JPH0576587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a DC stabilized power supply using switching control (hereinafter abbreviated as switching DC power supply).
Ripple voltage measurement that calculates the peak-to-peak voltage of the voltage, which is included in the output voltage and has spike-like switching noise voltage superimposed at the positive and negative peak positions, by removing the spike-like switching noise voltage, as the ripple voltage. It is related to the device.

Switching DC power supplies are often used as DC power sources for various electronic devices, but in this power supply, the switching elements are driven by oscillation pulses from a pulse oscillator of 10kHz to several 100kHz built into the power supply, so the DC output voltage is low. A spike-like switching noise voltage and a ripple voltage at the switching frequency are superimposed on the signal.

The amount of spike-like switching noise voltage and ripple voltage at the switching frequency included in the DC output voltage is one of the important indicators expressing the performance of a switching DC power supply. For example, a method is adopted in which the content is read by visually observing the waveform drawn on the image plane of a cathode ray tube oscilloscope.

However, there is still no clear standard for the amount of ripple voltage contained in the DC output voltage of a switching DC power supply, and reproducible measurements are not possible due to the uncertainty caused by visual errors.

FIG. 6 is a diagram showing an example of an AC component waveform included in the DC output voltage of a switching DC power supply, where the horizontal axis is time T, the vertical axis is voltage V, and the period T _O of the switching fundamental wave is the switching frequency of the switching element. The voltage V _N from the top to the bottom of the waveform, which is equal to the period, is called the spike-like switching noise voltage, and the voltage V _R excluding the spike-like switching noise voltage at the top and bottom is usually called the ripple voltage. It is.

The spike-like switching noise voltage V _N is clear by definition and there is no risk of misunderstandings, but the ripple voltage V _R is tentatively defined as a voltage excluding the spike-like switching noise voltage. The magnitude of the ripple voltage varies depending on how the spike-like switching noise voltage is removed.

A simple method for removing spike-like switching noise voltages is to remove high-frequency components using a low-pass filter, but this method cannot remove all spike-like switching noise voltage components. In addition, there is a drawback that the fundamental wave component waveform of switching changes depending on the characteristics of the filter, and as a result, the peak-to-peak voltage of the ripple voltage changes.

Furthermore, when measuring by visually observing the waveform drawn on the image plane of a cathode ray tube oscilloscope, the following drawbacks cannot be avoided.

That is, Fig. 7 (horizontal and vertical axes are the same as Fig. 6).
is a partially enlarged view of the waveform diagram shown in FIG. 6, in which the peak voltage of the switching fundamental wave is located at the intersection point A on the extension line of the positive and negative slope portions of the fundamental wave.
However, since the amplitude and steepness of the spike-like switching noise voltage superimposed near this intersection A often differ depending on the spike-like switching noise voltage, it is difficult to visually inspect it. Therefore, it is impossible to distinguish point A.

By slowing down the time-axis sweep speed of the CRT oscilloscope, the waveform on the image plane is compressed in the time axis direction, as shown in Figure 8 (the horizontal and vertical axes are the same as in Figure 6). The brightness of the switching fundamental wave component with a slow change in electron beam speed is high, and the brightness of the spike-like switching noise voltage component with a fast change in electron beam speed is low. A method of measuring 100% is also used, but highly reproducible measurements are not possible due to visual errors.

The present invention has a ripple voltage that is extremely close to the magnitude of the ripple voltage that peaks at point A explained with reference to FIG. The object of the present invention is to realize a device for measuring ripple voltage included in the output voltage of a switching DC power supply, which can measure with high reproducibility and has a simple configuration.

FIG. 2 (horizontal axis is time T, vertical axis is voltage V) is a waveform diagram for explaining the definition of ripple voltage in the present invention and the principle of construction of the measuring device of the present invention. The period is T _O and the time width of the spike-like switching noise voltage is T _N
In this case, T _N /T _O ×100=Ψ%...(1) is defined as the ripple noise separation ratio, and the difference between the positive and negative potentials corresponding to the value of Ψ is V _R
Let be the ripple voltage.

When setting the value of the ripple noise separation ratio Ψ, instead of setting one value Ψ ₁ for the same switching DC power supply under test, set any number of values Ψ ₁ to Ψ _o . , the ripple voltage for each value may be determined to allow a wider range of performance judgment of the switching DC power supply.

FIG. 1 is a diagram showing an embodiment of the present invention _.
is an input terminal, COM ₊ is a first voltage comparator consisting of an operational amplifier, and OPA ₊ is an operational amplifier which together with an integrating capacitor C ₊ forms a first current integrator that integrates the input current. D ₁₊ is the first reverse blocking diode, R ₁₊ is the second input resistor, D ₂₊ is the second reverse blocking diode, R ₂₊ is the second input resistor,
These diodes and resistors form a first current control circuit, ie, a current direction and magnitude control circuit. T _OUT+ is an output terminal, COM _- is a second voltage comparator consisting of an operational amplifier,
OPA _- is an operational amplifier, which together with the integrating capacitor C _- forms a second current integrator that integrates the input current. D _1- is the third reverse current blocking diode, R _1- is the third input resistor, D _2- is the fourth reverse current blocking diode, and R _2- is the fourth input resistor. Thus, a second current control circuit similar to the first current control circuit is formed. , T _OUT- is the output terminal, SUB is the subtraction circuit, T _OUT is the output terminal, +
RV is a ripple voltage positive potential measurement circuit, -RV is a ripple voltage negative potential measurement circuit, and the characteristics of components with the same sign that differ only by the suffixes + and - in the circuit components that make up both measurement circuits. , resistance value, capacitance, etc., are equal to each other or extremely close to each other.

At the input terminal T _IN
The potential of the inverting input terminal when applied to the inverting input terminal of the first voltage comparator COM + via the first voltage comparator COM ₊ is
If the integrated output voltage of operational amplifier OPA ₊ forming a current integrator is higher than the potential of the non-inverting input terminal of voltage comparator COM ₊ to which it is applied, the output voltage of voltage comparator COM ₊ becomes −V _C1 , and conversely The voltage comparator is set so that the output voltage of the voltage comparator COM ₊ becomes +V _C2 when the potential of the inverting input terminal is lower than the potential of the non-inverting input terminal.
COM ₊ has been formed.

Also, a first backflow blocking diode D ₁₊ and a second backflow blocking diode forming the first current control circuit.
The polarities of D ₂₊ are opposite to each other as shown in the figure, and the first input resistance R ₁₊ and the second input resistance
The resistance values of R ₂₊ are determined as described below, and when the output voltage of the voltage comparator COM ₊ is −V _C1 , a diode D is connected to the inverting input terminal of the operational amplifier OPA ₊ forming the first current integrator. ₁₊ and input resistance R ₁₊
A negative current _I1 flows through the voltage comparator
When the output voltage of COM ₊ is +V _C2 , a positive current I ₂ flows through the diode D ₂₊ and the input resistor R ₂₊ into the inverting input terminal of the operational amplifier OPA ₊ , which forms the first current integrator. It is structured as follows.

When the resistance values of resistors R ₁₊ and R ₂₊ are expressed as R ₁ and R ₂ , the magnitudes of currents I ₁ and I ₂ are: I ₁ = V _C1 − V _F1 / R ₁ (ampere)... (2) I ₂ = V _C2 −V _F2 /R ₂ (ampere) ...(3).

In equations (2) and (3), V _F1 and V _F2 are forward voltage drops across diodes D ₁₊ and D ₂₊ , which are smaller than V _C1 and V _C2 , respectively.

_{R 1+ , R 2+ ,} V _C1 and
Once each magnitude of V _C2 is determined, an input voltage containing a switching fundamental wave with a period T _O as shown in Figure 3 A (horizontal and vertical axes are the same as Figure 2) is applied to the input terminal T _IN . If applied, voltage comparator COM ₊
The output voltage changes as shown in Figure 3B (horizontal and vertical axes are the same as in Figure 2), and depends on the magnitude of the input negative current _I1 of the first current integrator and its inflow duration _T1 The relationship between is shown in Figure 3 C (horizontal axis is time T, vertical axis is current I)
The relationship between the magnitude of the input positive current I ₂ of the first current integrator and its inflow duration T ₂ is as shown in Figure 3 D (the horizontal and vertical axes are the same as in Figure 3 C). Therefore, focusing on one period of the switching fundamental wave, if the input negative current I ₁ continues for a time T ₁ , the integrated output voltage ΔV ₁ of the first current integrator
If the capacitance of the integrating capacitor C ₊ is expressed as C, then ΔV ₁ = 1/C・I ₁・T ₁ (volts) ...(5) If the input positive current I ₂ continues for a time T ₂ , the integrated output voltage -ΔV ₂ of the first current integrator is -ΔV ₂ = 1/C・I ₂・T ₂ (volt) ...(6), and the sum of ΔV ₁ and -ΔV ₂ is The integrator output voltage V _R1 converges to zero.

Therefore, from equations (5) and (6), I ₁・T ₁ =I ₂・T ₂ ...(7) From equations (4) and (7), Ψ=T ₁ /T ₁ +T ₂ ×100(%) ……(8) Since T ₁ =T _N T ₁ +T ₂ =T _O , equation (8) becomes Ψ=T _N /T _O ×100(%) ……(9) , the positive side potential of the ripple voltage V _R1 that matches the ripple-noise separation ratio Ψ defined above.
is required.

In the ripple voltage negative side potential measuring circuit -RV, when the voltage to be measured is applied to the inverting input terminal of the voltage comparator COM _- in FIG. 2 through the input terminal T _IN , the potential of the inverting input terminal is as follows. When the output voltage of the operational amplifier OPA _- forming the current integrator in Fig. 2 is higher than the potential of the non-inverting input terminal of the voltage comparator COM _- to which it is applied, the output voltage of the voltage comparator COM _- becomes -V _C3 , Conversely, the voltage comparator COM _{- is formed so that when the potential of the inverting input terminal is lower than the potential of the non-inverting input terminal, the output voltage of the voltage comparator COM - becomes} +V _C4 .

Further, the third reverse current blocking diode D _1- forming the second current control circuit and the first reverse current blocking diode D ₁₊ in the first current control circuit have opposite polarities to each other, so that The diodes are provided so that the fourth backflow blocking diode D _2- and the second backflow blocking diode D ₂₊ in the first current control circuit have opposite polarities.

Therefore, when the output voltage of the voltage comparator COM _- is -V _C3 , a diode is connected to the inverting input terminal of the operational amplifier OPA _- forming the second current integrator.
A negative current I ₃ flows through D _2- and input resistance R _2- ,
Operational amplifier forming the second current integrator when the output voltage of the voltage comparator COM _- is +V _C4
A positive current I ₄ flows into the inverting input terminal of OPA ₋ via the diode D ₁₋ and the input resistor R ₁₋ .

If the resistance values of the resistors R _2- and R _1- are represented by R ₃ and R ₄ , the magnitudes of the currents I ₃ and I ₄ are I ₃ = V _C3 − V _F3 / R ₃ (ampere)... (10) I ₄ =V _C4 −V _F4 /R ₄ (ampere) ...(11)

In equations (10) and (11), V _F3 and V _F4 are forward voltage drops across diodes D _2- and D _1- , and are assumed to be smaller than V _C3 and V _C4 , respectively.

V C3 , V _C4 , R ₂ are set so that the following relationship holds between currents I ₃ and I ₄ and ripple noise separation ratio Ψ: I ₃ = Ψ/100−Ψ・_{I 4} ...(12) _-as well as
By determining the magnitude of R _1- , the input negative current I ₃ is
If sustained for T ₂ , the integrated output voltage ΔV ₃ of the second current integrator increases the capacitance of the integrating capacitor C _- to C
Expressed as ΔV ₃ = 1/C・I ₃・T ₂ (volts)...(13) If the input positive current I ₄ continues for time T ₁ , the integral output of the second current integrator is The voltage -ΔV ₄ is -ΔV ₄ =-1/C・I ₄・T ₁ (volts)...(14) The integrated output voltage is such that the sum of ΔV ₃ and -ΔV ₄ is zero. Converges to V _R2 .

Therefore, from equations (13) and (14), I ₃・T ₂ =I ₄・T ₁ ...(15) From equations (12) and (15), Ψ=T ₁ /T ₁ +T ₂ ×100(%) ……(16) Since T ₁ =T _N T ₁ +T ₂ =T _O , equation (16) becomes Ψ=T _N /T _O ×100(%) ……(17) , the negative side potential of the ripple voltage that matches the ripple-noise separation ratio Ψ defined above.
This means that V _R2 is required.

Therefore, the voltage V _R1 determined by the ripple voltage positive side potential measurement circuit + RV and the voltage − V _R2 determined by the ripple voltage negative side potential measurement circuit - RV.
Subtraction circuit through output terminals T _OUT+ and T _OUT-
By introducing it into SUB and calculating the difference, the peak-to-peak voltage obtained by removing the spike-like switching noise voltage from the voltage where the spike-like switching noise voltage is superimposed at the positive and negative peak positions from the _output terminal T OUT, That is, the ripple voltage V _R can be extracted.

By appropriately selecting the resistance values of the input resistors R ₁₊ , R ₂₊ , R _1- and R _2- , the value of the ripple/noise separation ratio Ψ can be freely set and measurements can be made that are extremely close to the actual ripple voltage. It is possible to obtain the value.

In addition, one of the potential measuring circuits +RV or -RV on the positive or negative side of the ripple voltage is omitted so that the polarity of the reverse blocking diodes D ₁₊ and D ₂₊ or D ₁ and D _2- can be reversed. By forming one of the measuring circuits, it is possible to use either one of the measuring circuits for measuring the positive and negative potentials of the ripple voltage.

FIG. 4 is a diagram showing the main parts of another embodiment of the present invention, where E+ is a DC power supply, D ₁₊ is a first reverse current blocking diode, R ₁₊ is a first input resistor, and R ₃₊ is a A second input resistor, other symbols being the same as in FIG.

The input voltage to be measured to the input terminal T _IN (the same input voltage to be measured as in the previous example) is output to the output terminal.
If higher than the output voltage of T _OUT+ , the output voltage of voltage comparator COM ₊ will be −V _C1 and the operational amplifier
The magnitude of the negative current I _N flowing into the inverting input terminal of OPA ₊ is determined by the current flowing through the series circuit of diode D ₁₊ and resistor R ₁₊ as I ₁ , and the output voltage of DC power supply E+ as +
E _R , the current flowing through the resistor R ₃₊ is I ₃ , and the resistance values of the resistors R ₁₊ and R ₃₊ are expressed as R ₁ and R ₃ , then I _N = I ₁ − _{I 3} = V _C1 − V _F1 /R ₁ −E _R /R ₃ (ampere) ...(18)

However, the relationship between the magnitudes of the currents I ₁ and I ₃ is assumed to be I ₁ >I ₃ .

Conversely, if the input voltage to be measured at the input terminal T _IN is lower than the output voltage at the output terminal T _OUT+ , the output voltage of the voltage comparator COM ₊ will be +V _C2 , and the diode D ₁₊ will be reverse biased and the voltage comparator
The current due to the output voltage of COM ₊ does not flow into the current integrator, but the positive current I _P flows into the current integrator.
is only the current I ₃ , so I ₃ = E _R /R ₃ (ampere)...(19).

Also in this embodiment, between the negative current I ₁ − I ₃ and positive current I ₃ flowing into the current integrator and the ripple noise separation ratio Ψ, (I ₁ − I ₃ )Ψ/100−Ψ=I ₃ ……(20) R ₁₊ , R ₃₊ , E _R , V _C1
After determining _{the magnitude of each of} The integral output voltage such that the sum of the integral output voltage of the machine and the integral output voltage of the current integrator when the input positive current I ₃ continues for T ₂ hours is zero.
Converges to V _R1 .

Therefore, (I ₁ − I ₃ )T ₁ = I ₃・T ₂ ...(21) From equations (20) and (21), Ψ=T ₁ /T ₁ +T ₂ ×100 (%) ... ...(22) Since T ₁ = T _N T ₁ + T ₂ = T _O , equation (22) becomes Ψ = T _N /T _O ×100 (%) ...(23) and is defined as above. The positive side potential of the ripple voltage V _R1 that matches the ripple-noise separation ratio Ψ
is required.

From formula (20), I ₃ = Ψ / 100・I ₁ Ψ = I ₃ /I ₁ × 100 (%) = E _R /I ₁ · R ₃ × 100 (%) ... (24) In the above formula, If k=100/I ₁・R ₃ , then Ψ=kE _R ...(25) Therefore, by changing the output voltage E _R of the DC power supply E+, the ripple/noise separation ratio can be changed in proportion to E _R. Ψ can be changed.

This embodiment also has the same configuration as the ripple voltage positive side potential measuring circuit shown in FIG.
Replace the reverse blocking diode D ₁₊ with a second reverse blocking diode of opposite polarity and connect it to the input terminal of the second current integrator via a third input resistor, changing the polarity of the DC power source E+. , and is configured to have a polarity opposite to that shown in FIG. 4, and to supply a negative current to the second current integrator via the fourth input resistor. ) is provided, and the measured values of both measuring circuits are added to a subtraction circuit to obtain the ripple voltage. This is the same as in the previous embodiment.

FIG. 5 is also a diagram showing the main parts of another embodiment of the present invention, where -E+ is a DC power supply, R ₁₊ is a first input resistor,
R ₃₊ is the second input resistance, and other symbols are the same as in FIG.

Also in this embodiment, if the input voltage to be measured to the input terminal T _IN (the same input voltage to be measured as in the previous embodiment) is higher than the output voltage of the output terminal T _OUT+ , the output voltage of the voltage comparator COM ₊ is − V _C1
Therefore, the output voltage of DC power supply −E+ is −E _R
Then, the magnitude of the input negative current I _N to the current integrator is I _N = I ₂ + I ₃ = V _C1 /R ₁ +E _R /R ₃ (ampere) ...(26), and the input terminal T _IN If the measured input voltage to the output terminal T _OUT+ is lower than the output voltage at the output terminal T OUT+, the output voltage of the voltage comparator COM ₊ will be +V _C2 , and the input positive current I _P to the current integrator will be I _P = I ₁ − _{I 3} = V _C2 /R ₁ −E _R /R ₃ (ampere) ...(27).

However, the relationship between the magnitudes of the currents I ₁ and I ₃ is set as I ₁ ≧I ₃ .

Also in this embodiment, between the negative current I ₂ +I ₃ and positive current I ₁ -I ₃ flowing into the current integrator and the ripple noise separation ratio Ψ, (I ₂ +I ₃ )Ψ/100-Ψ= I ₁ − _{I 3} ...(28) R ₁₊ , R ₃₊ , E _R , V _C1
When the magnitudes of and V _C2 are determined, as in the case of the previous embodiment, when focusing on one cycle T _O of the switching fundamental wave, the current integrator when the input negative current I ₂ + I ₃ continues for T ₁ hour converges to an integral output voltage V _R1 such that the sum with the integral output voltage of V R1 is zero.

Therefore, (I ₂ + I ₃ )T ₁ = (I ₁ −I ₃ )T ₂ ...(29) From equations (28) and (29), Ψ=T ₁ /T ₁ +T ₂ ×100( %) ...(30) Since T ₁ = T _N T ₁ + T ₂ = T _O , equation (30) becomes Ψ = T _N /T _O ×100 (%) ... (31), and the above The positive side potential V _R1 of the ripple voltage that matches the ripple-noise separation ratio Ψ defined as
is required.

From equations (29) and (30), Ψ=I ₁ −I ₃ /I ₁ +I ₂ ×100(%) ...(32) is obtained, and changing I ₃ (=E _R /R ₃ ) According to
The ripple-noise separation ratio Ψ can be changed.

This embodiment also has the same configuration as the ripple voltage positive side potential measuring circuit shown in FIG. 5 (however, the polarity of the DC power supply -E+ is opposite to that shown in FIG. The input resistor is configured to supply a positive current to the second current integrator through the third voltage comparator, and is inserted between the output terminal of the second voltage comparator and the input terminal of the second current integrator. As in the previous embodiment, a negative side potential measuring circuit is provided for the input resistance (which becomes the input resistance), and the ripple voltage is obtained by adding the measured values of both measuring circuits to a subtraction circuit.

In any of _the above embodiments, _the voltage comparator
The non-inverting input of the operational amplifier that makes up the current integrator is configured to reverse the direction of the input current to the current integrator depending on whether the output voltages of COM ₊ and COM _- are positive or negative. The potential of the terminal may be set to any appropriate potential, and the direction of the input voltage to the current integrator may be reversed depending on whether the output voltage of the voltage comparator is positive or negative with respect to this potential.
Further, the current integrator is configured to be a non-inverting input type current integrator, and the input voltage to be measured is applied to the non-inverting input terminal of the current comparator, and the integrated output voltage of the current integrator is applied to the inverting input terminal. The present invention can also be practiced.

As is clear from the above description, the device of the present invention has a simple configuration and accurately calculates the peak-to-peak voltage of the voltage excluding the spike-like switching noise voltage included in the output voltage of the switching DC power supply as the ripple voltage. It can be measured accurately and with good reproducibility, and its effects are enormous.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, FIGS. 2 and 3 are waveform diagrams for explaining its operation, and FIGS. 4 and 5 are diagrams showing another embodiment of the present invention. Figures 6 and 7 are waveform diagrams for explaining the ripple voltage included in the output voltage of the switching DC power supply; Figure 8 is for explaining an example of a conventional ripple voltage measurement method. In the waveform diagram for T _IN
... Input terminals, COM ₊ and COM _- ... Voltage comparator, OPA ₊ and OPA _- ... Operational amplifier, D ₁₊ ,
D ₂₊ , D _1- and D _2- ...Reverse current blocking diode,
R ₁₊ , R ₂₊ , R _1- , R _2- and R ₃₊ ...input resistance, C ₊
and C _- ...integrating capacitor, T _OUT+ , T _OUT- and
T _OUT ...Output terminal, SUB...Subtraction circuit, +RV and -RV...Potential measurement circuit, E+ and -E+...
It is a DC power supply.

Claims (1)

[Claims] 1. A first current integrator that is composed of an operational amplifier and integrates the input current, and a spike-like switch included in the output voltage of the DC stabilized power supply by switching control and that has spike-like switches at positive and negative peak positions. The input voltage to be measured, which is a ripple voltage superimposed on a noise voltage, is compared with the integrated output voltage of the first current integrator, and the input voltage to be measured is compared with the integrated output voltage of the first current integrator. a first voltage comparator that outputs a negative voltage when the voltage is high and outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the first current integrator; One end of a parallel circuit including a series circuit of a diode and a first input resistor, and a series circuit of a second reverse current blocking diode and a second input resistor having a polarity opposite to that of the first reverse current blocking diode is connected to the first terminal.
is connected to an output terminal of a voltage comparator, the other end of which is connected to an input terminal of the first current integrator, and when the output voltage of the first voltage comparator is a positive voltage, a positive voltage is connected to the first current integrator. When the output voltage of the first voltage comparator is a negative voltage, the negative current is caused to flow into the first current integrator, and the magnitude of the positive current is equal to the magnitude of the negative current Ψ /(100−Ψ) times [Ψ=(T _N /T _O )×100,
T _N is the time width of the spike-like switching noise voltage, and T _O is the period of the ripple voltage. and the second integrating the input current
a current integrator; the input voltage to be measured is compared with the integrated output voltage of the second current integrator, and if the input voltage to be measured is higher than the integrated output voltage of the second current integrator; a second voltage comparator that outputs a negative voltage and outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the second current integrator; One end of a parallel circuit of a series circuit of input resistors No. 3 and a series circuit of a fourth input resistor and a fourth backflow blocking diode having a polarity opposite to that of the third backflow blocking diode is connected to the second end.
and the other end is connected to the output terminal of the voltage comparator, and the other end is connected to the input terminal of the second current integrator, and when the output voltage of the second voltage comparator is a positive voltage, a positive voltage is connected to the second current integrator. When the output voltage of the second voltage comparator is a negative voltage, the negative current is caused to flow into the second current integrator, and the magnitude of the negative current is equal to the magnitude of the positive current Ψ /(100−Ψ) times the output voltage of the ripple voltage and a second current control circuit formed so that the output voltage of the first current integrator and the second current control circuit are
a subtraction circuit to which an output voltage of a current integrator is added and obtains a peak-to-peak voltage of a voltage excluding spike-like switching noise voltage in the input voltage to be measured; and an output voltage extraction circuit of the subtraction circuit; A ripple voltage measuring device characterized by comprising: 2. The first current integrator, which is composed of an operational amplifier, integrates the input current, and the output voltage of the DC stabilized power supply is controlled by switching, and spike-like switching noise voltages are superimposed on the positive and negative peak positions. The input voltage to be measured consisting of a ripple voltage is compared with the integrated output voltage of the first current integrator, and if the input voltage to be measured is higher than the integrated output voltage of the first current integrator, a negative voltage is detected. a first voltage comparator that outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the first current integrator; and a first voltage comparator connected to the output terminal of the first voltage comparator. a first reverse current blocking diode which is cut off when the output voltage of the first voltage comparator is a positive voltage; and a first reverse current blocking diode inserted between the first reverse current blocking diode and the input terminal of the first current integrator. a first input resistor; and a DC power source that supplies a positive current to the input terminal of the first current integrator via a second input resistor, and when the first reverse blocking diode is cut off, the The magnitude of the positive current flowing into the current integrator 1 is
When the output voltage of the first voltage comparator is a negative voltage, Ψ/(100−Ψ) times the magnitude of the negative current flowing into the first current integrator [Ψ=(T _N /T _O )×
100, T _N is the time width of the spike-like switching noise voltage, T _O is the period of the ripple voltage]; The second circuit consists of an amplifier and integrates the input current.
a current integrator; the input voltage to be measured is compared with the integrated output voltage of the second current integrator, and if the input voltage to be measured is higher than the integrated output voltage of the second current integrator; a second voltage comparator that outputs a negative voltage and outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the second current integrator; and an output of the second voltage comparator. a second backflow blocking diode connected to the terminal and cut off when the output voltage of the second voltage comparator is a negative voltage; and between this second backflow blocking diode and the input terminal of the second current integrator. a third input resistor inserted, and a DC power supply supplying a negative current to the input terminal of the second current integrator through a fourth input resistor, and blocking the second reverse current blocking diode. When the magnitude of the negative current flowing into the second current integrator is
a second current control formed so that the magnitude of the positive current flowing into the second current integrator is Ψ/(100−Ψ) times when the output voltage of the second voltage comparator is a positive voltage; a circuit for measuring the negative side potential of ripple voltage, the output voltage of the first current integrator and the second current integrator;
a subtraction circuit to which an output voltage of a current integrator is added and obtains a peak-to-peak voltage of a voltage excluding spike-like switching noise voltage in the input voltage to be measured; and an output voltage extraction circuit of the subtraction circuit; A ripple voltage measuring device characterized by comprising: 3 The first current integrator, which consists of an operational amplifier, integrates the input current, and the output voltage of the DC stabilized power supply that is controlled by switching, and spike-like switching noise voltages are superimposed on the positive and negative peak positions. The input voltage to be measured consisting of a ripple voltage is compared with the integrated output voltage of the first current integrator, and if the input voltage to be measured is higher than the integrated output voltage of the first current integrator, a negative voltage is detected. a first voltage comparator that outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the first current integrator; A first current integrator inserted between the input terminals of the first current integrator.
and a DC power source that supplies a negative current to the input terminal of the first current integrator via a second input resistor, and when the output voltage of the first voltage comparator is a positive voltage. The magnitude of the positive current flowing into the first current integrator is equal to the magnitude Ψ of the negative current flowing into the first current integrator when the output voltage of the first voltage comparator is a negative voltage. /(100−Ψ) times [Ψ=(T _N /T _O )×100, T _N is the time width of the spike-like switching noise voltage, T _O is the period of the ripple voltage]. a ripple voltage positive potential measuring circuit consisting of a current control circuit; and a second circuit consisting of an operational amplifier and integrating the input current.
a current integrator; the input voltage to be measured is compared with the integrated output voltage of the second current integrator, and if the input voltage to be measured is higher than the integrated output voltage of the second current integrator; a second voltage comparator that outputs a negative voltage and outputs a positive voltage when the input voltage to be measured is lower than the integrated output voltage of the second current integrator; and an output of the second voltage comparator. a third current integrator inserted between the terminal and the input terminal of the second current integrator.
and a DC power source that supplies a positive current to the input terminal of the second current integrator via a fourth input resistor, and when the output voltage of the second voltage comparator is a negative voltage. The magnitude of the negative current flowing into the second current integrator is equal to the magnitude Ψ of the positive current flowing into the second current integrator when the output voltage of the second voltage comparator is a positive voltage. /(100-Ψ) times the output voltage of the ripple voltage and a second current control circuit formed such that the output voltage of the first current integrator and the second current control circuit are
a subtraction circuit to which an output voltage of a current integrator is added and obtains a peak-to-peak voltage of a voltage excluding spike-like switching noise voltage in the input voltage to be measured; and an output voltage extraction circuit of the subtraction circuit. A ripple voltage measuring device characterized by comprising: