Demodulation method and circuit of signal isolation system

Abstract

The invention discloses a demodulation method and circuit of a signal isolation system. The demodulation circuit comprises a signal conversion geminate transistor, a first current mirror, a second current mirror, a signal recovery circuit and an output stage which are electrically connected in sequence. The signal conversion geminate transistors are used for inputting differential signals and converting the two paths of differential key control voltage signals into two paths of differential key control current signals. The first current mirror is used for copying and outputting the first differential key control current signal. The second current mirror is used for copying and outputting the second path of differential key control current signal. The signal recovery circuit couples the first differential key control current signal and the second differential key control current signal into a demodulation current signal to realize a superposition function of the current signals, and converts the demodulation current signal into a demodulation voltage signal. The output stage module amplifies the demodulation voltage signal into a logic level signal. A modulation voltage signal is converted into a demodulation current signal to be processed, two high-speed comparators are not needed, and low-power-consumption design is achieved.

Description

technical field [0001] The invention relates to the field of digital signal isolators, in particular to a demodulation method and circuit of a signal isolation system based on switch key modulation. Background technique [0002] The function of circuit isolation is divided into signal isolation and power isolation transmission. There are signal isolation interfaces in industrial control, medical and communication systems. Digital isolators can exchange data signals between two circuit systems in different voltage domains. Common isolation techniques include optocoupler isolation, capacitive isolation, and inductive isolation. On-off keying (“OOK”) is a transmission protocol that can identify whether an input signal is high or low based on the type of signal passing through the isolation device; for example, when the input signal is high, a periodic signal is transmitted through the isolation device; when the input When the signal is low, no signal is transmitted. [0003] ...

AI Technical Summary

Problems solved by technology

Since the carrier signal is generally large (up to hundreds of megahertz or even gigahertz), the speed of the required comparator is high (large bandwidth), which will make the overall power consumption large

As a result, it is difficult to achieve low power design

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