates. The diaphragm is separated from each backplate by a 2-mum air gap. Experimental characterization of the microphone shows a sensitivity of 390 muV/Pa. The dynamic range of the microphone interfaced with a charge amplifier extends from the noise floor of 41 dB/ radicHz up to 164 dB and the resonant frequency is 178 kHz.

A differential capacitance detection circuit aiming at detection of rotating angle in a novel levitation structure is presented. To ensure the low non-linearity and high resolution, noise analysis and non-linearity simulation are conducted. In the capacitance interface, an integral charge amplifier is adopted as a front end amplifier to reduce the parasitic capacitance caused by connecting wire. For the novel differential capacitance bridge with a coupling capacitor, the noise floor and non-linearity of the detection circuit are analyzed, and the results show that the detecting circuit is capable of realizing angle detection with high angular resolution and relative low non-linearity. With a specially designed printed circuit board, the circuit is simulated by PSpice. The practical experiment shows that the detection board can achieve angular resolution as high as 0.04° with a non-linearity error 2.3%.

Calibration of the micro force sensors is necessary for the measurement of microNewton forces, which are critical to analytical applications of micro force sensor in the analysis of micromanipulators, microrobots and microgrippers. This paper proposes a novel calibration system to calibrate PZT thin film micro force sensor using the bimorph probe as the loading part. Sensitivities of PZT thin film micro force sensors were calibrated by the calibration system composed of the drive system and the testing system. The drive system combines 3-dimensional positioning stage, a bimorph probe and a frequency synthesizer, and the testing system combines an electronic balance for static state or a charge amplifier and a lock-in amplifier for the quasi static state.

A new procedure to obtain an online measurement of the beam intensity for charged particle accelerators, as well as the total charge deposited on a target, using a commercial beam profile monitor (BPM) is described in this paper. This procedure can be an alternative to the use of Faraday cups in experiments where their implementation is not feasible.

In this paper, a piezoelectric tube of the type typically used in scanning tunneling microscopes (STMs) and atomic force microscopes (AFMs) is considered. Actuation of this piezoelectric tube is hampered by the presence of a lightly damped low-frequency resonant mode. The resonant mode is identified and damped using a positive velocity and position feedback (PVPF) controller, a control technique proposed in this paper. Input signals are then shaped such that the closed-loop system tracks a raster pattern. Normally, piezoelectric tubes are actuated using voltage amplifiers. Nonlinearity in the form of hysteresis is observed when actuating the piezoelectric tubes at high amplitudes using voltage amplifiers. It has been known for some time that hysteresis in piezoelectric actuators can be largely compensated by actuating them using charge amplifiers. In this paper, high-amplitude actuation of a piezoelectric tube is achieved using a charge amplifier.

This paper presents a high-speed, high-sensitivity 512times512 CMOS image sensor with column parallel cyclic 12-bit ADCs and a global electronic shutter. Each pixel has a charge amplifier for high charge-to-voltage conversion gain despite of using a large-size photodiode, and two sample-and-hold stages for the global shutter and fixed pattern noise (FPN) canceling. High-speed column-parallel cyclic ADC arrays with 12-bit resolution having a small layout size of 0.09 mm 2 are integrated at both sides of image array. A technique for accelerating the conversion speed using variable clocking and sampling capacitance is developed. A digital gain control function using 14-bit temporal digital code is also set in the column parallel ADC. The fabricated chip in 0.25-mum CMOS image sensor technology achieves the full frame rate in excess of 3500 frames/s. The in-pixel charge amplifier achieves the optical sensitivity of 19.9 V/lxmiddots. The signal full scale at the pixel output is 1.8 V at 3.3-V supply and the noise level is measured to be 1.8mVrms, and the resulting signal dynamic range is 60 dB

High-efficiency speakers significantly improve electrical to sound power conversion efficiency by reducing the power dissipation over the speaker coil. However, they require some equalization of the input signal. In this paper, a new driving technique based on a pulsewidth-modulation switching amplifier is presented. This exploits a double voltage/current feedback to obtain automatic equalization. Furthermore, the double feedback allows the output resonant filter to be included in the feedback path, compensating for its nonlinearity. Finally, the mixed feedback acts as intrinsic current limiter. Both theoretical analysis and simulations demonstrate that this system is feasible. The results were also confirmed by measurements using a prototype

In this paper, we describe a method of carried charge signal conditioning associated to the pyroelectric effect: integration of the current in order to determine the temperature response measuring the power or the energy contained in optical radiations. The obtained results of investigation about the temperature response of a polyvinylidine fluoride (PVF2) pyroelectric detector to optical radiation using an appropriate electrical charge–current converter are reported. The experimental responses are compared to the ones obtained using a theoretical model which takes into account the wave propagation through the successive layers constituting the detector. A comparison of the responses obtained from two types of converters is presented and the independence of the pyroelectric detector from the topology of the conditioning circuit is also studied and demonstrated.

A high-sensitivity voltage-to-frequency converter (VFC) using an all-MOS voltage window comparator is presented in this work. The circuit is composed of one voltage-to-current converter, one charge and discharge circuit, and one all-MOS voltage window comparator. The input voltage is converted into a current which in turn triggers the charge and discharge circuit, where a built-in capacitor is driven. The voltage window comparator monitors the variated voltage on the capacitor and generate an oscillated output of which the vibration frequency is linearly dependent to the input voltage. In this way, the worst-case linear range of the output frequency of the proposed VFC is 0-55.40MHz verified by simulations given a 0-0.9V input range. The physical measurement of the proposed VFC shows a 0-52.95MHz output frequency given a 0-0.9V input range. The error in linearity is better than 8.5% while the power dissipation is merely 0.218mW.

This paper describes the design of a functional strain sensing module with large dynamic range (80 dB), DC to 10 kHz response, high resolution, and mini size for industrial applications, such as the rolling-element bearings research. The design of the MEMS capacitive strain sensor employs mechanical amplifications of package design and buckle beams as well as the linear differential comb capacitor. The sensor is interfaced with a low noise charge amplifier, mixer, and filter circuits to provide an analog output that demonstrated a resolution of 0.09 microstrains with a maximum range of ±1000 microstrains. The sensor and the electronic circuits, including a temperature sensor, can be integrated on a chip, and packaged as a small functional unit. Additional electronics were integrated with the interface circuit on the chip that provide A/D conversion, radio frequency power supply, and digital signal telemetry to a near-by control unit. Preliminary test results are compared with the design simulation.

An Analog Front End (AFE) for a multi-functional environmental sensor is proposed. The IC consists of a 8.2nV/VHz input referred noise, 0.22mm area instrumentation amplifier, a 25aC/√Hz, 0.12mm2 charge amplifier, and a 24bit continuous-time delta-sigma ADC, which are designed with a weak inversion biasing technique. The AFE has been fabricated in a 0.18μm CMOS process with 4.5mm2 die area. The current consumption at 2.56kHz output data rate is 2.5mA, reducing to 2μA at 0.01Hz.

The paper presents a prototype ASIC (CASCA: Charge Amplifier with Switched Capacitor Array) for a TPC based X-ray Polarimeter (XTP). It measures two dimensional photoelectron tracks generated by the incident X-ray photons with one dimensional strip readout. The other dimension is calculated by the drift time from the signal waveform. In order to achieve 100 μm track resolution fine pitch strips are used, requiring high density readout electronics with 20 MSPS waveform sampling capability. CASCA integrates 32 channel full function signal processing circuits and is fabricated in a 0.18μm CMOS process. Each channel consists of a charge sensitive preamplifier, a CR-RC shaper with a peaking time of 25 ns, a baseline holder, a discriminator and a 64-cell switched capacitor array (SCA). The analog front-end and the SCA circuits have been implemented and verified in two separate chips in the previous prototypes. Several modifications have also been made, such as using native NMOS capacitor to store the samples and changing the structure of the switched capacitor circuits. The test results of CASCA show that the equivalent noise charge (ENC) is about 1500e with 14.5pF input capacitance. The INL (Integrated Nonlinearity) is better than 0.6% and the center-of-gravity time jitter has been measured to be no more than 3 ns.

This paper presents an interfacing circuit for capacitive sensor using charge amplifier formed a capacitance-to-voltage converter. The proposed circuit is suitable for the front-end analog-to-digital converter (ADC) and wide variable range of sensing capacitance. The achieved output voltage provides a linear transfer characteristic and fast response. The circuit configuration is implemented using only commercially available devices. The performances of proposed circuit are confirmed by experimental results.

A noise-immune current-integration-based CMOS amperometric sensor platform with a bacteria-sized (1.2 μm × 2.05 μm) Au electroless-plated microelectrode array for robust bacteria counting is presented. For robust bacteria counting with sufficient signal-to-noise ratio (SNR), noise must be reduced because the bacteria-sized microelectrode surrounded by a wall can handle only small current (on the order of 100 pA). This is the first platform to employ a current integrator in conjunction with a bacteria-sized microelectrode array. As a result of the proposed current integration, noise associated with drift and the CMOS sensor array can be reduced. To verify the effectiveness of the proposed approach, a test chip was fabricated using 0.6 μm standard CMOS technology. Measurement results demonstrate successful high-sensitivity 2D direct counting of microbeads (1 μm diameter) with 27 dB SNR at 5-ms integration time.

This paper describes two DC-DC conversion techniques suitable for low-voltage mobile applications. Converters using the first technique realize high efficiency under light-load conditions by having an architecture with a simple common-source amplifier and a low-power differential amplifier. The measured efficiency of the first type of converter is 67% at an output current of 23 μA. A one-shot technique in the second type of converter reduces output-voltage fluctuation. A predetermined current is injected into the output capacitor when a load transient is detected by observing the capacitor current. This technique reduces overshoot voltage by 68% at a high-to-low load transient.

The piezoelectric actuators have high resolution, wide operating frequency and low power consumption, but they suffer hysteresis which affects their linearity. In this paper are presented comparatively the analog and digital techniques for improvement (reducing) of nonlinear behavior of this type of actuators using charge amplifiers. First an analog charge amplifier and its performance analysis are presented. Then a model of digital charge amplifier with linearity performance considerably improved (91% reduced), but which shows a pronounced drift is presented. In the last section several methods for drift reducing are presented and analyzed, one of them having a reduction with 87%. A number of functional diagrams and response graphs for the developed techniques and methods are presented. Introduction The application area of the piezoelectric actuators has been spectacular developed, especially due to their remarkable qualities. Compared to other nano-positioning actuators, these have high resolution, high force, wide operating frequency and low power consumption. It is enough to mention some of their applications [1, 2, 3]: in micro and nano-devices for mechanical positioning with below micrometrics accuracy (optical and electronics microscopy, high precision cutting devices (error correction), robotics and positioning of magnetic heads and optical recordingplayback); in deformable mirrors (adaptive optics systems); in ultrasonic motors; in the impact controlled on/off devices; in fuel injectors of diesel engines etc. But, the piezoelectric materials have important non-linear characteristics determi-ned by the existence of hysteresis and creep, which can reduce the positioning accuracy of a piezoelectric actuator. When it is applied to a piezoelectric actuator a sudden voltage, the length will quickly respond then it will change slowly due to the creep effect. Creep is the polarization result of the piezoelectric actuator which continues to change after the applied voltage reaches its final value. Commonly, this effect is an issue at low frequencies and it is not important for higher frequencies [4]. Hysteresis is another undesired effect: when the input voltage is gradually increased, the actuator displacement is different from when the voltage is decreased for the same voltage value applied. For hysteresis reducing, many techniques have been implemented: the model-based control [5]; the displacement feedback control [6]; the charge control [7]. Without going into details, it is worth mentioning that, none of these techniques do not provide an acceptably hysteresis dimi-nution to allow the piezoelectric actuators to do the very high precisions displacement. In this paper, a model of digital charge amplifier is presented. By this model, a significant reduction of the piezoelectric actuators nonlinear behaviour is obtained. 94 | T h e 3 9 t h A R A P r o c e e d i n g s In the following sections we present this digital model. The analog charge amplifier To make the transition to digital charge amplifier, we present a simple analog charge amplifier in this section. In Figure 1(a) the circuit diagram of this analog charge amplifier is shown. It contains a comparator (Ʃ) and amplifier (K), a stack piezoelectric (SP) with capacity, Cpa, a sensing capacitor with capacitance, CS. R1 is used to model the operational amplifier (OA) input terminal leakage, and R2 is due to the leakage of the sensing capacitor. The circuit feedback loop is used to equalize the reference voltage, Vr, with the actual voltage across the sensing capacitor. If the OA, SP and sensing capacitor would be ideal, R1 and R2 can be removed and ideal Laplace transfer function would be

To solve generator problem of the sensor nodes for floating bridge monitoring system, design a kind of self-sustaining circular sheet piezoelectric generator. Its most important feature is the use of a self-sustaining circular sheet piezoelectric structure, it converts the mechanical energy into vibration excitation source, so as to extend the load's continuous effect and correspondingly extend the generator time; Describe its operating principles, the output electricity energy increases when piezoelectric circular sheet becomes resonance. In order to test and analyze the electrical generation performance of self-sustaining piezoelectric generator, built the measuring platform based on vibration exciter to simulate vibration test, in the design of this measuring platform, displacement sensor is used to measure the amplitude of piezoelectric circular sheet, charge amplifier is used to measure the electricity quantity generated by piezoelectric circular sheet, and the test result shows that increase the exciter load and work under the natural working frequency of piezoelectric circular sheet will increase the generating capacity of self-sustaining circular sheet piezoelectric generator.

In this paper, a novel design scheme has been proposed to reduce output ripple of a Dickson charge pump with build-in capacitors. While a linear regulator is used to regulate the pump output to 15 V, an auxiliary transistor is utilized to improve the narrowband amplifier. It has also been proved that this design is effective to improve the system stability, and to serve as a soft-start circuit naturally. Finally, an error amplifier which consumes 7 μA is used and the pump output ripple is as low as 1 mV during light load.

The capacitor voltage feedback active damping control is an attractive way to suppress LCL-filter resonance especially for the systems where the capacitor voltage is used for grid synchronization, since no extra sensors are added. The derivative is the core of the capacitor voltage feedback active damping control. However, in digital systems, the discrete implementation of the derivative suffers from noise amplification and accuracy issues. To overcome these drawbacks, this paper proposes a new derivative method based on Second-Order Generalized Integrator. Theoretical study shows that the proposed derivative is more suited for capacitor voltage feedback active damping control. Experimental results validate the effectiveness of the proposed method.

Conference of Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems ; Conference Date: 4 May 2015 Through 6 May 2015; Conference Code:113177; International audience; This work describes the potential use of car windows as a long range acoustic sensing device for external alarm signals. The goal is to detect and localize siren signals (e.g. ambulances and police cars) and to alert presbycusic drivers of its presence by visual and acoustic feedback in order to improve individual mobility and increase the sense of security. The glab panes of a Renault Zoé operating as an acoustic antenna have been equipped with large 50 mm outer diameter piezoceramic rings, hidden in the lower part of the door structure and the lower part of the windshield and the rear window. The response of the glab to quasi-static signals and sweep excitation has been recorded. In general, the glab pane is acting as a high pab filter due to its inherent stiffneb and provides only little damping. This effect is compensated by using a charge amplifier electronic circuit. The detection capability up to 120 m as well as a dynamic test where the car is moving towards the sound source is reported.

This paper proposes a comprehensive optimization methodology to simultaneously determine the clock frequency, area ratio of pump capacitor to switching circuit, number of stages, and capacitor size of integrated switched-capacitor charge pump voltage multipliers. Power efficiency of the charge pump is also discussed in various views. How the top and bottom plate parasitic capacitance and the threshold voltage of the switching circuit affect power efficiency is reviewed. The optimization methodology is demonstrated. Comparisons of the model with SPICE simulation results are also provided for validation.

Bowel signal monitoring finds numerous applications in medical and pathological fields. A portable bowel sound monitoring system requires front end amplifiers, data converters, signal processors and power efficient operation. In this paper, a low power integrated bowel sound monitoring system has been proposed and implemented. The system consists of a tunable charge amplifier, a feature extraction block, a bowel sound detection unit and a bowel sound occurrence rate count block. The system is implemented in a standard 6 metal 1 poly 180nm CMOS process. The developed integrated system consumes 52µW of power from a 1V supply.

Anaesthesia chambers are a method to induce an anaesthetic state to small mammals in laboratory procedures (e.g. mice), when animal handling can alter the outcome of the tests performed due to induced stress [1]. Loss of rightning reflex (LORR) and respiratory rate (RR) are parameters in which the technician relies to evaluate the anaesthesia depth on a visual evaluation. Piezoelectric elements have been successfully presented as a method to monitor vital signs, namely RR, in mice as a non-invasive method [2]. In previous work of this research team, an instrumented chamber with built-in piezoelectric sensors was presented and an accurate measure of the subject's RR was achieved [3]. The aim for this work is to present a preliminary integrated solution for LORR detection and RR monitoring, in order to be implemented in future anaesthesia studies. The tests were conducted on three white NMRI female mice's, aging 2 months old and weighing between 38.6 and 40.8g. Each mice was placed inside the chamber and the anaesthetic state was induced at a 5% isoflurane concentration (Isoflo, Esteve Farma Lda., Carnaxide, Portugal) in 100% oxygen at 1 L/min until LORR. Then, the anaesthesia delivery was interrupted, and 100% oxygen at a delivery rate of 2 L/min was provided until recovery of the reflex was observed. One piezoelectric KPSG-100 (30 Vp-p, 1.2±0.2 kHz, Kingstate) sensor was placed underneath the anaesthesia chamber's footholds. The sensor was connected to a Kistler 5073-A model charge amplifier (Kistler Corporation, NY, USA). The charge amplifier was configured using Kirstler's ManuWare software. The amplified signal output was then measured using a NI DAQ USB-6251, 16-bit, Multifunction I/O device (National Instruments, Austin, TX, USA) and filtered using a point-to-point 2nd order Butterworth band-pass filter with bandwidth from 0.5 Hz to 5 Hz, in a developed acquisition application in LabVIEW 2013 (National Instruments, USA). LORR detection was achieved through the implementation of an identification algorithm, regarding piezoelectric signal obtained through the mice movement within the chamber or from its breathing cycle. RR was calculated using a peak-to-peak detection algorithm. In the tests performed, it was possible to correctly identify the LORR moment and to achieve RR monitoring during the anaesthesia protocol (Fig 1.). RR variation due to the anaesthesia depth was also noticeable, from a lowering RR right after LORR, to a dissipation of anaesthetic until the moment of recovery. Comparing with the previous results [3], the implementation of the new setup enables a simple LORR detection method with an enhanced RR related signal amplitude (8 mVp-p to 32 mVp-p). Further tests are recommended to observe the system response to mice weight variations and positioning within the chamber. Nonetheless, with the respective validation, the presented system indicates a novel method for anaesthesia related studies and laboratory animal handling.

In this paper a fully on-chip, any capacitor stable linear voltage regulator (LVR) using sub-unity gain positive feedback loop and NMOS pass element is presented. Sub-unity gain of the loop decouples loop stability from output capacitance value thus realizing any capacitor stable regulator. Regulator is shown to be stable for wide range of output capacitance values from 1nF to 40a#x03BC;F. Regulator output settles in 0.5a#x03BC;s with peak to peak voltage variation of 158mV for a load current step of 0 to 115mA in 0.14a#x03BC;s with 1nF output capacitance. Response becomes better for higher values of output capacitance. LVR generates 1.25V output from 1.6V input while using another 3.0V input supply and occupies 0.18mm2 in 65nm CMOS.

PTB-Mitteilungen. volume 125 (2015), no. 2. ISSN 0030-834X

PTB-Mitteilungen. volume 125 (2015), no. 2, page 52 - 61. ISSN 0030-834X, Was first published at 2015-01-07 in Metrologia volume 52 (2015), no. 1, page 72 - 81. ISSN 0026-1394

Closed-loop control or open-loop control of proportional valve can be completed when the drive current of electro-hydraulic proportional valve is provided by electro-hydraulic proportional amplifier. The control performance of proportional valve can be directly decided by the electro-hydraulic proportional amplifier. Electro- hydraulic proportional control amplifier is an important part of the control system of electro-hydraulic proportional. so the application research of electro-hydraulic proportional control amplifier has an important value and significance. In this article, development and composition of proportional control amplifier are simply introduced; Working principle of proportional control amplifier is discussed; Working principle of electro-hydraulic proportional amplifier on control circuit and driver circuit is analyzed; Working principle of the key components of the electro-hydraulic proportional control amplifier are described, and the application foreground of electro-hydraulic proportional amplifier is prospected. Combined with some new technologies of PID control, the state feedback control, adaptive control, variable structure control and fuzzy logic control, it is pointed out that electro-hydraulic proportional amplifier will be in this direction of state feedback control, adaptive control, variable structure control and fuzzy logic control, etc.

In compliance with ISO 16063-13, a shock calibration system for accelerometers ranging from 50 to 10,000 m/s2 and with pulse widths more than several milliseconds was developed. However, a piezoelectric accelerometer output voltage with zero shift was induced by the low-frequency response of the charge amplifier. So we designed a virtual amplifier with infinite impulse response filters as a digital replica of the charge amplifier. Since the virtual amplifier has the same input–output characteristics as the real charge amplifier, we can obtain the shock sensitivity of a piezoelectric accelerometer by applying the input acceleration to the virtual amplifier. As a result, we obtain flat charge sensitivities from 50 to 10,000 m/s2, which are comparable to the vibration calibration results.

A low-power high-speed source follower-based switched capacitor (SC) amplifier for pipelined analogue-to-digital converters (ADCs) is proposed. Using the source follower as the core of the SC amplifier, the power consumption can be significantly reduced while obtaining the same linearity and bandwidth. Meanwhile, through replicating the input signal to the drain of the input transistor, the channel-length modulation effect can be suppressed, achieving a high linearity (>60 dB). The functionality and linearity of the proposed SC amplifier are verified by simulation results. Accepted version

In this paper, design, implementation and characterization of a 3-V switched-capacitor (SC) DeltaSigma CMOS interface circuit for the closed-loop operation of a lateral capacitive micro-gravity silicon-on-insulator (SOI) accelerometer is presented. The interface circuit is based on a front-end programmable reference-capacitorless SC charge amplifier and a back-end second-order SC DeltaSigma modulator. The accelerometer is fabricated through a dry-release high aspect-ratio reduced-gap process. By incorporating the low-Q transfer function of the microaccelerometer in a feedback loop, the system's dynamic range is improved by 20 dB, leading to a measured resolution of 4 mug/radicHz and an output dynamic range of 95 dB at 20 Hz. The bias instability is 2 to 8 mug for 12 hours. The chip is fabricated in the 0.5-mum standard CMOS process with an area of 2.25 mm2. The integrated circuit (IC) consumes 4.5 mW of power

This paper proposes a Miller capacitor which has a wide input signal range. By discharging the charge of the capacitor connected between the input and output terminals of an amplifier before the output voltage of the amplifier exceeds its maximum range, the amplifier always operates in the active region and the Miller operation can be guaranteed. Thus a large value capacitor with a wide dynamic operation range can be realized using a small value capacitor. The Miller capacitor proposed in this paper is applied to a loop filter of phase locked loop (PLL) circuit that requires a large value capacitor to realize a low cutoff frequency. SPICE simulation of the PLL circuit using the Miller capacitor confirms the operation of the Miller capacitor and shows good performances that are similar to those obtained using a passive capacitor of a large value.

High-temperature hybrid miniature silicon-based charge amplifier has been designed, fabricated, and tested. The charge gain Gqap30 mV/pCplusmn1 dB at the reference frequency of 100 Hz. Frequency response deviation is plusmn1 dB at frequency range from about 0.5 Hz to about 10 kHz over the temperature range from -55degC to 175degC. The maximum change in gain is plusmn5% over that temperature range. The maximum output signal is 5 V peak at voltage supply of +24 V. The charge amplifier compromises standard components, and it is built on the ceramic disk substrate with a diameter of about 8 mm. This circuit made possible the development of the industry's first 100-mV/G miniature (cube with side of 14 mm), lightweight (12.5 g), low-cost, and low-noise piezoelectric triaxial accelerometer with integral silicon-based electronics having operating temperature from -55degC to 175degC. In the long-term active (with power supply) test, the circuit and the accelerometer operated at temperature of 175 degC for 1000 h without any signs of degradation

The design and implementation of instrumentation to collect real-time vibrational data from a quasi-steady state machine (a dry vacuum pump) for fault prediction diagnostics is presented. When simultaneous multiple data collection points are required on the same machinery, the use of conventional transducers such as piezoelectric accelerometers becomes impractical due to their price, as each needs an expensive associated charge amplifier. The use of inexpensive micromachined integrated micro-electrical-mechanical system accelerometers such as ADXL105 has been explored here as an alternative to piezoelectric accelerometers for obtaining reliable and predictable data for diagnostics. Surface micromachined accelerometers are a new technology and their usage for vibrational analysis has been conservative due to concerns over increased noise levels and tolerance to high temperatures. In this article, it is shown that such concerns can be allayed. The time and frequency domain vibration signatures obtained using both types of accelerometers are compared. The study shows that ADXL105 accelerometers can be an effective alternative low-cost high-quality solution for machine condition monitoring.

We are developing a prototype X-ray detection system that should be ideal for many types of synchrotron science. X-rays are captured directly in thick, high-resistivity, single-crystal, silicon pixel sensors. Unlike other X-ray detectors, which have a substantial dead area around their borders, these have "active edges"-edges formed from electrodes in the third dimension, perpendicular to the top and bottom surfaces, with full sensitivity to within a micron of the physical border. Each sensor is 0.96 mm/spl times/0.96 mm, having a 64/spl times/64 two-dimensional array of 150 /spl mu/m pixels. Behind each sensor, a custom CMOS readout chip is bump-bonded to the sensor. It provides high-speed (64/spl mu/s/full-array) readout of each pixel, with a dead time for each row, during pixel reset, of 1 /spl mu/s. On three edges, it lies completely hidden behind the sensor. A 3 mm wide region on the remaining edge of each CMOS chip contains readout circuits and connections. Here it protrudes beyond the sensor edge, but is covered by the active region of a neighboring sensor module in an array similar to that of shingles on a roof. Sensor units can be easily arrayed to cover large areas. The readout chip has 128 ADCs and, for each pixel, a charge amplifier. To save fabrication costs, the prototype readout has just 8/spl times/64 pixels. Using pulse heights, we should be able to combine signals when X-rays share charge between adjacent pixels. We have already made accurate quantum-counts of 0 to 7 X-ray events/pixel during each 64 /spl mu/s readout cycle.

We are developing CMOS monolithic active pixel sensors (MAPS) for High Energy Physics applications. We have successfully produced 3 test structures. They feature several different pixel types including: standard 3MOS, 4MOS allowing Correlated Double Sampling (CDS), charge amplifier pixels and a flexible APS (FAPS). The FAPS has a 10 deep pipeline on each pixel. This is specifically designed with the beam structure of the TESLA proposal for the Linear Collider in mind. Results of a laser test on our first device and source test results on two more recent test structures will be presented.

A new aggregate-like sensor using piezoelectric ceramic as sensing element was designed, fabricated and tested. The sensor was made by bonding together two cuboids of hardened cement paste with a commercially available piezoelectric ceramic plate in between, which is the sensing element. A new adhesive was developed during the fabrication of the sensor. The sensor was tested on its basic performance with a charge amplifier measuring system. First, the frequency response of the sensor was investigated in the general frequency range of civil engineering structure, which is from 0.01 Hz to 40 Hz. Then the relationship between output and input of the sensor was tested. Finally, complex, random and square loads were applied to observe the performance of the sensors. The excellent compatibility with concrete and the good sensing performance enable the aggregate-like sensor to be easily embedded into concrete structures like a real aggregate and to reliably monitor the vibration of host structure. There is a good potential for such a sensor to be used in structural health monitoring.

In this paper, we present a finger tip tactile sensor which can detect contact normal force as well as slip. The sensor is made up of two different materials, such as polyvinylidene fluoride (PVDF) known as piezoelectric polymer, and pressure variable resistor ink. In order to detect slip on the surface of the object, two PVDF strips are arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, a tactile sensing system is developed, which includes miniaturized charge amplifier to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.

Piezoelectric tube scanners are employed in high-resolution positioning applications such as scanning probe microscopy and nanofabrication. Much research has proceeded with the aim of reducing hysteresis and vibration-the two foremost problems associated with piezoelectric tube scanners. In this paper, two simple techniques are proposed for simultaneously reducing hysteresis and vibration: 1) A new dc accurate charge amplifier is shown to significantly reduce hysteresis while avoiding characteristic voltage drift. 2) Piezoelectric shunt damping, a technique previously resident in the field of smart structures, has been applied to damp tube vibration. By attaching an LCR impedance to a single tube electrode, the first mechanical mode is reduced in magnitude by more than 20 dB.

The paper addresses a design of an analog-to-digital converter based on event-driven successive charge redistribution intended to convert signals originated in voltage domain. Since the conversion is realized in charge domain, the sampling is substituted by a linear translation of the continuous-time input voltage to proportional input charge. Two methods of voltage-to-charge translation called respectively voltage-mode and current-mode are discussed in the paper. Furthermore, it is explicitly shown that the conversion adopts binary search algorithm with reducing quantization error by concurrent charge comparison and subtraction.

In this paper, a 3-electrode amperometric sensor readout circuit that can be used for multiple electrochemical sensor cells with an embedded integrator for charge determination is presented. The circuit consists of a wide current range amperometric sensor readout circuit that utilizes a PMOS source at the input thereby providing low input impedance. The circuit also has PMOS pass elements for Working Electrode (WE) selection. The front-end is coupled to a current integrator circuit formed by a Second Generation Current Conveyor (CCII) which gives the amount of charge generated over time by the redox reaction. Pre-layout simulations are carried out using HSPICE G2012.06. The circuit was implemented using TSMC 0.35um Mixed Mode CMOS Process.

The optimization of the input MOSFET for charge amplifiers in deep submicron technologies is discussed. After a review of the traditional approach, the impact of properly modeling the equivalent series noise and gate capacitance of the MOSFET is presented. It is shown that the enhanced MOSFET model, when compared to the classical, produces a different resolution estimate and input MOSFET optimization result. The minimum channel length and the maximum allocated power are not always the best choice in terms of resolution. Also, in an optimized front-end, the low frequency noise contribution to the Equivalent Noise Charge may depend on the time constant of the filter. As an example, results from the commercial TSMC 0.25 mum CMOS technology are reported

Driving piezoelectric actuators by charge, or current rather than voltage is known to significantly reduce the hysteretic nature of these actuators. Although this feature of piezoelectric transducers has been known to the researchers for some time, still voltage amplifiers are being used as the main driving mechanism for piezoelectric devices. This is due to the perceived difficulty in building charge/current amplifiers capable of driving highly capacitive loads such as piezoelectric actuators. Recently, a new charge amplifier has been proposed which is ideal for driving piezoelectric loads used in applications such as active damping of vibration. Consequently, it is now possible to effectively, and accurately control the charge deposited on the electrodes of a piezoelectric transducer, and thereby avoid hysteresis altogether. This paper further investigates properties of piezoelectric transducers driven by charge sources when used with resonant controllers for structural vibration control applications. The paper reports experimental results of a multivariable resonant controller implemented on a piezoelectric laminate cantilever beam.

We describe the design of the analog portion of an electronics system to process signals from the photomultiplier tubes of the ATLAS Tile Calorimeter. The system has a 16-bit dynamic range and is capable of measuring energy depositions in a single calorimeter cell from ∼ 20 MeV to ∼ 1.3 TeV . In order to maintain the calorimeter calibration at the 1% level the system includes a charge injection circuit and a current integrator for use with a cesium source system and with the time-averaged currents produced by the LHC. The system also provides a signal for an analog adder which produces an energy sum for each calorimeter tower. Over 10,000 channels of this system have been constructed and delivered for use.

In order to miniaturize a very low-level dc current amplifier and to speed up its output response speed, we proposed to employ the switched-capacitor circuit (SCC) as its negative feedback circuit, instead of the conventionally used high-ohmage resistor. However, in the case of using SCC, the output waveform had unnecessary components. To decrease the effect of these components and to speed up the response speed, we used a switched-capacitor filter (SCF), an offset controller, and a positive feedback circuit. As a result, we demonstrated that it was useful to use the amplifier using the SCC.

In this paper the noise analysis of a current integrator is carried out and measures to reduce the overall noise are presented. The effects of various noise sources are investigated and their dependence on the input capacitance and on the gate area of the input transistors of the OTA used for the readout is shown. Both, input capacitance and gate area, should be kept as small as possible. Moreover, the linearity of the integrator is examined. In addition to that, the available application of such sensor readout circuit, which is a CMOS photodetector readout, is introduced. It uses an automatic gain switching, so that the dynamic range is extended.

A fully differential switched-capacitor (SC) amplifier and integrator with an accurate gain of 2 are proposed. Both circuits are based on a novel capacitor mismatch compensation scheme which uses the same capacitor as the charge sampling and summing element. Therefore, the gain error which is linearly proportional to the capacitor mismatch in conventional SC circuits becomes proportional to the square of the mismatch. In addition, the proposed scheme does not require additional active blocks, and the valid output is generated within two clock cycles.

A modernized electronic unit for a feedback circuit of a negative feedback laser is described. The modernization of the unit resulted in expanding (approximately up to 1 GHz) the feedback circuit bandwidth. Attained characteristics together with the negative feedback effect allowed the laser to be switched to the mode locking operation, and this was demonstrated by the example of an Nd-glass laser. Upon including the broadband feedback on the basis of the developed amplifier as a component of a ΓOC-1001 laser operating in the negative feedback regime, it was possible to increase the total lasing power up to 5 J. The results obtained allow us to speak about promising practical applications of these systems.

The silicon pixel detector of the PANDA experiment is characterized by both high track density and the absence of a hardware trigger signal, thus leading to a huge amount of data to be acquired and transmitted to the DAQ. In order to cope with such challenging requirements, an ASIC based custom solution for the electronic readout has been chosen. The ASIC, named ToPiX, will provide the time position of each hit and a measure of the charge released with the Time over Threshold (ToT) technique. A reduced scale prototype in a CMOS 0.13 μ m technology has been designed and tested. The prototype includes four columns made of 128 pixel cells, four columns of 32 cells and the end of column readout with a 32 cells deep FIFO for each double column. Each cell embeds a charge amplifier with constant current feedback capacitor discharge, a comparator with per cell adjustable threshold, 12-bits leading and trailing edge register for time and ToT measurement and an 8 bits configuration register. All the readout logic has been SEU-hardened by design using either Hamming encoding or triple modular redundancy. The chip has been tested both electrically via a test pulse input and connected to a detector in a beam test.