Reference voltage generating circuit

Abstract

The invention provides a reference voltage generating circuit which improves temperature characteristics of band-gap reference voltage. The present invention is provided with: a first bipolar transistor and a second bipolar transistor; a first resistor connected between the second power supply terminal and the emitter of the first bipolar transistor; a second resistor connected in series between an end portion of the first resistor on a side connected to the emitter of the first bipolar transistor and an emitter of the second bipolar transistor; a third resistor connected between the first power supply terminal and the collector of the first bipolar transistor; a fourth resistor connected between the first power supply terminal and the collector of the second bipolar transistor; an amplifier using the collector of the first bipolar transistor and the collector of the second bipolar transistor as inputs; and a temperature compensation circuit that corrects the current of the emitter of the second bipolar transistor or the current of the collector of the first bipolar transistor.

Description

Technical Field

[0001] This invention relates to a reference voltage generation circuit. Background Technology

[0002] Patent Document 1 disclosed a technique for providing a current correction circuit for suppressing the temperature dependence of the reference voltage in a semiconductor integrated circuit having a bandgap reference voltage circuit.

[0003] The technique of setting a temperature correction circuit in a bandgap reference circuit is disclosed in Patent Document 2 below.

[0004] Patent Document 1: Japanese Patent No. 6716918

[0005] Patent Document 2: Japanese Patent No. 5965528 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the technologies of patent documents 1 and 2, it is required to adjust the correction amount of the secondary temperature characteristics according to the deviation of the component characteristics in the manufacturing process.

[0008] Methods for solving problems

[0009] One embodiment of the reference voltage generating circuit includes: a first bipolar transistor and a second bipolar transistor connected between a first power supply terminal and a second power supply terminal, with their bases connected to an output terminal; a first resistor connected between the second power supply terminal and the emitter of the first bipolar transistor; a second resistor connected in series between the end of the first resistor connected to the emitter of the first bipolar transistor and the emitter of the second bipolar transistor; a third resistor connected between the first power supply terminal and the collector of the first bipolar transistor; a fourth resistor connected between the first power supply terminal and the collector of the second bipolar transistor; an amplifier that takes the collectors of the first bipolar transistor and the second bipolar transistor as inputs; and a temperature compensation circuit that corrects the current at the collector of the second bipolar transistor or the collector of the first bipolar transistor.

[0010] According to one embodiment of the reference voltage generation circuit, the temperature characteristics of the bandgap reference voltage can be improved. Attached Figure Description

[0011] Figure 1 This is a diagram illustrating an example of the circuit structure of the reference voltage generating circuit according to the first embodiment.

[0012] Figure 2 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit of the comparative example.

[0013] Figure 3 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit of the first embodiment.

[0014] Figure 4 This is a diagram illustrating a first variation of the circuit structure of the reference voltage generating circuit of the first embodiment.

[0015] Figure 5 This is a diagram illustrating an example of the circuit structure of the reference voltage generating circuit in the second embodiment.

[0016] Figure 6 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit of the second embodiment.

[0017] Figure 7 This is a diagram showing a second variation that combines the first and second embodiments.

[0018] Figure 8 This is a diagram illustrating an example of the circuit structure of the reference voltage generating circuit according to the third embodiment.

[0019] Figure 9 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit of the third embodiment.

[0020] Figure 10 This is a diagram illustrating an example of the structure of the equivalent circuit of the reference voltage generating circuit in the third embodiment.

[0021] Figure 11 It means Figure 10 A diagram illustrating an example of the temperature characteristics of the current ratio α of currents I3 and I4 in the equivalent circuit shown.

[0022] Figure 12 It means in Figure 10 A diagram showing an example of a higher-order component of the voltage V2 generated by resistor R2 in the equivalent circuit shown.

[0023] Figure 13 It means Figure 10 A diagram showing an example of the higher-order components of the temperature characteristics of each voltage in the equivalent circuit shown.

[0024] Figure 14 This is a diagram showing an example of the layout of the transistors arranged in the reference voltage generation circuit of the first embodiment.

[0025] Figure 15 This is a diagram illustrating an example of the circuit structure of the reference voltage generation circuit for the comparative example. Detailed Implementation

[0026] Hereinafter, one embodiment will be described with reference to the accompanying drawings.

[0027] [First Implementation]

[0028] (Circuit structure of reference voltage generation circuit 100)

[0029] Figure 1 This is a diagram illustrating an example of the circuit configuration of the reference voltage generating circuit 100 in the first embodiment. Figure 1 The reference voltage generation circuit 100 shown is based on a so-called Brokaw-type bandgap reference voltage generation circuit, which generates a bandgap reference voltage and outputs the bandgap reference voltage from the output terminal VREF.

[0030] like Figure 1 As shown, the reference voltage generation circuit 100 of the first embodiment includes a first bipolar transistor TR1, a second bipolar transistor TR2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and an amplifier AMP.

[0031] The first bipolar transistor TR1 is, for example, an NPN type transistor, connected between the first power supply terminal VDD and the second power supply terminal VSS, with its base connected to the output of the amplifier AMP and the output terminal VREF.

[0032] The second bipolar transistor TR2 is, for example, an NPN transistor, connected between the first power supply terminal VDD and the second power supply terminal VSS, and its base is connected to the output and output terminal VREF of the amplifier AMP.

[0033] The emitter area ratio A:M*A of the first bipolar transistor TR1 to the emitter area of ​​the second bipolar transistor TR2 has different current densities. Here, A is a real number greater than 1, and M is a real number greater than 1. For example, A:M*A = 1:8.

[0034] The first resistor R1 is connected between the second power supply terminal VSS and the emitter of the first bipolar transistor TR1.

[0035] The second resistor R2 is connected in series between the end of the first resistor connected to the emitter of the first bipolar transistor and the emitter of the second bipolar transistor TR2.

[0036] The third resistor R3 is connected between the first power supply terminal VDD and the collector of the first bipolar transistor TR1.

[0037] The fourth resistor R4 is connected between the first power supply terminal VDD and the collector of the second bipolar transistor TR2.

[0038] The amplifier AMP is a two-stage amplifier connected between a first power supply terminal VDD and a second power supply terminal VSS. One input of the first stage of the amplifier AMP is connected to the collector of a first bipolar transistor TR1. The other input of the amplifier AMP is connected to the collector of a second bipolar transistor TR2. Furthermore, the amplifier AMP includes a long-tailed pair (emitter-coupled pair) with transistors TR3 and TR4. The control terminal of transistor TR3 is an inverting input, and the control terminal of transistor TR4 is a non-inverting input.

[0039] The second stage of the amplifier AMP is connected between the first power supply terminal VDD and the second power supply terminal VSS, and has a structure in which a PMOS transistor TR10 is connected in series with a sixth resistor R6. Specifically, one end of the PMOS transistor TR10 is connected to the first power supply terminal VDD, and the other end of the PMOS transistor TR10 is connected to the sixth resistor R6. Additionally, one end of the sixth resistor R6 is connected to the other end of the PMOS transistor TR10, and the other end of the sixth resistor R6 is connected to the second power supply terminal VSS. The control terminal of the PMOS transistor TR10 is connected to the collector of transistor TR4. Furthermore, the drain of the PMOS transistor TR10 is the output terminal of the amplifier AMP, connected to the output terminal VREF. That is, the output of the amplifier AMP is connected to the base of the first bipolar transistor TR1, the base of the second bipolar transistor TR2, and the output terminal VREF. Here, the reference voltage generation circuit 100 actually has a phase compensation circuit and a startup circuit, but these are omitted from the illustrations and descriptions in this specification.

[0040] Here, as an example of a temperature compensation circuit for correcting the current at the collector of the first bipolar transistor TR1, the reference voltage generation circuit 100 of the first embodiment has a first current source connected to the collector of the first bipolar transistor TR1.

[0041] Specifically, as an example of a first current source, the reference voltage generation circuit 100 of the first embodiment includes a transistor TR9, one end of which is connected to the first power supply terminal VDD, and the other end is connected to the collector of the first bipolar transistor TR1 and the non-inverting input of the amplifier AMP (the control terminal of transistor TR4), and the control terminal is connected to the control terminal of the PMOS transistor TR10.

[0042] Therefore, the reference voltage generation circuit 100 of the first embodiment can improve the temperature characteristics of the bandgap reference voltage by correcting the collector current of the first bipolar transistor TR1 according to changes in ambient temperature. Furthermore, since the reference voltage generation circuit 100 of the first embodiment does not use comparators, amplifiers, etc., in the temperature compensation circuit, it can suppress the increase in power consumption that would result from adding a temperature compensation circuit.

[0043] Furthermore, in the reference voltage generation circuit 100 of the first embodiment, the amplifier AMP has an asymmetrical differential pair 102 consisting of an inverting input transistor TR3 and a non-inverting input transistor TR4. Both the inverting input transistor TR3 and the non-inverting input transistor TR4 are NPN type transistors. In the differential pair 102, the emitter area ratio between the inverting input transistor TR3 and the non-inverting input transistor TR4 is B:N*B. Here, B is a real number greater than 1, and N is a real number greater than 1. For example, B:N*B = 1:8. Here, even if the emitter area ratio of the inverting input transistor TR3 and the non-inverting input transistor TR4 is not B:N*B, it is sufficient as long as the emitter current density ratio is N*B:B. This is because if the current density flowing through the emitters of the inverting input transistor TR3 and the non-inverting input transistor TR4 is N*B:B, the same effect can be obtained.

[0044] Furthermore, in the reference voltage generation circuit 100 of the first embodiment, the collector of the first bipolar transistor TR1, with an emitter area ratio of A (e.g., 1), is connected to the base of the non-inverting input transistor TR4, with an emitter area ratio of N*B (e.g., 8), and the collector of the second bipolar transistor TR2, with an emitter area ratio of M*A (e.g., 8), is connected to the base of the inverting input transistor TR3, with an emitter area ratio of B (e.g., 1). Moreover, as described above, even if the emitter area ratio is not specified, the same effect can be achieved as long as the current density flowing through the emitters of the first bipolar transistor TR1 and the second bipolar transistor TR2 becomes M*A:A.

[0045] Therefore, the reference voltage generation circuit 100 of the first embodiment can suppress manufacturing deviations in temperature characteristic correction.

[0046] Furthermore, in this embodiment, as a preferred example, the relationships A = B and M = N are present. For example, the relationships A = B = 1 and M = N = 8 are present. Utilizing this relationship, such as... Figure 14 As shown, bipolar transistors TR1 and TR2 can be configured in a square. Similarly, transistors TR3 and TR4 can be configured in a square. By arranging these bipolar transistors TR1, TR2, TR3, and TR4 close together, deviations in relative characteristics caused by manufacturing processes can be suppressed. Furthermore, for convenience, bipolar transistors TR1 and TR3 are divided into eight independent sections, but each section is electrically connected.

[0047] In addition, in the reference voltage generating circuit 100 of the first embodiment, the first resistor R1, the second resistor R2 and the resistor element R6 are configured as resistors of the same type (e.g., polyresistors, diffused layer resistors, metal resistors, etc.) with equal temperature characteristics, which can also suppress relative characteristic deviations caused by manufacturing.

[0048] Since the temperature characteristics of bipolar transistors and resistors are dominant in the higher-order temperature characteristics of the reference voltage generation circuit, the higher-order temperature characteristics can be stably corrected by suppressing the relative characteristic deviations of bipolar transistors and resistors.

[0049] (Improvement in temperature characteristics)

[0050] Figure 2 It means Figure 15 A diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit of the comparative example. Figure 3 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit 100 of the first embodiment. Figure 2 and Figure 3 In the chart shown, the horizontal axis represents ambient temperature [°C], and the vertical axis represents voltage [V].

[0051] like Figure 2 As shown, in the reference voltage generation circuit of the comparative example, the temperature characteristic of the bandgap reference voltage is convex on the upper side, and the voltage [V] changes by about 2 to 5 [mV] in the range of ambient temperature from -40°C to 120°C.

[0052] On the other hand, such as Figure 3 As shown, in the reference voltage generation circuit 100 of the first embodiment, the temperature characteristic of the bandgap reference voltage is obtained by adding the bandgap reference voltage with a concave shape on the lower side and the bandgap reference voltage with a convex shape on the upper side. The voltage [V] changes by about 250 [μV] in the range of ambient temperature of -40 [°C] to 120 [°C].

[0053] Thus, by setting a first current source as an example of a temperature compensation circuit, the reference voltage generation circuit 100 of the first embodiment suppresses the change in voltage [V] that accompanies the change in ambient temperature, compared with the reference voltage generation circuit of the comparative example.

[0054] (First variation of the first embodiment)

[0055] Figure 4 This is a diagram showing a first example of the circuit structure of the reference voltage generating circuit 100 of the first embodiment. Figure 4In the reference voltage generation circuit 100-2 shown, the gate connection of TR7 is different from that in the reference voltage generation circuit 100.

[0056] like Figure 4 As shown, in addition to the structure where the MOS transistor TR10 is connected in series with the sixth resistor R6, there is also a structure where the third PMOS transistor TR5 is connected in series with the NMOS transistor TR6. Specifically, the source of the third PMOS transistor TR5 is connected to the first power supply terminal VDD. The drain of the third PMOS transistor TR5 is connected to the drain of the NMOS transistor TR6, the control terminal, and the gate of TR7. The source of the NMOS transistor TR6 is connected to the second power supply terminal VSS.

[0057] [Second Implementation]

[0058] (Circuit structure of reference voltage generation circuit 200)

[0059] Figure 5 This is a diagram illustrating an example of the circuit structure of the reference voltage generating circuit 200 according to the second embodiment. Figure 5 The reference voltage generation circuit 200 shown is... Figure 4 The difference in the reference voltage generation circuit 100-2 shown is that it does not have a first current source (transistor TR9) as an example of a temperature compensation circuit. On the other hand, Figure 5 The reference voltage generation circuit 200 shown is... Figure 4 The difference in the reference voltage generation circuit 100-2 shown is that it has a second current source (transistor TR8) connected to the emitter of the second bipolar transistor TR2 as a temperature compensation circuit.

[0060] like Figure 5 As shown, NMOS transistor TR8 is positioned between the second bipolar transistor TR2 and the second power supply terminal VSS. Specifically, the control terminal of NMOS transistor TR8 is connected to the control terminal of NMOS transistor TR6. Additionally, one end of NMOS transistor TR8 is connected to the second power supply terminal VSS. The other end of NMOS transistor TR8 is connected to the emitter of the second bipolar transistor TR2.

[0061] That is, as an example of a temperature compensation circuit for correcting the current of the emitter of the second bipolar transistor TR2, a second current source (transistor TR8) is connected to the emitter of the second bipolar transistor TR2.

[0062] The reference voltage generation circuit 200 of the second embodiment can improve the temperature characteristics of the bandgap reference voltage by correcting the emitter current of the second bipolar transistor TR2 using the second current source (transistor TR8). Furthermore, since the reference voltage generation circuit 200 of the second embodiment does not use comparators, amplifiers, etc., in the temperature compensation circuit, it can suppress the increase in power consumption that would result from adding a temperature compensation circuit.

[0063] (Improvement in temperature characteristics)

[0064] Figure 6 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit 200 of the second embodiment. Figure 6 In the chart shown, the horizontal axis represents ambient temperature [°C], and the vertical axis represents voltage [V].

[0065] like Figure 2 As shown, in the reference voltage generation circuit of the comparative example, the temperature characteristic of the bandgap reference voltage is convex on the upper side, and the voltage [V] changes by about 2 to 5 [mV] in the range of ambient temperature of -40 [°C] to 120 [°C].

[0066] On the other hand, such as Figure 6 As shown, in the reference voltage generation circuit 200 of the second embodiment, the temperature characteristic of the bandgap reference voltage is obtained by adding the bandgap reference voltage with a concave shape on the lower side and the bandgap reference voltage with a convex shape on the upper side. The voltage [V] changes by about 250 [μV] in the range of ambient temperature of -40 [°C] to 120 [°C].

[0067] Thus, by providing a second current source as an example of a temperature compensation circuit, the reference voltage generation circuit 200 of the second embodiment suppresses the change in voltage [V] that accompanies changes in ambient temperature, compared to the reference voltage generation circuit of the comparative example.

[0068] (A second variation combining the first and second embodiments)

[0069] Figure 7 This is a diagram illustrating a second variation that combines the first embodiment and the second embodiment. Figure 7 The reference voltage generation circuit 200-2 shown is... Figure 4 The difference in the reference voltage generation circuit 100-2 shown is that, in the first variation of the first embodiment, the temperature compensation circuit, i.e. the second current source, of the second embodiment also includes an NMOS transistor TR8.

[0070] like Figure 7As shown, a second current source (transistor TR8) is added to the reference voltage generation circuit 100-2 of the variation of the first embodiment.

[0071] Thus, the reference voltage generating circuit 200-2 of the second variant, which combines the first embodiment and the second embodiment, has a first current source (transistor TR9) connected to the collector of the first bipolar transistor TR1 as an example of a temperature compensation circuit for correcting the current of the collector of the first bipolar transistor TR1, and has a second current source (transistor TR8) connected to the emitter of the second bipolar transistor TR2 as an example of a temperature compensation circuit for correcting the current of the emitter of the second bipolar transistor TR2.

[0072] Therefore, the reference voltage generating circuit 200-2 of the second modification, which combines the first and second embodiments, can improve the temperature characteristics of the bandgap reference voltage by correcting both the collector current of the first bipolar transistor TR1 and the emitter current of the second bipolar transistor TR2 according to changes in ambient temperature. Furthermore, since the reference voltage generating circuit 200-2 of the second modification, which combines the first and second embodiments, does not use comparators, amplifiers, etc., in its temperature compensation circuit, it can suppress the increase in power consumption that would result from adding a temperature compensation circuit.

[0073] [Third Implementation Method]

[0074] (Circuit structure of reference voltage generation circuit 300)

[0075] Figure 8 This is a diagram illustrating an example of the circuit structure of the reference voltage generating circuit 300 according to the third embodiment. Figure 8 The reference voltage generation circuit 300 shown is... Figure 1 The difference in the reference voltage generation circuit 100 shown is that it does not have a first current source (transistor TR9) as an example of a temperature compensation circuit. Instead, as another example of a temperature compensation circuit, it has a resistor element R5 connected to the emitter of a second bipolar transistor TR2. Specifically, one end of the resistor element R5 is connected to the emitter of the second bipolar transistor TR2, and the other end is connected to the output terminal VREF.

[0076] in addition, Figure 8 The reference voltage generation circuit 300 shown is similar to the following aspects: Figure 1The reference voltage generation circuit 100 shown is different. Specifically, the reference voltage generation circuit 300 has a structure in which a PMOS transistor TR11 and an NMOS transistor TR12 are connected in series. One end of the PMOS transistor TR11 is connected to the first power supply terminal VDD. The other end of the PMOS transistor TR11 is connected to one end of the NMOS transistor TR12. The other end of the NMOS transistor TR12 is connected to the second power supply terminal VSS.

[0077] The reference voltage generation circuit 300 of the third embodiment improves the temperature characteristics of the bandgap reference voltage by using the resistor element R5 to correct the emitter current of the second bipolar transistor TR2. Furthermore, since the reference voltage generation circuit 300 of the third embodiment does not use comparators, amplifiers, etc., in the temperature compensation circuit, it can suppress the increase in power consumption that would result from adding a temperature compensation circuit.

[0078] (Improvement in temperature characteristics)

[0079] Figure 9 This is a diagram illustrating an example of the temperature characteristics of the bandgap reference voltage in the reference voltage generation circuit 300 of the third embodiment. Figure 9 In the chart shown, the horizontal axis represents ambient temperature [°C], and the vertical axis represents voltage [V].

[0080] like Figure 2 As shown, in the reference voltage generation circuit of the comparative example, the temperature characteristic of the bandgap reference voltage is convex on the upper side, and the voltage [V] changes by about 2 to 5 [mV] in the range of ambient temperature of -40 [°C] to 120 [°C].

[0081] On the other hand, such as Figure 9 As shown, in the reference voltage generation circuit 300 of the third embodiment, the temperature characteristic of the bandgap reference voltage is obtained by adding the bandgap reference voltage with a concave shape on the lower side and the bandgap reference voltage with a convex shape on the upper side. The voltage [V] changes by about 300 [μV] in the range of ambient temperature of -40 [°C] to 120 [°C].

[0082] Thus, the reference voltage generating circuit 300 of the third embodiment, by setting the resistor element R5 as an example of a temperature compensation circuit, suppresses the change of voltage [V] that accompanies the change of ambient temperature, compared with the reference voltage generating circuit of the comparative example.

[0083] Furthermore, in the reference voltage generating circuit 300 of the third embodiment, the second resistor R2 and the resistor element R5 are made of the same type of resistor (e.g., polycrystalline resistor, diffused layer resistor, metal resistor, etc.) so that their temperature characteristics are equal.

[0084] (Function of the reference voltage generation circuit 300 in the third embodiment)

[0085] The following is for reference Figures 10-13 The function of the reference voltage generating circuit 300 in the third embodiment will be explained. Figure 10 This is a diagram showing the structure of the equivalent circuit of the reference voltage generating circuit 300 in the third embodiment. Figure 11 It means Figure 10 The diagram shows the temperature characteristics of the current ratio α of currents I3 and I4 in the equivalent circuit. Figure 12 It means in Figure 10 The diagram shows the higher-order components of the voltage V2 generated by resistor R2 in the equivalent circuit shown. Figure 13 It means Figure 10 The diagram shows the higher-order components of the temperature characteristics of each voltage in the equivalent circuit shown.

[0086] (1) First, in Figure 10 In the equivalent circuit shown, the resistor R2 of the Brokaw-type reference voltage source is made to allow the current I5, which depends on Vf, to flow into it. The current ratio α of the current I3 to the current I4 is calculated when there is a VT×ln(8) offset in the amplifier. Here, VT is the thermal voltage. Where I3:I4=α:1, I3=α×I4.

[0087] Based on the current ratio α, the voltage V2 generated in resistor R2 can be obtained by the following equation (1).

[0088] [Formula 1]

[0089] V2=VT×ln(8α)…(1)

[0090] Since the current I5 = Vf / R5 flows into the voltage V2, the current I4 can be obtained by the following equation (2).

[0091] [Formula 2]

[0092]

[0093] Based on the current ratio α, the current I3 is obtained by the following equation (3).

[0094] [Formula 3]

[0095]

[0096] Since the amplifier has an offset voltage VT×ln(8), the relationship between Vc1 and Vc2 is expressed by the following equation (4).

[0097] [Formula 4]

[0098] Vc2-Vc1=VT×ln(8)…(4)

[0099] Based on the above equations (2), (3), and (4), the following equation (5) holds true.

[0100] [Formula 5]

[0101]

[0102] When R33=R4=Rc

[0103]

[0104] In addition, if α = 1 + Δα, then when Δα is sufficiently small, according to the approximation ln(1 + Δα) ≈ Δα, ln(8 × α) is expressed by the following equation (6).

[0105] [Formula 6]

[0106]

[0107] Based on the above equations (5) and (6), the following equation (7) holds true.

[0108] [Formula 7]

[0109]

[0110] The term Δα2 is small enough that if it is ignored, it becomes the following equation (8).

[0111] [Formula 8]

[0112]

[0113] Therefore, according to α=1+Δα, the current ratio α is expressed by the following equation (9).

[0114] [Formula 9]

[0115]

[0116] (2) Next, the voltage V2 generated in resistor R2 is determined according to the current ratio α. According to the above equation (9), the voltage V2 is expressed by the following equation (10).

[0117] [Formula 10]

[0118]

[0119] like Figure 11 As shown, the current ratio α in equation (9) above has higher-order components. Furthermore, as... Figure 12 As shown, the second term of the above equation (10) has a concave higher-order component below.

[0120] (3) Next, the bandgap reference voltage output voltage VREF is calculated based on the current ratio α.

[0121] Based on the current ratio α, the voltage V2 generated in resistor R2 is obtained by the following equation (11).

[0122] [Formula 11]

[0123] V2=VT×ln(8α)…(11)

[0124] Therefore, the current I4 is obtained by the following equation (12).

[0125] [Formula 12]

[0126]

[0127] Based on the current I4, Vc2 is represented by the following equation (13).

[0128] [Formula 13]

[0129]

[0130] Since the amplifier has an offset voltage VT×ln(8), Vc1 can be obtained by the following equation (14).

[0131] [Formula 14]

[0132]

[0133] Therefore, the current I3 is obtained by the following equation (15).

[0134] [Formula 15]

[0135]

[0136] In addition, the current I1 is obtained by the following equation (16).

[0137] [Formula 16]

[0138]

[0139] In addition, the voltage V1 is obtained by the following equation (17).

[0140] [Formula 17]

[0141]

[0142] In addition, the voltage VREF is obtained by the following equation (18).

[0143] [Formula 18]

[0144]

[0145] like Figure 13 As shown, the temperature characteristics of voltage VREF are flattened by the upward convex higher-order component of the first term and the downward concave higher-order component of the second term in the above equation (18).

[0146] The above describes one embodiment of the present invention in detail, but the present invention is not limited to these embodiments. Various modifications or alterations can be made within the scope of the spirit of the present invention as described in the scope of the claims.

[0147] In each reference voltage generation circuit described in the embodiments, an amplifier with a structure other than that described in the embodiments may also be used as the amplifier AMP. For example, in the reference voltage generation circuit 100 of the first embodiment, an amplifier with a structure that replaces the NMOS load of the second stage output of the two-stage amplifier with the sixth resistor R6 is used as the amplifier AMP, but an amplifier with other structures (e.g., the structure of a two-stage amplifier (see reference 1)) may also be used. Figure 8 (e.g., replacing the first stage of a two-stage amplifier with a folded cascode structure). However, when the amplifier AMP is set to any structure, the emitter area ratio of the inverting input transistor TR3 to the non-inverting input transistor TR4 in the amplifier AMP is preferably B:N*B, while the current density is different.

[0148] Symbol Explanation

[0149] 100, 100-2, 100-3, 200, 300 reference voltage generation circuits

[0150] 102 Differential Pairs

[0151] TR1 First Bipolar Transistor

[0152] TR2 Second Bipolar Transistor

[0153] TR3 is the inverting input transistor.

[0154] TR4 is a non-inverting input transistor.

[0155] TR5 PMOS transistor (third current source)

[0156] TR6 NMOS transistor

[0157] TR8 NMOS transistor (second current source)

[0158] TR9 transistor (first current source)

[0159] TR10 PMOS transistor

[0160] TR11 PMOS transistor

[0161] TR12 NMOS transistor

[0162] R1 is the first resistor.

[0163] R2 is the second resistor.

[0164] R3 is the third resistor.

[0165] R4, the fourth resistor

[0166] R5 resistor element

[0167] R6, the sixth resistor

[0168] AMP amplifier

[0169] VDD first power terminal

[0170] VSS Second Power Terminal

[0171] VREF output terminal.

Claims

1. A reference voltage generating circuit, characterized in that, have: The output terminal outputs a reference voltage. A first bipolar transistor and a second bipolar transistor are connected between a first power supply terminal and a second power supply terminal, and their bases are connected to the output terminal. A first resistor is connected between the second power supply terminal and the emitter of the first bipolar transistor; The second resistor is connected in series between the end of the first resistor connected to the emitter of the first bipolar transistor and the emitter of the second bipolar transistor. A third resistor is connected between the first power supply terminal and the collector of the first bipolar transistor. A fourth resistor is connected between the first power supply terminal and the collector of the second bipolar transistor; An amplifier that takes the collector of the first bipolar transistor and the collector of the second bipolar transistor as inputs, and whose output is connected to the output terminal. A temperature compensation circuit that corrects the current at the collector or emitter of the second bipolar transistor, or the current at the collector or emitter of the first bipolar transistor.

2. The reference voltage generating circuit according to claim 1, characterized in that, The amplifier has a differential pair of inverting input transistors and non-inverting input transistors, with emitter current densities of N*B:B. The collector of the first bipolar transistor is connected to the non-inverting input transistor, and the collector of the second bipolar transistor is connected to the inverting input transistor. The emitter current density of the first bipolar transistor and the second bipolar transistor is a current density ratio of M*A:A. A and B are real numbers greater than or equal to 1, and M and N are real numbers greater than 1.

3. The reference voltage generating circuit according to claim 1, characterized in that, The amplifier has a differential pair with an inverting input transistor and a non-inverting input transistor having an emitter area ratio of B:N*B. The collector of the first bipolar transistor is connected to the non-inverting input transistor, and the collector of the second bipolar transistor is connected to the inverting input transistor. The emitters of the first bipolar transistor and the second bipolar transistor have an area ratio of A:M*A. A and B are real numbers greater than or equal to 1, and M and N are real numbers greater than 1.

4. The reference voltage generating circuit according to claim 2 or 3, characterized in that, The reference voltage generating circuit has the relationship that A = B and M = N.

5. The reference voltage generating circuit according to claim 2 or 3, characterized in that, The temperature compensation circuit has a first current source connected to the collector or emitter of the first bipolar transistor.

6. The reference voltage generating circuit according to claim 5, characterized in that, The amplifier has the following features: An emitter-coupled pair having a first transistor whose control terminal is an inverting input and a second transistor whose control terminal is a non-inverting input; and A MOS transistor is connected between the first power supply terminal and the second power supply terminal. The collector of the transistor whose input is connected to the non-inverting input of the amplifier is connected to the transistor, and the drain is connected to the output terminal.

7. The reference voltage generating circuit according to claim 6, characterized in that, The first current source has: a transistor, one end of which is connected to the first power supply terminal, and the other end of which is connected to the collector of the first bipolar transistor, and a control terminal connected to the control terminal of the MOS transistor.

8. The reference voltage generating circuit according to claim 2 or 3, characterized in that, The temperature compensation circuit has a second current source connected to the emitter of the second bipolar transistor.

9. The reference voltage generating circuit according to claim 8, characterized in that, The reference voltage generation circuit includes: a third PMOS current source; and an NMOS transistor whose drain and control terminal are connected to the drain of the third PMOS current source. The control terminal of the second current source is connected to the control terminal of the NMOS transistor, one end is connected to the second power supply terminal, and the other end is connected to the emitter of the second bipolar transistor.

10. The reference voltage generating circuit according to claim 2, characterized in that, The temperature compensation circuit includes a resistive element, one end of which is connected to the emitter of the second bipolar transistor, and the other end of which is connected to the output terminal.

11. The reference voltage generating circuit according to claim 10, characterized in that, The second resistor and the resistive element are made of the same type of resistor. It has the relationship that A = B and M = N.

12. The reference voltage generating circuit according to claim 2, characterized in that, The temperature compensation circuit has the following features: A first current source is connected to the collector of the first bipolar transistor; and A second current source is connected to the emitter of the second bipolar transistor.

13. The reference voltage generating circuit according to claim 12, characterized in that, The amplifier has: an emitter-coupled pair having a first transistor whose control terminal is an inverting input and a second transistor whose control terminal is a non-inverting input. The amplifier is connected between the first power supply terminal and the second power supply terminal. The collector of the second transistor of the amplifier is connected to the control terminal of the MOS transistor, and the output terminal is connected to the drain of the MOS transistor.

14. The reference voltage generating circuit according to claim 13, characterized in that, The first current source includes: a transistor, one end of which is connected to the first power supply terminal, and the other end of which is connected to the collector of the first bipolar transistor; and a control terminal connected to the control terminal of a MOS transistor. The reference voltage generation circuit includes: a third PMOS current source; and an NMOS transistor whose drain and control terminal are connected in common with the drain of the third PMOS current source. The second current source has: a transistor whose control terminal is connected to the control terminal of the NMOS transistor, one end of which is connected to the second power supply terminal, and the other end of which is connected to the emitter of the second bipolar transistor.

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