A Low-Voltage, Ultra-Low-Power, High-Gain Operational Amplifier Design for Portable Wearable Devices

Based on the SMIC 0.13 um CMOS technology, this paper uses a 0.8 V supply voltage to design a low-voltage, ultra-low-power, high-gain, two-stage, fully differential operational amplifier. Through the simulation analysis, when the supply voltage is 0.8 V, the design circuit meets the ultra-low power consumption and also has the characteristic of high gain. The five-tube, fully differential, and common-source amplifier circuits provide the operational amplifier with high gain and large swing. Unlike the traditional common-mode feedback, this paper uses the output of the common-mode feedback as the bias voltage of the five-tube operational transconductance amplifier load, which reduces the design cost of the circuit; the structure involves self-cascoding composite MOS, which makes the common-mode feedback loop more sensitive. The frequency compensation circuit adopts Miller compensation technology with zero-pole separation, which increases the stability of the circuit. The input of the circuit uses the current mirror. A small reference current is chosen to reduce power consumption. A detailed performance simulation analysis of this operational amplifier circuit is carried out on the Cadence spectre platform. The open-loop gain of this operational amplifier is 74.1 dB, the phase margin is 61°, the output swing is 0.7 V, the common-mode rejection ratio is 109 dB, and the static power consumption is only 11.2 uW.

The output stage of an operational amplifier on GaAs n-channel field-effect and GaAs p-n-p bipolar transistors with nonlinear negative feedback

<p>A new circuit of the output stage of an operational amplifier implemented on GaAs n-channel field-effect transistors with a control p-n junction and GaAs bipolar p-n-p transistors is investigated. Its peculiarity consists in the presence of a nonlinear negative feedback that stabilizes the drain current of the output transistor with an n-channel at a negative input voltage. The basic equations for the static mode of the output stage are given. The results of modeling in the LTspice simulation software of 3 modifications of the proposed circuit solutions are discussed.</p>

The output stage of an operational amplifier on GaAs n-channel field-effect and GaAs p-n-p bipolar transistors with nonlinear negative feedback

<p>A new circuit of the output stage of an operational amplifier implemented on GaAs n-channel field-effect transistors with a control p-n junction and GaAs bipolar p-n-p transistors is investigated. Its peculiarity consists in the presence of a nonlinear negative feedback that stabilizes the drain current of the output transistor with an n-channel at a negative input voltage. The basic equations for the static mode of the output stage are given. The results of modeling in the LTspice simulation software of 3 modifications of the proposed circuit solutions are discussed.</p>

DETERMINATION OF DYNAMIC RESPONSE COMPUTATION OF CONSTANT VOLTAGE PULSE CONVERTER MICROCHIPS

Work objective is the determination of data on the frequency-domain behavior of components in the composition of the microcircuit and within the microcircuit as a whole, intended for using in DC voltage pulse converters. Research methods: simulation modeling. Research results and novelty: for microcircuits with an external frequency weighing network a frequency analysis scheme using an auxiliary operational amplifier and an active low-pass filter of the second order is proposed. Using a simulator in the LT-spice environment, the amplitude and phase frequency response data of the microchips of the step-down and step-up converters have been obtained. The possibility of technical implementation of the proposed scheme for experimental determination of frequency-domain behavior including final control of the parameters of the appropriate microchips has been noted. For microchips having built-in frequency weighing circuit, the possibility of determining frequency-domain characteristics during the formation of a test signal in an external control circuit has been confirmed. It is found that the use of this method for microchips with increased dynamic properties is problematic. Conclusion: the frequency analysis scheme using an auxiliary operational amplifier is suitable for both step-down and step-up DC/DC converters with an external frequency weighing network. This scheme can be recommended for experimental determination of frequency-domain behavior, including final control of the parameters of the appropriate microchips.