A low-power wide tuning-range CMOS current-controlled oscillator

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 µA, 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 mV. 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 8.8×11.5 µm².     

A wide-band current-controlled oscillator using bipolar-JFET technology

A 256K/spl times/1 bit NMOS dynamic RAM, fabricated using conventional n-channel two-layer polysilicon gate technology, is described. The memory cell was laid out in 5.7 /spl mu/m/spl times/12.5 /spl mu/m, and the die measured 4.84 mm/spl times/8.59 mm which can use a standard 300 mil 16 pin DIP. Reduction of the bit line capacitance was accomplished using the second polysilicon layer for the bit line. Through the use of large memory cell capacitance and special device coating techniques, alpha particle immunity was increased. The memory offers a 160 ns typical access time, 350 ns cycle time, and 250 mW active power dissipation.     

A 1.2- mu m CMOS current-controlled oscillator

A simple, fully symmetrical, current-controlled CMOS oscillator is presented. The oscillator uses two grounded capacitors. This 5-V architecture permits relatively large capacitor voltage amplitudes, thus minimizing jitter. The design also operates with power supply voltages as low as 3 V. Because there are no special capacitor requirements, the design is compatible with standard scaled digital CMOS processes. The use of a double differential latching comparator allows high-speed operation with good control linearity. The circuit was successfully fabricated using a 1.2- mu m CMOS process.<>     

CMOS sinusoidal oscillator based on current-controlled current conveyors

A new realisation of a CMOS single resistance current-controlled current mode oscillator using active grounded resistances is described. A prototype has been realised in 0.8 /spl mu/m CMOS technology from AMS. Measurement results confirm oscillation over 10 MHz, low output distortion and wide tuning range.     

Sinusoidal frequency doubler and full-wave rectifier based on translinear current-controlled current conveyors

A circuit design technique that employs translinear current-controlled current conveyors as active circuit elements to design a sinusoidal frequency doubling and full-wave rectifying circuit is proposed. The circuit can realize the sinusoidal frequency doubler and full-wave rectifier without changing the circuit configuration. The proposed frequency doubling and rectifying action is exploited from the translinear characteristic of the current conveyor. Simulation and experimental results are given to confirm the theoretical predictions.     

A translinear SiGe BiCMOS current-controlled oscillator with 80 Hz–800 MHz tuning range

A novel identification and digital predistortion scheme of weakly nonlinear passband systems such as RF power amplifiers (PA) is presented. It is well known that for the identification of weakly nonlinear systems, despite the spectral regrowth, it suffices to sample the input-output (I/O) data of the system at the Nyquist rate of the input signal. Many applications such as linearization (digital predistortion) and mixed signal simulations require system models at a higher sampling rate than Nyquist. Up to now the construction of such high-rate predistorters has been done by oversampling the corresponding I/O data. This leads to high computational complexity, ill-posedness of the estimation, and high demand on the analog-to-digital converter (ADC) sampling rate for the implementation. This paper discusses an efficient way to obtain high-rate predistorters from low-rate system models and shows the validity of the proposed scheme for a 5th-order complex baseband PA model, where adjacent channel power suppression of 20 dB is achieved.     

Precise 90/spl deg/ quadrature current-controlled oscillator tunable between 50-130 MHz

A VLSI continuous time sinusoidal OTA-C quadrature oscillator fabricated in a standard double-poly 0.8 /spl mu/m CMOS process is presented. The oscillator is tunable in the frequency range from 50-130 MHz. The two phases produced by the oscillator show an extremely low phase difference error (less than 2/spl deg/ over the whole frequency range). A novel current mode amplitude control scheme is developed that allows for very small amplitudes. Experimental results are provided.     

A novel current-controlled memristor-based chaotic circuit

In this paper, a novel third-order autonomous memristor-based chaotic circuit is proposed. The circuit has simple topology and contains only four elements including one linear negative impedance converter-based resistor, one linear capacitor, one linear inductor, and one nonlinear current-controlled memristor. Firstly, the voltage-current characteristic analysis of the memristor emulator for different driving amplitudes and frequencies are presented. With dimensionless system, the symmetry, equilibrium point and its stability are analysed. It is shown that the system has two unstable saddle-foci and one unstable saddle. A set of typical parameters are chosen for the generation of chaotic attractor. Differing from the common period-doubling bifurcation route in smooth dynamical systems, this memristive system shows abrupt transition from the coexisting period-1 limit cycles to robust chaos when varying system parameters. Various dynamical behaviors are analysed using the numerical simulations and circuit verifications.     

Low-voltage low-power multifunction current-controlled conveyor

In this study, low-voltage low-power multifunction current-controlled conveyor (CCCII) is introduced. Multifunction current conveyors are able to achieve various CCCII structures with a small modification in the circuit. The proposed circuit required ±0.5 V as a power supply, a simple circuit structure and low power consumption. The power consumption is only 4.8 µW. Low-voltage operation is achieved by using changeable threshold voltage and PMOS level-shifter current mirror. This circuit is able to operate as CCCII± with both positive and negative intrinsic resistance, which have a wide tunable range with a small modification in the circuit connections.     

Synthesis of current-controlled nonlinear impedances

An integrable circuit technique is employed to obtain a class of current-controlled nonlinear impedances which is complementary to the recently proposed voltage-controlled class of nonlinear impedances.     

A lambda-type current-controlled negative resistance device

A new structure is presented for the implementation of a λ-type current-controlled negative resistance device in conventional bipolar technology. Expressions for the characteristic parameters, such as: the holding current, the peak current, and the peak voltage, are given.     

Switching technique for current-controlled AC-to-AC converters

The AC-to-AC converter called the matrix converter is very simple in structure and has powerful controllability. However, there are few practical applications, particularly in power electronics fields. The major reasons largely lie in the commutation problem and complexity of the control circuit. This paper proposes a novel commutation technique which is very simple to implement. This commutation scheme allows the deadtime to avoid current spikes of nonideal switches and, at the same time, establishes a current path of the inductive load to avoid voltage spikes. A switching technique of the matrix converter using a space-vector-modulation (SVM) based hysteresis current controller (HCC) is also proposed. The switching technique is implemented without any computational burden and is controlled with a simple control circuit. This technique utilizes advantages of the HCC and SVM technique. Simulation and experimental results obtained on a 5 kW single-phase AC chopper and an 11 kW three-phase to three-phase matrix converter are discussed     

An improved multioutput current-controlled source

For single-output unity-gain requirements, Wilson's current-controlled current source (CCS) significantly improves upon the gain accuracy of the current mirror; however, this advantage is small in nonunity-gain applications. A novel CCS which preserves its gain accuracy under nonunity-gain multioutput service is presented here.     

Allpass filters using a current-controlled current source

Two allpass filter realisations, using a current-controlled current source (CCCS) as the active element, are reported. Their performances are discussed. Experimental results, which confirm the validity of the theoretical analysis, are given for the two configurations.     

A current-controlled quasi-resonant converter forswitched-reluctance motor

A current-controlled quasi-resonant power converter suitable for switched-reluctance motor (SRM) feeding is presented. The converter operation is analyzed and its characteristics are determined in terms of the system parameters. The converter control strategy is studied for different operating conditions. Current control operation is considered and discussed. Theoretical predictions are verified and validated by experimental results obtained with a prototype SRM drive     

Current-conveyor-based single-element-controlled and current-controlled sinusoidal oscillators

A new single-element-controlled sinusoidal oscillator circuit that incorporates two second generation current conveyors (CCIIs), two grounded capacitors and two resistors is presented and analysed. The circuit is beneficial to monolithic integrated circuit implementation by the use of grounded capacitors. In addition, a new current-controlled sinusoidal oscillator using only two second generation current controlled conveyors (CCCIIs) and two grounded capacitors can be achieved by replacing CCIIs and resistors series at X terminals with CCCIIs. The oscillators provide extremely low passive ω₀-sensitivities and good frequency stability. Moreover, the oscillation frequencies of the CCII-based and the CCCII-based oscillators can be controlled, respectively, by a grounded resistor and by an external bias current. Experimental and SPICE simulation results that confirm the theoretical predictions are given.     

Bulk-material device with current-controlled negative resistance

Current-controlled negative resistance following avalanche breakdown is shown by structures of bulk ptype InSb up to 150°K and of ptype In(As, P) up to 300°K. The high speed of the InSb devices suggests applications as microwave sources or switches.     

An integrable precision current-controlled negative impedance converter

An easily integrable precision floating current-controlled negative impedance converter is proposed and experimentally demonstrated, The resulting converted negative impedance magnitude is both highly accurate and linear over the entire dynamic range. Either terminal voltage can be referenced. The circuit is stable for capacitive impedance convenions.     

A current-controlled negative-resistance effect in indium antimonide

A thin wafer of P-InSb exhibits a current-controlled negative resistance between nonsymmetrical ohmic contacts on opposite sides of the wafer. The small contact on one side of the wafer is made positive relative to the large contact on the other side. Most effective samples had small contact diameters one to four times the slab thickness. The negative resistance was present up to a temperature of 210°K for material having 2.5 × 10¹⁴/cm³acceptor concentration at 77°K. A magnetic field perpendicular to the current flow direction reduced the value of the maximum negative resistance and extended the range of bias current yielding negative resistance. Samples under 0.005 inch thick yielded negative resistance when operated continuously, for the doping of 2.5 × 10¹⁴/cm³, but thicker samples yielded negative resistance only in lower duty cycle operation. Microwave radiation lines presumably at harmonics of oscillation in the bias circuit were measured. Finally, a proposed mechanism, dependent on impact ionization, is used to predict operation to a transit-time limited frequency of, say, 8000 Mc/s for a sample whose thickness is 0.0025 inch.