阅读说明：本技术 一种门限电压可自适应调节的迟滞比较器 (Hysteresis comparator with threshold voltage capable of being adjusted in self-adaptive mode ) 是由 徐建 陈长江 石永柳 王鑫 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种门限电压可自适应调节的迟滞比较器,在传统的迟滞比较器的基础上将其中的阻值固定的电阻修改为一个MOS管,使其工作在可变电阻区,充当一个阻值可变的电阻,并在传统的迟滞比较器输入端引入一个信号幅度检测电路,通过检测迟滞比较器输入信号的幅度,根据检测结果利用预校正系统动态调整其门限电压,以达到能够在不同输入信号幅度下自适应调整门限电压,提高抗干扰能力和改善灵敏度。(The invention discloses a hysteresis comparator with a self-adaptive adjustable threshold voltage, which is characterized in that a resistor with a fixed resistance value is modified into an MOS (metal oxide semiconductor) tube on the basis of the traditional hysteresis comparator, so that the MOS tube works in a variable resistor area and serves as a resistor with a variable resistance value, a signal amplitude detection circuit is introduced into the input end of the traditional hysteresis comparator, the threshold voltage of the hysteresis comparator is dynamically adjusted by a pre-correction system according to the detection result by detecting the amplitude of an input signal of the hysteresis comparator, and the threshold voltage can be self-adaptively adjusted under different input signal amplitudes, so that the anti-jamming capability is improved, and the sensitivity is improved.)

1. A hysteresis comparator with threshold voltage capable of being adjusted in a self-adaptive mode is characterized by comprising a P-type double-conversion single-output five-tube differential pair, a common source stage amplifying circuit, a phase inverter, a signal detection circuit and an NMOS tube M12 working in a linear region; the NMOS transistor M12 is bridged between the source stages of a PMOS transistor M5 and a PMOS transistor M6 of a differential transistor input stage of the five-transistor differential pair, the output stage of the five-transistor differential pair is connected with the input end of the common-source amplification circuit, the output signal of the common-source amplification circuit is input into the inverter, and the output signal of the inverter and the output signal of the common-source amplification circuit are respectively and correspondingly sent into the gates of a PMOS transistor M3 and a PMOS transistor M4 which are connected in series with the branches of the PMOS transistor M5 and the PMOS transistor M6 of the differential transistor input stage; the signal detection circuit is used for detecting the peak voltage of an input signal of the comparator, the peak voltage outputs a control voltage to the gate end of the NMOS tube M12 after proportional operation, and the threshold voltage range of the comparator is changed by adjusting the resistance value of the NMOS tube M12 through the control voltage.

2. The hysteretic comparator (std) having adaptive adjustment of threshold voltage as claimed in claim 1, wherein said signal detection circuit is composed of a peak detection circuit and a same-direction proportional operation circuit connected together.

Technical Field

The invention relates to a novel comparator with a variable hysteresis threshold, and belongs to the technical field of analog circuits.

Background

The comparator is one of the most important modules in analog integrated circuits and digital-analog hybrid integrated circuits, and has input signals of reference voltage and signals to be processed and output signals of digital signals. However, since noise affects the stability of the circuit, in a noisy environment, the output of a normal comparator is accompanied by a narrow pulse, and a hysteresis comparator is introduced to eliminate the noise. The anti-interference power amplifier has strong anti-interference capability and is widely applied.

As shown in fig. 1, the conventional hysteresis comparator circuit includes: PMOS tubes M1, M2, M3, M4, M5, M6 and M10, NMOS tubes M7, M8, M9 and M11 and a resistor R. M1 and M5, M6, M7, M8 make up a P type double-rotating single-output five-tube differential pair, input Vref on the right, the signal that needs to be processed on the left, the output stage of the differential tube connects a common source amplifier that the constant current source does the load, output the signal again, and a part of output is sent back to the differential pair and forms the positive feedback loop through the phase inverter that M10, M11 form, the output signal flows into the differential tube from M3, M4 makes the left and right two-way current different, make a tube serving as the constant current source under the differential tube in the linear region, because of the function of middle resistance R, the voltage drop that produces on the resistance is the voltage of turning point. Because an output stage is required to provide a reasonable output voltage swing and output resistance, a signal is output to the common-source stage amplifier by the drain electrode of the differential tube M6, then the signal is output by the common-source stage amplifier, and the output state of the comparator is controlled by controlling the working state of the M9.

The resistor R connected across the differential input tube is fixed, so that the hysteresis width is kept unchanged during operation, and the threshold voltage range of the whole comparator is limited. As shown in fig. 2, the reference voltage is Vref, and when the swing of the input sine wave signal is smaller than the threshold voltage range (Vtrp + — Vtrp-), the output signal may have no transition, and at this time, the threshold voltage range needs to be narrowed, which improves the sensitivity but reduces the interference rejection. As shown in fig. 3, when the amplitude of the input sine wave signal is greater than the threshold voltage range (Vtrp + -/Vtrp-) due to the influence of noise and other factors, the threshold voltage range needs to be increased to filter out noise and improve the anti-interference capability. However, since the resistance value is fixed, the threshold voltage is fixed, and when the input signal is too large and too small, the interference rejection and sensitivity are lost.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the prior art, the hysteresis comparator with the threshold voltage capable of being adjusted in a self-adaptive mode is provided, and the problems that when the amplitude of an input signal is too large due to the fact that the threshold voltage of a traditional hysteresis comparator is fixed, the hysteresis comparator cannot filter noise accompanying the input signal due to the fact that the threshold voltage range is relatively small, and when the amplitude of the input signal is small, the output signal of the hysteresis comparator cannot jump and cannot be detected are solved.

The technical scheme is as follows: a hysteresis comparator with threshold voltage capable of being adjusted in a self-adaptive mode comprises a P-type double-rotation single-output five-tube differential pair, a common-source-stage amplification circuit, a phase inverter, a signal detection circuit and an NMOS tube M12 working in a linear region; the NMOS transistor M12 is bridged between the source stages of a PMOS transistor M5 and a PMOS transistor M6 of a differential transistor input stage of the five-transistor differential pair, the output stage of the five-transistor differential pair is connected with the input end of the common-source amplification circuit, the output signal of the common-source amplification circuit is input into the inverter, and the output signal of the inverter and the output signal of the common-source amplification circuit are respectively and correspondingly sent into the gates of a PMOS transistor M3 and a PMOS transistor M4 which are connected in series with the branches of the PMOS transistor M5 and the PMOS transistor M6 of the differential transistor input stage; the signal detection circuit is used for detecting the peak voltage of an input signal of the comparator, the peak voltage outputs a control voltage to the gate end of the NMOS tube M12 after proportional operation, and the threshold voltage range of the comparator is changed by adjusting the resistance value of the NMOS tube M12 through the control voltage.

Furthermore, the signal detection circuit is formed by connecting a peak detection circuit and a homodromous proportional operation circuit.

Has the advantages that: the novel hysteresis comparator with the self-adaptive adjustment threshold voltage changes a resistor with a fixed resistance value into an MOS (metal oxide semiconductor) tube on the basis of the traditional hysteresis comparator, so that the MOS tube works in a variable resistor area to serve as a resistor with a variable resistance value, part of an input signal is input into a signal detection circuit, and the detection circuit outputs a signal to control the size of the variable resistor. The signal detection circuit is used for detecting the voltage amplitude of an input signal and dynamically adjusting the voltage of the gate electrode of the MOS tube according to the detection result, so that the resistance value of the MOS tube is adjusted to achieve the aim of dynamically adjusting the threshold voltage of the MOS tube. This can realize the sensitivity of hysteresis comparator and compromise processing of the interference immunity ability.

Drawings

FIG. 1 is a schematic diagram of a conventional hysteresis comparator circuit;

FIG. 2 is a transmission curve of a conventional hysteretic comparator when the threshold voltage range of the comparator is too large;

FIG. 3 is a transmission curve of a conventional hysteretic comparator with an excessively small threshold voltage range;

FIG. 4 is a schematic diagram of the hysteresis comparator circuit of the present invention;

fig. 5 is a schematic diagram of a signal detection circuit.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in fig. 4, a hysteresis comparator with threshold voltage adaptive adjustment includes a P-type dual-conversion single-output five-transistor differential pair, a common-source stage amplification circuit, an inverter, a signal detection circuit, and an NMOS transistor M12 operating in a linear region. The PMOS tubes M1, M5 and M6 and the NMOS tubes M7 and M8 form a P-type double-rotation single-output five-tube differential pair. The NMOS transistor M12 is connected across the sources of the PMOS transistors M5 and M6 of the differential transistor input stage of the five-transistor differential pair, and the gates of the PMOS transistors M5 and M6 are respectively connected to the comparator input signal Vin and the reference signal Vref. The output stage of the five-tube differential pair is connected with the input end of a common-source amplifying circuit which takes a constant current source as a load, an output signal OUT of the common-source amplifying circuit is sent back to the differential pair to form a positive feedback loop after passing through a phase inverter consisting of a PMOS tube M10 and an NMOS tube M11, specifically, the output signal of the phase inverter and the output signal of the common-source amplifying circuit respectively control the gates of the PMOS tubes M3 and M4, the PMOS tubes M3 and M4 are respectively connected in series with the branch circuits where the differential tubes are located, so that the currents of the left branch circuit and the right branch circuit are different, and the voltage drop generated on the NMOS tube M12 is the turning point voltage. Meanwhile, an input signal is connected into a signal detection circuit, the signal detection circuit is used for detecting the peak voltage of the input signal of the comparator, the peak voltage outputs a proper control voltage to the grid end of the NMOS tube M12 after proportional operation, and the threshold voltage range of the comparator is changed by adjusting the resistance value of the NMOS tube M12 through the control voltage, so that the purpose of dynamically adjusting the threshold voltage range is achieved, the anti-interference capability is improved, and meanwhile, the sensitivity is considered.

The signal detection circuit added on the basis of the traditional hysteresis comparator is formed by connecting a peak detection circuit and a homodromous proportional operation circuit as shown in figure 5, has the functions of detecting the peak voltage of an input signal, outputting a proper voltage signal to M12 after the peak voltage passes through the proportional operation circuit, and outputting a proper voltage signal to the M12 by a linear region resistance formulaIt can be seen that the threshold voltage range can be changed by changing the gate voltage of M12 to change the resistance value. In the signal detection circuit, the peak detection circuit detects the peak voltage of the input signal, and in order to obtain a sufficient control gate voltage of the adjustable MOS resistor, the peak voltage needs to be sent to a subsequent homodromous proportional operation circuit. If the amplitude of the input signal is larger, the peak voltage output by the peak detection circuit is also larger, the voltage output by the syntropy proportion operation circuit is also larger, the voltage at the grid end of M12 is also larger, and the threshold voltage range of the hysteresis comparator is also larger. If the amplitude of the input signal is smaller, the peak voltage output by the peak detection circuit is also smaller, the voltage output by the homodromous proportional operation circuit is also smaller, the voltage at the grid end of M12 is also smaller, and the threshold voltage range of the hysteresis comparator is also smaller.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.