Voltage detector and communication circuit

Abstract

The invention discloses a voltage detector and a communication circuit. Compared with the prior art, the voltage detector can detect a lower input voltage. The result of the detection of the voltage detector of the invention can be used as a basis for adjusting circuit parameters, so that a condition that an excessively high input voltage damages a later-stage circuit can be avoided. According toan embodiment of the invention, the voltage detector includes an alternating current coupling circuit, a feedback amplifying circuit and an auxiliary circuit; the alternating current coupling circuitis used for generating a first input voltage and a second input voltage according to an input voltage; the feedback amplifying circuit is used for outputting shunt current according to source and sinkcurrent and determining an output voltage according to the first input voltage and the quantity of the shunt current; and the auxiliary circuit for determining the quantity of the source and sink current according to the second input voltage, wherein the source and sink current contains the shunt current. The output voltage increases with the rise of the first input voltage, and additionally increases as the shunt current increases, and therefore, the slope of the change of the ratio of the output voltage to the input voltage is larger, and testing can be benefitted.

Description

technical field [0001] The present invention relates to a voltage detector and a communication circuit, in particular to a voltage detector and a communication circuit capable of detecting low input voltage. Background technique [0002] Generally, a wireless communication circuit will amplify a received signal according to a gain (such as the gain of a low noise amplifier (LNA)) to generate an input signal for subsequent circuit processing. However, if the input signal is too large, the input signal may Damage to the subsequent circuit, therefore, in order to avoid the above problems, the wireless communication circuit usually includes a voltage detector to detect whether the voltage of the input signal exceeds a threshold voltage, if the detection result is yes, the wireless communication circuit will reduce the gain . [0003] figure 1 Displays the voltage of the input signal above V IN , output signal voltage V OUT , and the threshold voltage V TH Relationship. Suc...

AI Technical Summary

Problems solved by technology

However, with the development of technology, the operation complexity of the circuit is getting higher and higher, and the detection capability of the aforementioned voltage detector must be further improved in order to detect the specific voltage V 1 lower voltages, in other words, the V IN less than the voltage V 1 when (such as figure 2 shown, where V 2 less than figure 1 V 1 ), the voltage detector must obtain V OUT greater than V TH The test results can only meet the demand

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