JP4808047B2 - Current source circuit - Google Patents

Description

  The present invention relates to a current source circuit, and more particularly to a current source circuit that does not have temperature dependence and that can obtain an output current that is linearly proportional to a drive terminal voltage.

となる。この式から、トランジスタＱのベース−エミッタ間電圧Ｖ_BEを一定とした場合、駆動端子電圧Ｖ２に比例した出力電流Ｉoutを得られることが分かる。 In FIG. 12, one end of a resistor R is connected to the emitter of an NPN transistor Q whose base is a drive terminal by a drive terminal voltage V2, and the other end of the resistor R is connected to a reference potential (GND). This is a circuit representing a conventional current source circuit in which the collector of the output is output to the load 1. In this current source circuit, the output current Iout is

It becomes. From this equation, it can be seen that when the base-emitter voltage V _BE of the transistor Q is constant, an output current Iout proportional to the drive terminal voltage V2 can be obtained.

より、

となる。 However, the temperature coefficient TC _F output current Iout,

Than,

It becomes.

となり、動作温度範囲の中央付近の温度Ｔに対してこの式を満たすように駆動端子電圧Ｖ２を設定できれば、温度依存性をほとんど持たない出力電流Ｉoutを得ることができるが、実際には駆動端子電圧Ｖ２に制約があるため、この従来の電流源回路では温度依存性を持たない出力電流Ｉoutを得ることはできない。 Here, if the temperature coefficient TC _F = 0,

Thus, if the drive terminal voltage V2 can be set so as to satisfy this expression with respect to the temperature T near the center of the operating temperature range, an output current Iout having almost no temperature dependence can be obtained. Since the voltage V2 is limited, this conventional current source circuit cannot obtain the output current Iout having no temperature dependence.

  A SPICE simulation was performed on the current source circuit of FIG. FIG. 13 shows the simulation circuit, in which the resistor RL is a load resistor corresponding to the load 1 and Vcc is a power supply voltage. As an example, the change range of the drive terminal voltage V2 is 0.6 V (1.5 V to 2.1 V), and the circuit constant is set so that the output current Iout is about 30 μA.

  FIG. 14 shows a simulation result of the Iout-T characteristic of the current source circuit of FIG. The vertical axis represents the output current Iout [A], and the horizontal axis represents the temperature T [° C.], which represents the temperature dependence of the output current. In the conventional current source circuit of FIG. 13, it can be seen that the output current Iout has temperature dependence. FIG. 15 shows a simulation result of the Iout-V2 characteristic of the current source circuit of FIG. The vertical axis represents the output current Iout [A], and the horizontal axis represents the drive terminal voltage V2 [V], which represents the linearity of the output current with respect to the drive terminal voltage V2. It can be seen that the output current Iout varies approximately linearly with respect to the drive terminal voltage V2, but the slope of the output current Iout varies depending on the temperature dependence.

  In FIG. 16, the emitter of a PNP transistor Q2 and the emitter of a PNP transistor Q3 are connected to the emitter of a PNP transistor Q1 to which the drive terminal voltage V2 is input, and the base and collector of the transistor Q2 are connected to the base of the transistor Q1. The collector of the NPN transistor Q4 is connected, the collector of the transistor Q1 is connected to the base of the transistor Q3 and the collector of the NPN transistor Q5 whose emitter area is n times that of the transistor Q4, and the collector of the transistor Q3 is connected to the transistor Q4. The base of the transistor Q5 and the base of the NPN transistor Q6 are connected, one end of the resistor R1 and one end of the resistor R2 are connected to the emitter of the transistor Q4, and the other end of the resistor R1 is connected to the emitter of the transistor Q5. , Trang One other end of the resistor R3 is connected to the emitter of the star Q6, the other end of the resistor R2 and the other end of the resistor R3 are connected to the reference potential GND, and another conventional current having the collector of the transistor Q6 as the output of the current source circuit. The source circuit is shown. Except for the transistor Q6 and the resistor R3, a bandgap reference voltage generation circuit is configured.

の関係が成り立つので、図１６の回路においてトランジスタＱ６のベース電圧Ｖ１は、

となり、電圧Ｖ１の温度係数は、

となる。 In general, between the base-emitter voltage V _BE and the collector current Ic of a transistor,

Therefore, the base voltage V1 of the transistor Q6 in the circuit of FIG.

The temperature coefficient of voltage V1 is

It becomes.

となる。ここで、

となる。 The output current Iout is

It becomes. here,

It becomes.

となり、ＴＣ_F＝０とおくと、

となる。 The temperature coefficient TC _F of the output current Iout is

When TC _F = 0,

It becomes.

The collector current I _C4 of the transistor Q4 is determined by the resistors R1 and R2 and the emitter area magnification n, and the output current Iout is determined by the resistor R3. By adjusting the resistors R1, R2, and R3 and the emitter area magnification n so as to satisfy the above, an output current Iout having almost no temperature dependence can be obtained. However, in this circuit configuration, even if the drive terminal voltage V2 is changed, the output current Iout does not change and becomes constant.

  As described above, in the conventional current source circuit, the output current Iout is proportional to the drive terminal voltage V2 but has temperature dependence (FIG. 12), or has no temperature dependence but is a constant current (FIG. 16). ).

  An object of the present invention is to provide a current source circuit that solves the above-described problems, can obtain an output current having almost no temperature dependence, and can obtain an output current proportional to a drive terminal voltage. .

In order to achieve the above object, a current source circuit according to a first aspect of the present invention includes a first voltage generation circuit that outputs a voltage having a temperature dependency, and the temperature dependency output from the first voltage generation circuit. A voltage-current conversion circuit that inputs a voltage having a characteristic and outputs a current having no temperature dependence; and a second voltage supply circuit that supplies a drive terminal voltage to the first voltage generation circuit and the voltage-current conversion circuit And a voltage generation circuit, wherein an output current of the voltage-current generation circuit linearly changes in accordance with a change in drive terminal voltage supplied from the second voltage generation circuit.
According to a second aspect of the present invention, in the current source circuit according to the first aspect, the first voltage generation circuit includes a first output terminal connected to a first output terminal of the second voltage generation circuit. A first conductive type transistor; a first conductive type second transistor having an emitter connected to the first output terminal of the second voltage generating circuit and a base connected to the base of the first transistor; A third transistor of a first conductivity type having an emitter connected to the first output terminal of the second voltage generation circuit and a base connected to a collector of the first transistor; A fourth transistor of the second conductivity type connected to the bases of the first and second transistors and the collector of the second transistor, the base being connected to the collector of the third transistor; A fifth transistor of a second conductivity type having a reflector connected to the collector of the first transistor, a base connected to the base of the fourth transistor, and an emitter area n times the emitter area of the fourth transistor; One end connected to the emitter of the fifth transistor, one end connected to the other end of the first resistor and the emitter of the fourth transistor, and the other end connected to a reference potential. The voltage-current conversion circuit including an emitter connected to the reference potential via a third resistor, a base connected to the collector of the third transistor, and a collector connected to the fourth resistor. A second transistor of the second conductivity type connected to the first output terminal of the second voltage generation circuit via the second transistor, and a base connected to the collector of the sixth transistor. It is and a seventh transistor of the second conductivity type having an emitter current is taken out from the collector is connected to the reference potential via a fifth resistor, characterized in that.
According to a third aspect of the present invention, in the current source circuit according to the second aspect, a current generation circuit is connected between the collector of the third transistor and the reference potential in the first voltage generation circuit. It is characterized by.
According to a fourth aspect of the present invention, in the current source circuit according to the second or third aspect, a third voltage is provided between the collector of the second transistor and the collector of the fourth transistor in the first voltage generation circuit. The voltage generation circuit is inserted and connected, and a fourth voltage generation circuit is inserted and connected between the collector of the first transistor and the collector of the fifth transistor.
According to a fifth aspect of the present invention, in the current source circuit according to the second or third aspect, between the collector of the sixth transistor and the base of the seventh transistor in the voltage-current conversion circuit, At least one emitter follower connected between the first output terminal of the second voltage generation circuit and the reference potential is connected.
According to a sixth aspect of the present invention, in the current source circuit according to the fifth aspect, a fifth current source circuit is provided between a collector of the transistor constituting the emitter follower and the first output terminal of the second voltage generation circuit. A voltage generation circuit is inserted and connected.
According to a seventh aspect of the present invention, in the current source circuit according to the second, fifth or sixth aspect, the first output terminal of the second voltage generation circuit in the voltage-current conversion circuit is connected to the second output terminal. The second output terminal of the voltage generation circuit is replaced.

  According to the present invention, the output voltage of the first voltage generation circuit is temperature-compensated to have temperature independence, whereby an output current having a small temperature dependency can be obtained from the voltage-current conversion circuit. The output current can be linearly changed by the drive terminal voltage output from the second voltage generation circuit. Further, the operation potential of the transistor is adjusted by using the current generation circuit and the third and fourth voltage generation circuits, or the drive terminal voltages of the first voltage generation circuit and the voltage-current conversion circuit are made separate. As a result, the influence of the Early effect can be reduced, and an output current with better linearity can be obtained with respect to changes in the drive terminal voltage.

  Hereinafter, the present invention will be described in detail with reference to FIGS. The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.

  FIG. 1 is a block diagram showing a basic configuration example of a current source circuit according to an embodiment of the present invention. In the current source circuit according to the embodiment of the present invention, the current source circuit body 10 is configured by connecting the voltage-current conversion circuit 12 to the first voltage generation circuit 11, and the current source circuit body 10 has a second The drive terminal voltages V2 and V3 output from the voltage generation circuit 20 are supplied as power supply voltages. The temperature dependency of the output current Iout of the voltage-current conversion circuit 12 is eliminated by giving the first voltage generation circuit 11 temperature dependency so as to cancel the temperature dependency of the current source circuit body 10. Yes. Further, by changing the drive terminal voltage V2 of the second voltage generation circuit 2, the output current Iout can be changed linearly. Furthermore, the early effect is reduced by realizing the drive terminal voltages of the first voltage generation circuit 11 and the voltage-current conversion circuit 12 as separate voltages V2 and V3, thereby realizing better linearity.

  FIG. 2 is a circuit diagram showing a more specific example 1 based on the basic configuration example shown in FIG. In the circuit of FIG. 2, the emitter of a PNP transistor Q2 and the emitter of a PNP transistor Q3 are connected to the emitter of a PNP transistor Q1 to which the drive terminal voltage V2 is input, and the base of the transistor Q2 is connected to the base of the transistor Q1. The collector of the NPN transistor Q4 is connected to the collector of the transistor Q1, the collector of the transistor Q1 is connected to the base of the transistor Q3 and the collector of the NPN transistor Q5 having an emitter area n times that of the transistor Q4. Are connected to the base of the transistor Q4, the base of the transistor Q5 and the base of the NPN transistor Q6, one end of the resistor R1 and one end of the resistor R2 are connected to the emitter of the transistor Q4, and the other end of the resistor R1 is connected to the emitter of the transistor Q5. Connect One end of the resistor R3 is connected to the emitter of the transistor Q6, the other end of the resistor R2 and the other end of the resistor R3 are connected to the reference potential GND, one end of the resistor R4 is connected to the emitter of the transistor Q1, and the collector of the transistor Q6 is connected. The other end of the resistor R4 and the base of the NPN transistor Q7 are connected, one end of the resistor R5 is connected to the emitter of the transistor Q7, the other end of the resistor R5 is connected to GND, and the collector of the transistor Q7 is connected to the current source circuit. It is a circuit that outputs. Reference numeral 13 denotes a starting circuit for the first voltage generation circuit 11.

となる。各トランジスタのベース−エミッタ間電圧Ｖ_BEを一定（同一）とすると、出力電流Ｉoutは駆動端子電圧Ｖ２に比例するため、駆動端子電圧Ｖ２を可変することで出力電流Ｉoutを線形に可変できることが分かる。ここで、抵抗Ｒ３と抵抗Ｒ４を同種の抵抗にすれば、同じ温度係数を持つため、Ｒ４／Ｒ３＝Ｋ＝一定と置くことができる。 In the circuit of FIG. 2, the output current Iout is

It becomes. Assuming that the base-emitter voltage V _BE of each transistor is constant (same), the output current Iout is proportional to the drive terminal voltage V2. Therefore, it can be seen that the output current Iout can be varied linearly by varying the drive terminal voltage V2. . Here, if the resistors R3 and R4 are of the same type, they have the same temperature coefficient, so that R4 / R3 = K = constant.

となるため、出力電流Ｉoutの温度係数ＴＣ_Fは、

となる。 Therefore,

Becomes, the temperature coefficient TC _F of the output current Iout and,

It becomes.

となる。ここで、トランジスタＱ４のコレクタ電流Ｉ_C4は抵抗Ｒ１、Ｒ２とエミッタ面積倍率ｎによって決定され、トランジスタＱ６のコレクタ電流Ｉ_C6は抵抗Ｒ３によって決定され、更に出力電流Ｉoutは抵抗Ｒによって決定されるため、動作温度範囲の中央付近の温度Ｔに対して(2)式を満たすように抵抗Ｒ１、Ｒ２、Ｒ３、Ｒ４、Ｒ５とエミッタ面積倍率ｎを調整することで、温度依存性をほとんど持たない出力電流Ｉoutを得ることができる。 If TC _F = 0

It becomes. Here, the collector current I _C4 of the transistor Q4 is determined by the resistors R1 and R2 and the emitter area magnification n, the collector current I _C6 of the transistor Q6 is determined by the resistor R3, and the output current Iout is further determined by the resistor R. By adjusting the resistors R1, R2, R3, R4, R5 and the emitter area magnification n so that the equation (2) is satisfied with respect to the temperature T near the center of the operating temperature range, the output having little temperature dependence A current Iout can be obtained.

となる。したがって、実施例１ではアーリー電圧ＶＡの影響を無視し、ベース−エミッタ間電圧Ｖ_BEを一定としたが、実際のＶ_BEはＶＡの非線形の影響を受けるため、駆動端子電圧Ｖ２を可変した場合、トランジスタのアーリー効果によってその電圧Ｖ２に対する出力電流Ｉoutの線形性が損なわれる。 FIG. 3 shows a more specific embodiment 2 based on the basic configuration example shown in FIG. Generally, when the base-emitter voltage V _BE of a transistor is included including the early voltage VA of the transistor,

It becomes. Therefore, in the first embodiment, the influence of the early voltage VA is ignored and the base-emitter voltage V _BE is made constant. However, since the actual V _BE is influenced by the non-linear influence of VA, the drive terminal voltage V2 is varied. The linearity of the output current Iout with respect to the voltage V2 is impaired by the Early effect of the transistor.

  Therefore, in the second embodiment, with respect to the current source circuit of FIG. 2, one terminal of the current generation circuit 111 is connected to the collector of the transistor Q3, the other terminal of the current generation circuit 111 is connected to GND, and the current generation circuit 111 is connected. Is adjusted to adjust the base potential of the transistor Q3, that is, the collector potential of the transistor Q5, so that the effects of the Early effect of the transistors Q4 and Q5 are substantially equal, and the output current Iout with respect to the change of the drive terminal voltage V2 The linearity of has been improved. As the current generation circuit 111, for example, a resistor can be used.

  FIG. 4 shows a more specific embodiment 3 based on the basic configuration example shown in FIG. In the current source circuit of FIG. 4, instead of connecting the collector of the transistor Q4 to the base of the transistor Q1 shown in FIG. 3, one terminal of the voltage generating circuit 112 is connected to the base of the transistor Q1, and the collector of the transistor Q4 is connected. Instead of connecting the other terminal of the voltage generating circuit 112 and connecting the collector of the transistor Q5 to the collector of the transistor Q1, one terminal of the voltage generating circuit 113 is connected to the collector of the transistor Q1, and the voltage is generated to the collector of the transistor Q5. By connecting the other terminal of the circuit 113, the effect of the Early effect of the transistor Q4 and the transistor Q5 is reduced, and the linearity of the output current Iout with respect to the drive terminal voltage V2 is improved. For example, a resistor or a diode can be used as the current generation circuit 112 and the current generation circuit 113.

  FIG. 5 shows a more specific embodiment 4 based on the basic configuration example shown in FIG. In the current source circuit of FIG. 5, instead of using the collector of the transistor Q7 shown in FIG. 4 as the output of the current source circuit, the collector of the transistor Q7 is connected to one end of the resistor R4, and the NPN type emitter is connected to the emitter of the transistor Q7. The base of transistor Q8 is connected (transistor Q7 has an emitter follower configuration), one end of resistor R6 is connected to the emitter of transistor Q8 (transistor Q8 has an emitter follower configuration), the other end of resistor R6 is connected to GND, and transistor Q8 The output operating range is expanded by using the collector of the current source circuit as the output of the current source circuit. Further, the same operation is repeated, and the output operating range is further expanded by using the collector of the mth transistor Qm as the output of the current source circuit. In claim 5, although the description is made by expressing at least one stage of the emitter follower between the collector of the transistor Q6 (sixth transistor) and the base of the transistor Q7 (seventh transistor), the contents are the same.

となり、

となる。 In the circuit of FIG. 5, the output current Iout is

And

It becomes.

となる。 Therefore, the temperature coefficient TC _F output current Iout

It becomes.

となる。 If the temperature coefficient TC _F = 0,

It becomes.

The collector current I _C4 of the transistor Q4 is determined by the resistors R1 and R2 and the emitter area magnification n, the collector current I _C6 of the transistor Q6 is determined by the resistor R3, and the collector currents I _C7 to I _Cm-1 of the transistor Q7 are respectively Since the resistance R5 is determined by the resistance Rm _-3 and the output current Iout is further determined by the resistance Rm _-2 , the resistance R1 satisfies the expression (3) for the temperature T near the center of the operating temperature range. , R2, R3, R4, R5,..., R _m-3 , R _m-2 and the emitter area magnification n can be adjusted to obtain an output current Iout having almost no temperature dependence.

FIG. 6 shows a more specific embodiment 5 based on the basic configuration example shown in FIG. In the current source circuit of FIG. 6, instead of connecting the collector of the transistor Q7 to one end of the resistor R4 of FIG. 5, one terminal of the voltage generating circuit 125 is connected to one end of the resistor R4, and voltage is generated at the collector of the transistor Q7. The other terminal of the circuit 125 is connected. In addition, the same change is repeated from the transistor Q8 to the transistor Qm _-1 , thereby improving the linearity of the output current Iout with respect to the drive terminal voltage V2. For example, a resistor or a diode can be used as the voltage generation circuit 125 to the voltage generation circuit 12 _m−3 .

As an example of Example 5, a SPICE simulation was performed. FIG. 7 shows a simulation circuit according to the fifth embodiment. Here, resistors are used as the current generation circuit 111, the voltage generation circuits 112 and 113, and 125 to 12 _m−3 . This simulation circuit is the simplest example of Embodiment 5 (one emitter follower). The change range of the drive terminal voltage V2 was set to 0.6 V (2.5 V to 3.1 V) as in the conventional simulation, and the circuit constant was set so that the output current Iout was about 30 μA.

  FIG. 8 shows the simulation result of the Iout-T characteristic of Example 5. The vertical axis represents the output current Iout [A], and the horizontal axis represents the temperature T [° C.], which represents the temperature dependence of the output current Iout. Since the circuit constants are set by the method described in the above embodiment, it can be seen that the temperature dependency is improved with respect to the characteristics of the conventional example (FIG. 14).

  FIG. 9 shows the simulation result of the Iout-V2 characteristic of Example 5. The vertical axis represents the output current Iout [A], and the horizontal axis represents the drive terminal voltage V2 [V], which represents the linearity of the output current with respect to the drive terminal voltage V2. It can be seen that the output current Iout changes substantially linearly with respect to the change of the drive terminal voltage V2, and the slope of the output current Iout is improved with respect to different temperatures as compared with the characteristics of the conventional circuit (FIG. 15).

  FIG. 10 shows a more specific embodiment 6 based on the basic configuration example shown in FIG. The current source circuit of FIG. 10 is an embodiment in which one end of the resistor R4 is connected to another drive terminal voltage V3 instead of connecting one end of the resistor R4 to the collector of the transistor Q1 of FIG. The Early effect can be reduced by taking the drive terminal voltage separately so that the drive terminal voltage of the first voltage generation circuit 11 is V2 and the drive terminal voltage of the voltage-current conversion circuit 12 is V3. The same can be applied to the fourth and fifth embodiments.

  FIG. 11 shows a seventh embodiment in which the NPN transistor and the PNP transistor are replaced with each other in the current source circuit of FIG. Q4 'to Q10' and Qm 'are PNP transistors, and Q1' to Q3 'are NPN transistors. It can implement similarly also about Examples 1-5.

It is a block diagram which shows the basic structural example of the current source circuit of this invention. FIG. 3 is a circuit diagram of a current source circuit according to the first embodiment. 6 is a circuit diagram of a current source circuit of Example 2. FIG. FIG. 6 is a circuit diagram of a current source circuit of Example 3. FIG. 10 is a circuit diagram of a current source circuit of Example 4. FIG. 10 is a circuit diagram of a current source circuit of Example 5. FIG. 10 is a circuit diagram illustrating a simulation circuit according to a fifth embodiment. FIG. 10 is a characteristic diagram illustrating a simulation result of the Iout-T characteristic of Example 5. FIG. 10 is a characteristic diagram illustrating a simulation result of Iout-V2 characteristics of Example 5. FIG. 10 is a circuit diagram of a current source circuit of Example 6. FIG. 10 is a circuit diagram of a current source circuit of Example 7. It is a circuit diagram of the conventional current source circuit. It is a circuit diagram which shows the simulation circuit of the conventional current source circuit. It is a characteristic view which shows the simulation result of the Iout-T characteristic of the conventional current source circuit. It is a characteristic view which shows the simulation result of the Iout-V2 characteristic of the conventional current source circuit. It is a circuit diagram of another conventional current source circuit.

Explanation of symbols

1: Load 10: Current source circuit main body, 11: First voltage generation circuit, 12: Voltage-current conversion circuit 111: Current generation circuit, 112, 113, 125 to 128, 12 _m-3 : Voltage generation circuit 20: Second voltage generation circuit Vcc: power supply voltage V1: output voltage of the first voltage generation circuit 11 V2, V3: drive terminal voltage Iout: output current GND: reference potential

Claims (7)

A first voltage generation circuit that outputs a voltage having a temperature dependency, and a voltage that outputs a current having no temperature dependency by inputting the voltage having the temperature dependency output from the first voltage generation circuit. A current conversion circuit, and a first voltage generation circuit and a second voltage generation circuit for supplying a drive terminal voltage to the voltage-current conversion circuit,
A current source circuit characterized in that an output current of the voltage-current generation circuit linearly changes in accordance with a change in drive terminal voltage supplied from the second voltage generation circuit. The current source circuit according to claim 1,
The first voltage generation circuit includes a first transistor of a first conductivity type in which an emitter is connected to a first output terminal of the second voltage generation circuit, and an emitter of the second voltage generation circuit. A second transistor of a first conductivity type connected to the first output terminal and having a base connected to the base of the first transistor; and an emitter of the first output terminal of the second voltage generating circuit. A third transistor of the first conductivity type whose base is connected to the collector of the first transistor, and whose collector is connected to the bases of the first and second transistors and the collector of the second transistor A fourth transistor of the second conductivity type whose base is connected to the collector of the third transistor, and a collector connected to the collector of the first transistor. A fifth transistor of the second conductivity type connected to the base of the fourth transistor and having an emitter area n times the emitter area of the fourth transistor, and one end connected to the emitter of the fifth transistor. A first resistor, and a second resistor having one end connected to the other end of the first resistor and the emitter of the fourth transistor and the other end connected to a reference potential,
In the voltage-current conversion circuit, an emitter is connected to the reference potential via a third resistor, a base is connected to a collector of the third transistor, and a collector is connected to the collector of the third transistor to generate the second voltage. A sixth transistor of the second conductivity type connected to the first output terminal of the circuit; a base connected to a collector of the sixth transistor; and an emitter connected to the reference potential via a fifth resistor And a seventh transistor of the second conductivity type from which current is taken out from the collector. The current source circuit according to claim 2,
In the first voltage generation circuit, a current generation circuit is connected between a collector of the third transistor and the reference potential. The current source circuit according to claim 2 or 3,
In the first voltage generation circuit, a third voltage generation circuit is inserted and connected between the collector of the second transistor and the collector of the fourth transistor, and the collector of the first transistor and the fifth transistor A current source circuit, wherein a fourth voltage generating circuit is inserted and connected between the collectors of the transistors. The current source circuit according to claim 2 or 3,
In the voltage-current conversion circuit, connected between the collector of the sixth transistor and the base of the seventh transistor, between the first output terminal of the second voltage generation circuit and the reference potential. A current source circuit characterized by connecting at least one emitter follower. The current source circuit according to claim 5,
A current source circuit, wherein a fifth voltage generation circuit is inserted and connected between a collector of a transistor constituting the emitter follower and the first output terminal of the second voltage generation circuit. The current source circuit according to claim 2, 5 or 6,
In the voltage-current conversion circuit, the first output terminal of the second voltage generation circuit is replaced with a second output terminal of the second voltage generation circuit.

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