JP3402782B2 - Voltage-current converter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage-current converter which outputs a current having a magnitude corresponding to an input voltage.

[0002]

2. Description of the Related Art An inverter consisting of an odd number of stages, which are cascaded so that the output of each stage is sequentially input to the next stage and the output of the final stage is fed back to the front stage, is known as a ring oscillator and Function as an oscillator that outputs a pulse. In particular, a voltage controlled oscillator (hereinafter abbreviated as VCO) capable of controlling the oscillation frequency of a ring oscillator according to an input voltage is often used for the purpose of generating a system clock of an arbitrary frequency of a microcomputer, for example. ing.

FIG. 4 is a circuit diagram showing the internal structure of a conventional VCO. In FIG. 4, 30 is a ring oscillator composed of three-stage inverters, and 29 is a voltage-current converter for adjusting the output frequency of the ring oscillator 30.

In the ring oscillator 29, each one of the PMOS type FETs 25a to 25c having the same structure and each one of the NMOS type FETs 26a to 26c having the same structure to each other.
And are connected in series to form the inverter circuits 32a to 32c. These three
The inverter circuits 32a to 32c of the stages are cyclically connected to their outputs and inputs so as to form a ring oscillator. Then, the pulse is taken out through the output terminal 28 connected to the output of the inverter circuit 32c.

In the voltage-current converter 29, a PMOS type FET (first transistor) 2 and an NMOS type FET are used.
A series circuit of (third transistor) 1 and (fourth transistor) 4 is inserted between a positive power supply (first DC power supply potential line) 10 and a negative power supply (second DC power supply potential line) 11. In addition, a PMOS type FET (second transistor) 3 and NM
A series circuit with an OS type FET (sixth transistor) 23 is also interposed between the positive power source 10 and the negative power source 11. The gate electrode of the FET2, the drain electrode of the FET2, and the gate electrode of the FET3 are connected to each other, and an NMOS is connected between these connection points and the negative power supply 11.
Type FET (fifth transistor) 5 is inserted.
The gate electrode of FET1 is connected to the input terminal 6,
The gate electrodes of the FETs 4 and 5 are both connected to the positive power source 10.

Further, the positive power source 10 has PMOS type FETs (seventh transistors) 24a to 24 having the same structure.
The source electrodes of c and the source electrodes of the NMOS type FETs (eighth transistors) 27a to 27c having the same structure are connected to the negative power source 11. Inverter circuits 32a to 32c are provided between the drain electrodes of the FETs 24a to 24c and the drain electrodes of the FETs 27a to 27c.
1 is inserted.

The gate electrodes of the FETs 24a to 24c are connected to the gate electrode of the FET3, and the FET2
The gate electrodes of 7a to 27c are connected to the gate electrode of the FET 23. The gate electrode of the FET 23 is connected to its drain electrode. That is, FET2,
3, 24a to 24c form a current mirror circuit, and similarly, the FETs 23 and 27a to 27c form another current mirror circuit.

Since this VCO is constructed as described above, it operates as follows. A DC voltage signal (input voltage) V _I ranging from the zero potential which is the potential of the negative power source 11 to the potential (power source voltage) of the positive power source 10 is input to the input terminal 6 of the voltage-current converter 29. First, the voltage signal V _I is 0V
From the threshold voltage V _{TH of the} FET1 (gate-source voltage for switching the FET from off to on), the FET1 is turned off (cut off). At this time, the current I ₁ flowing from the positive power source 10 to the FET ₂ is
Further, it flows through the FET 5 to the negative power source 11.

Since the FET 5 is always on, it functions as a resistance element. Since the gate electrode and the drain electrode of FET2 is connected, the magnitude of the current I ₁ is (the relationship between the voltage and current between the gate and the source) the input-output characteristic of the ON resistance of the size and FET2 of FET5 Determined by The gate-source voltage of the FET2, because approximately equal to the threshold voltage V _TH, the magnitude of the current I ₁ is determined mainly by FET5 ON voltage.

Since the FET 2 and the FET 3 form a current mirror circuit, a current I ₂ proportional to the current I ₁ flows from the positive power source 10 to the FET ₃ . The proportional coefficient is FE
Channel width W and channel length L in T2 and FET3
If, for example, FET2 and FET3 are the same as each other, the current I ₂ has the same magnitude as the current I ₁ .

Further, since each of the FET2 and each of the FETs 24a to 24c constitutes a current mirror circuit, the FET2
A current I ₃ proportional to the current I ₁ flows through each 1 of 4a to 24c. The current I ₂ further passes through the FET 23 and flows to the negative power source 11. At this time, the gate-source voltage of the FET 23 is determined by the input / output characteristic of the FET 23 and the current I ₂ . And FET23 and FET27a-27
Since each 1 of c constitutes a current mirror circuit,
Each 1 T27a～27c, flows a current proportional to the current I _2.

Each of the FETs 27a to 27c and the FET 24
The same current I is applied to each of a to 24c. ₃So that
FET2, ratio of current between 24a-24c and FET2
The ratio of the currents between 3, 27a to 27c is the same as each other.
So that the channel width W,
The flannel length L is set.

As described above, when the voltage signal V _I has a value equal to or lower than the threshold voltage V _{TH of the} FET 1, the inverter circuit 3
A current I ₃ mainly determined by the on-resistance of the FET 5 is supplied to each 1 of 2a to 32c.

Next, when the voltage signal V _I has a value between the threshold voltage V _{TH of the} FET 1 and the power supply voltage, the FET ₁ is turned on, so that the current I ₁ is the current flowing through the series circuit of the FET ₁ and the FET 4. It is the sum of the current flowing through the FET5. Since the FET 4 is always on, it functions as a resistance element like the FET 5. The magnitude of the current flowing through the FET 1 depends on the voltage signal V _I , the on-resistance of the FET 4, and F
Determined by the input / output characteristics of ET1.

Since the gate-source voltage of the FET1 is approximately equal to its threshold voltage V _TH , the magnitude of the current flowing through the FET1 is mainly determined by the magnitude of the ON resistance of the FET4 and the voltage signal V _I. The higher the voltage signal V _I , the more F
The current flowing through ET1 becomes large. When the voltage signal V _I exceeds the threshold voltage V _TH , it is desirable that the magnitude of the current I ₁ is sensitively changed by the voltage signal V _I.
The on resistance of T4 is set sufficiently lower than the on resistance of FET5. That is, of the two components of the current I ₁ , the current flowing through the FET 4 is more dominant than the current flowing through the FET 5. Therefore, the voltage signal V _I
When exceeding the threshold voltage V _TH, the current I ₁ and the voltage signal V _I
Increases linearly with the rise of.

Since the higher the voltage signal V _I is, the larger the current I ₁ is, the current mirror effect causes the FETs 24a ...
The current I ₃ flowing through the 24c and the FETs 27a to 27c also becomes large. That is, the voltage signal V _I is the threshold voltage V ₁ of the FET 1.
When it exceeds _TH , each of the inverter circuits 32a to 32c has a current I _{3 of} a magnitude corresponding to the height of the voltage signal V _I.
Is supplied.

The oscillation frequency of the ring oscillator 30 is mainly the sum of the gate capacitance of each of the inverter circuits 32a to 32c and the wiring capacitance parasitic to the wiring connecting between the inverter circuits 32a to 32c, and these capacitances. It depends on the magnitude of the current I ₃ provided to discharge.
Since the gate capacitance and the wiring capacitance are constants, the oscillation frequency is mainly determined by the current I ₃ and is approximately proportional.

Therefore, in the region where the voltage signal V _I exceeds the threshold voltage V _TH , the frequency f _{OUT of the} output pulse output from the output terminal 28 rises approximately linearly with the rise of the voltage signal V _I. . Thus, in this VCO, it is possible to set the frequency f _{OUT of the} output pulse to a desired magnitude depending on the magnitude of the voltage signal V _I.

[0019]

The conventional VCO described above has a problem that the frequency f _{OUT of the} output pulse fluctuates with the fluctuation of the power supply voltage. FIG. 5 shows the frequency f for various power supply voltages V _CC .
₇ is a graph showing the relationship between _OUT and the voltage signal V _I. As shown in FIG. 5, even the voltage signal V _I constant, the frequency f _OUT is highly dependent on the power supply voltage V _CC, the frequency f _OUT as the power supply voltage V _CC is high is higher.

First, in the voltage-current converter 29, the higher the power supply voltage V _CC is, the higher the gate-source voltage in the FET 2 is, so that the current I ₁ is increased, and accordingly, the current I ₂ is increased. And mainly because the current I ₃ becomes large. That is, when expressed by a mathematical formula,

[0021]

[Equation 1]

[0022]

[Equation 2]

It becomes By increasing the current I ₃ supplied to the inverter circuits 32a to 32c, the frequency f
The rise of _OUT is brought.

Second, even if the current I ₃ supplied to the ring oscillator 30 is constant, the frequency f _OUT of the pulse output by the ring oscillator 30 changes as the power supply voltage V _CC changes. . For example, when the power supply voltage V _CC increases, the voltage applied to the ring oscillator 30 also increases, and the operating speed of the FETs 25a to 25c and 27a to 27c included in the ring oscillator 30 increases accordingly. As a result, the frequency f _OUT increases. This is another cause of the frequency f _OUT depending on the power supply voltage V _CC .

As described above, the conventional voltage-current converter 2
The VCO using 9 has a problem that the frequency f _{OUT of the} output pulse fluctuates with the fluctuation of the power supply voltage V _CC .

The present invention has been made to solve the above-mentioned problems in the conventional voltage-current converter.
An object of the present invention is to provide a voltage-current converter capable of outputting a pulse with a stable frequency by a voltage controlled oscillator even if the power supply voltage fluctuates.

[0027]

According to another aspect of the present invention, there is provided a voltage-current converter according to claim 1, wherein one main electrode of the first and second transistors forming a mutual current mirror circuit is a first DC power supply potential line. The control electrode and the other main electrode of the first transistor are connected to each other, and the third transistor is interposed between the other main electrode and the second DC power supply potential line, In a voltage-current converter capable of adjusting a current flowing through the second transistor according to an input voltage input to a control electrode of the third transistor, the voltage-current converter is interposed between the third transistor and the second DC power supply potential line. And a voltage generating means for supplying a control voltage to the control electrode of the fourth transistor, the voltage generating means increasing the power supply voltage. With the change to fine down and outputs the control voltage as the on resistance of the fourth transistor is increased and decreased, respectively.

According to a second aspect of the present invention, there is provided the voltage-current conversion device according to the first aspect, wherein the voltage-current conversion device is provided between the other main electrode of the first transistor and the second power supply potential line. A fifth transistor further inserted and connected in parallel with the third transistor;
Another voltage generating means for supplying a control voltage to the control electrode of the fifth transistor is further provided, and the other voltage generating means turns on the fifth transistor as the power supply voltage rises and falls. The control voltage is output so that the resistance increases and decreases, respectively.

According to a third aspect of the present invention, in the voltage-current converter according to the first aspect, one main electrode is connected to the second power supply potential line and the other main electrode and the control electrode are connected. And a sixth transistor connected to the other main electrode of the second transistor, and a current mirror circuit with the first transistor, and an odd number of first main electrodes connected to the first DC power supply potential line. 7
The present invention is characterized by including a transistor and a current mirror circuit together with the sixth transistor and the same number of eighth transistors as the seventh transistor whose one main electrode is connected to the second DC power supply potential line.

A voltage-current converter according to a fourth aspect of the present invention is the voltage-current converter according to the first or second aspect, wherein the voltage generating means includes a constant voltage generating means and an inverting amplifying means. And the inverting amplification means carries out inverting amplification of the power supply voltage using the output voltage of the constant voltage generation means as a reference voltage.

[0031]

[Action]

<Operation of the Invention According to Claim 1> In the voltage-current converter of the present invention, the current flowing through the second transistor can be taken out as the output current through the other main electrode of the second transistor. The magnitude of the output current flowing through the second transistor is proportional to the magnitude of the current flowing through the first transistor due to the current mirror effect. Furthermore, since the fourth transistor is interposed between the third transistor and the second DC power supply potential line, the current flowing through the first transistor is limited by the on resistance of the fourth transistor. Moreover, since the ON resistance of the fourth transistor increases and decreases with the rise and fall of the power supply voltage, respectively, due to the function of the voltage generating means, the variation in the current flowing through the first transistor due to the variation of the power supply voltage is It will be alleviated or eliminated, or it will be a fluctuation in the opposite direction. As a result, fluctuations in the output current are alleviated or eliminated, or fluctuations in the opposite direction occur.

<Operation of the Invention According to Claim 2> In the voltage-current converter of the present invention, the fifth transistor is provided between the first transistor and the second DC power supply potential line in parallel with the third transistor. Since it is inserted, the current flowing through the first transistor flows through the fifth transistor when an input voltage that cuts off the third transistor is applied. That is, even if the input voltage is applied so as to minimize the output current, a finite non-zero current flows through the first transistor. As a result, the minimum value of the output current becomes a finite value that is not zero.

Moreover, since the ON resistance of the fifth transistor increases and decreases with the rise and fall of the power supply voltage by the action of the other voltage generating means, the current flowing through the first transistor through the fifth transistor is increased. The fluctuation due to the fluctuation of the power supply voltage in
It will be alleviated or eliminated, or it will be a fluctuation in the opposite direction. As a result, fluctuations in the output current are alleviated or eliminated, or fluctuations in the opposite direction occur.

<Operation of the Invention of Claim 3> In the voltage-current converter of this invention, the output current can be taken out through the other main electrodes of the seventh and eighth transistors. The current flowing through the second transistor also flows through the sixth transistor, and since the seventh and eighth transistors form a current mirror circuit with the second and sixth transistors, respectively, the seventh and eighth transistors have A current proportional to the current flowing through the second transistor flows. Therefore, the fluctuations of the currents flowing through the seventh and eighth transistors, that is, the currents that can be taken out as the output currents due to the fluctuations of the power supply voltage are alleviated or eliminated, or the fluctuations in the opposite direction are caused.

<Operation of the Invention According to Claim 4> In the voltage-current converter of the present invention, the voltage generating means is easily constructed by using the constant voltage generating means and the inverting amplifying means.

[0036]

【Example】

<First Embodiment> First, a first embodiment of the present invention will be described. FIG. 1 is a circuit diagram showing the configuration of the voltage-current converter 42 of this embodiment. In the following figures, FIG.
The same parts as those of the conventional device shown in FIG. FIG. 1 shows a voltage-current converter 4
A ring oscillator 30 is depicted with 2 and these constitute the VCO. The voltage-current converter 42 is
A characteristic difference from the conventional voltage-current converter 29 is that the gate electrodes of the FET 4 and the FET 5 are connected to the voltage generator units (voltage generators) 8 and 9, respectively.

FIG. 2 is a circuit diagram showing the internal structure of the voltage generator unit 8. The voltage generator unit 9 is also configured similarly to the voltage generator unit 8, and therefore the voltage generator unit 8 represents both of them. The voltage generator unit 8 has a constant voltage circuit (constant voltage generating means) 41 and an inverting amplifier circuit (inverting amplifier means) 43 which are coupled to each other.

The inverting amplifier circuit 43 is a differential input type amplifier 2
1, the negative feedback resistor 20 is connected between the output of the amplifier 21 and the inverting input, and the input side resistor 19 is connected between the inverting input and the positive power supply 10. .
The output from the constant voltage circuit 41 is connected to the non-inverting input of the amplifier 21. Therefore, the inverting amplifier circuit 43 uses the output voltage supplied from the constant voltage circuit 41 as a reference voltage and has the amplification factor determined by the ratio of the resistance values of the two resistors 19 and 20, that is, the potential of the positive power source 10, that is, the power source voltage V _CC. Is inverted and amplified.

The constant voltage circuit 41 includes a positive power source 10 and a negative power source 1.
Two series circuits are inserted in parallel with each other. One series circuit is composed of a PMOS type FET 12, NMOS type FETs 14 and 16 and a resistor 18 which are connected in series from the positive power source 10 side in sequence.
Type FETs 15 and 17 are connected in series. FET
The gate electrodes are connected to each other between the FET 12 and the FET 13, and the FET 14 and the FET 15 and the FET 16 and the FE are connected.
The gate electrodes are also connected to each other during T17. Furthermore, in the FETs 12, 15, and 17, the respective gate electrodes and drain electrodes are connected to each other.

In the constant voltage circuit 41 thus constructed, a substantially constant current, which does not depend on the power supply voltage V _CC , flows in each series circuit. The magnitude of this current can be set to a desired magnitude by adjusting the resistance value of the resistor 18. The potential Vr of the gate electrode of the FET 15 is determined by the magnitude of the current flowing through the series circuit including the FET 15 and the input / output characteristics of the FETs 15 and 17.

Therefore, the potential Vr has a substantially constant value that does not depend so much on the power supply voltage V _CC . The gate electrode of this FET 15 is connected to the non-inverting input of the amplifier 21. That is, as the reference voltage of the inverting amplifier circuit 43, the power supply voltage V
_CC is supplied with a substantially constant potential Vr that does not depend so much.
As a result, as the power supply voltage V _CC fluctuates, the amplifier 2
The output voltage of 1 fluctuates in the opposite direction. This output voltage is supplied to the gate electrode of the FET 4 as the output voltage V _B of the voltage generator unit 8.

Next, this will be described quantitatively. The relationship between the output voltage V _B , the power supply voltage V _CC and the reference voltage Vr is

[0043]

[Equation 3]

It is expressed as In the formula 3, R ₁₉ ,
R ₂₀ is the resistance value of the input side resistance 19 and the negative feedback resistance 20, respectively. As described above, since the reference voltage Vr has little dependence on the power supply voltage V _CC , by appropriately setting the resistance values of the input side resistor 19 and the negative feedback resistor 20,

[0045]

[Equation 4]

It is possible to set At this time, when the power supply voltage V _CC increases, the on-resistance of the FET 4 increases, and conversely, when the power supply voltage V _CC decreases, the on-resistance decreases.

The same applies from the voltage generator 9 to the FE.
The same applies to the output voltage to the gate electrode of T5. As a result, making the current I ₂ independent of the power supply voltage V _CC or in the reverse direction, that is,

[0048]

[Equation 5]

It is possible to: At this time, the current I ₃ flowing in proportion to the current I ₂ is also

[0050]

[Equation 6]

It becomes

As described above, the resistance values of the input side resistor 19 and the negative feedback resistor 20 are properly set, in other words,
By appropriately setting the value of the negative amplification factor of the power supply voltage V _CC in the voltage generator unit 8, the current I ₂ and the current I ₃ are made constant values independent of the power supply voltage V _CC , or these currents are set. _Can depend on the supply voltage V _CC in the reverse direction.

By setting the current I ₃ to a constant value that does not depend on the power supply voltage V _CC , the current supplied to the ring oscillator 30 can be stabilized and the dependence of the frequency f _{OUT on} the power supply voltage V _CC can be relaxed. Furthermore, by making the current I ₃ negatively dependent on the power supply voltage V _CC ,
It is possible to cancel the dependency of the ring oscillator 30 itself on the power supply voltage V _CC , and make the frequency f _{OUT a} stable value that does not depend on the power supply voltage V _CC .

Alternatively, even if the current I ₃ still depends on the power supply voltage V _CC in the positive direction, but only by reducing the dependence, the power supply voltage V _OUT of the frequency f _OUT of the ring oscillator 30.
The dependence on _CC can be softened.

<Second Embodiment> Next, a second embodiment of the present invention will be described. FIG. 3 is a circuit diagram showing the configuration of the voltage-current converter 40 of this embodiment. As shown in FIG. 3, the voltage-current converter 40 includes a FET 23, 24a to 24c, 27a to 2 in a voltage-current converter 42.
It corresponds to the portion where 7c is removed. Voltage-current converter 40
Then, the output terminal 7 is connected to the drain electrode of the FET 3, and the current I ₂ is output as an output current through the output terminal 7. Therefore, by appropriately adjusting the input side resistor 19 and the negative feedback resistor 20 in the voltage generator unit 8 and the voltage generator unit 9, the output current (= current I ₂ ) is a stable value that does not depend on the power supply voltage V _CC. , Or a value that depends negatively on the power supply voltage V _CC . By doing so, this voltage-current converter 4
0 can be used not only for the VCO but also for various devices that require a stable output current or an output current negatively dependent on the power supply voltage V _CC .

[0056]

【The invention's effect】

<Effect of the Invention According to Claim 1> In the voltage-current converter of the present invention, the ON resistance of the fourth transistor increases and decreases with the rise and fall of the power supply voltage, respectively, due to the function of the voltage generating means. Therefore, the fluctuation of the output current due to the fluctuation of the power supply voltage is alleviated or eliminated, or becomes the fluctuation in the opposite direction. Therefore, by using this voltage-current converter for a VCO, for example, the dependency of the frequency of the output pulse on the power supply voltage can be alleviated or eliminated.

<Effect of the Invention According to Claim 2> Since the voltage-current converter of the present invention includes the fifth transistor, the minimum value of the output current becomes a finite value which is not zero. Therefore, when used for a VCO, for example, the minimum value of the frequency of the output pulse does not become zero, so there is no fear that the VCO will stop its function depending on the magnitude of the input voltage.
Moreover, since another voltage generating means is provided, fluctuations in the output current due to fluctuations in the power supply voltage are alleviated or eliminated, or fluctuations in the opposite direction occur. Therefore, by using this voltage-current converter for a VCO, for example, the dependency of the frequency of the output pulse on the power supply voltage can be alleviated or eliminated.

<Effect of the Invention According to Claim 3> In the voltage-current converter of this invention, the current flowing through the second transistor also flows through the sixth transistor, and the seventh and eighth transistors are provided.
Since the transistor forms a current mirror circuit with the second and sixth transistors, respectively, the seventh and eighth transistors are provided.
A current proportional to the current flowing through the second transistor flows through the transistor. As a result, the fluctuations of the currents flowing through the seventh and eighth transistors, that is, the fluctuations of the power supply voltage in the currents that can be taken out as the output currents are alleviated or eliminated, or the fluctuations in the opposite direction are caused. Therefore, by using this voltage-current converter for a VCO, for example, the dependency of the frequency of the output pulse on the power supply voltage can be alleviated or eliminated. Moreover, by inserting a ring oscillator, for example, between the other main electrode of the seventh transistor and the other main electrode of the eighth transistor, V
This voltage-current converter is particularly suitable for use in a VCO, since the CO can be easily constructed.

<Effect of Invention of Claim 4> In the voltage-current converter of this invention, the voltage generating means is easily constructed by using the constant voltage generating means and the inverting amplifying means.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a VCO in which a voltage-current converter of the first embodiment is incorporated.

FIG. 2 is a circuit diagram of a voltage generator unit of the first embodiment.

FIG. 3 is a circuit diagram of a voltage-current converter of a second embodiment.

FIG. 4 is a VC in which a conventional voltage-current converter is incorporated.
It is a circuit diagram of O.

FIG. 5: VC incorporating a conventional voltage-current converter
It is a graph which shows the characteristic of O.

[Explanation of symbols]

1 FET (third transistor), 2 FET (first transistor), 3 FET (second transistor), 4
FET (fourth transistor), 5 FET (fifth transistor), 8, 9 voltage generator unit (voltage generator),
10 Positive power supply (first DC power supply potential line), 11 Negative power supply (second DC power supply potential line), 23 FET (sixth transistor), 24a to 24c FET (seventh transistor), 27a to 27c FET (eighth transistor) ),
40, 42 voltage-current converter, 41 constant voltage circuit (constant voltage generating means), 43 inverting amplifier circuit (inverting amplifier means),
V _I voltage signal (input voltage), Vr reference voltage.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-14136 (JP, A) JP-A-1-137808 (JP, A) JP-A-5-343956 (JP, A) JP-A-59- 196613 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03F 3/34 H03K 3/03

Claims (4)

(57) [Claims] 1. A first main electrode of a first and a second transistor, which form a current mirror circuit, is connected to a first DC power supply potential line, and a control electrode and a second main electrode of the first transistor are connected to each other. In addition, the third transistor is inserted between the other main electrode and the second DC power supply potential line, so that the second transistor is opened in accordance with the input voltage input to the control electrode of the third transistor. A voltage-current converter capable of adjusting a flowing current, wherein a voltage for supplying a control voltage to a fourth transistor interposed between the third transistor and the second DC power supply potential line and a control electrode of the fourth transistor. The voltage generating means further includes an ON resistance of each of the fourth transistors as the power supply voltage rises and falls. Increases and the voltage-current conversion device and outputs the control voltage to decrease. 2. The voltage-current conversion device according to claim 1, wherein the voltage transistor is further interposed between the other main electrode of the first transistor and the second power supply potential line, and is connected in parallel with the third transistor. A fifth transistor that is
It further comprises another voltage generating means for supplying a control voltage to the control electrode of the fifth transistor, wherein the other voltage generating means turns on the fifth transistor as the power supply voltage rises and falls. A voltage-current converter, wherein the control voltage is output so that the resistance increases and decreases, respectively. 3. The voltage-current converter according to claim 1, wherein one main electrode is connected to the second power supply potential line, and the other main electrode and the control electrode are connected to the other main electrode of the second transistor. A sixth transistor, a current mirror circuit with the first transistor, and an odd number of seventh transistors whose main electrode is connected to the first DC power supply potential line, and a current mirror circuit with the sixth transistor In addition, the voltage-current conversion device is characterized in that the one main electrode includes the seventh transistor and the same number of eighth transistors connected to the second DC power supply potential line. 4. The voltage-current converter according to claim 1 or 2, wherein the voltage generating means comprises constant voltage generating means and inverting amplifying means, and the inverting amplifying means is the constant voltage generating means. A voltage-current converter characterized in that the power supply voltage is inverted and amplified by using an output voltage as a reference voltage.