JPH06273451A - Ripple voltage-measuring apparatus - Google Patents

Abstract

PURPOSE:To realize an apparatus where a ripple voltage contained in the output of a DC stabilized power supply device according to a switching control system is measured precisely and with good reproducibility. CONSTITUTION:A voltage, to be measured, in which a DC portion has been removed from an output from a DC stabilized power supply device according to a switching control system is applied to a voltage comparator COM+, and an output according to its compared result is integrated. A ripple-voltage positive-side-voltage measuring circuit RV+ which is constituted in such a way that the integrated voltage and an output voltage from a DC voltage source are applied differentially to an operational amplifier OPA+ and that its operated output is fed back to the voltage comparator COM+ and compared with the voltage to be measured, is provided, and a ripple-voltage negative-side-voltage measuring circuit RV- which is constituted in the same manner as the measuring circuit, is provided. The measuring apparatus is constituted in such a way that an output from the operational amplifier OPA+ in the ripple-voltage positive-side-voltage measuring circuit and an output from the operational amplifier OPA- in the ripple-voltage negative-side-voltage measuring circuit RV- are applied to an operation circuit SUB, and that a ripple voltage is found on the basis of its output.

Description

Detailed Description of the Invention

[0001]

[Industrial application] A stabilized DC power supply device (hereinafter abbreviated as switching DC power supply) by a switching control system that is widely used as a DC power supply for various electronic devices.
Is a switching element driven by the oscillating output of a pulse oscillator of several tens of kHz to several hundreds of kHz installed in the power supply, and interrupts a large current, converting this intermittent current at a high speed into a required voltage through a transformer. After that, since it is configured to rectify and obtain a required DC voltage, the DC output voltage has a spike-shaped ripple noise voltage that contains a lot of high-frequency components, and a high-frequency ripple voltage (hereinafter, Abbreviated as ripple voltage) and
A low frequency ripple voltage having a fundamental frequency of 50 Hz or 60 Hz of the commercial power supply frequency or twice the frequency thereof will be superimposed. Therefore, the amount of spike-shaped ripple noise voltage and ripple voltage included in the DC output voltage is one of the important indicators of the performance of the switching DC power supply.
The present invention relates to an apparatus for measuring this ripple voltage separately from spike-like ripple noise voltage.

[0002]

2. Description of the Related Art As a method for measuring the ripple voltage included in the output voltage of a switching DC power supply by separating it from the spike-shaped ripple noise voltage, conventionally, for example, the waveform drawn on the image plane of a cathode ray tube oscilloscope is visually observed. The method of reading the content of the ripple voltage is used.

[0003]

In the method of reading the content of the ripple voltage by visually observing the waveform drawn on the image plane of the cathode ray tube oscilloscope, a reproducible measurement can be performed due to uncertainty due to visual error. Not only is it impossible, but the following drawbacks cannot be avoided. That is, FIG. 20 (horizontal axis represents time T, vertical axis represents voltage V) shows a ripple voltage V _R and a spike-shaped ripple noise voltage V _N having a switching frequency included in the output voltage of the switching DC power supply as a fundamental wave. In the waveform diagram, the peak voltage of the ripple voltage V _R is appropriate to be seen as the intersection A on the extension line of the positive and negative slope portions of the waveform indicating the ripple voltage, but in the vicinity of this intersection A The spike-shaped ripple noise voltage V _N is superimposed on the
It is impossible to tell the dots. As a simple method to remove spike-shaped ripple noise voltage, a method of removing high frequency components by a low pass filter has been used conventionally.
Not only is it impossible to remove all spike-like ripple noise voltage with this method, but the ripple voltage component waveform with the switching frequency as the fundamental wave changes according to the characteristics of the low-pass filter, and as a result, However, there is a drawback that the peak-to-peak voltage of the ripple voltage changes. As shown in FIG. 21 (the horizontal axis and the vertical axis are the same as those in FIG. 20) by slowing down the sweep speed of the time axis in the cathode ray tube oscilloscope, when the waveform on the image plane is compressed in the time axis direction, the electrons in the cathode ray tube are reduced. The brightness of the ripple voltage component whose fundamental wave is the switching frequency with a slow speed change of the beam is high, and the brightness of the spike-like ripple noise voltage with a fast speed change of the electron beam is low. A method of reading the amplitude and measuring the ripple voltage is also used, but measurement with high reproducibility is impossible due to visual error.

[0004]

According to the present invention, a voltage to be measured is applied to one of the input terminals of a first voltage comparator, and an output voltage of the first voltage comparator is applied to a first voltage comparator.
Of the first integrating circuit and the integrated output voltage of the first integrating circuit and the output voltage of the first variable DC voltage source are differentially applied, and are applied to one of the input terminals of the first voltage comparator. A first operational amplifier that applies an operation output voltage having the same polarity as the measured voltage to the other input terminal of the first voltage comparator, and a second voltage comparison in which the measured voltage is applied to one of the input terminals. A second integrator circuit to which the output voltage of the second voltage comparator is applied, the integrated output voltage of the second integrator circuit and the output voltage of the second variable DC voltage source are differentially applied, A second operational amplifier that applies an operational output voltage having the same polarity as the voltage under measurement applied to one of the input terminals of the second voltage comparator to the other input terminal of the second voltage comparator; And a subtraction circuit to which each operational output voltage of the second operational amplifier is added, By implementing the ripple voltage measuring device provided with a subtraction output extraction circuit of the subtraction circuit, it is intended to Nozoko conventional drawbacks.

[0005]

FIG. 1 (horizontal axis represents time T, vertical axis represents voltage V) is a waveform diagram showing an example of a noise component waveform included in the DC output voltage of the switching DC power supply, that is, in the output voltage of the switching DC power supply. In the waveform diagram of the voltage that cuts off the DC component and the low frequency ripple voltage component, in the switching DC power supply, the rectangular wave voltage intermittent at the switching frequency of several tens of kHz to several hundreds of kHz has the AC component suppressed by the smoothing filter and integrated. There is a triangular ripple-shaped ripple voltage component that is generated, and a spike-shaped ripple noise voltage component that is generated when the current is interrupted due to switching is superimposed near the apex of the ripple voltage waveform. In Figure 1, the sum of the voltages V _{R +} and V _R- is the ripple voltage, the voltage
The sum of V _{RN +} and V _RN- is the spike-shaped ripple noise voltage. In the present invention, the switching period is T _O , the time width of the spike-like ripple noise voltage is T _N, and T _N / T _O = ψ (1) is defined as the ripple / noise separation ratio, Voltage V _{R +} and
It is intended to realize a device for determining the ripple voltage corresponding to the sum of V _R-. When the value of the ripple / noise separation ratio ψ in the equation (1) is changed, the voltages V _{R +} and V _R- also change to ψ.
The ripple voltage as a function of the ripple / noise separation ratio ψ is calculated in accordance with the change of the value of. Hereinafter, for convenience of quantitative analysis, an ideal triangular wave voltage is assumed as the ripple voltage for description. FIG. 2 is a diagram showing an embodiment of the present invention, in which T _IN is a common input terminal, COM ₊ is a first voltage comparator, COM ₋ is a second voltage comparator, and R ₊ and C ₊ are first voltage comparators. Resistor and capacitor forming an integrating circuit INT _{+ of} 1, R ₋
And C ₋ are resistors and capacitors forming a second integration circuit INT ₋ , BAT ₊ is a first variable DC voltage source, BAT ₋ is a second variable DC voltage source, OPA ₊ is a first operational amplifier, OPA _-Is the second
Operational amplifier, T _{O +} and T _O- are output terminals, SUB is a subtraction circuit, T _OUT is an output terminal, RV + is a ripple voltage positive side voltage measuring circuit, and RV- is a ripple voltage negative side voltage measuring circuit.
Of the circuit components that make up both measurement circuits RV + and RV-, those components that have the same sign but differ only in the suffixes + and − have the same characteristics, resistance values, capacitances, etc., or those that are as close as possible to each other.

[0006] When the voltage applied to the non-inverting input terminal of the voltage comparator COM ₊ in the positive-side voltage measurement circuit RV + ripple voltage is higher than the voltage applied to the inverting input terminal, an output voltage V2 of the voltage comparator COM ₊ becomes V _C, when the voltage applied to the non-inverting input terminal is lower than the voltage applied to the inverting input terminal is reversed, a voltage comparator COM ₊ as the output voltage V2 of the voltage comparator COM ₊ becomes 0 Forming and operational amplifier OPA ₊
Negative feedback (a negative feedback circuit is not shown) is applied so that the voltage amplification degree becomes β. Further, the time constant τ of the integrating circuit INT _{+ including} the resistor R ₊ and the capacitor C ₊ is formed to be sufficiently larger than the switching cycle T _O.
When the resistance value of the resistor R ₊ is represented by R and the capacity of the capacitor C ₊ is represented by C, τ = CR >> T _O ... (2) The variable DC voltage source BAT ₊ is separated into ripple and noise by the output positive voltage. It is a DC voltage source for setting the ratio ψ. In the negative side voltage measurement circuit RV- of the ripple voltage,
Voltage comparator COM _- inverted if the voltage applied to the input terminal is lower than the voltage applied to the non-inverting input terminal, the voltage comparator COM _- voltage of the output voltage becomes V _C, applied to the inverting input terminal to the opposite If There higher than the voltage applied to the non-inverting input terminal, the voltage comparator COM _- the output voltage is zero so that the voltage comparator COM _- to form, operational amplifier OPA _- the positive side voltage measurement of the ripple voltage like the operational amplifier OPA ₊ in the circuit RV +, the voltage negative feedback as amplification degree is beta (negative feedback circuit is not shown) are multiplied by. Resistor R _- and capacitor C _- more composed integrator circuit INT _- the time constant tau of, similarly to the time constant integrator circuit INT ₊ of the positive-side voltage measurement circuit RV + ripple voltage tau, sufficiently large compared to the switching period T _O It is formed so that The variable DC voltage source BAT _- is a DC power source for setting the ripple / noise separation ratio ψ by its output positive voltage, like the variable DC voltage source BAT ₊ in the ripple voltage positive side voltage measuring circuit RV +.

FIG. 3 is a waveform diagram for explaining the operation of the measuring apparatus of the present invention. FIG. 3 (a) is a low frequency ripple voltage whose fundamental wave is the DC component in the output voltage of the switching DC power supply and the commercial power supply frequency. The measured voltage V1 excluding the components is shown, and the horizontal axis and the vertical axis are the same as those in FIG. Figure 3 (b)
Indicates the output voltage V2 of the voltage comparator COM ₊ , the horizontal axis represents time T, and the vertical axis represents voltage V2. FIG. 3C shows an integration circuit INT ₊
, The horizontal axis is time T, and the vertical axis is the integrated voltage V3. For convenience of quantitative analysis, the ripple voltage at the measured voltage V1 shown in FIG. 3 (a) is an ideal triangular waveform, similar to the waveform shown in FIG.
At the same time that the voltage applied to the non-inverting input terminal of M ₊ is higher than the voltage applied to the inverting input terminal, the voltage comparator COM ₊
Rising as shown in V _C of the output voltage FIG. 3 (b), the same time when the voltage applied to the non-inverting input terminal of the voltage comparator COM ₊ becomes lower than the voltage applied to the inverting input terminal, the voltage comparator COM ₊ The output voltage V5 of the operational amplifier OPA ₊ applied to the non-inverting input terminal of the voltage comparator COM ₊ is shown in FIG. 3A.
Of the spike-shaped ripple noise voltage waveform included in the measured voltage V1, that is, at the intersections B and C of the curve indicating the ripple voltage waveform and the curve indicating the spike-shaped ripple noise voltage waveform. The state is shown. Under the conditions assumed above, the measured voltage
When V1 is applied to the non-inverting input terminal of the voltage comparator COM ₊ via the terminal T _IN , the voltage under test is measured on the positive side of the voltage under test V1.
The output voltage V2 of the voltage comparator COM ₊ rises at the same time as V1 becomes higher than the voltage V5, and the output voltage of the voltage comparator COM ₊ falls at the same time as the measured voltage V1 becomes lower than the voltage V5. In the output voltage V _C of the voltage comparator COM ₊ integrator circuit INT _+, 3
It is integrated as shown in (c). The integrated output voltage of the integrator INT ₊ is applied to the non-inverting input terminal, and the output positive voltage of the variable DC voltage source BAT ₊ is applied to the inverting input terminal.The output voltage V5 of the operational amplifier OPA ₊ is applied to the voltage comparator COM ₊ . It is applied to the inverting input terminal and compared with the measured voltage V1 applied to the non-inverting input terminal. As shown in FIG. 3A, since the triangular waveform of the ripple voltage at the measured voltage V1 and the triangular waveform having the time width T _N of the spike-like ripple noise voltage as the base are similar to each other, the following equation holds. To do. T _O / 2: T _N = V _P : (V _P −V5) (3) where V _P is the peak voltage of the measured voltage V1. From equations (1) and _{(3), V5 = V P} (1-2ψ) ···· (4) as described above, the measured voltage V1 applied to the non-inverting input terminal of the voltage comparator COM ₊ is Voltage V5 applied to the inverting input terminal
At the same time as it becomes higher, the output voltage of the voltage comparator COM ₊ rises to the voltage V _C , and the measured voltage V1 applied to the non-inverting input terminal becomes lower than the voltage V5 applied to the inverting input terminal, and at the same time the output voltage rises. Since it is assumed that the value of the voltage V5 is downward and the value of the voltage V5 is coincident with the points B and C in FIG. 3 (a), it is clear from FIG. 3 (a) and FIG. 3 (b) that the voltage comparison Output of COM ₊ Square wave voltage V _C
The pulse width of the rectangular wave voltage V _C is equal to ψ because the time width of T is equal to T _N and the period is equal to T _O. Therefore, when the output voltage V5 of the operational amplifier OPA ₊ after the elapse of the time constant τ of the integrating circuit INT ₊ , the output voltage of the variable DC voltage source BAT ₊ is V4, V5 = (V _C ψ−V4) β ··· (5) From equations (4) and (5), (V _C · ψ-V4) · β = V _P (1-2 ψ) ψ · β · V _C −β · V4 = V _P − 2ψ · V _P ψ (β · V _C + 2V _P ) = V _P + β · V4 ψ = (β · V4 + V _P ) / (β · V _C + 2V _P ) ··· (6) Formula (4) and formula From (6), V5 = V _P {1-2 (β ・ V4 + V _P ) / (β ・ V _C + 2V _P )} ... (7)

An actual method for measuring the ripple voltage by the measuring apparatus of the present invention having the above-mentioned structure will be described below. The ripple / noise separation ratio ψ varies depending on the configuration of the switching DC power supply, etc.
Even if it becomes large, it is almost 10% or less. The ripple / noise separation ratio ψ is set by the voltage of the DC voltage source BAT ₊ as described above.
Although it is performed by appropriately setting V4, since the ripple / noise separation ratio ψ is a function of the unknown voltage V _P as shown in the equation (6), it is actually obtained from the equation (6). The problem is difficult. Therefore, although it is approximate, the setting is performed by the following method. That is, assuming that the peak voltage V _{P of the} measured voltage V1 is extremely small, the numerator on the right side of the equation (6) is β · V4 >> V _P , and the denominator on the right side is β · V.
_{Since C} >> 2V _P , ψ≈V4 / V _C V4 / V _C is expressed as ψ _A = V4 / V _C in the sense of an approximate ripple / noise separation ratio. Now, when the output voltage V _C of the voltage comparator COM ₊ is configured to be 5 V, the variable DC voltage source
Setting BAT ₊ voltage V4 to 50 mV results in an approximate ripple
The noise separation ratio ψ _A becomes 1%, and when the voltage V4 of the variable DC voltage source BAT ₊ is set to 500 mV, the approximate ripple noise separation ratio ψ _A becomes 10%.

Table 1 shows that the output voltage V _C of the voltage comparator COM ₊ in the measuring apparatus of the present invention is 5 V, and the amplification factor β of the operational amplifier OPA ₊ is β.
Is set to 100, and the peak voltage V _P of the measured voltage V1 excluding the DC component and low-frequency ripple voltage component in the output voltage of the switching DC power supply is 1.0 V, 10 V
When adjusting to 0 mV and 10 mV and inputting to the common terminal T _IN , setting the voltage V4 of the variable DC voltage source BAT ₊ to 50 mV and 500 mV and setting the approximate ripple noise separation ratio ψ _A to 1% and 10% shows an example of measurement results of the present measuring apparatus in, in Table 1, V5 _C is the measured voltage V1 pin - operational amplifier OPA determined by calculation from the click voltage V _P and the approximate separation ratio [psi _{a +} Output voltage, V5 is the measured value of the output voltage of the operational amplifier OPA ₊ , and ψ is the peak voltage V _{P of the} measured voltage V1.
And the ripple / noise separation ratio obtained by calculation from the actually measured value V5 of the output voltage of the operational amplifier OPA ₊ .

As is apparent from Table 1, the measured values of the peak voltage V _{P of the} measured voltage V1 and the output voltage of the operational amplifier OPA _+.
The difference between the ripple / noise separation ratio ψ calculated from V5 and the approximate separation ratio ψ _A is extremely small. Therefore, when the actual ripple / noise separation ratio ψ is known, by setting this known separation ratio, it is possible to obtain an accurate positive-side voltage of the ripple voltage to the extent that there is no practical problem. Also, when measuring the ripple voltage at an arbitrary ripple / noise separation ratio ψ, by setting this arbitrary separation ratio, the positive side voltage of the ripple voltage at this arbitrary separation ratio will be practically acceptable. Can be obtained with the accuracy of. When the ripple voltage is calculated when the actual ripple / noise separation ratio ψ is unknown, if the set approximate separation ratio ψ _A is smaller than the actual separation ratio ψ, a spike-shaped ripple noise voltage component is included. When the measurement result is obtained and the set approximate separation ratio ψ _A is larger than the actual separation ratio ψ, a value lower than the actual positive voltage of the ripple voltage is obtained.

In order to eliminate such measurement error, an approximate separation ratio ψ _A, which is considered to be appropriately larger than the expected actual separation ratio ψ, is set, and the output voltage of the operational amplifier OPA ₊ is set.
When V5 is actually measured, and then the output voltage V5 of the operational amplifier OPA ₊ is repeatedly measured by resetting the approximate separation ratio ψ _A to a value that is appropriately smaller than the previous time, the voltage V5 becomes the approximate separation ratio. It increases corresponding to almost twice the rate of change of ψ _A , that is, when ψ in equation (4) is replaced by ψ _A ,
In the region where the voltage V5 increases while maintaining the relationship of the expression (4), the voltage V5 does not include the spike-shaped ripple noise voltage component, but the increase rate of the voltage V5 is determined from the relationship of the expression (4). In a large area, the voltage V5 contains a spike-shaped ripple noise voltage component.
Therefore, the value of the voltage V5 corresponding to the set value of the approximate separation ratio [psi _A made slightly smaller than the set value of the approximate separation ratio [psi _A corresponding to the change points of the rate of increase of voltage V5, positive ripple voltage The value is extremely close to or matches the side voltage. Although measurement of the negative voltage is performed in the ripple voltage in the same manner as the positive side voltage measurement circuit RV ripple voltage + even negative side voltage measurement circuit of the ripple voltage RV-, variable DC voltage source BAT _- the setting of the output voltage In conjunction with the setting of the output voltage of the variable DC voltage source BAT _{+ in} the positive side voltage measurement circuit RV +, set the voltage settings of both voltage sources to be equal to each other, and the voltage measurement in the negative side voltage measurement circuit RV- Positive voltage measurement circuit RV +
Simultaneously with the voltage measurement at. Variable DC voltage source BAT ₊ and BAT _- To set equal to each other voltage in conjunction with the output voltage of, for example, the output voltage of the common DC voltage source Potenshiome - in addition to data, the divided voltage positive side voltage measurement circuit RV with added to the operational amplifier OPA ₊ inverting input terminal in +, operational amplifier OP in the negative-side voltage measurement circuit RV-
A _- is formed so as to apply the non-inverting input terminal. As mentioned above, the ripple voltage positive and negative voltage measurement circuit RV +
And in RV-, variable DC voltage source BAT ₊ and BAT _- When measuring in parallel while varying the output voltage changing the set value of the approximate separation ratio [psi _A, operational amplifier OPA ₊ and OP
A _- for because each output voltage is applied to the subtractor circuit SUB through an output terminal T _{O +} and T _O-, operational amplifiers OPA ₊ and OPA _-
Approximate separation ratio ψ _A corresponding to the change point of the increase rate of each output voltage is slightly smaller than the set value of the approximate separation ratio ψ _A.
An accurate ripple voltage (V _{R +} + V _R- ) can be obtained from the output voltage of the subtraction circuit SUB after setting _A.

Next, the integrating circuits INT ₊ and IN shown in FIG.
When the time constant τ of T ₋ is examined, the measurement response time is shortened when the time constant τ is small, but the pulsating current voltage is superimposed on each output voltage of the operational amplifiers OPA ₊ and OPA ₋ , and the measurement accuracy is When it deteriorates and the time constant τ becomes large, it takes a long time until the respective outputs of the operational amplifiers OPA ₊ and OPA ₋ are determined. The pulsating voltage, the voltage comparator COM ₊ (or COM _-) because it is output through the output square wave voltage V _C of the integrator circuit INT ₊ (or INT _{- -)} and an operational amplifier OPA ₊ (or OPA) some because, peak of the pulsating voltage - click Taipi - click voltage V _5PP is

[Equation 1]

Table 2 shows that the output voltage V _C of the voltage comparator COM ₊ is 5
V, time constant τ of integrating circuit INT ₊ is 500 ms, operational amplifier OPA ₊
Of the variable DC voltage source
BAT ₊ voltage V4 is 50 mV and 500 mV, and the approximate ripple / noise separation ratio ψ _A is set to 1% and 10%, and the DC component and low frequency ripple voltage in the output voltage of the switching DC power supply with the switching period T _O of 20 μs. The peak voltage V _P of the measured voltage V1 excluding the components is 1.0 V, 100 mV and 10
Ripple voltage when adjusted to mV and input to terminal T _IN
It shows V _5PP and pulsation rate V _5PP / V 5. As is clear from Table 2, the magnitude of the pulsating voltage V _5PP is constant regardless of the peak voltage V _P of the measured voltage V1, and the pulsation rate V _5PP / V5 is the _peak voltage V _P. The lower, the higher. Accordingly, peak of the measured voltages V1 - as ripple factor in the region of low click voltage V _P is equal to or less than the target value, it is necessary to determine the time constant of the integration circuit.

FIG. 4 is a diagram showing another embodiment of the present invention.
In the present embodiment, the first multiplier MLT ₊ provided after the first operational amplifier OPA _+, multiplier output of the operational amplifier OPA ₊
Enter the MLT ₊ input terminals X and Y to activate the multiplier MLT ₊ as the square multiplier, the voltage comparator COM the multiplied output ₊
Together configured to apply the inverting input terminal, a second operational amplifier OPA _- the provided operational amplifier OPA _{- -} second multiplier MLT downstream of the input terminals X and Y of _- output multiplier MLT of input to the multiplier MLT _- is operated as the square multiplier, the multiplication output voltage comparator COM _- other configured to apply the non-inverting input terminal has the same configuration as the previous example. In this embodiment, the measured voltage V1 is applied to the non-inverting input terminal of the voltage comparator COM _+, compared with the multiplier MLT ₊ the output voltage V6 applied to the inverting input terminal of the voltage comparator COM _+, voltage
Output voltage V2 of voltage comparator COM ₊ when V1 is higher than voltage V6
Becomes V _C , the voltage V _C is integrated in the integration circuit INT ₊ ,
With integrated voltage V3 is applied to the operational amplifier OPA _+, operational amplifier OPA ₊ in the variable DC voltage source BAT ₊ output positive voltage and differentially combining applied, the operational amplifier OPA ₊ the output voltage V5 is the multiplier MLT ₊ Is applied to the input terminals X and Y. Multiplier MLT ₊ output voltage V6 after the lapse of the integration circuit INT ₊ time constant τ, as in the case of derivation of equation (5), V6 = {( V C · ψ-V4) · β} 2 · (10) Further, the multiplier MLT ₊ output voltage V6, peak of the measured voltages V1 - relationship click voltage V _P and ripple noise separation ratio ψ is in the same manner as in the derivation of formula (4) _{Te, V6 = V P (1-2ψ)} ···· (11) ripple noise separation ratio ψ of the formula (10) and (11)
Can be calculated from the following equation.

[Equation 2]

Table 3 shows the voltage comparator COM ₊ in this embodiment.
Output voltage V _C of 5 V, operational amplifier OPA ₊ gain β is 100
The voltage V4 of the variable DC voltage source BAT ₊ is set to 50
Approximate ripple noise separation ratio ψ as mV and 500 mV
Set _A to 1% and 10% and adjust the peak voltage V _P of the measured voltage V1 excluding the DC component and low frequency ripple voltage component in the output voltage of the switching DC power supply to 1.0 V, 100 mV and 10 mV. when input to the terminal T _iN Te, of the measured voltages V1 peak - click voltage V _P and the approximate separation ratio ψ multiplier was calculated from _a MLT ₊ output voltage V6 _C, the multiplier MLT ₊ the output voltage 5 shows the ripple / noise separation ratio ψ calculated from the measured value V6 of the measured voltage V1, the peak voltage V _{P of the} measured voltage V1 and the measured value V6 of the output voltage of the multiplier MLT ₊ .

[0016] Next, consider the ripple voltage contained in multiplier MLT ₊ output voltage V6, the multiplier MLT ₊ input voltage,
That is, the relationship between the output voltage V5 of the operational amplifier OPA ₊ and the output voltage V6 of the multiplier MLT ₊ is

[Equation 3] The pulsating current voltage V _6PP included in the output voltage V ₆ of the multiplier MLT ₊ is given by the following equation (9) and equation (13):

[Equation 4] Table 4 shows the output voltage V _C of the voltage comparator COM ₊ in this embodiment.
Is 5 V, time constant τ of integrating circuit INT ₊ is 500 ms, operational amplifier
It is configured so that the amplification degree β of OPA ₊ is 100, the voltage V4 of the variable DC voltage source BAT ₊ is 50 mV and 500 mV, and the approximate ripple / noise separation ratio ψ _A is set to 1% and 10%, and the switching cycle is set. Adjust the peak voltage V _P of the measured voltage V1 excluding the DC component and low frequency ripple voltage component in the output voltage of the switching DC power supply with T _o of 20 μs to 1.0 V, 100 mV and 10 mV, and input to the terminal T _IN . It shows the pulsating current voltage V _6PP and the pulsation rate V _6PP / V ₆ in the case of _performing . Table 4 As is clear from Table 4, in this embodiment, the pulsation rate when the peak voltage V _{P of the} measured voltage V1 is low is improved in comparison with the previous embodiment. Also in this embodiment, the same measurement as the above-mentioned measurement in the positive side voltage measurement circuit RV + of the ripple voltage is performed in the negative side voltage measurement circuit RV-, and the output voltages V _{R +} and V _R- of both circuits are introduced into the subtraction circuit SUB. Then, the combined value of both voltages is obtained as in the previous embodiment.

FIG. 5 is also a diagram showing another embodiment of the present invention. In this embodiment, the multiplier MLT in the previous embodiment is used.
_{+ Represents} the first non-linear circuit forming operational amplifier OPA ₁₊ , the negative feedback resistor R _1+, and the first non-linear circuit forming diode D _+.
Replaced by a non-linear circuit further comprising, a multiplier MLT _- a second non-linear circuit for forming an operational amplifier OPA _1-, negative feedback resistor R _1-and second non-linear circuit for forming a diode - de D _- consisting more It is replaced with a non-linear circuit, and the integrated voltage V3 of the first integrator circuit INT ₊ is applied to the inverting input terminal of the first operational amplifier OPA ₊ as the first
Output of the variable DC voltage source BAT ₊ of the operational amplifier OPA ₊
The non-inverting input terminal of applied respectively, the second integration circuit INT _- to the non-inverting input terminal of the second variable DC voltage source BAT _{- -} integrated voltage of the second operational amplifier OPA is output positive voltage operational amplifier OPA _- to the inverting input terminal of the addition constituted as applied respectively the same configuration as the previous embodiment. Multiplier MLT ₊ and MLT in previous examples _- is operated as squarer, at which input-output characteristic nonlinear type, but is obtained by utilizing the fact that the differential coefficient is positive, in this embodiment diodes as the non-linear element - de D ₊ and D _- used, in which current characteristic with respect to the forward voltage using that exhibit exponential characteristics, operational amplifier OPA ₁₊ (or OPA _1-)
The output voltage V7 of the diode - de D ₊ (or D _-) is proportional to the current flowing in and diodes - de D ₊ (or D _-) of the input voltage
It changes exponentially with respect to V61. Operational amplifier OPA ₁₊
(Or OPA _1-) the output voltage V7 of the polarity is reversed with respect to the input voltage, the operational amplifier OPA ₊ provided at the preceding stage (or OPA _-) is reversed relative to the previous embodiments the polarities of the input terminals of the The ripple voltage measuring circuit is configured to operate normally. Other configurations and operations are similar to those of the previous embodiment.

FIG. 6 is a diagram showing another embodiment of the present invention.
Non-linear circuit forming diode D ₊ and in the previous embodiment
When a silicon diode is used as D ₋ , almost no current flows in the region where the forward voltage is from 0 V to about 0.5 V, and it has a characteristic that the current flows only when it exceeds about 0.5 V. In order to operate as a diode when the forward voltage is near 0 V, the first operational amplifier is provided.
OPA ₊ a first non-linear circuit for forming diodes - during de D _+, diode - de D ₊ series with a first forward bias voltage for forming a DC voltage source BAT ₁₊ insertion connection to diode - The second operational amplifier OP is configured so as to apply a forward voltage to the gate D _+.
A _- a second non-linear circuit for forming diodes - during, diode - _- de D de D _- series with a second forward bias voltage for forming a DC voltage source BAT _1-insertion connection to diode - de D _- to which was configured to provide a forward voltage, the other code, the configuration and operation is similar to the previous embodiment.

Table 5 shows the voltage comparator COM ₊ in this embodiment.
Output voltage V _C of 5 V, the operational amplifier OPA _{+ has} an amplification degree β of 10, and the output voltage V1 of the switching DC power supply excluding the DC component and low frequency ripple voltage component is measured. -Adjust the voltage V _P to 1.0 V, 100 mV and 10 mV and input it to the common terminal T _IN , and set the voltage V4 of the variable DC voltage source BAT ₊ to 50 mV and 500 mV to obtain an approximate ripple noise separation ratio ψ _A. An example of the measurement results when set to 1% and 10% is shown. In Table 5, V7 _C is calculated from the peak voltage V _{P of the} measured voltage V1 and the approximate separation ratio ψ _A. the output voltage of the operational amplifier OPA _1+, V7 are actually measured value of the output voltage of the operational amplifier OPA _1+, [psi
Is the peak voltage V _{P of the} measured voltage V1 and the operational amplifier OPA.
_{This is} the ripple / noise separation ratio obtained by calculation from the measured value V7 of the ₁₊ output voltage.

In this embodiment, the output voltage V _C of the voltage comparator COM ₊ is 5 V, the time constant τ of the integrating circuit INT ₊ is 500 ms, and the amplification degree β of the operational amplifier OPA ₊ is 10 and
A silicon diode whose model number is 1S1588 is used as the diode D ₊ , and a 1 kΩ resistor is used as the negative feedback resistor R ₁₊ .
When the voltage V4 of the variable DC voltage source BAT ₊ is set to 50 mV and 500 mV, the approximate ripple noise separation ratio ψ _A is set to 1% and 10%, and the DC component in the output voltage of the switching DC power supply with the switching period T _O of 20 μs and The peak voltage V _P of the measured voltage V1 excluding the low frequency ripple voltage component is 1.0 V,
Ripple voltage included in the output voltage V7 of the operational amplifier OPA ₁₊ when adjusted to 100 mV and 10 mV and input to the terminal T _IN.
Table 6 shows V _7PP and pulsation rate V _7PP / V ₇ . As is clear from the comparison results of Tables 2 and 6, the magnitude of the pulsating voltage and the pulsation rate in the embodiment shown in FIG. 2 are compared with the magnitude of the pulsating voltage in the embodiment shown in FIG. The pulsation rate is particularly improved when the peak voltage V _P of the measured voltage V1 is low and when the approximate separation ratio ψ _A is large.

Next, FIG. 2 shows the response time and the pulsation rate from the input of the measured voltage V1 to the terminal T _IN until the measured value of the ripple voltage reaches the accuracy within 1% of the final value. Table 7 shows the results of simulated measurement (simulation) using a computer for each positive-side voltage measurement circuit RV + of the embodiment and the embodiment shown in FIG. As the measured voltage V1, the period T _O is 20 μs, the peak voltage V _P is 1.0 V,
Approximate separation ratio ψ using triangular voltage of 100 mV and 10 mV
_A is set to 1% and 10%, the output voltage V _C of the voltage comparator COM ₊ is set to 5 V, and the time constant τ of the integration circuit INT ₊ is set to standardize the worst value of the pulsation rate to 2%. Was selected to be 5.8 seconds in the embodiment shown in FIG. 2 and 0.45 seconds in the embodiment shown in FIG. Table 7 As is clear from Table 7, the measurement response time is relatively short even in the embodiment shown in FIG. 2, but is extremely excellent in the embodiment shown in FIG.

In each of the above embodiments, the voltage comparator COM ₊
The case where a voltage comparator configured so that the output voltage becomes V _C or 0 according to the level of the voltage applied to the two input terminals as COM ₋ and COM ₋ has been described. _A variable DC voltage source BAT for setting the approximate ripple / noise separation ratio ψ _A is used while using a voltage comparator configured so that the output voltage has arbitrary binary values V _A and V _B according to the level of the applied voltage. ₊ and BAT _- the output voltage V4 of the can implement the present invention by finding the following equation. V4 = ψ _A (V _A −V _B ) + V _B (15) As described in the above embodiments, the voltage comparator COM ₊
And COM _- output voltage, V _A = V _C, in the case of V _B = 0, the
Variable DC voltage source from the equation (15) BAT ₊ and BAT _- voltage V4
And by selecting the _{V4 = ψ A (V C -0} ) + 0 = ψ A · V C, the [psi _A setting value becomes ψ _A = V4 / V _C.

In any of the embodiments described above, while the voltage to be measured applied to the non-inverting input terminal of the voltage comparator COM ₊ in the positive side voltage measuring circuit RV + of the ripple voltage maintains the positive polarity, the voltage comparator COM ₊ The voltage fed back to the inverting input terminal, that is, the output voltage of the operational amplifier OPA ₊ (FIG. 2), the output voltage of the multiplier MLT ₊ (FIG. 4), the output voltage of the operational amplifier OPA ₁₊ (FIGS. 5 and 6). ) Keeps the positive polarity, the input polarity of the operational amplifier OPA ₊ (Figs. 2 and 4), the operational amplifier OP
Input polarities of A ₊ , diode D ₊ and operational amplifier OPA ₁₊ (Fig. 5), operational amplifier OPA ₊ , DC voltage source BAT ₁₊ , input polarity of diode D ₊ and operational amplifier OPA ₁₊ The present invention can be implemented by appropriately setting (Fig. 6) and adjusting the phase of the voltage. In the negative-side voltage measurement circuit of the ripple voltage RV-, the voltage comparator COM _- during which the measured voltage applied to the inverting input terminal keeps the negative polarity, the voltage comparator
COM _- a non-inverting input voltage feedback input to the terminal, i.e., the operational amplifier OPA of _- the output voltage (FIG. 2) of the multiplier MLT _- output voltage (FIG. 4) of the operational amplifier OPA _1-output voltage (FIG. 5
And FIG. 6) keep the negative polarity, the input polarities of the operational amplifier OPA ₋ (FIGS. 2 and 4), the operational amplifier OPA ₋ , the diode D ₋ and the operational amplifier OPA _{1 −} (FIG. 5). ),
The present invention is implemented by appropriately setting the input polarities (FIG. 6) of the operational amplifier OPA ₋ , the DC voltage source BAT ₁₋ , the diode D _−, and the operational amplifier OPA ₁₋ , and adjusting the voltage phase. be able to.

The above means that the voltages applied to the two input terminals of the voltage comparator COM ₊ in the ripple voltage positive side voltage measuring circuit RV + maintain the same polarity, and the ripple voltage negative side voltage measuring circuit RV-. Since the phase adjustment is performed in the circuit so that the voltages applied to the two input terminals of the voltage comparator COM _-in the above will maintain the same polarity, as long as this condition is satisfied, the voltage comparators COM ₊ and Voltage comparator
COM _- the measured voltage applied to each non-inverting input terminal of the, if you apply a feedback voltage to each inverting input terminal, the voltage comparator
COM ₊ and the voltage comparator COM _- the measured voltage applied to each inverting input terminal of the, if you apply a feedback voltage to each non-inverting input terminal, the measured voltage is applied to the inverting input terminal of the voltage comparator COM ₊ , together with the added feedback voltage to the non-inverting input terminal, the voltage comparator COM _- the measured voltage is applied to the non-inverting input terminal of the, present invention is also applicable to any case if you apply a feedback voltage to the inverting input terminal, of Can be carried out. That is, apply the measured voltage to one input terminal of the voltage comparator COM ₊ , apply the feedback voltage to the other input terminal, and apply the measured voltage to either input terminal of the voltage comparator COM _- side. In addition, the present invention can be implemented by applying a feedback voltage to the other input terminal and adjusting the phase so as to satisfy the above condition.

Further, in any of the embodiments, instead of forming the integrating circuits INT ₊ and INT ₋ with resistors and capacitors, for example, as shown in FIG. 7, an operational amplifier OPA is used.
_It may be formed by a circuit composed of ₂₊ , an integrating resistor R ₂₊ and an integrating capacitor C ₁₊ . FIG. 8 is a diagram showing an example of an integrating circuit for improving the characteristics of the integrating circuit shown in FIG. 7. In the operational amplifier, the input terminal can be considered as a virtual ground terminal in the low frequency region, but in the high frequency region. Since this idea does not hold, the amplification degree generally decreases in the high frequency region, the potential of the inverting input terminal increases, and the integrated output voltage tends to become higher than the ideal value. As shown in FIG. 8, the operational amplifier OPA ₂₊ , the integrating resistor R ₂₊ and the integrating capacitor C _{1 +}
By adding a frequency characteristic compensating circuit composed of a frequency characteristic compensating resistor R ₃₊ and a frequency characteristic compensating capacitor C ₂₊ to the integrator circuit, the integration error due to the characteristic of the operational amplifier as described above is reduced. be able to.

[0026] In either embodiment above, by adding a variable DC voltage source BAT ₊ output voltage to the operational amplifier OPA _+, a case has been exemplified as constructed to set the ripple noise segregation, 7 When using the integration circuit shown in,
As shown in FIG. 9, the output negative voltage of the variable DC voltage source BAT ₊ is _supplied to the integrating circuit forming operational amplifier OPA _{2 +} via the input resistor R _4+.
It may be configured to be added to the inverting input terminal of. In this case, the output voltage V4 of the variable DC voltage source BAT ₊ required to set the required ripple / noise separation ratio ψ _A is the output voltage of the voltage comparator COM ₊ that is, for example, two input terminals. When the resistances R ₂₊ and R ₄₊ are configured to be V _C or 0 according to the comparison result of the applied voltage, R 2 and R 4,

[Equation 5] It is represented by. When the integrating circuit shown in FIGS. 7 to 9 is used, the phases between the input and the output of the integrating circuit are opposite to each other, so that the phase adjustment is performed by the other circuit constituent elements and the voltage comparator COM ₊ It is necessary to configure so that the voltages applied to the two input terminals have the same polarity.

FIG. 10 is a diagram showing an example of a voltage source that can be used in place of the forward bias voltage forming DC voltage source BAT ₁₊ in the embodiment shown in FIG. 6, and is an operational amplifier OPA ₃₊ (non-inverting input). The output terminal of the operational amplifier OPA ₊ shown in FIG. 6 is connected to the terminal, and the output terminal is connected to the cathode of the diode D ₊ in FIG. 6), the resistor R ₅₊ , the resistor R ₆₊ and the diode. - in a circuit consisting of de D _1+, operational amplifiers OPA diode is inserted into the feedback circuit of ₃₊ - equal to de D ₊ the forward voltage - as de D _1+, forward voltage diode shown in FIG. 6 Or
By using almost equal diodes, the diode
A voltage corresponding to the forward voltage of D ₊ can be obtained. 7 to 10 show a positive voltage measuring circuit for ripple voltage.
The component of RV + is illustrated, but the negative side voltage measurement circuit
The present invention can be implemented by using the same constituent element in the RV-. However, the circuit shown in FIG. 10 is a negative side voltage measuring circuit for ripple voltage in the embodiment shown in FIG.
When used as a DC voltage source for forming the forward bias voltage of RV-, the polarity of the diode D1 ₊ must be opposite to that shown in FIG.

Although FIGS. 5 and 6 exemplify the case where the diodes D ₊ and D ₋ are used as the non-linear elements, the present invention can be realized even if the diode characteristics of the transistor are utilized. It can be carried out. Fig. 11 shows the connection between the electrodes when the diode characteristics between the base and collector of the NPN transistor are used, and Fig. 12 shows the diode characteristics between the base and emitter of the PNP transistor. 7A and 7B are diagrams showing connection between electrodes in the case of performing both, and both can be used in place of the diode D ₊ in FIGS. 5 and 6. FIG. 13 shows the connection between the electrodes when the diode characteristics between the base and emitter of the NPN transistor are used, and FIG. 14 shows the diode characteristics between the base and collector of the PNP transistor. 7A and 7B are diagrams showing the connection between the electrodes in the case of performing both, and both can be used in place of the diode D ₋ in FIGS. 5 and 6. Figure 1
5 utilizes the non-linear characteristic of the emitter input voltage-collector output current characteristic in the base-grounded NPN transistor and can be used in place of the diode D ₊ in FIGS. 5 and 6. Figure 16 shows the grounded PNP
This utilizes the non-linear characteristic of the emitter input voltage-collector output current characteristic in the transistor, and can be used instead of the diode D ₋ in FIGS. 5 and 6.

FIG. 17 is a diagram showing another embodiment of the present invention. T _IN is a common input terminal, COM ₊ and COM ₋ are voltage comparators, OPA ₂₊ and OPA ₂₋ are operational amplifiers, and BAT _+. and BAT _-
Is a variable DC voltage source, R ₄₊ and R _4- are input resistances, R ₂₊ and R _2- are integration resistances, C ₁₊ and C _1- are integration capacitors, and R ₃₊ and R _3- are frequency characteristic compensation. Resistor, C ₂₊ and C ₂₋ are capacitors for frequency characteristic compensation, D ₂₊ and D ₂₋
Is a diode for forming the forward bias voltage, BAT ₂₊ and
BAT _2-forward bias voltage for forming a DC voltage source, R _{7 +} and R _7- current limiting resistor, D ₊ and D _- non-linear circuit forming silicon diode is - de, OPA ₁₊ and OPA _1-is Operational amplifier for nonlinear circuit formation, R ₁₊ and R _1- are feedback resistors, RV +
Is the ripple voltage positive side voltage measurement circuit, RV- is the ripple voltage negative side voltage measurement circuit, SUB is the subtraction circuit, and T _OUT is the output terminal.

Operational amplifier OPA ₂₊ , integrating resistor R ₂₊ , integrating capacitor C ₁₊ , frequency characteristic compensating resistor in this embodiment
R ₃₊ , a circuit consisting of frequency characteristic compensation capacitor C ₂₊ ,
And the operational amplifier OPA _2- , the integrating resistor R _2- , the integrating capacitor C _1- , the frequency characteristic compensating resistor R _3- , and the frequency characteristic compensating capacitor C _2- corresponds to the circuit shown in FIG. 8, respectively. To do. Variable DC voltage source BAT _+, the circuit consisting of the input resistance R _4+, and a variable DC voltage source BAT _-, input resistance R _4-
The circuits made up of these correspond to the voltage application circuits shown in FIG. 9, respectively. Forward bias voltage forming diode D ₂₊ ,
Forward bias voltage forming DC voltage source BAT ₂₊ , current limiting resistor R ₇₊ circuit, forward bias voltage forming diode D _2- , forward bias voltage forming DC voltage source BAT _2- , current limiting resistor R _{7 -} and more made circuit, a forward bias voltage for forming a DC voltage source BAT as shown in FIG. 6, respectively
₁₊ and BAT ₁₋ or the bias voltage forming circuit shown in FIG. That is, a diode with a forward voltage slightly lower than or almost equal to the forward voltage of the non-linear circuit forming silicon diode D ₊ is used as the forward bias voltage forming diode D ₂₊ , and the current limiting is used. A bias current is supplied from a DC voltage source BAT ₂₊ for forward bias voltage formation through a resistor R ₇₊ to a diode D ₂₊ for forward bias voltage formation.
Is formed so as to generate a forward bias voltage. Forward bias voltage forming diode
De D _2- , forward bias voltage forming DC voltage source BAT _2- ,
The circuit including the current limiting resistor R _7- is also formed in the same manner as described above so as to generate the forward bias voltage. Nonlinear circuit forming silicon diode - de D _+, the non-linear circuit for forming an operational amplifier OPA _1+, negative feedback resistor R circuit consisting _1+, and non-linear circuit forming silicon diode - de D _-, nonlinear circuit formed The operational amplifier OPA ₁₋ and the negative feedback resistor R ₁₋ are connected to the non-linear circuit forming diode D ₊ , the non-linear circuit forming operational amplifier OPA ₁₊ and the negative feedback resistor R _{1+ in FIG} . And a circuit including a non-linear circuit forming diode D ₋ , a non-linear circuit forming operational amplifier OPA ₁₋ , and a negative feedback resistor R ₁₋ .

The measurement operation in this embodiment is almost the same as that of the embodiment shown in FIG. 6, but in this embodiment, the integration operation and integration are performed by a circuit mainly composed of operational amplifiers OPA ₂₊ and OPA _2-. As a result of adding the frequency characteristic compensating circuit to the integrating circuit while performing the differential combining operation of the voltage and the set voltage of the ripple / noise separation ratio, as shown in Table 8, the measured voltage is input to the terminal T _IN . After that, the response time and the pulsation rate until the measured value of the ripple voltage reaches the accuracy within 1% of the final value can be significantly improved as compared with the other examples. Table 8 shows the result of the simulated measurement of the positive side voltage measuring circuit RV + of the ripple voltage in this embodiment using a computer.
, The period T _O is 20μs, the peak voltage V _P is 1.0V, 100mV
And the triangular wave voltage of 10 mV, the approximate separation ratio ψ _{A is set} to 1
% And 10%, the output voltage V _C of the voltage comparator COM ₊ was set to 5 V, and the time constant τ of the integrating circuit was selected to be 0.45 sec. As is clear from Table 8, the response time in this example is significantly improved and shortened compared to the response times (Table 7) in the examples shown in FIGS. 2 and 6.

Therefore, the measuring device of the present invention shown in FIG. 17 is suitable as a measuring device for the following measuring object. The frequency component of the ripple voltage included in the output voltage of the switching DC power supply is 50Hz or 60Hz as described above.
Such as a low frequency ripple voltage component whose fundamental wave is a commercial power supply frequency or a frequency twice as high as that of the commercial power supply, and a high frequency ripple voltage component of several tens of kHz or more generated by switching of a switching element installed in the switching DC power supply. A spike-shaped ripple noise voltage is superimposed on the peak portion of the ripple voltage, and has a waveform as shown in, for example, FIG. 18 (horizontal axis represents time T, vertical axis represents voltage V). When the frequency of the commercial power supply is, for example, 50 Hz, the period of the ripple voltage component whose fundamental wave is 100 Hz is 10 ms, and the measurement response time in the embodiment shown in FIG. 17 is 0.3 to 0.4 m.
s is much shorter than the low frequency ripple voltage component, and the peak voltage on the positive side in the waveform shown in FIG.
It is possible to measure + V _P and negative peak voltage -V _P.
On the other hand, in the embodiment in which the measurement response time is relatively long, the peak-to-peak peak of the high frequency ripple voltage component in the measured voltage excluding the direct current component and the low frequency ripple voltage component in the output voltage of the switching DC power supply. It is suitable for measuring only the black voltage. FIG. 19 is a diagram showing an example of a circuit device suitable for measuring the peak voltage + V _{P to the} peak voltage −V _P in the waveform shown in FIG. 18, where T _IN is a common input terminal. , RV + is the ripple voltage positive side voltage measurement circuit in FIG. 17, RV- is the ripple voltage negative side voltage measurement circuit in FIG. 17, PH + is the positive side peak-hold circuit,
PH- is a negative-side peak-hold circuit, and the peak-hold circuits PH + and PH- are among the conventionally known peak-hold circuits. It is composed of a sufficiently long analog type peak-hold circuit. SU
B is a subtraction circuit, and T _OUT is an output terminal.

When a voltage to be measured in which the direct current component in the output voltage of the switching DC power supply is cut off is applied to the terminal T _IN , the voltage V _{R +} in the positive side voltage measurement circuit RV + of the ripple voltage
(FIG. 1) is measured, and the measured value is stored and held in the positive peak-hold circuit PH +. If the next measured value of the voltage V _{R +} of the positive-side voltage measurement circuit RV + ripple voltage becomes larger than the previous reading, the positive-side peak - Kuho - holding value of hold circuit PH + is updated the next time measurements are retained It In the negative side voltage measuring circuit RV- of the ripple voltage and the negative side peak-hold circuit PH-, the measurement and storage of the voltage V _R- (Fig. 1) are performed in the same manner as the positive side circuit. Pi - Kuho - the holding value of the hold circuit PH + and PH- is by subtraction processing is performed read to the subtraction circuit SUB, subtraction result, i.e., peak - click voltage + V _P Taipi - click voltage -V _P is Output from the terminal T _OUT .
Peak in the measurement voltage - click voltage + V _P Taipi - The measuring means of click voltage -V _P, the indicated peak 19 - Kuho - instead of using the hold circuit, the ripple voltage positive side voltage measurement circuit RV
The + output voltage is sequentially converted to a digital value by an analog-digital converter, the output voltage of the ripple voltage negative side voltage measuring circuit RV- is processed in the same way, and these digital conversion values are introduced into the computer. , The peak voltage of the measured voltage + V _P vs.
The voltage -V _P may be obtained.

[0034]

The device of the present invention can accurately and quickly determine the ripple voltage contained in the output voltage of the switching DC power supply.
In an embodiment in which the measurement can be performed with good reproducibility and the measurement response speed is particularly fast, the peak pair of the measured voltage including the low frequency ripple voltage component whose fundamental wave is the commercial power frequency or twice the frequency thereof is used. Since it is possible to measure the peak voltage, it is extremely effective as a device for accurately grasping the performance of the switching DC power supply.

[Brief description of drawings]

FIG. 1 is a waveform diagram of a voltage to be measured by the measuring device of the present invention.

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

FIG. 3 is a waveform diagram for explaining the operation of the measuring apparatus of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing another embodiment of the present invention.

FIG. 7 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 8 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 9 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 10 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 11 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 12 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 13 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 14 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 15 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 16 is a diagram showing an example of the main configuration of the measuring apparatus of the present invention.

FIG. 17 is a diagram showing another embodiment of the present invention.

FIG. 18 is a waveform diagram of a voltage to be measured by the measuring device of the present invention.

FIG. 19 is a diagram showing another embodiment of the present invention.

FIG. 20 is a waveform diagram for explaining conventional measuring means.

FIG. 21 is a waveform diagram for explaining conventional measuring means.

[Explanation of symbols]

T _IN input terminal COM ₊ voltage comparator COM _- voltage comparator R ₊ integrating resistance R _- integrating resistance C ₊ integrating capacitor C _- integrating capacitor INT ₊ integrating circuit INT _- integrating circuit OPA ₊ operational amplifier OPA _- operational amplifier BAT ₊ variable DC Voltage source BAT _- Variable DC voltage source T _{O +} Output terminal T _O- Output terminal SUB Subtraction circuit T _OUT Output terminal RV + Ripple voltage positive side voltage measurement circuit RV- Ripple voltage negative side voltage measurement circuit MLT ₊ Multiplier MLT _- Multiply Device D ₊ Diode D _- Diode OPA ₁₊ Operational amplifier OPA _1- Operational amplifier R ₁₊ Feedback resistor R _1- Feedback resistance BAT ₁₊ DC voltage source BAT _1- DC voltage source OPA ₂₊ Operational amplifier R _{2 +} Integration resistance C 1 ₊ Integration capacitor R _{3 +} Frequency characteristic compensation resistance C 2 ₊ Frequency characteristic compensation capacitor R _{4 +} Input resistance OPA _{3 +} Op _Amp R 5 ₊ Resistance R _{6 +} Resistance D 1 ₊ Diode R _{2 -} integrating resistor R _4-input resistor R _3- frequency characteristic compensation resistor C _2-frequency characteristic compensation capacitor C _{1-integrating} capacitor OPA _2- Operational amplifier R _{7 +} Current limiting resistor R _7- Current limiting resistor BAT _{2 +} DC voltage source BAT _2- DC voltage source D _{2 +} Diode D _2- Diode PH + Peak hold circuit PH-P -Cold circuit

Claims (8)

[Claims] 1. A first voltage comparator to which a voltage to be measured is applied to one of the input terminals, a first integrating circuit to which an output voltage of the first voltage comparator is applied, and the first voltage comparator. The differential output voltage of the integrating circuit and the output voltage of the first variable DC voltage source are differentially applied and have the same polarity as the measured voltage applied to one of the input terminals of the first voltage comparator. A first operational amplifier that applies an operation output voltage to the other input terminal of the first voltage comparator; a second voltage comparator that applies the measured voltage to one of the input terminals; A second integrator circuit to which the output voltage of the second voltage comparator is applied, and an integrator output voltage of the second integrator circuit and an output voltage of the second variable DC voltage source are applied differentially, A voltage applied to one of the input terminals of the second voltage comparator. A second operational amplifier that applies an operational output voltage having the same polarity as the constant voltage to the other input terminal of the second voltage comparator, and a subtraction that adds the operational output voltages of the first and second operational amplifiers. A ripple voltage measuring device comprising a circuit and a subtraction output extraction circuit of the subtraction circuit. 2. A first voltage comparator to which a voltage to be measured is applied to one of the input terminals, a first integration circuit to which an output voltage of the first voltage comparator is applied, and the first voltage comparator. A first operational amplifier to which the integrated output voltage of the integrator circuit and the output voltage of the first variable DC voltage source are differentially added; and the operational output voltage of the first operational amplifier is added to the first operational amplifier. A first square multiplier for applying to the other input terminal of the first voltage comparator a multiplication output voltage having the same polarity as the measured voltage applied to one of the input terminals of the voltage comparator; A second voltage comparator whose voltage is applied to one of the input terminals; a second integrating circuit to which the output voltage of the second voltage comparator is applied; and an integrated output voltage of the second integrating circuit And the output voltage of the second variable DC voltage source is applied differentially. An operational output voltage of the second operational amplifier, and a multiplied output voltage having the same polarity as the measured voltage applied to one of the input terminals of the second voltage comparator. A second square multiplier applied to the other input terminal of the second voltage comparator, a subtraction circuit to which the multiplication output voltages of the first and second square multipliers are added, and a subtraction of the subtraction circuit A ripple voltage measuring device comprising an output extracting circuit. 3. A first voltage comparator to which a voltage to be measured is applied to one of the input terminals, a first integrating circuit to which an output voltage of the first voltage comparator is applied, and the first voltage comparator. A first operational amplifier to which the integrated output voltage of the integrator circuit and the output voltage of the first variable DC voltage source are differentially applied; and a first operational amplifier to which the operational output voltage of the first operational amplifier is applied.
The non-linear element of the first non-linear element and the output voltage of the first non-linear element
An output voltage having the same polarity as the voltage to be measured applied to one of the input terminals of the first voltage comparator is applied to the other input terminal of the first voltage comparator, A first non-linear circuit forming operational amplifier forming a linear circuit; a second voltage comparator to which the measured voltage is applied to one of the input terminals; and an output voltage of the second voltage comparator. A second integrator circuit to which is added, a second operational amplifier to which an integrated output voltage of the second integrator circuit and an output voltage of the second variable DC voltage source are differentially applied, and the second operation The second to which the operational output voltage of the amplifier is applied
The non-linear element of the second non-linear element and the output voltage of the second non-linear element
An output voltage having the same polarity as the measured voltage applied to one of the input terminals of the second voltage comparator is applied to the other input terminal of the second voltage comparator, A second non-linear circuit forming operational amplifier forming a linear circuit, a subtracting circuit to which respective output voltages of the first and second non-linear circuit forming operational amplifiers are added, and a subtraction output extracting circuit of the subtracting circuit And a ripple voltage measuring device. 4. The ripple voltage measuring device according to claim 3, wherein the first and second non-linear elements are diodes. 5. The ripple voltage measuring device according to claim 3, wherein the first and second nonlinear elements are transistors. 6. A first voltage comparator to which a voltage to be measured is applied to one of the input terminals, a first integrating circuit to which an output voltage of the first voltage comparator is applied, and the first voltage comparator. A first operational amplifier to which the integrated output voltage of the integrator circuit and the output voltage of the first variable DC voltage source are differentially applied; and the operational output voltage of the first operational amplifier is a first forward bias. An output voltage having the same polarity as the measured voltage applied via the series circuit of the voltage source and the first non-linear element and applied to one of the input terminals of the first voltage comparator is set to the first voltage. A first non-linear circuit forming operational amplifier that forms a non-linear circuit together with the first non-linear element, in addition to the other input terminal of the voltage comparator; A second voltage comparator applied to the Second integrator circuit to which the output voltage of the voltage comparator is added, and a second operational amplifier to which the integrated output voltage of the second integrator circuit and the output voltage of the second variable DC voltage source are differentially applied. And an operational output voltage of the second operational amplifier is applied via a series circuit of a second forward bias voltage source and a second non-linear element, and one of the second voltage comparators is connected. An output voltage having the same polarity as the measured voltage applied to the input terminal is applied to the other input terminal of the second voltage comparator, and a second non-linear circuit that forms a non-linear circuit together with the second non-linear element is provided. A linear circuit forming operational amplifier, a subtracting circuit to which each output voltage of the first and second non-linear circuit forming operational amplifiers is added, and a subtraction output extracting circuit of the subtracting circuit. Ripple voltage measuring device. 7. The ripple voltage measuring device according to claim 6, wherein the first and second non-linear elements are diodes. 8. The ripple voltage measuring apparatus according to claim 6, wherein the first and second nonlinear elements are transistors.