Comparator applications

About: Comparator applications is a research topic. Over the lifetime, 2518 publications have been published within this topic receiving 26639 citations.

Hysteresis comparator circuit consuming a small current

Abstract: A hysteresis comparator circuit and a waveform generating circuit reduce a power consumption of a DC/DC converter so as to improve a power consumption efficiency when the DC/DC converter is operated with a relatively small load. The hysteresis comparator circuit is connected to a reference voltage source providing a reference voltage. A hysteresis comparator compares an input voltage with one of a first threshold voltage and a second threshold voltage. A hysteresis voltage generating circuit selectively generates one of the first and second threshold voltages by controlling a state of electric charge stored in each of the capacitors. An electric charge stored in the capacitors is provided from the reference voltage source.

All-optical analog comparator.

Abstract: An analog comparator is one of the core units in all-optical analog-to-digital conversion (AO-ADC) systems, which digitizes different amplitude levels into two levels of logical ‘1’ or ‘0’ by comparing with a defined decision threshold. Although various outstanding photonic ADC approaches have been reported, almost all of them necessitate an electrical comparator to carry out this binarization. The use of an electrical comparator is in contradiction to the aim of developing all-optical devices. In this work, we propose a new concept of an all-optical analog comparator and numerically demonstrate an implementation based on a quarter-wavelength-shifted distributed feedback laser diode (QWS DFB-LD) with multiple quantum well (MQW) structures. Our results show that the all-optical comparator is very well suited for true AO-ADCs, enabling the whole digital conversion from an analog optical signal (continuous-time signal or discrete pulse signal) to a binary representation totally in the optical domain. In particular, this all-optical analog comparator possesses a low threshold power (several mW), high extinction ratio (up to 40 dB), fast operation rate (of the order of tens of Gb/s) and a step-like transfer function.

Inductive proximity sensor oscillator

Abstract: An inductive proximity sensor oscillator (A) having a differential comparator (38) in combination with a negative feedback network (38) and a positive feedback network connected to the comparator. The positive feedback network (22, 36) determines the frequency and amplitude of the generated oscillations. An LC resonant tank circuit (22) is connected between a non-inverting input (30) and a fixed reference voltage (20), and a current limiting resistor (36) connected between the non-inverting input and the output of the comparator. The negative feedback network (38) provides a simple, fast and reliable start-up mechanism. It comprises a capacitor (40) connected between the inverting input of the comparator and the circuit ground and a resistor (42)

Signal mode converter and processor

Abstract: An analog signal comparator is coupled to provide its output to a data processor which has digital outputs coupled through a digital-to-analog converter to an input of the comparator, for periodically producing in the processor digital representations of samples of another analog signal that is also applied to the comparator. In each sampling period, additional data processing is carried out with respect to the digital representations; and an output circuit coupled to the converter output employs a filter circuit to select only the results of the last-mentioned processing. The additional processing is shown for digital filters featuring single and tandem sections.

Oscillators having charge/discharge circuits with adjustment to maintain desired duty cycles

Abstract: An oscillator comprises a comparator and first and second switches for alternately connecting first and second respective reference voltages to a first input of the comparator. A capacitor is connected to a second input of the comparator, and a current source and a current sink are alternately connected to the capacitor via third and fourth switches. The first and third switches are closed simultaneously based on one output level of the comparator, and the second and fourth switches are closed simultaneously based on the other output level of the comparator. This causes the output of the compartor to alternate and thereby generate an oscillation signal. To provide precision in the duty cycles, either the second reference voltage, the current source or the current sink is adjusted to maintain desired duty cycles of the high and low levels output from the comparator. The adjustment to the second reference voltage, current source or current sink is based on an average voltage of the capacitor in relation to a third reference voltage.