Zero-crossing detection circuit for eliminating high-frequency glitches

Abstract

The invention relates to a zero cross detection circuit for eliminating high frequency burrs. The zero cross detection circuit comprises a comparator circuit, a first phase inverter, a first buffer, a second buffer, a first Schmitt trigger, a second Schmitt trigger, a second phase inverter, a third phase inverter, a first falling edge detector, a second first falling edge detector and a RS (reset-set) trigger, wherein the output end of the comparator circuit is respectively connected with the first phase inverter and the first buffer, the output end of the first phase inverter is connected with the second buffer, the output end of the first buffer is serially connected with the first Schmitt trigger, the second phase inverter and the first falling edge detector, the output end of the second buffer is serially connected with the second Schmitt trigger, the third phase inverter and the second falling edge detector, and the output end of the first falling edge detector and the output end of the second falling edge detector are respectively connected with ends R and S of the RS trigger. The zero cross detection circuit has the advantages that the frequency and phase of an input signal are accurately tracked, the high-frequency burrs can be eliminated, and the phase error is avoided.

Description

Technical field [0001] The invention relates to a zero-crossing detection circuit. Background technique [0002] In the digital-analog hybrid circuit, a large number of analog signals need to be converted into square wave signals with the same frequency and phase in order to provide clocks for subsequent switching circuits, or to provide carrier signals for other modules such as modem modules. However, there is a problem in the actual circuit, that is, at the zero signal, due to noise or crosstalk in other places, the analog signal waveform is prone to high-frequency interference glitch signals, resulting in multiple transition edges of the square wave signal, which is zero-crossing detection The design of the circuit presents challenges. [0003] One of the simplest zero-crossing detectors only needs a high-speed comparator. This circuit structure is simple, but the shortcomings are also obvious. When the input signal is jittered near the DC point, the edge of the output square...

AI Technical Summary

Problems solved by technology

The zero-crossing detection circuit in the prior art either uses a simple hysteresis comparator to eliminate the zero-crossing glitch, or adopts a complex structure that requires more digital modules

Neither technique is the best choice for solving high frequency glitch interference

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