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The paper describes an extension, at the approximation level, of shunt-peaking technique to increase the filter/amplifier bandwidth. The frequency dependent square modulus of transfer function is multiplied by a polynomial of squared frequency. Using a standard procedure of restoration one finds the new transfer function which is the result of multiplication of initial transfer function by the zeros...
A new transistor model is used for design of two LDO regulators using a differential stage loaded by a current amplifier and the voltage feedback. The first LDO has a constant bias current, the second LDO has an additional adaptable bias circuit controlled by the load current. The LDOs are analyzed and compared. When the load is absent, the transistors in both circuits are operating in weak inversion;...
The paper describes operation and design of a memory retention LDO regulator. The LDO regulator is operating in a very wide range of the output currents (up to 100 uA) with a very small quiescent current (in the range of 100–300 nA). In the proposed circuit this range is achieved using a nonlinear translinear cell added to the the unity gain stage (voltage follower). The cell provides the load controlled...
The paper proposes analytical definitions of moderate inversion and moderate saturation. These definitions are introduced considering two different series expansions for the function ln2(x). The expansions are “matched”: the upper limit for convergence of the first series and the lower limit for convergence of the second series define the border and transition from weak to moderate inversion/saturation...
It is shown that if a rational function F (s) does not change when 1/ s is substituted instead of s then F (s) is the rational function of s + (1/ s). If the transfer function is a ratio of recursive (symmetric) polynomials, the application of this property can simplify the network synthesis, and, in case of filter synthesis, may result in new filter configurations. In addition, the method chosen...
The paper presents a cascoded power stage with automatic dead time generation. The circuit is using the inter-transistor node voltages of the cascode configuration as feedback control signals to delay turning ON the power transistors. The circuit is designed as the output stage of a fully-integrated buck converter. The steady-state operation is described. The waveforms simulated on 45-nm CMOS process...
The paper presents a self-oscillating DC-DC integrated converter which is operable in the frequency range of 200MHz–260MHz. The circuit includes a cascoded power stage, an integrated transformer, duty-cycle detector, and pulse shaper. The primary of the transformer provides the transmission of power to the converter load. The secondary, via detector and shaper, provides the feedback signal to the...
The paper presents a cascoded power stage with automatic dead time generation. The circuit is using the inter-transistor node voltages of the cascode configuration as feedback control signals to delay turning ON the power transistors. The circuit is designed as the output stage of a fully-integrated buck converter. The steady-state operation is described. The waveforms simulated on 45-nm CMOS process...
The paper presents a self-oscillating DC-DC integrated converter which is operable in the frequency range of 200MHz–260MHz. The circuit includes a cascoded power stage, and an integrated transformer. The primary of the transformer provides the transmission of power to the converter load. The secondary provides the feedback signal to the gates of cascoded transistors in the power stage. The feedback...
The paper presents a new approach to design of current amplifiers. The amplifying cell core represents the connection of three transistors: a bias transistor and a differential pair. The bias transistor sets the distribution of currents in the differential pair. When an external current signal is applied to the core input the outputs of the differential pair provide two complementary current signals...
The paper considers a new class of polynomial filters with transfer functions calculated via a recurrent relationship. The procedure starts choosing two kernel algebraic ratios u0 (s) = 1 and u1 (s) = 1 + 1 / s where s is the complex variable. Further ratios are obtained via the recurrent relationship un+1 (s) = [(2n + d) / s]un (s) + un−1 (s) where n ≥ 1 and d is a parameter. The numerators of these...
The paper demonstrates that the source follower is the core of such seemingly disparate circuits as the wideband amplifier, crystal oscillator and emitter-coupled multivibrator. It is shown that the input impedance of the follower loaded by a capacitor has a negative real part. This part compensates partially or completely the resistive component of the signal source impedance. The compensation develops...
The paper considers a new push-pull RC-oscillator/multivibrator. In the sinusoidal regime the circuit develops two counter-phase oscillations located at different DC levels. The DC level of the first oscillation is close to the power supply level, the DC level of the second oscillation is close to the ground. The transition from sinusoidal oscillations to the relaxation ones is achieved by changing...
The paper considers a new class of filters with transfer functions using the polynomials introduced by the British physicist Sir G.G. Stokes. The filters are transitional between Bessel and Butterworth ones. When one compares the step-responses of Bessel, Stokes, and Butterworth filters of the same order and the same −3dB bandwidth then the result is following. The Bessel filters have a certain delay...
A realizable transfer function providing the impulse response approximating a pulse of finite duration can be obtained using the following procedure. The function should be considered as consisting of the entire function (having no poles) of complex variable, and the delay multiplier. The entire function part representing spectral content of the impulse response is approximated by a finite degree...
A CMOS voltage reference using compensation of mobility and threshold voltage temperature effects is proposed. In this reference, the nested connection of two NMOS transistors supplies a voltage with positive temperature coefficient, and the diode-connected NMOS transistor supplies a voltage with negative temperature coefficient. These two circuits are connected in series via an operational amplifier,...
When multivibrators are forced to operate at high frequencies one usually observes transition from relaxation to sinusoidal oscillations. One considers that at these frequencies the parasitic capacitors of active devices become comparable with functional capacitors, and the effect of parasitic produces this ldquosmoothingrdquo of oscillations. This paper considers a counterintuitive example: the oscillator...
Synchronization of two oscillators coupled via second harmonic is analyzed. The system of two differential equations is given, and, as an example of analysis, the solution for Rayleigh oscillators is found. Identical oscillators, with second harmonic coupling, will oscillate in quadrature at the frequency of individual oscillators, and there is no frequency shift characterizing coupling via first...
This paper considers two oscillators (van der Pol or Robinson type) synchronized using capacitive coupling. Equations are derived for the oscillation frequency and amplitudes. They show that the frequency of synchronous oscillation is different from the frequencies of individual oscillators. The amplitudes of oscillation are also different: one oscillator becomes a master and the second oscillator...
A tunable CMOS active inductor is presented. The circuit uses a cross-coupled pair of transistors providing positive feedback for enhanced quality factor. The circuit is biased with a controllable current source varying the feedback and tuning the inductor. The proposed inductor is designed and simulated in a 90 nm digital CMOS process. It shows a wide-frequency range inductive impedance and a very...
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