JPH0140526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to voltage sources, and more particularly to reference voltage sources. The reference voltage source of the present invention has application in automatic measurement systems where the reference voltage source can be used as a temporally stabilized calibration signal source.

Reference voltage sources are known in the art, which have two closed control loops, each of which includes a compensating DC voltage stabilizer of opposite polarity. The two closed loops are connected alternately to the output of the reference voltage source (see US Pat. No. 3,458,723, Class 307-240).

The reference voltage source under consideration is characterized by a low output resistance, while a time-stable resistor is installed in the divider circuit in order to ensure a high temporal stability of the output voltage of this reference voltage source. must be used so that the error of the resistor divider is proportional to the error of the reference voltage source as a whole. Not only is it difficult to control the DC component of the output voltage of this square wave voltage source, but it is also difficult to control the amplitude of the output voltage over a wide range using electrical signals.

Also, other AC voltage sources are known in the past,
The alternating current voltage source includes a sinusoidal voltage generator whose amplitude is controlled, a square wave alternating current reference voltage source, a thermal converter to which the output voltage of the sinusoidal voltage generator and the voltage of the reference voltage source are alternately applied; and a detector for detecting a difference signal at the output of the transducer to control the amplitude of the sinusoidal voltage generator (U.S. Pat. No. 3,484,705, Class, 328-149 or FL Hanson, “High-
Accuracy AC Voltage Calibration”, Hewlett
(See Pakard Journal, Vol. 19, No. 10, July 1968).

The AC voltage source described above provides an output sinusoidal voltage that is very accurate and has good stability due to the stable voltage provided by the reference voltage source. On the other hand, it is not possible to obtain a square wave voltage at the output of this voltage source, although this may be necessary for certain applications. The voltage source under consideration is further disadvantageous in the following respects. That is, because this system utilizes deep negative feedback, the short-term stability of the output voltage of the sine wave generator is limited because the noise at the input of the detector is significantly amplified.

Also, other reference voltage sources are known in the past,
This reference voltage source includes a bridge circuit, which has two operational amplifiers connected alternately to the output terminals of the reference voltage source.
It includes avalanche diodes in one opposing arm and resistors in the other two arms.

The inverting input and output of the first of the two operational amplifiers are respectively connected to the anode and cathode of one avalanche diode (see USSR Inventor's Certificate No. 445037, Class G05F, 1/56) .

This reference voltage source has the following disadvantages. That is, this reference voltage source does not allow simultaneous control of the DC component and the amplitude of the output voltage of the square wave AC voltage.

It is an object of the invention to provide a reference voltage source that makes it possible to simultaneously control the DC component and the amplitude of a square wave AC output voltage.

The present invention substantially comprises first and second bipolar elements held at a constant DC voltage at opposite ends thereof, and first and second resistors in opposite arms thereof; A reference voltage source is provided that includes a bridge circuit included in the arm. According to the present invention, the reference voltage source further includes an output terminal for outputting a reference voltage, an input terminal to which a first control voltage for coarsely controlling the DC component of the reference voltage at the output terminal is applied, an inverting input and a non-inverting input, respectively. has an input,
first and second operational amplifiers whose outputs are alternately connected to the output terminal, wherein the inverting input and output of the first operational amplifier are connected to the anode and cathode of the first bipolar element, respectively; The inverting input and output of the second operational amplifier are connected to the anode and cathode of the first bipolar element, respectively, and the non-inverting input of the second operational amplifier is connected to the input terminal. an AC-to-DC converter, the input of which is connected to the output terminal of the reference voltage source; a DC voltage setting circuit that generates a second control voltage that finely controls the DC voltage at the output terminal; a comparator having a first input connected to the output of the AC to DC voltage converter and a second input connected to the output of the DC voltage setting circuit; It is characterized in that it is connected to a non-inverting input of the first operational amplifier.

According to the invention, the first input is connected to the first and second inputs.
an integrator circuit alternately connected to the output of the operational amplifier, the second input being connected to the input terminal;
The output of the integrating circuit is connected to the non-inverting output of the second operational amplifier.

Conveniently it comprises amplifiers connected alternately to the first and second operational amplifiers and an integral feedback loop connected in parallel to the amplifiers, the output of the amplifier serving as the output of the reference voltage source. It is true.

The comparator includes an operational amplifier whose inverting input is connected to two resistors, the two resistors are input resistances of the comparator, and the output of the operational amplifier is connected to the operational amplifier via a capacitor. Preferably connected to the inverting input of the amplifier.

Preferably, it includes amplifiers connected alternately to the first and second operational amplifiers and an integral feedback loop connected in parallel to the amplifiers, the output of the amplifier serving as the output of the reference voltage source.

Preferably, the integrating circuit is formed to include an operational amplifier.

Preferably, the integral feedback loop includes an integral operational amplifier.

According to the invention, a reference voltage source is provided with a time-varying transition voltage ratio whose inputs are connected alternately to the outputs of the first and second operational amplifiers and whose outputs are connected to the output terminals. Contains circuits with

The circuit having a time-varying transition voltage ratio is formed including a summing operational amplifier having a resistor and at least two circuits connected in parallel to an inverting input of the summing operational amplifier; Preferably, each of the two circuits comprises a controlled switch and a resistor arranged in series.

The connection point between the controlled switch and the resistor in each of the two circuits is connected to the non-inverting input of the summing operational amplifier via each switch.

Conveniently, the output of the circuit with the time-varying transition voltage ratio is connected to a low-pass filter.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the invention, taken in conjunction with the accompanying drawings.

The reference voltage source according to the invention is based on a bridge circuit, which has avalanche diodes 1 and 2 (first
) and has resistors 3 and 4 in the other two arms. Of course, in place of the avalanche diodes 1 and 2, other bipolar elements whose both ends are maintained at a constant DC voltage may be used. This reference voltage source further includes two operational amplifiers 5 and 6, the output of the first operational amplifier 5 is connected to the cathode of the unbalanced diode 1, and the output of the first operational amplifier 5 is connected to the cathode of the unbalanced diode 1;
The output of the operational amplifier 6 is connected to the anode of the avalanche diode 2. The inverting input 7 of the amplifier 5 is connected to the remote pole of the avalanche diode 1. The inverting input 8 of the amplifier 6 is connected to the cathode of the avalanche diode 2. The output of each amplifier 5 and 6 is connected to a switch 11 and 1, respectively.
2 inputs 9 and 10. Control inputs 13 and 14 of switches 11 and 12 are connected to the output of clock pulse generator 15, respectively. The outputs of switches 11 and 12 are connected to output terminal 16 of a reference voltage source.

According to the invention, the reference voltage source further includes an AC-to-DC voltage converter (AC-DC converter) 17 whose input is connected to the output terminal 16 and a circuit 18 for setting the DC voltage. The output of the converter 17 and the output of the circuit 18 are connected to the input of a comparator 19 whose output is connected to the non-inverting input 20 of the amplifier 5. A non-inverting input 21 of the operational amplifier 6 is connected to an input terminal 22;
A control voltage is applied to 2.

In order to provide a constant bias to the output voltage with respect to DC voltage, the reference voltage source according to the invention includes an integrator circuit 23 (FIG. 2), the input 24 of which is connected to the input of the reference voltage source. terminal 22
is combined with Input 25 of integrating circuit 23 is connected to the combined output of switches 11 and 12. The output of the integrating circuit 23 is connected to the non-inverting input 21 of the amplifier 6.

The integrating circuit 23 includes an operational amplifier 2 having an input resistor 27 and a capacitor 28 arranged in a feedback loop.
It is optimally configured including 6. The non-inverting input of this operational amplifier 26 is the input 24 of the circuit 23. Arranged at the inverting input of amplifier 26 is a switch 29 whose control input 30 is connected to generator 15 .

In order to provide a high voltage with a low resistance output, it is necessary to place an amplifier 31 (FIG. 3) on the output side of the reference voltage source and provide an integral feedback loop 32. Amplifier 3
1's input 33 is connected to the combined outputs of switches 11 and 12. The amplifier 31 includes a resistor 3 arranged in the input and feedback loops respectively.
The operational amplifier 34 includes operational amplifiers 5 and 36.

Also connected within the integral feedback loop 32 is an integral operational amplifier 37 having a resistor 38 placed on the inverting input side and a capacitor 39 connected within the feedback loop. A switch 40 is arranged on the inverting input side, the control input 41 of which is connected to the output of the clock pulse generator 15.

FIG. 4 shows an alternative embodiment of the converter 17 and comparator 19 to the previously described embodiment. According to FIG.
6. A resistor 42 is connected to a common connection point 45 between resistors 43 and 44 .

Capacitors 47 and 48 are connected to the inverting input and output of the operational amplifier 46, respectively. Diodes 49 and 50 are arranged in the feedback loop, which are also connected to resistor 43.
and 44.

Comparator 19 comprises an integrated operational amplifier 51 having a capacitor 52 and input resistors 53 and 54 arranged in a feedback loop.

A switch 55 is connected to the inverting input side of the operational amplifier 51.
is connected, and the control input 56 of this switch 55 is connected to the output of the clock pulse generator 15.

Non-inverting inputs 57, 58, 59 of amplifiers 37, 46, 51, respectively, are grounded.

According to another embodiment shown in FIG. 5, the reference voltage source of the invention includes a time-varying transition voltage ratio circuit 60 whose input 61 is the combination of The output of the circuit 60 serves as the output of the reference voltage source.

Circuit 60 includes a summing operational amplifier 62 (FIG. 6) having a resistor 63 placed in a return loop. Inverting input 6 of amplifier 62
4 is connected to a resistor 65 and n parallel circuits, each of which includes a resistor and a switch. Figure 6 shows a simplified circuit with resistors 66, 67, 68 and switch 6.
It consists of three circuits containing circuits 9, 70, and 71, respectively. Switches 75, 76, 77 are connected to the connection points of resistors 66, 67, 68 and switches 69, 70, 71, respectively, and all of these switches 75, 76, 77 are connected to the non-inverting input of amplifier 62. 78.

The control inputs 79, 80, 81 of the switches 69, 70, 71, respectively, are connected to the clock pulse generator 15.
connected to the output of

A low pass filter 85 is connected to the output of circuit 60.

The reference voltage source according to the invention (FIGS. 1 to 4) operates as follows.

The operational amplifiers 5 and 6 are powered by bipolar power supplies, so that their output voltages vary over a wide range.

When operating in steady state, the voltage formed at the output of operational amplifier 5 is at its non-inverting input 20
The avalanche diode 1 for the voltage at
The voltage formed at the output of operational amplifier 6 is biased positively by a value corresponding to the voltage drop across .
It is negatively biased relative to the voltage at its non-inverting input 21 by a value appropriate to the voltage across the avalanche diode 2. The output voltages of amplifiers 5 and 6 are applied to output terminal 16 by switches 11 and 12, either directly or via amplifier 31.

The waveform at output 16 is independent of whether amplifier 31 is provided with an integral feedback loop 32 or whether amplifier 31 is connected to switches 11, 12
and the output terminal 16 is substantially a square wave alternating voltage.

This square wave alternating voltage at the output of the switch can be amplified by amplifier 31 with a gain K31. In this case, the gain K31 is expressed by the following equation and is proportional to the resistance ratio of the resistors 36 and 35.

K31=R36/R35 In this case, the non-inverting input of amplifier 34 is considered to be grounded as far as the alternating current voltage is concerned. The integral feedback loop 32 only modifies the zero line bias of the AC voltage at the output terminal 16 of the amplifier 31.

The output resistance of the device at output terminal 16 is reduced by amplifier 31, similar to that at the output of any amplifier with negative feedback. Output terminal 16
The magnitude of the alternating voltage at the amplifier 34 is actually
Due to the effect of negative feedback at , it becomes independent of the load resistance at the same output terminal.

The AC to DC converter 17 smoothes the output voltage of the reference voltage source and converts it to a DC voltage by full wave rectification. Comparator 19 then compares the rectified voltage with a predetermined DC voltage, and then the rectified voltage is applied to non-inverting input 20 of amplifier 5. If the output voltage exceeds the set voltage, a negative signal is formed at the output of the comparator 19, so that the output voltage of the amplifier 5 decreases so that the signals at the input of the comparator 19 are equalized. .

The operation of the AC to DC converter 17 will be explained in more detail.

The AC voltage signal from the output terminal 16 is applied to the resistor 4
2, 43 and 44 at a common connection point 45. Resistor 42 is necessary to reduce the signal when the output voltage at terminal 16 is high. The square wave AC voltage from common node 45, when positive, forms a current through resistor 44, diode 50 and capacitor 48 to the output of operational amplifier 46, and also through resistor 43, capacitor 47 and A current is formed through diode 50 and capacitor 48 to the output of operational amplifier 46 . in this case,
Diode 49 is cut off and if capacitor 47 has a sufficiently high capacitance, the AC voltage at the inverting input of operational amplifier 46 will be approximately equal to zero.

If the voltage at the common node 45 is negative, a current is formed through the resistor 46, the diode 49 and the capacitor 48 to the output of the amplifier 46, and through the resistor 44, the capacitor 47, the diode 49 and the capacitor 48 to the output of the amplifier 46. A current is formed leading to the output of . In this case diode 50 is cut off.

As can be seen from the above description, for both polarities of the AC voltage, the current through the capacitor 47 is a current in the same direction that charges the capacitor 47. This capacitor is discharged via resistors 43 and 44 which are connected in series with each other.

Therefore, full-wave rectification of the AC voltage output signal is performed. Inverting input of operational amplifier 46, resistor 43,
The output signal of converter 17 from the common connection point of capacitor 47 and diode 49 exhibits a DC voltage with negligible AC component. The AC voltage at the inverting input of operational amplifier 46 is equal to Uout46/K46, where Uout46 is the output AC voltage of operational amplifier 46 and K46 is the gain of amplifier 46, typically 10,000.

In this way, the AC to DC converter 17 converts the AC voltage applied thereto into a smoothed DC voltage.

Comparator 19 operates as follows. Applied to the input of the comparator, that is, applied to the inverting input of the operational amplifier 51, is the full-wave rectified voltage from the converter 17 and the DC voltage setting circuit 18 via the resistors 53 and 54. is the negative DC voltage. The difference in current flowing through resistors 53 and 54 is integrated by integrating amplifier 51 and applied to the input of amplifier 5. When the output voltage of the reference voltage source exceeds the predetermined voltage of the DC voltage setting circuit 18, the compensation current flowing through the resistor 54
over the compensation current flowing through it, which causes the voltage at the output of amplifier 51 to become negative.
As a result, the output voltage of operational amplifier 51 and amplifier 3
The voltages at the input and output of comparator 19 decrease until the input voltages of comparator 19 are equal. This means that the currents flowing through resistors 53 and 54 are equal in magnitude and opposite in polarity.

Operational amplifiers 5 and 6 using bridge circuits
Apart from the coarse stabilization of the output voltage of I can do it. The reference voltage source according to the invention is characterized by a high degree of noise immunity and good temporal stability.

The integrating circuit 23 is connected to the non-inverting input 21 of the operational amplifier 6.
, so that the DC component of the signal at the outputs of switches 11 and 12 is equal to the control voltage at terminal 22.

Outputs of switches 11 and 12, i.e. circuit 2
The DC component of the signal at input 25 of 3 is connected to terminal 2.
2, a current flows through the resistor 27 and the output voltage of the circuit 23, that is, the voltage at the non-inverting input 21 of the amplifier 6, the output of the operational amplifier 6, and the input 25 change. Capacitor 28 is charged until the DC component of the signal at the input of circuit 23 and the control voltage at terminal 22 are equal.

The reference voltage source of FIGS. 5 and 6 operates as follows. The output voltage of amplifiers 5 and 6 is set by switch 1.
1 and 12 alternately to the inputs of the circuit 60 with a certain time-varying transition voltage ratio;
It is then applied via the low pass filter 85 to the output terminal 16 of the reference voltage source. The sinusoidal output voltage thus formed is converted into a smoothed DC voltage by the converter 17, and then the comparator 19 compares this smoothed DC voltage with a predetermined DC voltage,
The difference between these voltages is the non-inverting input 2 of the operational amplifier 5.
If the output voltage exceeds the desired value, the output signal of the comparator 19 becomes negative, thereby causing the output voltage of the operational amplifier 5 to decrease. In accordance with the preferred embodiment shown in FIG. 6, a circuit 60 with a time-varying transition voltage ratio
is equipped with a summing operational amplifier 62, the inverting input 64 of which is connected to the outputs of switches 11 and 12. As shown in FIG. 7a, the voltage across resistor 65 is applied continuously to input 64, while resistor 66 and switch 69
is applied to the inverting input 64 of the operational amplifier 62 only during the periods t ₁ to t ₇ and t ₉ to t ₁₅ (FIG. 7b). Resistor 67 and switch 70
The voltage across is applied during the periods t ₂ to t ₆ and t ₁₀ to t ₁₄ (FIG. 7c). The voltage across resistor 68 and switch 71 is from t ₃ to t ₅ and from t ₁₁ to
It is applied for a period up to t ₁₃ (FIG. 7d).

The current pulses through the resistors 65, 66, 67, 68 are shown in FIG. 7a, b, c, d, respectively, and since they are applied together,
A voltage close to a sine wave is formed at the output of the operational amplifier (Fig. 7e).

By suitably selecting the number of parallel circuits and suitably selecting the resistances of resistors 65, 66, 67, 68, this approximation can be made highly accurate.

The signal thus obtained is applied to a low-pass filter 85, which suppresses higher harmonic components. For example, low pass filter 85 may be a third order filter in which the overall distortion of the sinusoidal signal at its output is less than 0.005 percent.

When switches 69, 70, 71 are in the off position, switches 75, 76, 77 are connected to resistor 6.
6, 67, and 68 to direct the respective currents to the common bus. As a result, there is no surge voltage at the outputs of switches 11 and 12, and the output signal of operational amplifier 62 is
9, 70, and 71 are not affected by the peak voltage at the moment when they are switched. Otherwise, the reference voltage values of FIGS. 5 and 6 operate similarly to the previous embodiment described with respect to FIGS. 1-4.

The comparator 19, the integrator circuit 23 and the integrator feedback loop 32 are each equipped with a switch 55, 29, 40 (FIG. 4), so that when a DC voltage is applied to the output terminal 16, the operational amplifiers 5, 6, 34
The DC voltage is maintained as that at the non-inverting input of the converter. Switches 55, 29, 40 are turned "on" and the DC voltage at the output of amplifiers 51, 26, 37 is
Since no current flows through 2, 28, and 39, they remain unchanged. This makes it convenient to test the circuits and devices of the reference voltage source. This is because an accurate digital electrometer can be used to determine the different polarity output voltages of the resistors 42, 43, 53, 54 with a certain resistance ratio. If necessary, the resistance ratios of these resistors can be adjusted while keeping the output voltage within a predetermined range.

switches 11, 12, 29, 40, 55, 69, controlled by clock pulse generator 15;
The operations of 70, 71, 75, 76, and 77 are as follows.

The control inputs of switches 11 and 12 are connected to the output of clock pulse generator 15 and switch in opposite phases. The output signal of clock pulse generator 15 is a square wave whose frequency and duty ratio correspond to the desired output signal of the reference voltage source.

The other output signal from the output of clock pulse generator 15, which is connected to the control inputs of switches 29, 40 and 55, is advantageously formed synchronously with the control signals of switches 11 and 12 and is The value of is established based on the requirements of a certain situation of use of the reference voltage source, in particular during testing of the reference voltage source as described above.

From the corresponding output of the clock pulse generator 15 to the input 7 of the corresponding switches 69, 70 and 71
The control signals supplied to 9, 80, and 81 are such that the circuit controlled by a given switch is connected to obtain a particular step-approximation harmonic function at the output of the circuit with a time-varying transition voltage ratio. It must have the same temporal distribution as that of the time intervals. Input 8 of switches 75, 76, and 77
The control signals applied to switches 75, 83, and 84 are controlled by the control signals.
76 and 77 are the corresponding switches 69 and 7
It must allow current to reach the common bus through resistors 66, 67 and 68, respectively, during the periods when 0 and 71 are closed. In the example shown in FIG.
The frequency of the control signals applied to switches 0, 81 and 82, 83, 84 is twice the frequency of the control signals applied to the control inputs of switches 11 and 12.

The accuracy of the reference voltage source according to the invention is less than 0.01 percent, and the resistors 53, 54, 42, 43,
It depends only on the selection accuracy of the 44 resistance ratios.

The reference voltage source shown in FIGS. 5 and 6 has certain advantageous features.

Circuit 6 with a certain time-varying transition voltage ratio
0 converts the square wave signal into a step signal that approximates a sine wave, and the low pass filter 85 suppresses the higher harmonics so that a sine wave signal is obtained at the output of the reference voltage source. The manner in which the step signal approximates a sine wave is as follows. That is, there are 4 m changes at equal intervals in one cycle, so the step signal is symmetrical about the center of the half cycle and crosses zero at the same point as when the sine wave is approximated. As a result, the output signal is free of higher harmonics. By choosing a certain ratio between the additional step voltage changes, the signal can be filtered out of the first m-number harmonic components and at the same time as the sequence number higher than the sequence number of the first high-frequency component. is 4m・
It is possible to remove harmonic components represented by k (k=1, 2, 3...). For example, with three additional switches, the first higher harmonic component of the signal is 15, and its amplitude is 1/15 of the fundamental harmonic. By using a third-order reduction filter,
The total distortion at the output is less than 0.005%. The reference voltage source according to the invention thus makes it possible to obtain a substantially sinusoidal signal at its output.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a reference voltage source according to the invention, and FIG. 2 is a block diagram according to the invention. FIG. 3 is a block diagram of a reference voltage source including an integrator circuit and an amplifier according to the invention; FIG. 4 is a further embodiment of a reference voltage source according to the invention. FIG. 5 is a circuit diagram of a circuit according to the present invention with a time-varying transition voltage ratio.
FIG. 4 is a block diagram of a reference voltage source; FIG. 6 is a block diagram of another embodiment of a circuit with time-varying transition voltage ratios according to the invention; FIGS. 7a, b,
Figures c, d, and e are temporal operation explanatory diagrams for explaining the operation of a circuit having a temporally varying transition voltage ratio according to the present invention. 1, 2... Avalanche diode, 5, 6...
...Operation amplifier, 17...AC to DC voltage converter, 1
8...DC voltage setting circuit, 19...Comparator, 2
3... Integrating circuit, 26... Operational amplifier, 31...
Amplifier, 32... Integral feedback loop of amplifier 31,
37... Integrating operational amplifier of loop 32, 51...
Integrating operational amplifier, 52...Feedback capacitor of amplifier 51, 60...Circuit with time-varying transition voltage ratio, 62...Summing operational amplifier, 85...
low pass filter.

Claims (1)

[Claims] 1. One opposing arm includes first and second bipolar elements 1 and 2, both ends of which are held at a constant DC voltage, and first and second resistors 3; and 4 in the other opposing arm, an output terminal 16 that outputs a reference voltage, and an input terminal 22 to which a first control voltage that roughly controls the DC component of the reference voltage at the output terminal 16 is applied, respectively. first and second operational amplifiers 5 and 6 having inverting inputs 7 and 8 and non-inverting inputs 20 and 21, the outputs of which are connected alternately to the output terminal 16;
The inverting input 7 and output of the first operational amplifier 5 are connected to the anode and cathode of the first bipolar element, respectively, and the inverting input 8 and output of the second operational amplifier 6 are the second bipolar element 2
The non-inverting input 21 of the second operational amplifier 6 is connected to the input terminal 22, and the input is connected to the output terminal 16 of the reference voltage source. an AC to DC converter 17; a DC voltage setting circuit 18 for generating a second control voltage that finely controls the DC voltage at the output terminal 16; and a first input to the output of the AC to DC voltage converter 17. a comparator 19 connected to the DC voltage setting circuit 18 and having a second input connected to the output of the DC voltage setting circuit 18, the output of the comparator 19 being connected to the non-inverting input 20 of the first operational amplifier 5 Connected reference voltage source. 2 an integrator circuit 23 whose first input 25 is connected alternately to the outputs of the first and second operational amplifiers 5 and 6 and whose second input is connected to the input terminal 22; Reference voltage source according to claim 1, wherein the output of is connected to the non-inverting input 21 of the second operational amplifier 6. 3 includes amplifiers 31 alternately connected to the first and second operational amplifiers 5 and 6, and an integral feedback loop 32 connected in parallel to the amplifiers 31, the output of the amplifier 31 being connected to the reference voltage source. A reference voltage source according to claim 1, which is adapted to act as an output of a reference voltage source. 4 The comparator 19 has two resistors 5 at its inverting input.
3 and 54 are connected,
The two resistors 53 and 54 are input resistances of the comparator 19, and the output of the operational amplifier 51 is connected via a capacitor 52 to the inverting input of the operational amplifier 51. Paragraph 1 or 3
Reference voltage source as described in section. 5 includes an amplifier 31 connected alternately to the first and second operational amplifiers 5 and 6, and an integral feedback loop 32 connected in parallel to the amplifier 31, the output of the amplifier 31 being connected to the reference voltage source. 3. The reference voltage source according to claim 2, wherein the reference voltage source serves as an output of the reference voltage source. 6 The comparator 19 has two resistors 5 at its inverting input.
3 and 54 are connected,
The two resistors 53 and 54 are input resistances of the comparator 19, and the output of the operational amplifier 51 is connected via a capacitor 52 to the inverting input of the operational amplifier 51. Reference voltage source according to item 2. 7. The reference voltage source according to claim 5 or 6, wherein the integrating circuit 23 is formed including an operational amplifier 26. 8 The integral feedback loop 32 is an integral operational amplifier 37
The reference voltage source according to claim 3 or 5, which is formed by including: 9 includes first and second bipolar elements 1 and 2, both ends of which are held at a constant DC voltage, in one opposing arm; first and second resistors (3 and 4) in the other; bridge circuits included in the opposing arms of the output terminal 16, which outputs a reference voltage; 8 and non-inverting inputs 20 and 21, the first operational amplifier 5 having an inverting input 7;
and an output are connected to the anode and cathode of the first bipolar element, respectively, and an inverting input 8 and an output of the second operational amplifier 6 are connected to the cathode and anode of the second bipolar element 2, respectively. The non-inverting input 21 of the second operational amplifier 6 is connected to the input terminal 22, and the input 61 is alternately connected to the outputs of the first and second operational amplifiers 5 and 6. a time-varying transition voltage ratio circuit 60 having an output connected to the output terminal 16; an input connected to the output terminal 16 of the reference voltage source; an AC to DC converter 17 that converts voltage to a DC voltage; a DC voltage setting circuit 18 that generates a second control voltage that finely controls the DC component at the output terminal 16; A comparator 19 connected to the output of the voltage converter 17 and having a second input connected to the output of the DC voltage setting circuit 18, the output of the comparator 19 being connected to the first operational amplifier. 5, connected to the non-inverting input 20 of the reference voltage source. 10 The circuit 60 having the time-varying transition voltage ratio includes a resistor 65 and a summing operational amplifier 62.
The summing operational amplifier 62 has at least two circuits connected in parallel to the inverting input 64 of the summing amplifier 62, each of which has a controlled switch 69, 70, 71 and a resistor 66, 6
10. The reference voltage source according to claim 9, wherein the reference voltage source is configured by arranging 7 and 68 in series. 11 the controlled switches 69, 70, 71 and the resistors 66, 67, 68 of each of the two circuits;
The connection points 72, 73, 74 are connected to the non-inverting input 78 of the summing operational amplifier 62 via the respective switches 75, 76, 77, and are connected to the reference voltage according to claim 10. source. 12 the output of the circuit 60 with the time varying transition voltage ratio is connected to a low pass filter 85;
A reference voltage source according to any one of claims 9 to 11.