JPH0954121A - Detection circuit for voltage between peak values - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection circuit which can obtain an output signal which can be measured stably, precisely and with high accuracy irrespective of an input waveform even when a random waveform such as a ripple voltage to be output by a DC output power-supply unit is detected for a measurement. SOLUTION: Voltage signals which are output from a positive-voltage rectification part 10 and a negative-voltage rectification part 20 which are connected to a DC cutoff circuit 1 used to cut off a DC voltage to be input are added by an addition circuit 9 so as to be output as a DC voltage. The positive-voltage rectification part 10 is provided with a signal rectification circuit 3 to which an AC signal is input by a sneak-path preventing circuit 2 so as to be half-wave rectified and which outputs a positive voltage signal and with a peak rectifying circuit 4 which is connected to the output of the signal rectifying circuit 3. The negative-voltage rectification part 20 is provided with an inverting circuit 6 to which an AC signal is input via a sneak-path preventing circuit 5 and which inverts a polarity, with a signal rectifying circuit 7 which receives the output of the inverting circuit so as to be half-wave rectified and which outputs a negative voltage signal and with a peak rectifying circuit 8 which is connected to the output of the signal rectifying circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peak-to-peak voltage detection circuit for detecting a voltage difference between peak values of an input AC voltage, and more particularly, it is possible to improve the detection accuracy of the peak value. The present invention relates to a peak-to-peak voltage detection circuit.

[0002]

2. Description of the Related Art Conventionally, in this type of peak-to-peak voltage detecting circuit, as described in, for example, Japanese Patent Application Laid-Open No. 1-23742, the peak value of a negative potential is set to the ground potential, and positive and negative operations are performed. A circuit for peak rectification is described in.

This circuit comprises a separating capacitor, a shunt rectifier connected to ground, a charging rectifier connected between the separating capacitor and the shunt rectifier, and a post connection to this rectifier. A peak-to-peak voltage detector composed of a storage capacitor is included.

Further, according to the disclosed technique, the voltage value of the output signal detected by the inter-peak value voltage detector is converted into a digital value and the liquid crystal numeral is instructed, while the waveform of the output signal is the maximum of the oscilloscope. It has been achieved that both leading values appear in the row or in the bottom row so that the measurement of the periodic signal and control voltage, which is not actually sinusoidal, is made accurately.

[0005]

SUMMARY OF THE INVENTION In the above-mentioned conventional inter-peak value detection circuit, the waveform of the output signal is obtained for the purpose of accurately measuring the periodic signal and the control voltage. With regard to the detection of the peak value voltage, the ground potential is set to the negative peak value, so in the case of a random waveform, the ground potential is not stable,
In addition, the peak detection method is different for each positive and negative, and the circuit impedance is also different, so the operation is unstable. Furthermore, since a diode is used as a component,
There is a problem that the influence of distortion is great.

In particular, in the above circuit, when measuring the ripple voltage of the output of the DC output power supply unit, the ripple voltage has a random waveform, so the measurement of the detection voltage is unstable and inaccurate, and the accuracy is lowered. There is a problem in terms of practical use that is inevitable.

An object of the present invention is to provide a stable, accurate and highly accurate measurement regardless of an input waveform even when a random waveform such as a ripple voltage of the output of a DC output power supply unit is detected for measurement. It is an object of the present invention to provide a voltage detection circuit between peak values capable of obtaining an output signal that can be obtained.

[0008]

A peak-to-peak voltage detecting circuit according to the present invention cuts off a DC voltage in a peak-to-peak voltage detecting circuit for detecting a voltage difference between peak values of an input AC voltage. A DC blocking circuit, a positive voltage rectifying unit that half-wave rectifies an AC voltage that is input via the DC blocking circuit, and outputs a positive voltage signal, and inverts the positive / negative of the AC voltage that is input via the DC blocking circuit. Half-wave rectification and output as a negative voltage signal converted to a positive voltage, and the voltage signals output from the positive and negative voltage rectification units are input to obtain peak values and add And an adder circuit for outputting as a DC voltage.

One of the concrete means is to connect the input terminal and cut off the input DC voltage with a capacitor, and a capacitor for forming a sneak prevention circuit on the positive voltage side. A signal rectifier circuit on the positive voltage side that inputs the output of the DC cutoff circuit, half-wave rectifies and outputs as a positive voltage signal, and a peak on the positive voltage side that connects the output of the signal rectifier circuit to the ground via a capacitor A positive voltage rectifier having a rectifier circuit and a capacitor forming a sneak prevention circuit on the negative voltage side receive the output of the DC cutoff circuit and receive the output of an inverting circuit that inverts the positive and negative sides, and receives the output of the positive voltage side. A signal rectifier circuit that has the same circuit configuration as the signal rectifier circuit and that performs half-wave rectification on the negative voltage side and outputs the signal rectifier circuit to a ground via a capacitor. A negative voltage rectifier having a continuous peak rectifier on the negative voltage side, and an adder circuit that inputs the voltage signals output by the positive voltage rectifier and the negative voltage rectifier, adds them, and finally outputs a DC voltage. Is equipped with.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. In the inter-peak voltage detection circuit shown in FIG. 1, the positive voltage rectification unit 10 and the negative voltage rectification unit 20 which are connected to the DC cutoff circuit 1 for inputting the measurement signal, the positive voltage rectification unit 10 and the negative voltage rectification unit 10 are connected. It is composed of an adder circuit 9 which is connected to the two outputs of the rectification unit 20 and which inputs these outputs and adds them to finally output a DC voltage.

The positive voltage rectification unit 10 includes a sneak prevention circuit 2 having a capacitor for preventing sneak in on the input side, and a signal rectification circuit 3 for half-wave rectifying the output signal of the sneak prevention circuit 2 to output a positive voltage signal. , And a peak rectifier circuit 4 for rectifying the peak value by connecting the output positive voltage signal to the ground via a capacitor.

On the other hand, in the negative voltage rectifying unit 20, an inverting circuit 6 for additionally inputting the output signal of the sneak prevention circuit 5 by a capacitor to the constituent elements of the positive voltage rectifying unit 10 and inverting the positive / negative of this signal is additionally inserted. ing. Therefore, the signal rectifying circuit 7 of the negative voltage rectifying unit 20 outputs a half voltage rectified negative voltage signal. The peak rectifier circuit 8 rectifies the peak value by connecting the output negative voltage signal to the ground via a capacitor.

Next, the procedure for detecting the ripple voltage of the output of the DC output power supply unit and outputting it as a DC voltage will be described with reference to FIG. 1 and the waveform diagram of FIG.

First, it is assumed that the input measurement signal has a ripple voltage and a waveform A at the input side A of the DC cutoff circuit 1. The AC signal of the waveform A has the DC voltage removed by the DC blocking circuit 1 at the output side B of the DC blocking circuit 1, and is converted into the AC signal of the waveform B in which the ripple voltage is separated into positive and negative.

The AC signal of the waveform B is input to the signal rectification circuit 3 via the sneak prevention circuit 2 in the positive voltage rectification unit 10 on one side, half-wave rectified into a positive DC voltage, and the positive voltage signal of the waveform C is obtained. Becomes In the other negative voltage rectification unit 20, the AC signal of the waveform B is input to the inverting circuit 6 via the sneak prevention circuit 5, and the positive / negative of the waveform B is inverted to become the AC signal of the waveform D. The AC signal is input to the signal rectifier circuit 7 and half-wave rectified into a negative DC voltage to become a negative voltage signal having a waveform E.

Here, the output of the positive voltage rectifying section 10 has a DC voltage Vdc1 as illustrated by the waveform (C), while the output of the negative voltage rectifying section 20 is illustrated by the waveform (E). As described above, it is assumed to have a DC voltage Vdc2.

The adder circuit 9 receives these two DC voltages Vdc
1 and DC voltage Vdc2 are input and added, and a signal of peak-to-peak voltage Vp-p having a waveform H as shown in the figure is output by DC voltage.

The two voltage rectifiers described above have the same constituent elements except that one of them includes an inverting circuit, and can exhibit well-balanced performance.

In the above description, only the detection circuit for outputting the signal of the peak-to-peak voltage Vp-p by the DC voltage has been described. However, the above-mentioned configuration is especially random like the ripple voltage of the output of the DC output power supply unit. It can be effectively applied when detecting various waveforms for measurement.

In the above description, the circuit is illustrated and described by the functional blocks and the capacitors, but the separation and merging of the functions by the functional distribution of the blocks and the circuit configuration are free as long as the above functions are satisfied, and the above description is the main matter. It does not limit the invention.

[0022]

EXAMPLES Next, one example of the above-described embodiment will be specifically described in detail with reference to FIG. 3 and FIGS. Operational amplifier A1 shown in FIG.
The "+" terminal of each of A4 to A4 is connected to the ground.

FIG. 3 is a circuit diagram showing one embodiment of the present invention. In the peak-to-peak voltage detection circuit shown in FIG. 3, a capacitor C1 for blocking the DC voltage having the waveform A at the output of the DC output power supply unit having the ripple voltage is connected to the input terminal of the measurement signal as the DC blocking circuit 1. Has been done. The AC signal output via the low-pass filter circuit configured by the capacitor C1 and the resistor R1 is the operational amplifier A
1 and is amplified by the AC amplifier circuit 11. A filter circuit 12 including a capacitor C2 and a resistor R2 is connected in parallel to the AC amplifier circuit 11,
The AC signal of waveform B is output.

On the other hand, the AC signal having the waveform B output from the AC amplifier circuit 11 is sent to the positive voltage rectifying section 10 (FIG. 1) constituted by the sneak prevention circuit 2, the signal rectifying circuit 3, and the peak rectifying circuit 4. input. Positive voltage rectifier 10
Inputs the AC signal of the waveform B into the capacitor C3 forming the sneak prevention circuit 2 and outputs the DC signal of the waveform C from the signal rectification circuit 3. This output is connected to the peak rectifier circuit 4 which is connected to the ground via the capacitor C4. The signal rectifier circuit 3 connected to the capacitor C3 is a series circuit of a resistor R3, an operational amplifier A2 and a forward rectifier RE1 in the direction from the input to the output, and a forward rectifier connected in parallel to the operational amplifier A2. RE2 and operational amplifier A
2 and a resistor R4 connected in parallel to the series circuit of the forward rectifier RE1.

On the other hand, the AC signal of the waveform B output from the AC amplifier circuit 11 is further composed of a sneak prevention circuit 5, an inverting circuit 6, a signal rectifying circuit 7 and a peak rectifying circuit 8 and a negative voltage rectifying section 20. Fill in (Fig. 1). The negative voltage rectification unit 20 inputs the AC signal of the waveform B into the capacitor C5 forming the sneak prevention circuit 5, converts the AC signal into the AC signal of the waveform D via the inverting circuit 6, and outputs the AC signal of the waveform rectification circuit 7. Output DC signal. This output is connected to the peak rectifier circuit 4 which is connected to the ground via the capacitor C4. The inverting circuit 6 connected to the capacitor C5 is
Resistor R6, operational amplifier A in the direction from input to output
3 and capacitor C6 in series circuit, and operational amplifier A3
And a resistor R7 connected in parallel to
An AC signal having a waveform D that inverts the positive and negative of is output.

The signal rectifier circuit 7 connected to the inverting circuit 6 has a circuit configuration similar to that of the signal rectifier circuit 3, and includes a resistor R8, an operational amplifier A4 and a forward rectifier RE3 in the direction from the input to the output. A series circuit, a forward rectifier RE4 connected in parallel to the operational amplifier A4, and an operational amplifier A4.
4 and a resistor R9 connected in parallel to the series circuit of the forward rectifier RE3.

The final-stage adder 9 inputs the DC signal having the waveform C output from the positive voltage rectifying unit 10 via the resistor R5, and outputs the negative voltage rectifying unit 20 via the resistor R10. Input a DC signal having a waveform E
The resistors R5 and R10 are connected to the "+" terminal of the operational amplifier A5 together with the grounded R11. Operational amplifier A5
Is connected to the ground through a resistor R12, and the output of the operational amplifier A5 is connected to the resistor R13.
Connected through.

[0028]

As described above, according to the present invention, a direct current cutoff circuit for cutting off a direct current voltage and a positive voltage signal for half-wave rectifying an alternating voltage input through the direct current cutoff circuit and outputting it as a positive voltage signal. A voltage rectification unit, a negative voltage rectification unit that inverts the positive / negative of an AC voltage input via the DC cutoff circuit to perform half-wave rectification, and outputs as a negative voltage signal. There is obtained an inter-peak value voltage detection circuit including an adder circuit that inputs a voltage signal to obtain a peak value, adds the sum value, and outputs the sum as a DC voltage.

With this configuration, even when a random waveform such as a ripple voltage of the output of the DC output power supply unit is detected for measurement, stable and accurate measurement can be performed regardless of the input waveform. An output signal can be obtained.

[Brief description of drawings]

FIG. 1 is a functional block connection diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an embodiment of the present invention.

FIG. 3 is a functional circuit diagram showing a specific example of the present invention.

[Explanation of symbols]

 1 DC cutoff circuit 2, 5 sneak prevention circuit 3, 7 Signal rectification circuit 4, 8 Peak rectification circuit 6 Inversion circuit 9 Addition circuit 10 Positive voltage rectification unit 11 AC amplification circuit 12 Filter circuit 20 Negative voltage rectification unit

Claims (3)

[Claims] 1. A peak-to-peak voltage detection circuit for detecting a voltage difference between peak values of an input AC voltage, and a DC cutoff circuit for cutting a DC voltage, and an AC voltage input via the DC cutoff circuit. Half-wave rectified, and a positive voltage rectifier that outputs as a positive voltage signal, and half-wave rectify by inverting the positive and negative of the AC voltage that is input via the DC cutoff circuit, and as a negative voltage signal converted to a positive voltage. A negative voltage rectifier that outputs the voltage, and an adder circuit that inputs the voltage signals output from the positive and negative voltage rectifiers to obtain a peak value, adds the peak value, and outputs the sum as a DC voltage. Head-to-peak voltage detection circuit. 2. A peak-to-peak voltage detection circuit for detecting a voltage difference between peak values of an input AC voltage, and a DC cutoff circuit which is connected to an input terminal and cuts the input DC voltage by a capacitor. A signal rectifier circuit on the positive voltage side, which receives the output of the DC cutoff circuit via a capacitor forming a sneak prevention circuit on the voltage side, rectifies it half-wave and outputs it as a positive voltage signal, and the output of the signal rectifier circuit A positive voltage rectification unit having a positive voltage side peak rectification circuit that connects to the ground via a capacitor and a capacitor that forms a sneak prevention circuit on the negative voltage side, and input the output of the DC cutoff circuit to obtain a positive or negative sign. A negative voltage-side signal rectifying circuit that has the same circuit configuration as the positive voltage-side signal rectifying circuit that receives the output of the inverting circuit that inverts, and that performs half-wave rectification and outputs the signal. A negative voltage rectification unit having a peak rectification circuit on the negative voltage side for connecting the output of the current circuit to the ground via a capacitor, and the voltage signals output from the positive voltage rectification unit and the negative voltage rectification unit, respectively, and added. And an adder circuit for finally outputting a DC voltage. 3. A peak-to-peak voltage detection circuit that detects a voltage difference between peak values of an input AC voltage, and a capacitor that forms a DC cutoff circuit that cuts off a DC voltage that is input to the input terminal. An operational amplifier forming an AC amplification circuit for inputting and amplifying the output of the DC cutoff circuit, a capacitor and a resistor forming a filter circuit connected in parallel to the AC amplification circuit, and an output of the AC amplification circuit A signal which is connected to one of the two capacitors forming the sneak-in prevention circuit to be connected and one of the two outputs of the sneak-in prevention circuit and which has a feedback path through a rectifier and is half-wave rectified to obtain a positive voltage signal. The operational amplifier that constitutes the rectifier circuit, the capacitor that constitutes the peak rectifier circuit of the positive voltage signal by connecting the output to the output of the signal rectifier circuit, and the two outputs of the sneak prevention circuit. The same as the above-mentioned signal rectifier circuit which is connected to the other and constitutes an inverting circuit for inverting the positive / negative of a signal, and which has an output of the inverting circuit and which has a feedback path through a rectifier and obtains a positive voltage signal. An operational amplifier that forms a signal rectifier circuit that obtains a negative voltage signal with the configuration of
A capacitor that forms a negative voltage signal peak rectifier circuit by connecting the output to the output of the signal rectifier circuit;
An inter-peak voltage detection circuit, comprising: an operational amplifier that constitutes an adder that inputs the outputs of two signal rectifier circuits, adds the outputs, and outputs the final outputs.