JP2003157119A - Band-gap reference voltage generating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band-gap reference voltage generating circuit which can suppress variation and variance in output voltage even when the circuit is sealed with filler-containing resin. SOLUTION: First and second band-gap reference voltage generation parts 1 and 2 are provided to generate constant voltages; and the output voltages of the 1st and 2nd band-gap reference voltage generation parts 1 and 2 are inputted to an OR circuit, which outputs the higher voltage. The output from the OR circuit 4 is the output voltage Vout of the band-gap reference voltage circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bandgap reference voltage circuit capable of outputting a constant voltage, and in particular,
It is suitable for application to a high-precision bandgap reference voltage circuit such as that formed in a semiconductor device mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, a bandgap reference voltage circuit has been used as a circuit for forming a reference voltage inside an IC. When a semiconductor device in which the IC chip having the bandgap reference voltage circuit formed therein is sealed with a resin containing a filler,
It was confirmed that the circuit characteristics fluctuated and the output voltage decreased, and it was also confirmed that the amount of fluctuation varied from sample to sample. FIG. 8 shows this result, and the output voltage does not change much at the beginning of resin coating, but as the resin solidifies, the output voltage varies depending on the magnitude of the applied stress. I understand that.

When the output voltage fluctuates or fluctuates in this manner, the bandgap reference voltage circuit cannot be used as a reference voltage under the condition that high accuracy is required.

Generally, when stress is applied to an IC chip,
It is known that the electrical characteristics of IC chips fluctuate.
In the case of a bandgap reference voltage circuit, when stress is applied, the VBE of the transistor in the circuit (VF of the diode) becomes small and the output voltage drops.

Therefore, the present inventors considered that some kind of stress was generated by the resin encapsulation, and conducted various experiments. As a result, if the sealing resin is removed after the semiconductor device is manufactured, the output voltage of the bandgap reference voltage circuit returns to that before the resin sealing. It was confirmed that there were fluctuations and variations. From these results, it can be inferred that some kind of stress is applied to the entire surface of the IC chip by the sealing resin.

Further, since it is considered that the filler contained in the resin also contributes to the stress, a resin-sealed semiconductor device was manufactured by using the sealing resin excluding the filler. As a result, compared with the case of using a sealing resin containing a conventional filler,
The fluctuations and variations in the output voltage of the bandgap reference voltage circuit were smaller after resin sealing. From this, it is considered that the filler contained in the sealing resin is involved in the fluctuation and variation of the output voltage. For example, various stresses concentrate on the filler that contacts the surface of the IC chip,
It is speculated that the output voltage fluctuates due to vertical compressive stress from the filler applied to the chip surface. Further, the size of the filler present in the sealing resin is not uniform,
In the sealing resin, the density of the fillers varies depending on the site, and the number of fillers that contact depending on the area occupied by the bandgap reference voltage circuit varies. It is presumed that the variation is large.

According to these studies, it can be said that by removing the filler contained in the encapsulating resin, it is possible to suppress an increase in fluctuations and variations in the output voltage. However, if the filler is not contained, the thermal expansion coefficient of the encapsulating resin will increase. Since it is larger than IC chips and leads, it cannot be used in fields where the operating temperature range is wide.

In view of the above points, an object of the present invention is to provide a bandgap reference voltage circuit which can suppress fluctuations and variations in output voltage even when it is sealed with a resin containing a filler.

[0009]

In order to achieve the above object, according to the invention of claim 1, a bandgap reference voltage circuit for outputting a constant voltage, the first bandgap reference voltage forming a constant voltage is provided. A forming unit (1) and a second bandgap reference voltage forming unit (2) that forms a constant voltage are provided, and the higher one of the output voltages of the first and second bandgap reference voltage forming units is output. Therefore, it is characterized in that it is configured to output a constant voltage.

With such a configuration, the higher output voltage of the output voltages of the first and second band gap reference voltage forming sections is output. Therefore, even if stress is received from the sealing resin and the output voltage of either the first or second bandgap reference voltage forming unit drops, the output voltage on the higher side is less affected by the stress. It is output as the output voltage of the gap reference voltage circuit. Therefore, fluctuations and variations in the output voltage of the bandgap reference voltage circuit can be reduced. As a result, the output voltage of the bandgap reference voltage circuit becomes a substantially constant voltage, and even if the resin is filled with filler, the output voltage fluctuates,
A bandgap reference voltage circuit with less variation can be provided.

In this case, as described in claim 2, the first,
Of the output voltage of the second band gap reference voltage forming unit,
A selection unit (4) that outputs the higher voltage may be provided.

For example, as described in claim 3, in the first band gap reference voltage forming portion, the first and second transistors (T11, T12) through which currents having different current densities are made to flow.
And the first and second potential points (A, A) at which the potential fluctuates according to fluctuations in the currents flowing through the first and second transistors
The first operational amplifier (5a, 6a,
7a, 8a, 9a), the currents flowing through the first and second transistors are adjusted based on the output of the first operational amplifier, and the second bandgap reference voltage is formed. The third and fourth transistors (T21, T22) in which currents having different current densities flow, and the third and fourth transistors in which the potentials fluctuate according to fluctuations in the currents flowing in the third and fourth transistors, respectively. Second operational amplifier (5b, 6b, 7b, 8b, 9b) to which the potential of the potential point is input
It is possible to employ a circuit configuration in which the current flowing through the third and fourth transistors is adjusted based on the output of the second operational amplifier.

Further, as described in claim 4, in the first band gap reference voltage forming portion, first and second transistors (T31, T32) through which currents having different current densities are made to flow.
And the first and second potential points (A ′, A ′, where the potential fluctuates according to the fluctuations of the currents flowing in the first and second transistors
First operational amplifier (52a) to which the potential of B ') is input
And a first resistor (R34) connected in series to the first and second transistors, and the current flowing through the first and second transistors is adjusted based on the output of the first operational amplifier. The second bandgap reference voltage forming unit includes third and fourth transistors (T41, T42) through which currents having different current densities are supplied,
A second operational amplifier (52b) to which the potentials of the third and fourth potential points whose potentials vary according to the variation of the current flowing through each of the fourth transistors are input, and a third operational amplifier connected in series to the third and fourth transistors. It is also possible to employ a circuit configuration that is configured by including two resistors (R44), and that adjusts the currents flowing through the third and fourth transistors based on the output of the second operational amplifier.

According to the fifth aspect of the present invention, the third band gap reference voltage forming portion (3a) forming a constant voltage and the maximum value of the change in the output voltage of the third band gap reference voltage forming portion with respect to temperature are: A first level shift circuit section (3b) that shifts the output voltage of the first and second bandgap reference voltage forming sections so as to deviate from the maximum value.
The output voltage of the third band gap reference voltage forming unit is the highest voltage, and the constant voltage is output.

With this structure, the highest voltage among the output voltages of the first to third band gap reference voltage forming sections is output as the output voltage. For example, in the low temperature to room temperature region, the output voltage of the first and second band gap reference voltage forming units, and in the room temperature to high temperature region, the output voltage of the third band gap reference voltage forming unit is output as the output voltage of the band gap reference voltage circuit. It Therefore, the output voltage of the bandgap reference voltage circuit becomes a substantially constant voltage in a wide temperature range, and the bandgap reference voltage circuit in which the change of the output voltage with temperature is small can be obtained.

According to the sixth aspect of the invention, the maximum value of the change in the output voltage of the fourth bandgap reference voltage forming section for forming a constant voltage and the fourth bandgap reference voltage forming section with respect to temperature is the third band. A second level shift circuit unit (3b) for shifting the output voltage of the gap reference voltage forming unit to be equal to the maximum value, and the highest voltage among the output voltages of the first to fourth band gap reference voltage forming units. Is configured to output a constant voltage.

As described above, the fourth bandgap reference voltage forming section and the second bandgap reference voltage forming section having the same structure are also used for the third bandgap reference voltage forming section and the first level shift circuit section.
By providing the level shift circuit section, the same effect as that of the first aspect can be obtained.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a block configuration of a bandgap reference voltage circuit to which an embodiment of the present invention is applied. This bandgap reference voltage circuit is formed on an IC chip and is sealed with a resin containing a filler together with leads and the like to form a semiconductor device.

As shown in FIG. 1, the bandgap reference voltage circuit according to the present embodiment comprises first and second bandgap reference voltage forming sections 1 and 2 and an OR circuit section 4 corresponding to a selecting section. It has been configured.

The first and second bandgap reference voltage forming sections 1 and 2 have the same structure, and both form a circuit for generating a predetermined constant voltage as an output voltage. Then, the output voltages of the first and second bandgap reference voltage forming units 1 and 2 are input to the OR circuit unit 4, and the OR circuit unit 4 outputs the output voltage Vout of the bandgap reference voltage circuit. ing.

According to such a circuit configuration, the first and second
The higher output voltage of the output voltages of the band gap reference voltage forming units 1 and 2 is output from the OR circuit unit 4. Therefore, if stress is applied from the resin for sealing, the first and second bandgap reference voltage forming sections 1 and 2 are generated.
Even if the output voltage of either one of the above decreases, the output voltage on the higher side, which is less affected by stress, is output from the OR circuit 4 as the output voltage Vout of the bandgap reference voltage circuit.

Therefore, fluctuations and variations in the output voltage Vout of the bandgap reference voltage circuit can be reduced. As a result, the output voltage Vout of the bandgap reference voltage circuit becomes a substantially constant voltage, and it is possible to obtain a bandgap reference voltage circuit in which variations and variations in the output voltage Vout are small even when the resin is filled with a filler.

The OR circuit section 4 shown here is provided as necessary, and may be O depending on the circuit configuration.
Even if the R circuit section 4 is not provided, the higher one of the output voltages of the first and second bandgap reference voltage forming sections 1 and 2 can be selected.

FIG. 2 shows a specific circuit configuration example of the bandgap reference voltage circuit shown in FIG. In the bandgap reference voltage circuit shown in FIG. 2, the right side of the drawing forms the first bandgap reference voltage forming section 1, and the left side of the drawing forms the second bandgap reference voltage forming section 2. In addition,
In the circuit configuration shown here, the higher one of the output voltages of the first and second band gap reference voltage forming units 1 and 2 is selected without the OR circuit unit 4 in FIG.
The circuit unit 4 is not provided.

The first band gap reference voltage forming section 1 is
Adjustment unit 5a, differential pair 6a, current mirror circuit unit 7a,
The gain forming section 8a and the emitter follower circuit section 9a are provided.

The adjusting section 5a includes a resistor R11 and a transistor T11 and resistors R12 and R13 and a transistor T12.
Are connected in parallel, and the bases of the transistors T11 and T12 are connected to each other. Then, by supplying currents having different current densities to the resistor R11 and the transistor T11 and the resistors R12 and R13 and the transistor T12, the characteristic change with respect to temperature is played. In this embodiment, the transistors T11 and T12 correspond to the first and second transistors in the present invention.

The differential pair 6a includes a transistor T13 to which a connection point (first potential point) A between the resistor R11 and the transistor T11 is input as a base voltage, and a connection point between the resistor R12 and the transistor T11 (second potential point). ) B has a transistor T14 to which a base voltage is input, and a resistor R14 connected to the emitters of the transistors T13 and T14.

The current mirror circuit section 7a includes a differential pair 6a.
It is configured to have transistors T15 and T16 whose bases are connected to each other, so that an equal current flows through each of the transistors T15 and T16.

The gain forming section 8a amplifies a variation in the current supply of the transistor T17, which supplies the current to the transistor T14 provided in the differential pair 6a, the resistor R15 which is directly connected to the transistor T14, and the transistor T17. Therefore, the transistor T18 that gains a gain is configured.

The emitter follower circuit portion 9a is composed of a transistor T19 and a resistor R16 connected between the base and collector of the transistor T19.

The differential pair 6a, the current mirror circuit section 7a, the gain forming section 8a, and the emitter follower circuit section 9a constitute an operational amplifier (first operational amplifier). The capacitor C1 is provided for phase compensation of the operational amplifier composed of these,
Prevent oscillation.

The first bandgap reference voltage forming section 1 thus configured has the transistor T11 and the transistor T12 connected to the resistors R11 and R12, respectively.
The following operations are performed by passing currents having different current densities.

Transistor T11 and transistor T12
And are connected to each other's bases. Therefore, the collector current of the transistor T11 is Ic1, the base-emitter voltage is VBE11, and the transistor T12 is
Collector current of Ic2, base-emitter voltage of VB
When E12 is set, Ic2 flowing through the resistor R13 has a current value corresponding to the difference voltage between the base-emitter voltages VBE11 and VBE12. That is, it is expressed by the following equation.

[0035]

Ic2 = (VBE11−VBE12) / R13 Further, assuming that the base current of the transistor T11 is Ib1, the emitter current is Ie1, the base current of the transistor T12 is Ib2, and the emitter current is Ie2, the base currents Ib1 and Ib2 are Since the collector currents Ic1 and Ic2 are sufficiently smaller than the collector currents Ic1 and Ic2 and can be ignored, the emitter currents Ie1 and Ie2 are equal to the collector currents Ic1 and Ic2.
Can be said to be equivalent to. Therefore, each transistor T1
When the base-emitter voltages VBE11 and VBE12 change due to the characteristic change of 1 and T12, the collector current Ic2 flowing through the resistor 23 changes accordingly, and the potential relationship between the connection points A and B changes. Then, the potentials at these connection points A and B are fed back as the base voltages of the two transistors T13 and T14 forming the differential pair 6a.

Here, the collector currents of the transistors T13 and T14 are I1 and I2, respectively.
3. Let I be the current flowing in the resistor R14 connected to the collectors of T3 and T14, and take-out transistor T1 connected to both transistors T13 and T14.
5, 5 and T16 are connected in a current mirror, and the collector currents I3 and I4 of the transistors T15 and T16 are equal, so that the currents I1 and I2 are basically I / 2.

However, as described above, the connection point A,
When the potential relationship of B changes, the transistors T13, T
The values of the collector currents I1 and I2 flowing through 14 vary.
Therefore, for example, the current I flowing through the transistor T14
When 2 tends to be larger than I / 2, the collector currents I3 and I4 of the transistors T15 and T16 connected in the current mirror can take only equal values, so that the shortage current amount is supplemented by the base current of the transistor T17. Then, the collector current I5 of the transistor T17, in other words, the value of the current flowing through the resistor R15, increases, and the collector current I6 of the transistor T18 also increases accordingly.

The collector current I6 is generated by the resistor R16.
Corresponding to the current I7 flowing through the collector current I
The increase of 6 or the increase of the current I7 lowers the base potential and the emitter potential of the transistor T19.
As a result, the potentials at the connection points A and B are adjusted, and the output voltage Vout is fed back to become a constant potential.

On the other hand, the second band gap reference voltage forming section 2 includes an adjusting section 5b, a differential pair 6b, a current mirror circuit section 7b, a gain forming section 8b and an emitter follower circuit section 9.
b. These parts 5b, 6b, 7
The configurations of b, 8b, and 9b are the components 5a, 6a, 7a, 8a, and 9 included in the first bandgap reference voltage forming unit 1.
It has the same configuration as a and each plays the same role. Specifically, the resistors R21 to R26 correspond to the resistors R11 to R16, respectively, and the transistors T21 to T29.
Corresponds to the transistors T11 to T19, and the capacitor C
2 corresponds to the capacitor C1. In this embodiment, the transistors T21 and T22 are the third and
It corresponds to the fourth transistor. The connection point between the resistor R21 and the transistor T21 and the connection point between the resistor R22 and the transistor T22 correspond to the third and fourth potential points.

According to such a circuit configuration, the first and second
The higher one of the output voltages of the band gap reference voltage forming units 1 and 2 is output as the output voltage Vout of the band gap reference voltage circuit. With such a circuit configuration, the effects described above can be obtained.

(Second Embodiment) In the first embodiment,
The circuit configuration shown in FIG. 2 is shown as an example of the bandgap reference voltage circuit shown in FIG. 1, but the circuit configuration shown in FIG. 3 can be used.

As shown in FIG. 3, in this embodiment, the first
The bandgap reference voltage forming unit 1 is composed of an adjusting unit 51a and an operational amplifier (first operational amplifier) 52a, and the second bandgap reference voltage forming unit 2 is also an adjusting unit 51.
b and an operational amplifier (second operational amplifier) 52b.

The adjusting section 51a includes resistors R31 and R32, a transistor T31, a resistor R33 and a transistor T3.
2 are connected in parallel, and a resistor R34 is connected to the emitters of the transistors T31 and T32. The resistors R31 and R33 have the same resistance value. Further, the transistors T31 and T32 have different areas formed on the semiconductor substrate.
31 has a larger area than the transistor T32.
Then, the connection point (first potential point) A ′ of the resistor R31 and the transistor T31, the resistor R33 and the transistor T3.
The potential at the connection point (second potential point) B ′ of 2 is the operational amplifier 52.
It is configured so that the output of the operational amplifier 52a is input to a and becomes the base voltage of the transistors T31 and T32.

In such a configuration, the resistors R31 and R33 are
The following operations are performed by passing currents having different current densities through the transistors T31 and T32 connected to each other.

Let I31 be the current flowing through the resistor R31 and the transistor T31, and let the resistor R33 and the transistor T3.
If the current flowing through 2 is I32, the resistors R31 and R33
Since the resistance values of I3 and I3 are equal,
2 becomes equal. At this time, the transistors T31 and T3
The formation area of 2 is set to the above relationship, and the base-emitter voltage VBE32 of the transistor T32 is equal to the transistor T31.
Since it is smaller than the base-emitter voltage VBE31 of the above, even if the currents I31 and I32 are made equal, currents having different current densities flow in the transistors T31 and T32.

When the potentials at the connection points A'and B'are fed back to the operational amplifier 52a, the operational amplifier 5
The base voltage to each of the transistors T31 and T32 is adjusted by the output of 2a. For example, when the value of one of the currents I31 and I32 is about to increase, the increase amount is reduced by the operational amplifier 52a.

On the other hand, the adjusting section 51b has the same structure as the adjusting section 51a and operates in the same manner. Specifically, the resistors R41 to R44 are the resistors R31 to 33 and the transistor T.
41 and T42 play the same role as the transistors T31 and T32. Further, the operational amplifier 52b is also the operational amplifier 52.
It has the same configuration as a and operates similarly.

Even if such a circuit configuration is adopted, the same effect as that of the first embodiment can be obtained.

In this embodiment, the transistor T3
Each of 1, T32, T41, and T42 corresponds to the first to fourth transistors in the present invention. Also, the resistance R3
4 and R44 correspond to the first and second resistors in the present invention. The connection point between the resistor R41 and the transistor T41 and the connection point between the resistor R42 and the transistor T42 correspond to the third and fourth potential points.

(Third Embodiment) It is preferable that the bandgap reference voltage circuit be capable of outputting a constant voltage even if the temperature changes. However, since the transistors and the like included in the bandgap reference voltage circuit have temperature characteristics, the bandgap reference voltage circuit actually has a quadratic coefficient with respect to temperature.
The output voltage characteristic of the bandgap reference voltage circuit with respect to temperature is represented as shown in FIG. 4, and shows a characteristic that is convex upward with respect to temperature change. When a bandgap reference voltage circuit is used as a reference voltage for a high-precision power supply or the like, the above-described quadratic coefficient becomes a problem, and a bandgap reference voltage circuit that requires less change in output voltage with temperature is required.

Therefore, in the present embodiment, not only the fluctuation of the output voltage caused by the stress but also the fluctuation of the output voltage caused by the temperature is prevented.

FIG. 5 shows a block configuration of the bandgap reference voltage circuit in this embodiment. As shown in this figure, in the present embodiment, the third embodiment is different from the first embodiment.
The difference is that a bandgap reference voltage forming unit 3a and a level shift circuit unit (first level shift circuit unit) 3b are provided.

Third band gap reference voltage forming section 3a
Has basically the same configuration as the first and second bandgap reference voltage forming units 1 and 2, and constitutes a circuit for generating a predetermined constant voltage as an output voltage. The level shift circuit section 3b shifts the temperature characteristic of the output voltage of the third band gap reference voltage forming section 3a.
With this level shift circuit section 3b, the temperature when the output voltage of the third bandgap reference voltage forming section 3a has a maximum value is the first and second bandgap reference voltage forming sections 1 and 2.
The output voltage of is shifted from the temperature at which it takes a maximum value.
For example, the maximum value of the output voltage of the first and second band gap reference voltage forming units 1 and 2 is located in the low temperature to room temperature region, and the maximum value of the output voltage of the third band gap reference voltage forming unit 3a is in the room temperature to high temperature region. Set the values to be in position.

The output voltages of the first to third bandgap reference voltage forming sections 1, 2, 3a are input to the OR circuit section 4, and the OR circuit section 4 outputs the output voltage Vout of the bandgap reference voltage circuit. It is supposed to be done.

According to such a circuit configuration, the first to the third
The higher output voltage among the output voltages of the band gap reference voltage forming units 1, 2, 3a is output from the OR circuit unit 4. Therefore, for example, in the low temperature to room temperature region, the output voltage of either the first or second band gap reference voltage forming unit 1 or 2, and in the room temperature to high temperature region, the output voltage of the third band gap reference voltage forming unit 3a is the band gap. It is output as the output voltage Vout of the reference voltage circuit.

Therefore, in the range of low temperature to room temperature and room temperature to high temperature, the output voltages of the first to third band gap reference voltage forming portions 1, 2, 3a are combined to output the output voltage Vout.
Therefore, the fluctuation of the output voltage Vout can be reduced. As a result, the output voltage Vout becomes a substantially constant voltage in a wide temperature range, and a bandgap reference voltage circuit in which the change in output voltage with temperature is small can be obtained.

FIG. 6 shows a specific configuration example of the bandgap reference voltage circuit according to this embodiment. In the bandgap reference voltage circuit shown in FIG. 6, the right side of the paper is the first bandgap reference voltage forming unit 1, and the left side of the paper is the third bandgap reference voltage forming unit 3a and the level shift circuit unit 3b. Although the second bandgap reference voltage forming unit 2 is not shown here for simplification of the drawing, the first bandgap reference voltage forming unit 1 and the third bandgap reference voltage forming unit 3a are actually shown. Exists.

Third band gap reference voltage forming section 3a
Is an adjusting unit 5c, a differential pair 6c, a current mirror circuit unit 7
c, gain forming section 8c, and emitter follower circuit section 9c
Is configured. Of these, the adjusting unit 5c, the differential pair 6c, the current mirror circuit unit 7c, and the gain forming unit 8c.
And the emitter follower circuit portion 9c includes an operational amplifier (3rd
Operational amplifier) is configured. A resistor R60 corresponding to the level shift circuit section 3b is connected to the third band gap reference voltage forming section 3a.

The configurations of the adjusting section 5c, the differential pair 6c, the current mirror circuit section 7c, the gain forming section 8c and the emitter follower circuit section 9c are the same as those of the first and second band gap reference voltage forming sections 1 and 2, respectively. Plays a similar role. Specifically, the resistors R61 to R66 are respectively resistors R
11 to R16, R21 to R26, and transistors T61 to T69 are transistors T11 to T19 and T21.
Corresponding to T29, the capacitor C3 is the capacitor C1,
Corresponds to C2.

The resistor R60 corresponding to the level shift circuit section 3b is directly connected to the resistor R61 and the transistor T61 and the resistor R62 and the transistor T62 which are connected in parallel. With this resistor R60, the third
The relationship of the output voltage characteristic with respect to the temperature of the band gap reference voltage forming unit 3a is made different from that of the first and second band gap reference voltage forming units 1 and 2.

With such a configuration, the output voltage Vout becomes a substantially constant voltage in a wide temperature range, and the bandgap reference voltage circuit in which the change of the output voltage with respect to temperature is small can be obtained.

When the output voltage characteristics with respect to the temperatures of the first to third band gap reference voltage forming portions 1, 2, 3a were examined by simulation, the result as shown in FIG. 7A was obtained. This figure is as shown in FIG.
First to third band gap reference voltage forming sections 1, 2, 3a
The output voltage of each is obtained, and these are combined. From this simulation result, it can be confirmed that the temperatures at which the output voltages of the first to third band gap reference voltage forming units 1, 2, and 3a have the maximum values are different.

Since the higher one of the output voltages of the first to third band gap voltage forming sections 1, 2, 3a becomes the output voltage Vout, the first to third band gap voltage forming sections 1, 2 are formed. As shown in FIG. 7A, it can be seen that when the temperature at which the maximum value of each output voltage of 3a shifts, the fluctuation of the output voltage Vout becomes small within the range of low temperature to high temperature.

(Other Embodiments) In the first to third embodiments, as an example of the bandgap reference voltage circuit, FIG.
Although the circuit configurations shown in FIGS. 3 and 6 are shown, other commonly known configurations may be adopted.

Further, in the second embodiment, the currents I31, I
Although the resistors R31 and R33 have the same resistance value in order to make 32 have an equal current, it may be realized by using a current mirror circuit.

Further, in the third embodiment, another set of the fourth band gap reference voltage circuit section and the second level shift circuit section having the same structure as the third band gap reference voltage section 3a and the level shift circuit section 3b is provided. If provided, the effect shown in the first embodiment can be obtained even if the output voltage of these bandgap reference voltage portions fluctuates due to stress.

Further, also in the case of suppressing the fluctuation of the output voltage with respect to the temperature change as in the third embodiment, the bandgap reference voltage circuit shown in the second embodiment can be adopted. In this case, for example, a third band gap reference voltage forming unit having the same configuration as the first band gap reference voltage forming unit 1 in FIG.
By adjusting the resistance value of the resistor corresponding to 4, the temperature at which the maximum value of the output voltage of the third band gap reference voltage forming unit is shifted from that of the first and second band gap reference voltage forming units 1 and 2. It is possible.

In the above description, the case where two first and second bandgap reference voltage forming sections 1 and 2 are provided has been described, but the number is not limited to two, and more similar configurations are provided. By providing the above, a more accurate bandgap reference voltage circuit can be obtained. Of course, it is possible to use two or more components equivalent to the third band gap reference voltage unit 3a and the level shift circuit unit 3b.

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration of a bandgap reference voltage circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a specific circuit configuration of the bandgap reference voltage circuit shown in FIG.

FIG. 3 is a diagram showing a bandgap reference voltage circuit according to a second embodiment.

FIG. 4 is a diagram showing a relationship between temperature and output voltage Vout in a conventional bandgap reference voltage circuit.

FIG. 5 is a diagram showing a block configuration of a bandgap reference circuit according to a third embodiment of the present invention.

6 is a diagram showing an example of a specific circuit configuration of the bandgap reference voltage circuit shown in FIG.

7 is a diagram showing the relationship between temperature and output voltage Vout when the bandgap reference voltage circuit shown in FIG. 6 is used.

FIG. 8 is a diagram showing the amount of change in stress with respect to temperature.

[Explanation of symbols]

1st, 2nd, 3a ... 1st, 2nd band gap reference voltage formation part, 3b ... Level shift part, 4 ... OR circuit part, 5a-5
c ... adjusting unit, 6a to 6c ... differential pair, 7a to 7c ... current mirror circuit unit, 8a to 8c ... gain forming unit, 9a to 9
c ... Emitter follower circuit section.

Claims (6)

[Claims] 1. A bandgap reference voltage circuit for outputting a constant voltage, comprising: a first bandgap reference voltage forming unit (1) for forming the constant voltage; and a second bandgap reference voltage for forming the constant voltage. Forming part (2), and outputting the higher voltage of the output voltages of the first and second bandgap reference voltage forming parts so as to output the constant voltage. Characteristic bandgap reference voltage circuit. 2. The selection unit (4) for outputting the higher voltage of the output voltages of the first and second bandgap reference voltage formation units is provided. Bandgap reference voltage circuit. 3. The first bandgap reference voltage forming unit includes first and second transistors (T11, T12) through which currents having different current densities flow, and currents flowing through the first and second transistors, respectively. And a first operational amplifier (5a, 6a, 7a, 8a, 9a) to which the potentials of the first and second potential points (A, B) whose potentials fluctuate according to the fluctuation of The currents flowing through the first and second transistors are adjusted based on the output of the first operational amplifier, and the second bandgap reference voltage forming unit receives the currents having different current densities. 3rd and 4th transistor (T2
1, T22) and the second operational amplifiers (5b, 6) to which the potentials of the third and fourth potential points whose potentials fluctuate according to the fluctuations of the currents respectively flowing in the third and fourth transistors are input.
b, 7b, 8b, 9b) and the second
2. The bandgap reference voltage circuit according to claim 1, wherein the currents passed through the third and fourth transistors are adjusted based on the output of the operational amplifier. 4. The first bandgap reference voltage forming unit includes first and second transistors (T31, T32) through which currents having different current densities flow, and currents flowing through the first and second transistors, respectively. A first operational amplifier (52a) to which the potentials of the first and second potential points (A ', B') whose potentials fluctuate in accordance with the fluctuation of the first and second potentials are input, A first resistor (R34), and the current flowing through the first and second transistors is adjusted based on the output of the first operational amplifier. The reference voltage forming unit includes third and fourth transistors (T4) through which currents having different current densities flow.
1, T42) and the second operational amplifier (52b) to which the potentials of the third and fourth potential points whose potentials fluctuate according to the fluctuations of the currents respectively flowing in the third and fourth transistors are input.
And a second transistor connected in series with the third and fourth transistors.
And a resistor (R44) of the second operational amplifier, the current flowing through the third and fourth transistors is adjusted based on the output of the second operational amplifier. 1. The bandgap reference voltage circuit according to 1. 5. A third bandgap reference voltage forming part (3a) for forming the constant voltage, and a maximum value of a change of an output voltage of the third bandgap reference voltage forming part with respect to temperature, the first and the second maximum values. A first level shift circuit unit (3b) for shifting the output voltage of the second band gap reference voltage forming unit so as to deviate from the maximum value of the output voltage of the first to third band gap reference voltage forming units. The bandgap reference voltage circuit according to any one of claims 1 to 4, wherein the constant voltage is output by outputting the highest voltage. 6. A fourth bandgap reference voltage forming unit that forms the constant voltage, and a maximum value of a change in an output voltage of the fourth bandgap reference voltage forming unit with respect to temperature is a third bandgap reference voltage forming unit. A second level shift circuit unit that shifts the output voltage of each unit so as to be equal to a maximum value, and outputs the highest voltage among the output voltages of the first to fourth band gap reference voltage forming units, The bandgap reference voltage circuit according to claim 5, wherein the bandgap reference voltage circuit is configured to output the constant voltage.