CN111404516A - A symmetrical voltage triangular wave generator and its realization method - Google Patents

Abstract

The invention discloses a symmetrical voltage triangular wave generator and a realization method thereof. The symmetrical voltage triangular wave generator comprises an integrator and a super servo circuit, the reverse input end of the integrator is connected to a square wave signal, and the super servo circuit connects The bias voltage output by the integrator is fed back to the non-inverting input of the integrator. The super servo circuit includes an AC filtering DC zero-drift sampling circuit and a DC zero-drift amplifying circuit. The invention adds a super servo circuit on the basis of the existing square wave to triangular wave circuit, and feeds the bias voltage output by the voltage triangular wave generator back to the input end, because the capacitor in the circuit attenuates the AC component and amplifies the DC part, thereby making the integral The bias voltage of the amplifier is rapidly amplified and fed back to its input terminal, so that the voltage at the input terminal of the integrating amplifier follows the output adjustment in real time, thereby improving the triangle wave symmetry of the output of the integrating amplifier.

Description

A symmetrical voltage triangular wave generator and its realization method

technical field

The invention relates to a symmetrical voltage triangular wave generator and a realization method thereof, belonging to the technical field of metrology verification instruments.

Background technique

In the fields of communication, radar, and PWM, triangular waves are often used as carrier signals, so a symmetrical triangular wave with high precision and no DC bias voltage is crucial for signal transmission in this field.

As shown in Figure 1, a traditional method is to use a single-chip analog chip (NE555) or a hysteresis comparison circuit to exceed the threshold voltage output inversion characteristic, and add peripheral transistors, capacitors and other devices to form an oscillator circuit. This method constitutes a stable circuit frequency. Poor performance, large output offset bias voltage, and poor triangular wave symmetry. As shown in Figure 2, there is another solution, which is to generate a square wave to control the switch to switch the current source through a single-chip microcomputer, and then convert the square wave into a triangular wave through an integrating circuit.

The symmetry of the output waveform of the current circuit depends on the offset voltage of the pre-amplifier, and the reliability is poor. In addition, at the initial stage of integrating the square wave into a triangular wave, there is a bias voltage at the negative input end of the integrating circuit amplifier, so the output triangular wave will always have a large bias voltage, even when the input bias voltage is too large, The output waveform is a DC instead of a triangle wave. Therefore, if the circuit is to generate a symmetrical triangle wave without DC zero-drift, further optimization is required.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention proposes a symmetrical voltage triangular wave generator and a realization method thereof, which can improve the symmetry of the outputted triangular wave and improve the symmetry of the outputted triangular wave.

The technical scheme adopted by the present invention to solve its technical problems is:

On the one hand, a symmetrical voltage triangular wave generator provided by an embodiment of the present invention includes an integrator and a super servo circuit, the inverting input of the integrator is connected to a square wave signal, and the super servo circuit converts the output of the integrator to a square wave signal. The bias voltage is fed back to the non-inverting input of the integrator.

As a possible implementation of this embodiment, the super servo circuit includes an AC-filtered DC zero-drift sampling circuit and a DC zero-drift amplifying circuit, and the input end of the AC-filtered DC zero-drift sampling circuit is connected to the output end of the integrator , the output end is connected with the input end of the DC zero-drift amplifying circuit, and the output end of the DC zero-drift amplifying circuit is connected with the input end of the integrator.

As a possible implementation of this embodiment, the integrator includes a resistor Rt5, a capacitor C4 and an operational amplifier U5, one end of the resistor Rt5 is connected to the output end of the current source, and the other end and the adjustable end of the resistor Rt5 are respectively It is connected with the reverse input terminal of the operational amplifier U5, and the two ends of the capacitor C4 are respectively connected with the reverse input terminal and the output terminal of the operational amplifier U5. Filtering DC zero-drift sampling circuit and DC zero-drift amplifying circuit.

As a possible implementation of this embodiment, the current filtering DC zero-drift sampling circuit attenuates the AC component in the bias voltage output by the integrator, and the DC zero-drift amplifying circuit reduces the bias voltage output by the integrator. The DC part is amplified.

As a possible implementation of this embodiment, the super servo circuit rapidly amplifies the bias voltage output by the integrator and feeds it back to the input end of the integrator, so that the voltage at the input end of the integrator follows the output of the integrator to adjust in real time.

As a possible implementation manner of this embodiment, the square wave signal is generated by a single-chip microcomputer, a circuit switch and a current source that are connected in sequence.

On the other hand, the embodiment of the present invention provides a method for implementing a symmetrical voltage triangular wave generator, wherein the bias voltage output by the voltage triangular wave generator is attenuated by the AC component, amplified by the DC part, and fed back to the input end of the voltage triangular wave generator.

As a possible implementation manner of this embodiment, the voltage triangular wave generator adopts the above-mentioned symmetrical voltage triangular wave generator.

The beneficial effects that the technical solutions of the embodiments of the present invention can have are as follows:

The invention adds a super servo circuit on the basis of the existing square wave to triangular wave circuit, and feeds the bias voltage output by the voltage triangular wave generator back to the input end, because the capacitor in the circuit attenuates the AC component and amplifies the DC part, thereby making the integral The bias voltage of the amplifier is rapidly amplified and fed back to its input terminal, so that the voltage at the input terminal of the integrating amplifier follows the output adjustment in real time, thereby improving the triangle wave symmetry of the output of the integrating amplifier.

The present invention optimizes the influence of the input offset voltage on the output in the square wave to triangular wave circuit by using the super servo feedback adjustment, so that the output will not be asymmetric or even distorted due to the input offset voltage. The simplicity and rapid adjustment performance of the super servo circuit of the present invention make the triangular wave generator more symmetrical, and improve the precision and reliability of the triangular wave generator.

Description of drawings:

Figure 1 is a circuit diagram of a traditional triangular wave generation;

Fig. 2 is another kind of existing square wave conversion triangular wave circuit diagram;

Fig. 3 is a schematic block diagram of a symmetrical voltage triangular wave generator according to an exemplary embodiment.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

In order to clearly illustrate the technical features of the solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the invention. In order to simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in different instances. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted from the present invention to avoid unnecessarily limiting the present invention.

Fig. 3 is a schematic block diagram of a symmetrical voltage triangular wave generator according to an exemplary embodiment. As shown in FIG. 3 , a symmetrical voltage triangular wave generator provided by an embodiment of the present invention includes an integrator and a super servo circuit. The inverting input end of the integrator is connected to a square wave signal, and the super servo circuit integrates The bias voltage output by the integrator is fed back to the non-inverting input of the integrator. The invention optimizes the performance of the triangular wave generating circuit through the super servo circuit, realizes the adjustment of the input offset voltage, and improves the symmetry of the output triangular wave.

As a possible implementation of this embodiment, the super servo circuit includes an AC-filtered DC zero-drift sampling circuit and a DC zero-drift amplifying circuit, and the input end of the AC-filtered DC zero-drift sampling circuit is connected to the output end of the integrator , the output end is connected with the input end of the DC zero-drift amplifying circuit, and the output end of the DC zero-drift amplifying circuit is connected with the input end of the integrator.

As a possible implementation of this embodiment, the integrator includes a resistor Rt5, a capacitor C4 and an operational amplifier U5, one end of the resistor Rt5 is connected to the output end of the current source, and the other end and the adjustable end of the resistor Rt5 are respectively It is connected with the reverse input terminal of the operational amplifier U5, and the two ends of the capacitor C4 are respectively connected with the reverse input terminal and the output terminal of the operational amplifier U5. Filtering DC zero-drift sampling circuit and DC zero-drift amplifying circuit.

As a possible implementation of this embodiment, the current filtering DC zero-drift sampling circuit attenuates the AC component in the bias voltage output by the integrator, and the DC zero-drift amplifying circuit reduces the bias voltage output by the integrator. The DC part is amplified.

As a possible implementation of this embodiment, the super servo circuit rapidly amplifies the bias voltage output by the integrator and feeds it back to the input end of the integrator, so that the voltage at the input end of the integrator follows the output of the integrator to adjust in real time.

As a possible implementation manner of this embodiment, the square wave signal is generated by a single-chip microcomputer, a circuit switch and a current source that are connected in sequence.

The embodiment of the present invention provides a method for implementing a symmetrical voltage triangular wave generator, wherein the bias voltage output by the voltage triangular wave generator is attenuated by the AC component, amplified by the DC part, and fed back to the input end of the voltage triangular wave generator.

As a possible implementation manner of this embodiment, the voltage triangular wave generator adopts the above-mentioned symmetrical voltage triangular wave generator, as shown in FIG. 3 .

The principle of realizing the symmetrical voltage triangular wave generator in the present invention is: the square wave signal charges and discharges C4 through Rt5, and the current is controlled by Rt5, so the frequency is also controlled by Rt5. The input bias voltage is integrated to the output end with the integrator, the input square wave signal is converted into a triangular wave, and then fed back to the same-direction input end of U5 through the super servo circuit. Since the filter circuit in the servo circuit amplifies the DC component and attenuates the AC component, the AC component triangular wave in the output component of U5 is rapidly attenuated during the feedback to the input terminal, and the DC bias voltage is rapidly amplified, so that in the feedback process Almost all of the components at the non-inverting input terminal of U5 are DC components. Through servo feedback adjustment, even if the input offset voltage of U5 is large, the output can quickly adjust the offset voltage part of the triangular wave signal to pull the output triangular wave to a symmetrical position.

The present invention optimizes the influence of the input offset voltage on the output in the square wave to triangular wave circuit by using the super servo feedback adjustment, so that the output will not be asymmetric or even distorted due to the input offset voltage. The simplicity and rapid adjustment performance of the super servo circuit of the present invention make the triangular wave generator more symmetrical, and improve the precision and reliability of the triangular wave generator.

The above are only the preferred embodiments of the present invention. For those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications are also regarded as the present invention. the scope of protection of the invention.

Claims (8)

1. A symmetrical voltage triangular wave generator is characterized by comprising an integrator and a super servo circuit, wherein a square wave signal is connected to the reverse input end of the integrator, and the bias voltage output by the integrator is fed back to the same-direction input end of the integrator by the super servo circuit.

2. A symmetrical voltage triangular wave generator according to claim 1, wherein the super servo circuit comprises an ac filtered dc null shift sampling circuit and a dc null shift amplifying circuit, wherein an input terminal of the ac filtered dc null shift sampling circuit is connected to an output terminal of the integrator, an output terminal of the ac filtered dc null shift sampling circuit is connected to an input terminal of the dc null shift amplifying circuit, and an output terminal of the dc null shift amplifying circuit is connected to an input terminal of the integrator.

3. The symmetrical voltage triangular wave generator of claim 2, wherein the integrator comprises a resistor Rt5, a capacitor C4 and an operational amplifier U5, one end of the resistor Rt5 is connected to an output end of the current source, the other end and the adjustable end of the resistor Rt5 are respectively connected to an inverting input end of the operational amplifier U5, two ends of the capacitor C4 are respectively connected to an inverting input end and an output end of the operational amplifier U5, and a dc filtering dc null-shift sampling circuit and a dc null-shift amplifying circuit are connected in series between the output end and a same-direction input end of the operational amplifier U5.

4. A symmetrical voltage triangular wave generator according to claim 2, wherein the flow filtering dc null shift sampling circuit attenuates the ac component of the bias voltage output from the integrator, and the dc null shift amplifying circuit amplifies the dc component of the bias voltage output from the integrator.

5. A symmetrical voltage triangular wave generator according to any of claims 1-4, wherein the super servo circuit rapidly amplifies the bias voltage from the integrator output and feeds it back to the input of the integrator, thereby causing the voltage at the input of the integrator to follow the integrator output in real time.

6. A symmetrical voltage triangular wave generator according to any of claims 1-4, wherein the square wave signal is generated by a single chip, a circuit switch and a current source connected in series.

7. A method for realizing a symmetrical voltage triangular wave generator is characterized in that bias voltage output by the voltage triangular wave generator is subjected to alternating current component attenuation and direct current part amplification and then fed back to the input end of the voltage triangular wave generator.

8. The method of claim 7, wherein the triangular wave generator is a symmetrical triangular wave generator according to any one of claims 1 to 6.

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