JPH11136105A - Voltage comparator circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a voltage comparator circuit with a wider dynamic range of output signals, capable of realizing a stable operation without being affected by the temperature characteristics of a transistor. SOLUTION: A differential pair is constituted of transistors Q1 and Q2, wherein a constant current i0 corresponding to a bias voltage Vbs is supplied to the differential pair by a current source composed of a transistor Q3 and a resistance element R3. By a transistor Q4 for which the bias voltage Vbs is applied to its base and a resistance element R20 connected between the emitter and a power supply voltage Vcc , a reference voltage supply circuit 20 is constituted. The emitter voltage of the transistor Q4 is inputted to the base of the transistor Q2 as a reference voltage Vref which is compared with an input voltage Vin applied to the base of the transistor Q1, thus a voltage Vout corresponding to a compared result is outputted. Thus, the transistor is free from saturation, and its characteristics not affected by temperature changes, so that the stable operation is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage comparison circuit comprising a bipolar transistor IC circuit for comparing a voltage of an input signal with a predetermined reference voltage and supplying a signal according to the comparison result.

[0002]

2. Description of the Related Art A voltage comparison circuit is generally constituted by a differential amplifier circuit, a voltage to be compared is input to one input terminal of the differential amplifier circuit, and a reference voltage for comparison is input to the other input terminal. Voltage is input. The differential amplifier circuit outputs a voltage signal having a predetermined level according to the level of the input voltage and the reference voltage. For example, when the level of the input voltage is higher than the reference voltage, the voltage V _out1 is output. Conversely, when the level of the input voltage is lower than the reference voltage, the voltage V _out1 is output.
A voltage V _out2 having a level different from _out1 is output.

FIG. 3 shows an example of a voltage comparison circuit generally used for a bipolar transistor IC. As shown, the voltage comparison circuit of the present example includes a bias voltage generation circuit 10, a differential amplifier circuit, and a reference voltage generation circuit 20.

The bias voltage generating circuit 10 has npn transistors Q5 and Q6 whose bases are connected to each other, and a transistor Q7 whose base is connected to the collector of the transistor Q5 and whose emitter is connected to the collector of the transistor Q6. Further, transistors Q5 and Q6
Are connected to the collector of the transistor Q6. The collector of the transistor Q5 is a resistor R4
Via connected to the supply line of the power supply voltage V _CC, via respective emitter resistance elements R5 and R6 of the transistors Q5 and Q6, and is grounded.

[0005] In the bias voltage generating circuit 10, between the power supply voltage V _CC and the ground potential GND, PN junction between the base and emitter of the two resistance elements and the two transistors are interposed, each resistor element depending on the resistance and the base-emitter voltage of the transistor, the bias voltage, i.e., the base voltage V _bs illustrated transistors Q5 and Q6 are determined. The transistors Q5, Q
6 and Q7 constitute a current mirror circuit.
The operating current supplied to the differential amplifier circuit is set by the current mirror circuit. Further, based on the bias voltage _Vbs set by the current mirror circuit, a reference voltage _Vref supplied to the differential amplifier circuit is set.

[0006] The differential amplifier circuit includes transistors Q1, Q2, and Q3 as shown in the figure. Based on the input voltage V _in of the transistor Q1 is applied, the reference voltage V _ref generated by the reference voltage generating circuit 20 to the base of the transistor Q2 is inputted. Transistor Q
The emitters of 1 and Q2 are connected to each other, and the connection point is connected to the collector of transistor Q3. The collectors of the transistors Q1 and Q2 are resistance elements R1 and R2, respectively.
Through 2, is connected to the supply line of the power supply voltage V _CC, to the base of transistors Q3, the bias voltage V _bs is applied,
Its emitter is grounded via a resistor R3.

[0007] The reference voltage generation circuit 20
Transistors Q11 and Q12, resistance elements R11 and R12
And R13. The bias voltage V _bs is applied to the base of the transistor Q11, the emitter is grounded via the resistor R13, and the collector is connected to the emitter of the transistor Q12. The base of resistance element R11 is connected to the connection point between resistance elements R11 and R12, and the collector is connected to the supply line of power supply voltage V _CC . The resistance elements R11 and R12 are connected in series between the power supply voltage V _CC and the ground potential GND.

[0008] Therefore, in the reference voltage generating circuit 20, the voltage value of the divided voltage V ₀ is determined according to the resistance value of a resistance element R11 R12. In response, the reference voltage V _ref
Is lower than the divided voltage V ₀ by the base-emitter voltage V _{be of the} transistor Q12. That is, a predetermined reference voltage _Vref can be obtained by adjusting the resistance values of the voltage dividing resistance elements R11 and R12.

[0009] In the differential amplifier circuit, the input voltage V _in and the reference voltage V _ref is inputted to the respective transistors Q1 and Q2, for example, when the input voltage V _in is higher than the reference voltage V _ref, supplied by transistor Q3 Most of the generated current flows to the transistor Q1 side, and the transistor Q1
Almost no current flows on the two sides. That is, the transistor Q
1 is held at a low level and the transistor Q
2 is held high. If the input voltage V _in is lower than the reference voltage V _ref to the contrary, the transistor Q
3. Most of the current supplied by 3 flows to the transistor Q2 side, and almost no current flows to the transistor Q1 side. In response, the collector of transistor Q1 is held at a high level, and the collector of transistor Q2 is held at a low level. As a result, in accordance with the level of the input voltage V _in and the reference voltage V _ref, the output voltage V of the differential amplifier circuit
_out is different, and the result of the voltage comparison can be seen from the output voltage _Vout .

[0010]

In the conventional voltage comparison circuit described above, when it is desired to widen the dynamic range of the output signal of the differential amplifier circuit, the input voltage V
_The comparison voltage needs to be as low as possible within the slicable range of in. However, at this time, if the voltage is not set in consideration of the temperature characteristics of the transistor, the transistor Q3 constituting the current source for supplying the operating current to the differential amplifier circuit is saturated, and the differential amplifier circuit operates normally. There is a disadvantage that it will not be.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to obtain a wide dynamic range of an output signal and to always realize stable operation without being affected by the temperature characteristics of a transistor. Another object of the present invention is to provide a simple voltage comparison circuit.

[0012]

In order to achieve the above object, a voltage comparison circuit of the present invention compares an input voltage with a predetermined reference voltage and outputs a signal having a predetermined level according to the comparison result. A voltage comparison circuit for generating a predetermined bias voltage according to a power supply voltage, a first transistor to which the input voltage is applied to a control electrode, and an application of the reference voltage to a control electrode Second
A differential amplifier circuit, wherein an operating current according to the bias voltage is supplied to a connection point between the emitters of the first and second transistors, and the bias voltage is applied to a control electrode; A collector is connected to a connection point between the emitters of the first and second transistors, and a third transistor whose emitter is grounded via a load element, the bias voltage is applied to a control electrode, and the collector is grounded. A fourth transistor having an emitter connected to a power supply voltage line via a resistance element, wherein the emitter voltage of the fourth transistor constitutes the differential amplifier circuit as the reference voltage. 2 is applied to the control electrodes of the two transistors.

In the present invention, preferably, the fourth transistor has a different channel conductivity type from the first and second transistors constituting the differential amplifier circuit, and the bias voltage generation circuit preferably controls The electrodes are connected,
The fifth and sixth transistors are configured such that an emitter is grounded, a collector is connected to a power supply voltage supply line via a load element, and one collector is connected to the control electrodes. The voltage between the control electrodes of the sixth transistor is output to the outside as the bias voltage.

The voltage comparison circuit according to the present invention is a voltage comparison circuit that compares an input voltage with a predetermined reference voltage and outputs a signal having a predetermined level according to the comparison result.
A bias voltage generation circuit for generating a predetermined bias voltage according to a power supply voltage, a first transistor having the input voltage applied to a control electrode, and a second transistor having the reference voltage applied to a control electrode. A differential amplifier circuit in which an operating current according to the bias voltage is supplied to a connection point between emitters of the first and second transistors, the bias voltage is applied to a control electrode, and the collector is A third transistor connected to the connection point between the emitters of the first and second transistors, the emitter being grounded via a load element, the bias voltage being applied to a control electrode, the collector being grounded, and the emitter being And a fourth transistor connected to a power supply voltage supply line via at least two resistance elements connected in series. Voltage at the connection point between at least two resistive elements being continued is applied to the control electrode of the second transistor constituting the differential amplifier circuit as the reference voltage.

Further, in the present invention, preferably, the fourth type
Is connected between the collector of the transistor and the ground potential. Further, the bias voltage generation circuit includes:
A fifth transistor and a sixth transistor whose control electrodes are connected in common and whose emitters are respectively grounded via resistive elements, a control electrode is connected to the collector of the fifth transistor, and the connection point is A seventh transistor is connected to the power supply line via a resistance element, the emitter is connected to the collector of the sixth transistor, and the collector is connected to the power supply line.

According to the present invention, the input voltage is applied to one control electrode of the two transistors constituting the differential amplifier circuit, and the reference voltage is applied to the control electrode of the other transistor. Since the level of the output voltage of the differential amplifier circuit is set according to the level, the comparison result between the input voltage and the reference voltage can be determined based on the output voltage of the differential amplifier circuit.

Further, according to the present invention, the differential amplifier circuit is supplied with the operating current from the current source including the third transistor to which the bias voltage generated by the bias voltage generating circuit is applied to the control electrode. In the reference voltage generation circuit, the bias voltage is applied to the base, and the collector includes a fourth transistor connected to the power supply voltage supply line via a resistance element. The emitter voltage of the fourth transistor is used as a reference voltage. It is supplied to a differential amplifier circuit. As a result, the voltage between the collector and the emitter of the third transistor that supplies the operating current to the differential amplifier circuit is equal to the voltage of the fourth transistor and the differential amplifier circuit that constitute the reference voltage supply circuit, regardless of the bias voltage. Since the third transistor is determined by the voltage between the base and the emitter of the transistor, the third transistor is prevented from becoming saturated due to a temperature change or the like, and the voltage comparison circuit can always operate stably.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a circuit diagram showing a first embodiment of a voltage comparison circuit according to the present invention. As illustrated, the voltage comparison circuit according to the present embodiment includes a bias voltage generation circuit 10, a differential amplifier circuit, and a reference voltage generation circuit 30.

[0019] In the differential amplifier circuit, npn transistors Q1 and Q2 form a differential pair, the input voltage V _in to be compared to the base of the transistor Q1 is applied, the reference voltage generating circuit 30 to the base of transistor Q2 The generated reference voltage _Vref is applied. Transistor Q1
And the emitter of Q2 are connected to each other, and the connection point is connected to the collector of npn transistor Q3. The bias voltage _Vbs generated by the bias voltage generation circuit 10 is applied to the base of the transistor Q3, and the emitter is grounded via the resistor R3.

[0020] The collector of the transistor Q1 and Q2, respectively via a resistor element R1 and R2, is connected to the supply line of the power supply voltage V _CC. Transistors Q1 and Q
The output terminals of the differential amplifier circuit are constituted by the two collectors, and the voltage _Vout between these output terminals is output to the outside as the output voltage of the voltage comparison circuit.

As shown in the figure, the bias voltage generation circuit
It is composed of npn transistors Q5, Q6, Q7, and resistance elements R4, R5 and R6. The bases of the transistors Q5 and Q6 are connected to each other, and the connection point is connected to the collector of the transistor Q6. Further, the emitters of the transistors Q5 and Q6 are grounded via the resistance elements R5 and R6, respectively.

The collector of the transistor Q7 has the power supply voltage V
_It is connected to the supply line of _CC , the base is connected to the collector of the transistor Q5, and the connection point is connected to the supply line of the power supply voltage V _CC via the resistance element R4. The emitter of the transistor Q7 is commonly connected to the collector of the transistor Q6 and the bases of the transistors Q5 and Q6.

In the bias voltage generating circuit 10 thus configured, the transistors Q5, Q6 and Q
When the current amplification factor h _{fe of S7} is sufficiently large, it is considered that the collector current of the transistor Q7 and the current flowing through the resistor R4 are approximately the same, and the emitter currents of the transistors Q5 and Q6 are also approximately the same. That is, the transistors Q5, Q6, and Q7 constitute a current mirror circuit. The operating current supplied to the differential amplifier circuit is set by the current mirror circuit. Further, the bias voltage V set by the current mirror circuit is used.
_bs , the reference voltage V _ref supplied to the differential amplifier circuit
Is set.

Here, assuming that the resistance value of resistance element R4 is r ₄ , the resistance values of resistance elements R5 and R6 are also r ₅ , and the base-emitter voltages of transistors Q5, Q6 and Q7 are both V _be. , The bias voltage V _bs generated by the bias voltage generation circuit 10 is obtained by the following equation.

[0025]

[Number 1] _{V bs = V be + (V} CC -2V be) · r 5 / (r 4 + r 5) ... (1)

As described above, the bias voltage V _bs is determined by the power supply voltage V _cc , the voltage between the base and the emitter of the transistor, and the resistance value of the resistance element.

In the differential amplifier circuit, the transistor Q3
The bias voltage V _bs described above to the base of the is applied, the current i ₀ which flows into the emitter of the transistors Q3,
It is determined by the bias voltage _Vbs , the base-emitter voltage of the transistor Q3, and the resistance of the resistor R3.
Here, the base-emitter voltage of the transistor Q3 is V
As _{it is,} when the resistance value of the resistor element R3 and r _3, the current i ₀ is calculated by the following equation.

[0028]

I ₀ = (V _bs −V _be ) / r ₃ (2)

[0029] That is, once the base-emitter voltage of the bias voltage V _bs, and transistors Q3, current i ₀ is determined. Thus, the transistor Q3 and the resistor R3
Thereby, a constant current source for supplying an operating current to the emitters of the transistors Q1 and Q2 is formed. By the constant current source, the operating current i ₀ is supplied to the connection point between the emitters of the transistors Q1 and Q2.

The differential amplifier operates by receiving an operating current i ₀ . For example, the input voltage V _in when higher than the reference voltage V _ref, the current i ₀ flows to the transistor Q1 side, little current flows through the transistor Q2 side. That is, the transistor Q1 is kept on and the transistor Q2 is kept off. In this case, the transistor Q1
Collector voltage V _{1 of, (V CC -r 1 · i} 0) , and the
The collector voltage V of the transistor Q2 becomes the power supply voltage V _CC . That is, in this case, the output voltage V of the voltage comparison circuit
_out1 is obtained by the following equation.

[0031]

V _out1 = V ₁ −V ₂ = −r ₁ · i ₀ (3)

[0032] Conversely, if the input voltage V _in is lower than the reference voltage V _ref, the current i ₀ flows to the transistor Q2 side, little current flows through the transistor Q1 side. That is, the transistor Q1 is kept off and the transistor Q2 is kept on. In this case, the transistor Q
The collector voltage V ₁ of the 1, next to the power supply voltage V _CC, the collector voltage V of the transistor Q2 _{is, (V CC -r 1 · i} 0)
Becomes That is, in this case, the output voltage V _{out2 of the} voltage comparison circuit
Is obtained by the following equation.

[0033]

V _out2 = V ₁ −V ₂ = r ₁ · i ₀ (4)

[0034] As described above, the input voltage V _in and the reference voltage V
According to the level of _ref , the output voltage V _{out of the} voltage comparison circuit
Levels are different. In response to the output voltage V _out, it is possible to determine the level of the input voltage V _in.

The reference voltage generating circuit 30 includes a resistor R20
And a pnp transistor Q4. A bias voltage _Vbs is applied to the base of the transistor Q4,
Its collector is grounded, and its emitter is connected to the supply line of the power supply voltage V _CC via the resistance element R20. The emitter voltage of the transistor Q4 is supplied to the differential amplifier as a reference voltage _Vref .

Here, the base-emitter voltage of the pnp transistor Q4 is changed to npn which constitutes a differential amplifier circuit.
As with the transistors Q1, Q2 and Q3, when the V _BE, the reference voltage V _ref is obtained by the following equation.

[0037]

V _ref = V _bs + V _be (5)

That is, the reference voltage _Vref is equal to the bias voltage _Vref.
bs and the base-emitter voltage of the pnp transistor Q4.

Here, assuming that the emitter voltage of the transistor Q3 is V _e , (V _e = V _bs -V _be ). If the input voltage V _in is lower than the reference voltage V _ref, the as described above, the transistor Q1 is turned off, the transistor Q2
Are kept on. In this case, the collector voltage of the transistor Q3, i.e., the emitter voltage of transistor Q2, (V _ref -V _be), and the collector-emitter voltage V _ce of transistor Q3 is determined by the following equation.

[0040]

V _ce = (V _ref −V _be ) −V _e = V _be (6)

[0041] That is, regardless of the temperature changes, the collector-emitter voltage V _ce of transistor Q3 is always maintained at a constant level V _BE, without the transistor Q3 is saturated, the differential amplifier circuit is stable It is operable.

On the other hand, the input voltage V _in is higher than the reference voltage V _ref, the transistor Q1 is turned on, the transistor Q2 is respectively held in the OFF state. Here, the differential voltage between the input voltage V _in and the reference voltage V _ref When [Delta] V,
In this case, the collector-emitter voltage _Vce of the transistor Q3 is expressed by the following equation.

[0043]

V _ce = V _be + ΔV (7)

Also in this case, the differential amplifier circuit can operate normally without saturating the transistor Q3. Thus, regardless of the result of comparison between the input voltage V _in and the reference voltage V _ref, without transistor Q3 for supplying the operating current to the differential amplifier circuit is saturated in either case, it can operate normally. Further, the reference voltage _Vref can be set low, and a wide dynamic range of the output signal can be obtained.

As described above, according to the present embodiment, a differential amplifier circuit is constituted by the transistors Q1, Q2 and Q3, and the constant current source including the transistor Q3 and the resistance element R3 corresponds to the bias voltage _Vbs . A constant current is supplied to the differential amplifier circuit. The transistors Q4 and its emitter and the power supply voltage V _CC resistive element R20 that is connected between the bias voltage V _bs is applied to the base, it constitutes a reference voltage supply circuit 20, a reference voltage V emitter voltage of the transistor Q4 and input to the base of the transistor Q2 as _ref, and compared to the input voltage V _in applied to the base of the transistor Q1, and outputs the voltage V _out in accordance with the comparison result. As a result, the transistor Q3 forming the current source is prevented from becoming saturated without being affected by the temperature characteristics of the transistor, and the differential amplifier circuit can always operate in a stable state.

Second Embodiment FIG. 2 is a circuit diagram showing a second embodiment of the voltage comparison circuit according to the present invention. In this embodiment, since the components of the bias voltage generating circuit and the differential amplifier circuit are the same as those of the first embodiment of the present invention shown in FIG. Only the current source supplying i ₀ and the reference voltage generation circuit 40 are shown.

As shown, the current source is a transistor Q
3 and a resistance element R3. A bias voltage _Vbs is applied to the base of the transistor Q3.
3 is grounded via a resistor R3.
Constant current i ₀ to the collector of the transistor Q3 flows. The current i ₀ is supplied to the differential amplifier circuit as an operation current. Note that the current i ₀ is obtained by Expression (2).

As shown in the figure, the reference voltage generation circuit 40
It comprises an np transistor Q4a and resistance elements R20, R21 and R22. Base bias voltage V _bs transistor Q4a is applied, a collector is grounded via the resistor R22, the emitter via a resistor R20 and R21 which are connected in series, the power supply voltage V _CC
Connected to the supply line. In the present embodiment, the resistance element R22 has a small resistance value, and the resistance element R22 can be omitted. That is, the transistor Q4a
May be directly grounded.

The voltage at the connection point between the resistance elements R20 and R21 is output as a reference voltage _Vref . The reference voltage V
_ref is supplied to the differential amplifier circuit and applied to the base of the transistor Q2. Here, the base-emitter voltage of the transistor Q4a and V _BE, further resistive element R2
Assuming that the voltage drop that occurs in 1 is α, the reference voltage V _ref in the present embodiment is obtained by the following equation.

[0050]

V _ref = V _bs + V _be + α (8)

For this reason, in the present embodiment, the voltage between the collector and the emitter of the transistor Q3 constituting the current source of the differential amplifier circuit is increased by α compared to the above-described first embodiment. The transistor Q3 is less likely to be saturated than in the first embodiment, and the differential amplifier circuit can always operate stably.

[0052] As described above, according to this embodiment, the reference voltage generating circuit 40, provided with a pnp transistor Q4a the bias voltage V _bs is applied to the base, the resistance element R20 in series with the emitter of the transistor Q4a And the power supply voltage V _cc via R21 and the voltage at the connection point of the resistance elements R20 and R21 to the reference voltage V _ref.
Since supplied to the differential amplifier circuit as a collector-emitter voltage of the operating current i ₀ of the supply transistor Q3 in the differential amplifier circuit, the voltage is drop only increased retention of the resistance element R21, the transistor Q3 is saturated And stable operation is always obtained regardless of the temperature. This embodiment is different from the first embodiment described above in that
Since the reference voltage _Vref is set to be slightly larger, the dynamic range of the output signal is also narrowed accordingly. However, the collector-emitter voltage of the transistor Q3 constituting the current source increases, which is affected by the temperature characteristics of the transistor. Without causing saturation, the operation stability of the voltage comparison circuit is further improved.

[0053]

As described above, according to the voltage comparison circuit of the present invention, the dynamic range of the output signal can be widened and the stable operation can be always realized without being affected by the temperature characteristics of the transistor. is there.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a voltage comparison circuit according to the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the voltage comparison circuit, and is a circuit diagram showing a configuration of a reference voltage generation circuit.

FIG. 3 is a circuit diagram illustrating an example of a conventional voltage comparison circuit.

[Explanation of symbols]

10. Bias voltage generation circuit, 20, 30, 40 ... Reference voltage generation circuit, Q1, Q2, Q3, Q5, Q6, Q7 ...
npn transistor, Q4, Q4a ... pnp transistor, R1, R2, R3, R4, R5, R5, R11, R
12, R13, R20, R21, R22 ... resistance element, V
_CC : power supply voltage, GND: ground potential.

Claims (10)

[Claims] 1. A voltage comparison circuit for comparing an input voltage with a predetermined reference voltage and outputting a signal having a predetermined level according to a result of the comparison, wherein the voltage comparison circuit generates a predetermined bias voltage according to a power supply voltage. A bias voltage generating circuit, a first transistor to which the input voltage is applied to a control electrode, and a second transistor to which the reference voltage is applied to a control electrode, wherein the first and second transistors A differential amplifier circuit in which an operating current according to the bias voltage is supplied to a connection point between the emitters of the first and second transistors; and a bias voltage is applied to a control electrode, and a collector connects the emitters of the first and second transistors. A third transistor which is connected to a point and whose emitter is grounded through a resistance element, the bias voltage is applied to the control electrode, the collector is grounded, and the A fourth transistor connected to a power supply voltage line via a load element;
A voltage comparison circuit in which an emitter voltage of the transistor is applied as a reference voltage to a control electrode of the second transistor constituting the differential amplifier circuit. 2. The voltage comparison circuit according to claim 1, wherein said fourth transistor has a channel conductivity type different from said first and second transistors constituting said differential amplifier circuit. 3. The voltage comparison circuit according to claim 1, wherein a load element is connected between a collector of said fourth transistor and a ground potential. 4. The bias voltage generating circuit according to claim 1, wherein the control electrodes are connected to each other, an emitter is grounded, a collector is connected to a power supply voltage line via a load element, and one collector is connected to the control electrodes. Fifth connected
2. The voltage comparison circuit according to claim 1, wherein the voltage comparison circuit comprises a third transistor and a sixth transistor, and a voltage between control electrodes of the fifth and sixth transistors is output to the outside as the bias voltage. 5. A bias voltage generating circuit comprising: a fifth transistor and a sixth transistor in which control electrodes are connected in common and whose emitters are respectively grounded through a resistance element; And a connection point is connected to a power supply voltage supply line via a load element, an emitter is connected to the collector of the sixth transistor, and a collector is connected to the power supply voltage supply line. 2. The voltage comparison circuit according to claim 1, further comprising: 6. A voltage comparison circuit for comparing an input voltage with a predetermined reference voltage and outputting a signal having a predetermined level according to a result of the comparison, wherein the voltage comparison circuit generates a predetermined bias voltage according to a power supply voltage. A bias voltage generating circuit, a first transistor to which the input voltage is applied to a control electrode, and a second transistor to which the reference voltage is applied to a control electrode, wherein the first and second transistors A differential amplifier circuit in which an operating current according to the bias voltage is supplied to a connection point between the emitters of the first and second transistors; and a bias voltage is applied to a control electrode, and a collector connects the emitters of the first and second transistors. A third transistor connected to a point, the emitter of which is grounded via a load element, the bias voltage applied to the control electrode, the collector grounded, and the emitter A fourth transistor connected to the power supply voltage line via at least two resistance elements connected in series with each other, and a connection point between the at least two resistance elements connected in series. A voltage comparison circuit in which a voltage is applied as a reference voltage to a control electrode of the second transistor constituting the differential amplifier circuit. 7. The voltage comparison circuit according to claim 6, wherein said fourth transistor has a different channel conductivity type from said first and second transistors constituting said differential amplifier circuit. 8. The voltage comparison circuit according to claim 6, wherein a load element is connected between a collector of said fourth transistor and a ground potential. 9. The bias voltage generating circuit, wherein control electrodes are connected to each other, an emitter is grounded, a collector is connected to a power supply voltage line via a load element, and one collector is connected to the control electrodes. Fifth connected
7. The voltage comparison circuit according to claim 6, further comprising a sixth transistor, wherein a voltage between control electrodes of the fifth and sixth transistors is output to the outside as the bias voltage. 8. 10. A bias voltage generating circuit comprising: a fifth transistor and a sixth transistor in which control electrodes are connected in common and whose emitters are each grounded via a resistance element; The transistor is connected to the power supply voltage supply line via a resistor, the emitter is connected to the collector of the sixth transistor, and the collector is connected to the power supply voltage supply line. 7. The voltage comparison circuit according to claim 6, comprising: