Comparator applications

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

Low voltage, low power RC oscillator circuit

Abstract: A resistor-capacitor oscillator circuit (10) is provided and includes a voltage comparator circuit (12). A capacitor (20) is connected to an input terminal (14) of the voltage comparator circuit (12). A resistor divider network (30) is coupled to an input terminal (16) of the voltage comparator circuit (12) for generating a reference voltage. A delay circuit (50, 52) is coupled to an output terminal (42) of the voltage comparator circuit (12). A discharge device (54) is coupled to the delay circuit (50, 52) and to the capacitor (20) for discharging the capacitor (20). A switching device (40) is coupled to the output (42) of the voltage comparator circuit (12) and to the resistor divider network (30) for controlling the application of the reference voltage to voltage comparator circuit (12).

Converter comparator cell with improved resolution

Abstract: A comparator having a differential sense amplifier connected to the output of an input comparator, and the decoding logic connected between the sense amplifier and the output latch. The comparator is designed for a flash A/D converter having a reference signal generator for one or more of the sense amplifiers.

Programmable voltage hysteresis on a voltage comparator

Abstract: A programmable voltage comparator having a programmable hysteresis function controlling the comparator's output relative to first and second comparator input voltage variables. The programmable voltage comparator comprises an inverting and non-inverting input for receiving a first and second input voltages and an output providing a logic state signal reflecting the amplitude of the inverting and non-inverting input voltages. The comparator includes level shift circuitry coupled to the inverting and non-inverting inputs for programmably shifting the amplitude of the voltages applied to the inverting and non-inverting inputs responsive to the logic state output of the comparator. In one embodiment, the comparator includes a differential amplifier having inverting and non-inverting outputs, wherein the level shift circuitry comprises a first level shift circuit coupled to the non-inverting voltage input and having a feedback element coupling to the non-inverting output. A second level shift circuit is coupled to the inverting input with a feedback element coupled to the inverting output.

Phase/frequency comparator for timing recovering circuit

Abstract: The phase/frequency comparator comprises a known phase comparator for comparing the phases of an digital input signal with a clock signal of which the period varies to within one time interval with respect to the period of the input signal. Such a phase comparator produces a first error signal whose sign, and preferably magnitude, vary as a function of the difference between the phases. The phase/frequency comparator is intended to produce a second error signal which replaces the first error signal and whose sign, and preferably magnitude, vary as a function of the difference between the periods. According to a preferred embodiment, a phase shift assessing circuit detects a predetermined phase shift, e.g. substantially equal to 0, between the clock signal and the input signal during a clock period. A sign detecting circuit detects the sign of the difference between the periods for the predetermined phase shift, and a logic circuit derives two signals having pulse widths as a function of said periods thereby deriving the second error signal by differentiation. The phase/frequency comparator is particularly intended for a phase locked loop for recovering the timing of the input signal.

Comparator offset calibration for A/D converters

Abstract: An A/D converter includes at least one comparator array (COMP1-COMP7) for flash A/D conversion of an analog signal. Means (CCU, SW1-SW7) pro-vide, for each comparator in the array, a common reference signal to both comparator input terminals. Means (CCU, DAC1-DAC7) force each compara-tor in the array into the same logical output state. Finally, means (CCU, DAC1-DAC7) adjust the comparator trip-point for each comparator by a ramp signal until the logical output state is inverted.