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ABSTRACT: This paper exhibits the generation of an operational
transconductance amplifier and capacitor (OTA-C) arbitraryphase-
shift sinusoidal oscillator (APSO) for an order n ≥ 3 for
various advanced applications. A new nth-order quadrature oscillator
(QO) is obtained via the algebraic quadrature manipulations
of an oscillatory characteristic equation. Based on a phase shift
transformation from a quadrature, an APSO is then generated
by superposing OTAs with required +/− transconductance(s) in
parallel with some grounded capacitor(s) on the QO. For eliminating
nonideal and parasitic effects to improve phase accuracy,
phase compensation schemes are proposed. A new native amplitude
control exploiting the nonlinearity of all employed OTAs of
the APSO is presented as well to lead to rather low THD and a
lower variation of THD with respect to amplitude enlargement. A
fourth-order APSO is demonstrated and simulated using Hspice
with a 0.35-μm process for validation. In addition, its real application
to a polyphase rectifier is improved. Finally, an experiment
using LM13700s shows favorable potential of APSOs.
IEEE Transactions on Instrumentation and Measurement 08/2012; 61(8):2305-2319. · 1.21 Impact Factor
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ABSTRACT: A novel simple control technique for on-chip all-digital three-phase alternating current to direct current (AC/DC) power-metal oxide semiconductor field-effect transistors (MOSFET) converter with least components, which is employed to obtain small current and DC output voltage ripples as well as excellent performance, and using a feedforward simple control method for DC output voltage regulation is proposed. The proposed all-digital feedforward controller has the features of low cost, simple control, fast response, independence of load parameters and the switching frequency, it has no need for compensation, and high stability characteristics; moreover, the proposed controller consists of three operation amplifiers and few digital logic gates that are directly applied to the three-phase converter. The power-MOSFETs are also known as power switches, whose control signals are derived from the proposed all-digital feedforward controller. Instead of thyristors or diodes, the application of power-MOSFETs can reduce the loss of AC/DC converter that is proper to the power supply system. The input stage of an AC/DC converter functions as a rectifier and the output stage is a low pass inductor capacitor (LC) filter. The input AC sources may originate from miniature three-phase AC generator or low-power three-phase DC/AC inverter. The maximum output loading current is 0.8 A and the maximum DC output ripple is less than 200 mV. The prototype of the proposed AC/DC converter has been fabricated with Taiwan Semiconductor Manufacturing Company (TSMC) 0.35 mum 2P4M complementary MOS (CMOS) processes. The total chip area is 2.333 1.960 mm<sup>2</sup>. The proposed AC/DC converter is suitable for the following three power systems with the low power, DC/DC converter, low-dropout linear regulator and switch capacitor. Finally, the theoretical analysis is verified to be correct by simulations and experiments.
IET Circuits Devices & Systems 09/2009; · 0.55 Impact Factor
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ABSTRACT: This study presents a controllable integration time readout integrated circuit (ROIC) with a 32 by 32 indium gallium arsenide (InGaAs) detector array. This ROIC is designed for InGaAs photodiode (PD) array detectors to operate at low input current and is suitable for the focal plane array (FPA) in near infrared (NIR) field. The integration time of this ROIC can be controlled by an external clock pulse, and is adjustable from 0.5 s to infinity by varying the light intensity. Moreover, the pre-stage of ROIC is based on the buffer gate modulation input (BGMI) architecture with differential structure and a double delta sampling (DDS) circuit, providing better sensitivity, a wider dynamic range, a higher injection efficiency and reduced noise. Further, because this ROIC is built into a sample-and-hold circuit in the unit cell, it can operate in the full frame snapshot mode. The proposed ROIC has 1024 pixels and a 30-mum pixel pitch. It is implemented using Taiwan Semiconductor Manufacturing Company (TSMC) 0.35 mum Complementary Metal-Oxide-Semiconductor (CMOS) process with a 5-V power supply. The output swing is over 2.2 V. It has 5 non-linearity, 91.559 mW chip power dissipation and a chip area of 1.628 2.341 mm<sup>2</sup> without pads.
IET Circuits Devices & Systems 07/2009; · 0.55 Impact Factor
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ABSTRACT: A new building block called the multiplication-mode current conveyor (MMCC) is proposed here. The structure consists of a differential voltage current conveyor (DVCC) and a folded Gilbert cell without any other auxiliary circuits. Based on the MMCC, a four-quadrant analogue multiplier is designed in TSMC 0.35 mum CMOS 2P4M processes with power supply plusmn 1.65 V. HSPICE post-layout simulation results show that the maximum DC operating range is plusmn 200 mV, the loading range is from 1 to 10 kOmega, the bandwidth is about 90 MHz, the total harmonic distortion (THD) is 0.85 , the power consumption is 1.08 mW and the chip area without pads is 0.48 times 0.36 mm<sup>2</sup>. The new square summer and analogue divider applications employing MMCCs are also presented.
IET Circuits Devices & Systems 03/2009; · 0.55 Impact Factor
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ABSTRACT: This paper presents a new compact CMOS Li-Ion battery charger for portable applications that uses a charge-pump technique. The proposed charger features a small chip size and a simple circuit structure. Additionally, it provides basic functions with voltage/current detection, end-of-charge detection, and charging speed control. The charger operates in dual-mode and is supported in the trickle/large constant-current mode to constant-voltage mode with different charging rates. This charger is implemented using a TSMC 0.35-mum CMOS process with a 5-V power supply. The output voltage is almost 4.2 V, and the maximum charging current reaches 700 mA. It has 67.89% power efficiency, 837-mW chip power dissipation, and only 1.455times1.348 mm<sup>2</sup> in chip area including pads
Circuits and Systems I: Regular Papers, IEEE Transactions on 05/2007; · 1.97 Impact Factor
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ABSTRACT: The authors present a new fully differential current-mode third-order Butterworth very high frequency G<sub>m</sub>-C filter using current-mode linear transformation (CMLT) techniques. The systematic design method and procedure are developed to realise CMLT G<sub>m</sub>-C filters efficiently. A third-order Butterworth lowpass filter with 200 MHz cutoff frequency, embedded bandgap reference and bias circuit is implemented in a TSMC 0.18 mum 1P6M process. The total harmonic distortion of the proposed current-mode filter is -46.5 dB at 200 MHz with input signal 0.4 mA. Power dissipation is 16.77 mW under 1.8 V supply voltage. Its core area occupies 0.163times0.186 mm<sup>2 </sup>. Both post-layout simulation and experimental results confirm the theoretical analysis. The proposed circuits can be extended to high-order Chebychev and elliptic filters
IEE Proceedings - Circuits Devices and Systems 01/2007; · 0.36 Impact Factor
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ABSTRACT: An on-chip current sensing technique for a hysteresis current controlled step-down DC-DC converter is presented. This current sensing technique has been designed with standard 0.35 μm CMOS 2P4M processes. Experimental results show that the current sensing circuit measures full-time the inductor current whether the high-side or low-side switch is turned on.
Electronics Letters 02/2005; · 0.96 Impact Factor
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ABSTRACT: A low-voltage four-quadrant multiplier using floating-gate MOSFETs
is presented. This circuit has been implemented in a 0.8 μm
double-poly double-metal CMOS process. Experimental results show that
for a single power supply of 2.5 V, the total harmonic distortion is
less than 1.4% with input range up to 1 V<sub>P·P</sub>. The
modulation application of this multiplier can be operated over 20 MHz.
Moreover, it can operate satisfactorily regardless of the transistor
body connection. This circuit is expected to be useful in low-voltage
analogue signal processing applications
IEE Proceedings - Circuits Devices and Systems 03/1998; · 0.36 Impact Factor
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ABSTRACT: A multiphase sinusoidal oscillator using the parasitic poles of
current feedback operational amplifiers (CFOAs) is presented. The
oscillator can generate n signals which are equal in amplitude and
equally spaced in phase. The oscillator using the parasitic poles of
CFOAs is suitable for high frequency applications and monolithic IC
fabrication. The effects caused by the nonlinearity of the CFOA on the
oscillation frequency and condition have been analysed. Experimental
results show that a three-phase sinusoidal oscillator has a wide
operating range from 10 kHz to 10 MHz and a large output voltage swing
up to 7 V peak to peak while using ±5 V power supply. The total
harmonic distortion (THD) of each oscillation frequency is dominated by
its third harmonic component which is at least 33 dB down from its
fundamental
IEE Proceedings - Circuits Devices and Systems 03/1995; · 0.36 Impact Factor
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ABSTRACT: Linear transformation (LT) active filters using operational
transconductance amplifiers (OTAs) and capacitors are presented. Based
on the LT, two simple and systematic design tables are given to realise
OTA-C filters efficiently. Using the proposed design tables, the
synthesised all-pole and elliptic filters employ minimum numbers of OTAs
and only grounded capacitors. As an example, a new third-order elliptic
lowpass filter is realised. Experimental results are obtained to verify
the theoretical analysis
Electronics Letters 12/1994; · 0.96 Impact Factor
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ABSTRACT: A new multifunction filter using minimum components is presented.
This filter which possesses single input and four outputs can
simultaneously generate second-order highpass, bandpass, and lowpass
filtering functions at individual output terminals. The filter has the
following merits; it uses only two grounded capacitors which makes it
suitable for integrated circuit implementation, no matching condition is
required, offering multifunction outputs and has low passive and active
sensitivities. Experimental results agree very well with the theoretical
result
Electronics Letters 05/1994; · 0.96 Impact Factor
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ABSTRACT: Using a current feedback amplifier (CFA), new series
resistor-inductor and capacitor-frequency-dependent negative resistance
configurations are proposed. Second-order highpass, lowpass and bandpass
filters using the proposed circuits are also presented. Experimental
results that confirm the theoretical analysis are obtained
Electronics Letters 04/1994; · 0.96 Impact Factor
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ABSTRACT: A CMOS four-quadrant multiplier using bias offset crosscoupled pairs is presented. Simulation results show that a for a power supply of +or-5 V, the linearity error is less than 1% over a +or-2.5 V input range. The effect of mobility reduction is also analysed. The results will be useful in analogue signal processing applications.
Electronics Letters 10/1993; · 0.96 Impact Factor
