JP3666448B2 - Band gap reference voltage generation circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bandgap reference voltage circuit capable of outputting a constant voltage, and is particularly suitable for application to a high-accuracy bandgap reference voltage circuit formed in a semiconductor device mounted on a vehicle.
[0002]
[Background Art and Problems to be Solved by the Invention]
Conventionally, a bandgap reference voltage circuit has been used as a circuit for forming a reference voltage inside an IC. When manufacturing a semiconductor device in which an IC chip on which this bandgap reference voltage circuit was formed was sealed with a resin containing a filler, it was confirmed that the circuit characteristics fluctuated and the output voltage was lowered. It was confirmed that the fluctuation amount was varied every time. FIG. 8 shows this result. The output voltage does not change much at the initial stage when the resin is coated. However, as the resin solidifies, the output voltage fluctuates depending on the magnitude of the applied stress. I understand that
[0003]
If the output voltage fluctuates or varies in this way, the bandgap reference voltage circuit cannot be used as a reference voltage under conditions where high accuracy is required.
[0004]
In general, it is known that when a stress is applied to an IC chip, the electrical characteristics of the IC chip change. In the case of the band gap 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 decreases.
[0005]
For this reason, the present inventors considered that some stress was generated by resin sealing, and conducted various experiments. As a result, if the sealing resin is removed after manufacturing the semiconductor device, the output voltage of the band gap reference voltage circuit returns to the state before the resin sealing, and the output voltage of the band gap reference voltage circuit is no matter where the IC chip is located. It was confirmed that fluctuations and variations occurred. Also from these results, it can be inferred that some stress is applied to the entire surface of the IC chip by the sealing resin.
[0006]
Also, the filler contained in the resin was considered to be a cause of the stress, and a resin-encapsulated semiconductor device was manufactured using an encapsulating resin excluding the filler. As a result, fluctuations and variations in the output voltage of the bandgap reference voltage circuit were smaller after sealing with the resin than when a sealing resin containing a conventional filler was used. From this, it is considered that the filler contained in the sealing resin is involved in fluctuations and variations in the output voltage. For example, it is presumed that various stresses are concentrated on the filler in contact with the IC chip surface, the vertical compressive stress from the filler is applied to the IC chip surface, and the output voltage fluctuates. In addition, the size of the filler present in the sealing resin is not uniform, the density of the filler in the sealing resin varies depending on the site, and the filler that is in contact with the area occupied by the band gap reference voltage circuit It is presumed that the applied stress varies and the output voltage varies greatly due to the difference in the quantity of output.
[0007]
According to these studies, it can be said that by removing the filler contained in the sealing resin, it is possible to suppress fluctuations in output voltage and increase in dispersion. However, if the filler is not included, the thermal expansion coefficient of the sealing resin is reduced to an IC chip or Since it is larger than the lead, it cannot be used in fields where the operating temperature range is wide.
[0008]
SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a band gap reference voltage circuit that can suppress fluctuations and variations in output voltage even when sealed with a resin containing a filler.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to a first aspect of the present invention, there is provided a bandgap reference voltage circuit for outputting a constant voltage, the first bandgap reference voltage forming unit (1) for forming a constant voltage, and a constant voltage. The second bandgap reference voltage forming unit (2) that forms a voltage, the third bandgap reference voltage forming unit (3a) that forms a constant voltage, and the change in the output voltage of the third bandgap reference voltage forming unit with respect to temperature A first level shift circuit section (3b) for shifting the maximum value so as to deviate from the maximum value of the output voltage of the first and second band gap reference voltage forming sections , and the first to third band gap reference voltages It is characterized by outputting a constant voltage by outputting the highest voltage among the output voltages of the forming section.
[0010]
According to such a configuration, the higher output voltage among the output voltages of the first to third band gap reference voltage forming units is output. For this reason, even if stress is received from the sealing resin and the output voltage of one of the first and second bandgap reference voltage forming portions is reduced, the higher output voltage that is less affected by the stress is banded. It is output as the output voltage of the gap reference voltage circuit. Therefore, fluctuations and variations in the output voltage of the band gap 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 when sealed with a resin containing filler, a bandgap reference voltage circuit with little fluctuation and variation in output voltage can be obtained. Further, for example, the output voltage of the first and second bandgap reference voltage forming units in the low temperature to room temperature region, and the output voltage of the third bandgap reference voltage forming unit as the output voltage of the bandgap reference voltage circuit in the room temperature to high temperature region. Is output. Therefore, the output voltage of the bandgap reference voltage circuit is substantially constant over a wide temperature range, and a bandgap reference voltage circuit with little change in output voltage with respect to temperature can be obtained.
[0011]
In this case, as shown in claim 2, a selection unit (4) for outputting the highest voltage among the output voltages of the first to third bandgap reference voltage forming units can be provided.
[0012]
For example, as shown in claim 3, the first bandgap reference voltage forming unit includes the first and second transistors (T11, T12) through which currents having different current densities flow and 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 potential varies according to the variation of the current flowing in the circuit are input. 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 supplies the currents with different current densities. 3, a second operational amplifier (T21, T22), and a second operational amplifier to which the potentials of the third and fourth potential points whose potentials fluctuate according to the fluctuations of the currents flowing in the third and fourth transistors are input. 5b, 6b 7b, 8b, are configured to have 9b) and can be third on the basis of the output of the second operational amplifier, the current flowing to the fourth transistor to adopt a circuit configuration as adjusted.
[0013]
According to a fourth aspect of the present invention, the first bandgap reference voltage forming unit includes the first and second transistors (T31 and T32) through which currents having different current densities flow and the first and second transistors, respectively. Is connected in series to the first operational amplifier (52a) to which the potentials of the first and second potential points (A ′, B ′) whose potential varies according to the variation of the current flowing through the first and second transistors are input. And 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, and the second band gap reference The voltage forming unit includes third and fourth transistors (T41 and T42) through which currents having different current densities are passed, and third and fourth potentials that change according to changes in currents flowing through the third and fourth transistors. 4th potential point The second operational amplifier 52b is input, and the second resistor R44 is connected in series to the third and fourth transistors. It is also possible to adopt a circuit configuration in which the current flowing through the four transistors is adjusted.
[0016]
According to the fifth aspect of the present invention, the maximum value of the change in the output voltage of the fourth band gap reference voltage forming unit that forms the constant voltage and the fourth band gap reference voltage forming unit with respect to the temperature is the third band gap reference voltage. A second level shift circuit section (3b) that shifts the output voltage to be equal to the maximum value of the output voltage of the forming section, and outputs the highest voltage among the output voltages of the first to fourth band gap reference voltage forming sections. Thus, it is configured to output a constant voltage.
[0017]
As described above, the third band gap reference voltage forming unit and the first level shift circuit unit also include the fourth band gap reference voltage forming unit and the second level shift circuit unit having the same configuration, and Similar effects can be obtained.
[0018]
In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
(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 band gap reference voltage circuit is formed on an IC chip and sealed with a resin containing filler together with leads and the like to form a semiconductor device.
[0020]
As shown in FIG. 1, the band gap reference voltage circuit shown in the present embodiment includes a first and second band gap reference voltage forming units 1 and 2 and an OR circuit unit 4 corresponding to a selection unit. It has become.
[0021]
The first and second bandgap reference voltage forming units 1 and 2 have the same configuration, and both form a circuit that generates a predetermined constant voltage as an output voltage. 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 output voltage Vout of the bandgap reference voltage circuit is output from the OR circuit unit 4. ing.
[0022]
According to such a circuit configuration, the higher output voltage of the output voltages of the first and second band gap reference voltage forming units 1 and 2 is output from the OR circuit unit 4. For this reason, even if stress is received from the sealing resin and the output voltage of one of the first and second bandgap reference voltage forming units 1 and 2 decreases, the output on the high side that is less affected by the stress The voltage is output from the OR circuit 4 as the output voltage Vout of the bandgap reference voltage circuit.
[0023]
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 even when sealed with a resin containing filler, a bandgap reference voltage circuit with little fluctuation and variation in the output voltage Vout can be obtained.
[0024]
The OR circuit unit 4 shown here is provided as necessary, and the first and second bandgap reference voltage forming units 1 and 2 may be provided without the OR circuit unit 4 depending on the circuit configuration. The higher one of the output voltages can be selected.
[0025]
FIG. 2 shows a specific circuit configuration example of the bandgap reference voltage circuit shown in FIG. In the band gap reference voltage circuit shown in FIG. 2, the right side of the drawing constitutes the first band gap reference voltage forming unit 1, and the left side of the drawing constitutes the second band gap reference voltage forming unit 2. In the circuit configuration shown here, the higher one of the output voltages of the first and second bandgap reference voltage forming units 1 and 2 is selected without the OR circuit unit 4 in FIG. The part 4 is not provided.
[0026]
The first band gap reference voltage forming unit 1 includes an adjusting unit 5a, a differential pair 6a, a current mirror circuit unit 7a, a gain forming unit 8a, and an emitter follower circuit unit 9a.
[0027]
The adjustment unit 5a has a configuration in which a resistor R11 and a transistor T11, a resistor R12, 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, R13, and the transistor T12, they play a role of adjusting the characteristic change with respect to temperature. In the present embodiment, the transistors T11 and T12 correspond to the first and second transistors referred to in the present invention.
[0028]
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 (second potential point) B between the resistor R12 and the transistor T11. The transistor T14 is input as a base voltage, and a resistor R14 is connected to the emitters of the transistors T13 and T14.
[0029]
The current mirror circuit unit 7a serves as an extraction port of the differential pair 6a, and is configured to include transistors T15 and T16 connected to each other's base so that an equivalent current flows through the transistors T15 and T16. It has become.
[0030]
The gain forming unit 8a gains by amplifying fluctuations in the current supply of the transistor T17, the transistor T17 that supplies current to the transistor T14 provided in the differential pair 6a, the resistor R15 directly connected to the transistor T14, and the transistor T14. And a transistor T18 that earns.
[0031]
The emitter follower circuit section 9a is composed of a transistor T19 and a resistor R16 connected between the base and collector of the transistor T19.
[0032]
The differential pair 6a, the current mirror circuit unit 7a, the gain forming unit 8a, and the emitter follower circuit unit 9a constitute an operational amplifier (first operational amplifier). The capacitor C1 is provided for phase compensation of an operational amplifier constituted by these, and prevents oscillation.
[0033]
The first bandgap reference voltage forming unit 1 configured as described above performs the following operation by flowing currents having different current densities through the transistors T11 and T12 connected to the resistors R11 and R12, respectively.
[0034]
The bases of the transistor T11 and the transistor T12 are connected to each other. Therefore, when the collector current of the transistor T11 is Ic1, the base-emitter voltage is VBE11, the collector current of the transistor T12 is Ic2, and the base-emitter voltage is VBE12, Ic2 flowing through the resistor R13 is the base-emitter voltage VBE11, VBE12. The current value corresponds to the differential voltage. That is, it is expressed as the following equation.
[0035]
[Expression 1]
Ic2 = (VBE11−VBE12) / R13
If 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 sufficiently smaller than the collector currents Ic1 and Ic2 and can be ignored. Therefore, it can be said that the emitter currents Ie1 and Ie2 are equivalent to the collector currents Ic1 and Ic2. For this reason, when the base-emitter voltages VBE11 and VBE12 change due to the characteristic changes of the transistors T11 and T12, the collector current Ic2 flowing through the resistor 23 changes accordingly, and the relationship between the potentials at the connection points A and B Changes. The potentials at these connection points A and B are fed back as the base voltages of the two transistors T13 and T14 constituting the differential pair 6a.
[0036]
Here, when the collector currents of the transistors T13 and T14 are I1 and I2, and the current flowing through the resistor R14 connected to the collectors of the transistors T13 and T14 is I, the extraction connected to the transistors T13 and T14, respectively. The current transistors I15 and T16 are basically equal to I / 2 since the collector currents I3 and I4 of the transistors T15 and T16 are equal to each other.
[0037]
However, when the relationship between the potentials at the connection points A and B changes as described above, the values of the collector currents I1 and I2 flowing through the transistors T13 and T14 change. For this reason, for example, if the current I2 flowing through the transistor T14 is 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. It is supplemented by the base current of 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 accordingly, the value of the collector current I6 of the transistor T18 also increases.
[0038]
Since the collector current I6 corresponds to the current I7 flowing through the resistor R16, the base potential and the emitter potential of the transistor T19 are lowered by the increase of the collector current I6, that is, the increase of the current I7. As a result, the potentials of the connection points A and B are adjusted, and the output voltage Vout is fed back to become a constant potential.
[0039]
On the other hand, the second bandgap reference voltage forming unit 2 includes an adjusting unit 5b, a differential pair 6b, a current mirror circuit unit 7b, a gain forming unit 8b, and an emitter follower circuit unit 9b. The configuration of each of these units 5b, 6b, 7b, 8b, 9b is the same as the configuration of each unit 5a, 6a, 7a, 8a, 9a provided in the first bandgap reference voltage forming unit 1, and each is the same. Play a role. Specifically, the resistors R21 to R26 correspond to the resistors R11 to R16, the transistors T21 to T29 correspond to the transistors T11 to T19, and the capacitor C2 corresponds to the capacitor C1. In the present embodiment, the transistors T21 and T22 correspond to the third and fourth transistors in the present invention. A connection point between the resistor R21 and the transistor T21 and a connection point between the resistor R22 and the transistor T22 correspond to the third and fourth potential points.
[0040]
According to such a circuit configuration, the higher one of the output voltages of the first and second 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 as described above can be obtained.
[0041]
(Second Embodiment)
In the first embodiment, the circuit configuration of FIG. 2 is shown as an example of the band gap reference voltage circuit shown in FIG. 1, but a circuit configuration as shown in FIG. 3 is also possible.
[0042]
As shown in FIG. 3, in the present embodiment, the first bandgap reference voltage forming unit 1 is configured by an adjustment unit 51a and an operational amplifier (first operational amplifier) 52a, and the second bandgap reference voltage forming unit 2 is also configured. An adjustment unit 51b and an operational amplifier (second operational amplifier) 52b are included.
[0043]
The adjustment unit 51a is configured by connecting resistors R31 and R32, a transistor T31, a resistor R33, and a transistor T32 in parallel, and connecting a resistor R34 to the emitters of the transistors T31 and T32. The resistors R31 and R33 have the same resistance value. The transistors T31 and T32 have different areas formed on the semiconductor substrate, and the transistor T31 has a larger area than the transistor T32. Then, the connection point (first potential point) A ′ of the resistor R31 and the transistor T31 and the potential of the connection point (second potential point) B ′ of the resistor R33 and the transistor T32 are input to the operational amplifier 52a, and the output of the operational amplifier 52a is the transistor. The base voltage is set to T31 and T32.
[0044]
In such a configuration, the following operations are performed by flowing currents having different current densities through the transistors T31 and T32 connected to the resistors R31 and R33, respectively.
[0045]
Assuming that the current flowing through the resistor R31 and the transistor T31 is I31 and the current flowing through the resistor R33 and the transistor T32 is I32, since the resistance values of the resistors R31 and R33 are equal, the currents I31 and I32 are equal. At this time, the formation areas of the transistors T31 and T32 have the above relationship, and the base-emitter voltage VBE32 of the transistor T32 is smaller than the base-emitter voltage VBE31 of the transistor T31. Currents having different current densities flow through T31 and T32.
[0046]
When the potentials at the connection points A ′ and B ′ are fed back to the operational amplifier 52a, the base voltage to the transistors T31 and T32 is adjusted by the output of the operational amplifier 52a. For example, when the value of any of the currents I31 and I32 is to increase, the operation is performed so that the increase is reduced by the operational amplifier 52a.
[0047]
On the other hand, the adjustment unit 51b has the same configuration as the adjustment unit 51a and operates in the same manner. Specifically, the resistors R41 to R44 play the same role as the resistors R31 to R33, and the transistors T41 and T42 play the same role as the transistors T31 and T32. The operational amplifier 52b has the same configuration as the operational amplifier 52a and operates in the same manner.
[0048]
Even if such a circuit configuration is employed, the same effects as those of the first embodiment can be obtained.
[0049]
In the present embodiment, each of the transistors T31, T32, T41, and T42 corresponds to the first to fourth transistors in the present invention. The resistors R34 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.
[0050]
(Third embodiment)
The bandgap reference voltage circuit is preferably configured to output a constant voltage even when a temperature change occurs. However, since the transistors and the like provided in the band gap reference voltage circuit have temperature characteristics, the band gap reference voltage circuit actually has a second-order coefficient with respect to temperature. The output voltage characteristic with respect to the temperature of the band gap reference voltage circuit is expressed as shown in FIG. 4, and shows an upward convex characteristic with respect to the temperature change. When a bandgap reference voltage circuit is used as a reference voltage for a high-precision power source or the like, the above-described second order coefficient becomes a problem, and a bandgap reference voltage circuit with less change in output voltage with respect to temperature is required.
[0051]
Therefore, in this embodiment, not only fluctuations in output voltage due to stress, but also fluctuations in output voltage due to temperature are prevented.
[0052]
FIG. 5 shows a block configuration of the bandgap reference voltage circuit in the present embodiment. As shown in this figure, the present embodiment is provided with a third band gap reference voltage forming unit 3a and a level shift circuit unit (first level shift circuit unit) 3b as compared with the first embodiment. Different.
[0053]
The third bandgap reference voltage forming unit 3a has basically the same configuration as the first and second bandgap reference voltage forming units 1 and 2, and includes a circuit that generates a predetermined constant voltage as an output voltage. It is composed. The level shift circuit unit 3b shifts the temperature characteristic of the output voltage of the third band gap reference voltage forming unit 3a. By this level shift circuit unit 3b, the temperature when the output voltage of the third bandgap reference voltage forming unit 3a takes a maximum value is the same as the output voltage of the first and second bandgap reference voltage forming units 1 and 2. Is shifted from the temperature when taking 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 of the output voltage of the third band gap reference voltage forming unit 3a is set in the room temperature to high temperature region. Set the value to be located.
[0054]
The output voltages of the first to third bandgap reference voltage forming units 1, 2, and 3a are input to the OR circuit unit 4, and the output voltage Vout of the bandgap reference voltage circuit is output from the OR circuit unit 4. It has become.
[0055]
According to such a circuit configuration, the higher output voltage among the output voltages of the first to third bandgap reference voltage forming units 1, 2, 3 a 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.
[0056]
Accordingly, the output voltage Vout is formed by synthesizing the output voltages of the first to third bandgap reference voltage forming units 1, 2, and 3a in the low temperature to room temperature and room temperature to high temperature ranges. Can be reduced. As a result, the output voltage Vout becomes a substantially constant voltage over a wide temperature range, and a bandgap reference voltage circuit with little change in output voltage with respect to temperature can be obtained.
[0057]
FIG. 6 shows a specific configuration example of the bandgap reference voltage circuit in the present embodiment. In the band gap reference voltage circuit shown in FIG. 6, the first band gap reference voltage forming unit 1 is on the right side of the drawing, and the third band gap reference voltage forming unit 3a and the level shift circuit unit 3b are on the left side of the drawing. Here, in order to simplify the drawing, the second band gap reference voltage forming unit 2 is not shown, but actually, the first band gap reference voltage forming unit 1 and the third band gap reference voltage forming unit 3a Exists.
[0058]
The third band gap reference voltage forming unit 3a includes an adjusting unit 5c, a differential pair 6c, a current mirror circuit unit 7c, a gain forming unit 8c, and an emitter follower circuit unit 9c. Among these, the adjustment unit 5c, the differential pair 6c, the current mirror circuit unit 7c, the gain formation unit 8c, and the emitter follower circuit unit 9c constitute an operational amplifier (third operational amplifier). A resistor R60 corresponding to the level shift circuit unit 3b is connected to the third band gap reference voltage forming unit 3a.
[0059]
The configurations of the adjustment unit 5c, the differential pair 6c, the current mirror circuit unit 7c, the gain formation unit 8c, and the emitter follower circuit unit 9c are the same as those of the first and second band gap reference voltage formation units 1 and 2. Play a role. Specifically, the resistors R61 to R66 correspond to the resistors R11 to R16 and R21 to R26, the transistors T61 to T69 correspond to the transistors T11 to T19, T21 to T29, and the capacitor C3 corresponds to the capacitors C1 and C2. .
[0060]
Further, the resistor R60 corresponding to the level shift circuit unit 3b is directly connected to the resistor R61, the transistor T61, the resistor R62, and the transistor T62 connected in parallel. By this resistor R60, the relationship of the output voltage characteristics with respect to the temperature of the third 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.
[0061]
With such a configuration, the output voltage Vout becomes a substantially constant voltage in a wide temperature range, and a bandgap reference voltage circuit with little change in output voltage with respect to temperature can be obtained.
[0062]
When the output voltage characteristics with respect to the temperature of the first to third band gap reference voltage forming units 1, 2, and 3a were examined by simulation, a result as shown in FIG. 7A was obtained. In this figure, as shown in FIG. 7B, the output voltages in the first to third bandgap reference voltage forming units 1, 2, 3a are obtained and synthesized. Also from this simulation result, it can be confirmed that the temperatures when the output voltages of the first to third bandgap reference voltage forming units 1, 2, 3a take the maximum values are different.
[0063]
Since the higher one of the output voltages of the first to third band gap voltage forming units 1, 2, 3a is the output voltage Vout, the first to third band gap voltage forming units 1, 2, 3a As shown in FIG. 7A, when the temperature at which each output voltage reaches its maximum value is shifted, it can be seen that the fluctuation of the output voltage Vout is small in the range of low temperature to high temperature.
[0064]
(Other embodiments)
In the first to third embodiments, the circuit configurations shown in FIGS. 2, 3, and 6 are shown as examples of the band gap reference voltage circuit. However, other generally known configurations are adopted. It doesn't matter.
[0065]
Further, in the second embodiment, the resistors R31 and R33 are set to have the same resistance value in order to make the currents I31 and I32 equal to each other. However, this may be realized by using a current mirror circuit.
[0066]
In the third embodiment, another set of the fourth band gap reference voltage circuit unit and the second level shift circuit unit having the same configuration as that of the third band gap reference voltage unit 3a and the level shift circuit unit 3b is provided. Then, even if the output voltage of these bandgap reference voltage sections varies due to stress, it is possible to obtain the effects shown in the first embodiment.
[0067]
Furthermore, the bandgap reference voltage circuit shown in the second embodiment can also be adopted when suppressing fluctuations in the output voltage against temperature changes as in the third embodiment. In this case, for example, a third bandgap reference voltage forming unit having a configuration equivalent to that of the first bandgap reference voltage forming unit 1 in FIG. 3 is provided, and the resistance value of the resistor corresponding to the resistor R34 is adjusted. It is possible to shift the temperature at which the output voltage of the three band gap reference voltage forming unit becomes a maximum value from that of the first and second band gap reference voltage forming units 1 and 2.
[0068]
In the above description, the case where the first and second band gap reference voltage forming units 1 and 2 are provided has been described. However, the number of the first and second band gap reference voltage forming units 1 and 2 is not limited to two. In this way, a more accurate bandgap reference voltage circuit can be obtained. Of course, two or more equivalents of the third band gap reference voltage unit 3a and the level shift circuit unit 3b can be used.
[Brief description of the 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.
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 in a second embodiment.
FIG. 4 is a diagram showing the 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. 5. FIG.
7 is a graph showing the relationship between temperature and output voltage Vout when the bandgap reference voltage circuit shown in FIG. 6 is used. FIG.
FIG. 8 is a diagram showing the amount of change in stress with respect to temperature.
[Explanation of symbols]
1, 2 and 3a ... 1st and 2nd band gap reference voltage formation part, 3b ... Level shift part, 4 ... OR circuit part, 5a-5c ... Adjustment part, 6a-6c ... Differential pair, 7a-7c ... Current Mirror circuit unit, 8a to 8c, gain forming unit, 9a to 9c, emitter follower circuit unit.

Claims (5)

A band gap reference voltage circuit that outputs a constant voltage,
A first band gap reference voltage forming part (1) for forming the constant voltage;
A second band gap reference voltage forming part (2) for forming the constant voltage ;
A third bandgap reference voltage forming part (3a) for forming the constant voltage;
A first level shift that shifts the maximum value of the change in the output voltage of the third band gap reference voltage forming unit with respect to the temperature so as to deviate from the maximum value of the output voltage of the first and second band gap reference voltage forming units. A circuit unit (3b) ,
A band gap reference voltage circuit configured to output the constant voltage by outputting the highest voltage among the output voltages of the first to third band gap reference voltage forming units. The bandgap reference voltage circuit according to claim 1, further comprising a selection unit (4) that outputs the highest voltage among the output voltages of the first to third bandgap reference voltage forming units. The first bandgap reference voltage forming unit is configured to respond to fluctuations in currents flowing through the first and second transistors (T11 and T12) through which currents having different current densities flow and 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) where the potential varies are input. The currents flowing through the first and second transistors are adjusted based on
The second bandgap reference voltage forming unit is responsive to fluctuations of currents flowing through the third and fourth transistors (T21 and T22) through which currents having different current densities flow and the third and fourth transistors, respectively. And a second operational amplifier (5b, 6b, 7b, 8b, 9b) to which the potential of the third and fourth potential points where the potential varies is input, and the second operational amplifier is configured based on the output of the second operational amplifier. 3. The band gap reference voltage circuit according to claim 1, wherein a current flowing through the third and fourth transistors is adjusted. The first bandgap reference voltage forming unit is configured to respond to fluctuations in currents flowing through the first and second transistors (T31 and T32) through which currents having different current densities flow and the first and second transistors, respectively. A first operational amplifier (52a) to which the potentials of the first and second potential points (A ′, B ′) where the potential varies and a first resistor (R34) connected in series to the first and second transistors are provided. ), 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 is responsive to fluctuations of currents flowing through the third and fourth transistors (T41 and T42) through which currents having different current densities flow and the third and fourth transistors, respectively. A second operational amplifier (52b) to which the potential of the third and fourth potential points where the potential varies is input, and a second resistor (R44) connected in series to the third and fourth transistors. 2. The bandgap reference voltage circuit according to claim 1, wherein a current flowing through the third and fourth transistors is adjusted based on an output of the second operational amplifier. A fourth band gap reference voltage forming unit for forming the constant voltage;
A second level shift circuit unit that shifts the maximum value of the change in the output voltage of the fourth band gap reference voltage forming unit with respect to temperature so as to be equal to the maximum value of the output voltage of the third band gap reference voltage forming unit; With
Band according to claim 1, wherein by outputting the highest voltage among the first to fourth band-gap reference voltage generating portion of the output voltage, characterized in that it is configured to output the constant voltage Gap reference voltage circuit.

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