Reference voltage generation circuit and method

Abstract

This invention provides a reference voltage generation circuit that improves the temperature dependence of output voltage through a simple circuit. The reference voltage generation circuit includes: a bandgap reference voltage circuit (10) that generates a predetermined reference voltage; and a first correction current generation circuit (20) that generates a first correction current (Is) in response to temperature changes. The first correction current generation circuit (20) generates a plurality of voltage peaks in the output voltage of the reference voltage generation circuit that vary with temperature by injecting the first correction current (Is) into the bandgap reference voltage circuit (10). The output voltage characteristic constituting each of the plurality of voltage peaks is configured such that the output voltage changes continuously with temperature changes. The first correction current generation circuit (10) includes: a temperature setting circuit (Q4, 31) that sets a plurality of temperatures corresponding to the plurality of voltage peaks to be changeable.

Description

Technical Field

[0001] The present invention relates to a reference voltage generation circuit, such as a bandgap reference voltage generation circuit, and a method for generating a reference voltage circuit. Background Technology

[0002] In many systems and semiconductor circuits, bandgap reference voltage circuits are used as a means to generate a moderately stable DC reference voltage relative to temperature. Previously, many attempts have been made to reduce the temperature dependence of this output and generate the reference voltage with high accuracy.

[0003] Conventional bandgap reference voltage generation circuits generate a reference voltage by adding two voltages that are balanced and have opposite temperature tilts. One voltage is the forward voltage of the PN junction, which is the base-emitter voltage Vbe (i.e., the base-emitter voltage of a bipolar transistor, with a temperature coefficient of -2mV / ℃) with a negative temperature characteristic. The other voltage is based on the positive temperature characteristic of the forward voltage difference ΔVbe between the PN junctions.

[0004] For example, Patent Document 1 aims to provide a reference voltage generation circuit that balances high and low temperature characteristics and expands the temperature range from which good voltage accuracy can be obtained. This reference current generation circuit is a reference voltage generation circuit that outputs a bandgap-based reference voltage. Furthermore, the reference voltage generation circuit includes a reference voltage output section having a PN junction element and multiple resistive elements, and outputs a voltage whose bandgap has been corrected by the multiple resistive elements. Further, the reference voltage generation circuit includes: a switch that changes the temperature characteristics of the output voltage of the reference voltage output section; and a switch operation section that operates the switch based on temperature.

[0005] Since the voltage obtained by adding the two voltages also includes a nonlinear term of the base-emitter voltage Vbe, the output voltage has a curve that bulges upward around a certain temperature. However, there are cases where the temperature characteristics are insufficient depending on the intended use. To address this issue, Patent Document 2 discloses a reference voltage generation circuit that, compared to existing technologies, can improve the temperature dependence of the output voltage using a simpler circuit.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2007-018377

[0009] Patent Document 2: Japanese Patent No. 6765119 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, while numerous inventions related to bandgap reference voltage circuits have been reported, many still suffer from insufficient temperature characteristics depending on the intended use and temperature range. Furthermore, although circuits exist that correct output voltage based on temperature changes, these often suffer from circuit complexity or limitations in correction conditions, such as the need to uniquely determine the correction temperature based on the characteristics of the components used.

[0012] The purpose of this invention is to solve the above problems and provide a reference voltage generation circuit and a reference voltage generation circuit method that can improve the temperature dependence of the output voltage with a simpler circuit compared with the prior art.

[0013] Methods for solving problems

[0014] The reference voltage generating circuit according to one aspect of the present invention includes:

[0015] The bandgap reference voltage circuit generates a specified reference voltage; and

[0016] The first correction current generating circuit generates a first correction current in response to temperature changes.

[0017] The first correction current generating circuit injects the first correction current into the bandgap reference voltage circuit, thereby generating a plurality of voltage peaks in the output voltage of the reference voltage generating circuit that vary with temperature. The output voltage characteristic of each of the plurality of voltage peaks is configured such that the output voltage changes continuously with temperature.

[0018] The first correction current generating circuit includes a temperature setting circuit that sets multiple temperatures corresponding to the multiple voltage peaks to be changeable.

[0019] Invention Effects

[0020] Therefore, the reference voltage generation circuit and the like according to the present invention can improve the temperature dependence of the output voltage with a simpler circuit compared to the prior art. Attached Figure Description

[0021] Figure 1 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 1.

[0022] Figure 2 It means Figure 1 The temperature characteristic curve of the base voltage Vb4 in the correction current generating circuit 20.

[0023] Figure 3 It means in Figure 1 The circuit diagram of the currents I1 to I3 flowing through the reference voltage generation circuit when the temperature Temp is less than the temperature threshold Tvth.

[0024] Figure 4 It means in Figure 1 The circuit diagram of the reference voltage generation circuit with currents I1 to I4 flowing when the temperature Temp is above the temperature threshold Tvth.

[0025] Figure 5 It means Figure 1 A graph showing the temperature characteristics of the PTAT (Proportional to Absolute Temperature) current Iptat in the reference voltage generation circuit.

[0026] Figure 6 This is a circuit diagram showing the structure of the reference voltage generation circuit disclosed in Patent Document 2, which relates to the prior art.

[0027] Figure 7 (a) is a graph showing the temperature characteristics of the output voltage of the reference voltage generation circuit involved in the prior art. Figure 7 (b) is a graph showing the temperature characteristics of the output voltage of the reference voltage generation circuit according to Embodiment 1.

[0028] Figure 8 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 2.

[0029] Figure 9 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 3.

[0030] Figure 10 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 4.

[0031] Figure 11 It means Figure 10 The temperature characteristic curve of the output voltage of the reference voltage generation circuit.

[0032] Figure 12 This is a circuit diagram illustrating the structural example of the reference voltage generation circuit involved in Modification Example 1.

[0033] Figure 13 This is a circuit diagram illustrating the structural example of the reference voltage generation circuit involved in Modification Example 2. Detailed Implementation

[0034] Hereinafter, embodiments and variations of the present invention will be described with reference to the accompanying drawings. Furthermore, the same reference numerals are used to denote the same or identical constituent elements.

[0035] (The inventor's perspective)

[0036] In existing technologies, the temperature correction temperature for temperature characteristics is uniquely determined based on the base / emitter voltage Vbe characteristic of a bipolar transistor. This results in insufficient temperature characteristics depending on the temperature range. In this embodiment, the objective is to provide a high-precision reference voltage with minimal temperature deviation based on the temperature of the output voltage, without increasing the circuit size, compared to existing technologies.

[0037] (Implementation Method 1)

[0038] Figure 1 This is a circuit diagram illustrating a structural example of the reference voltage generating circuit according to Embodiment 1. In Embodiment 1... Figure 1 In contrast to the bandgap reference voltage circuit 10 in the prior art, the reference voltage generating circuit in Embodiment 1 further includes a correction current generating circuit 20. Similar to the prior art circuit, by utilizing the operating characteristics of a bipolar transistor, the PTAT current Iptat (a current proportional to absolute temperature) is varied with temperature, thereby forming a reference voltage generating circuit with two peak voltages instead of one peak voltage in the temperature characteristics of the output voltage.

[0039] exist Figure 1 In this circuit, the bandgap reference voltage circuit 10 is a circuit that uses the bandgap of a bipolar transistor to generate a predetermined reference voltage, and is configured with resistors R1 to R3, bipolar transistors Q1 and Q2, and operational amplifier 11. The output voltage terminal 30 is grounded via resistor R1 and the emitter and collector of bipolar transistor Q1, and also via resistors R2 and R3 and the emitter and collector of bipolar transistor Q2. Furthermore, the bases and collectors of bipolar transistors Q1 and Q2 are interconnected and grounded. The non-inverting input terminal of operational amplifier 11, which operates on power supply voltage VDD, is supplied with a voltage at the junction P1 of resistor R1 and the emitter of bipolar transistor Q1, and the inverting input terminal is supplied with a voltage at the junction P2 of resistors R2 and R3. A predetermined constant voltage is output from the output terminal of operational amplifier 11 via the output voltage terminal 30.

[0040] The correction current generating circuit 20 is configured to include: resistors R4 and Rx; a voltage divider circuit 31 including voltage divider resistors Rt and Rb; bipolar transistors Q3 and Q4; and a current mirror circuit CM1 including MOS transistors Q5 and Q6. The output voltage terminal 30 is grounded via resistor Rx and the emitter and base of the bipolar transistor Q3, whose emitter is grounded. The voltage at the junction P3 of resistor Rx and the emitter of bipolar transistor Q3 is divided by the voltage divider circuit 31, and the voltage at the junction P5 of the series-connected voltage divider resistors Rt and Rb is applied to the base of bipolar transistor Q4 (an example of a control terminal). Furthermore, the output voltage terminal 30 is grounded via the source and drain of MOS transistor Q5, resistor R4, and the emitter and collector of bipolar transistor Q4, and is connected to the junction P1 of the bandgap reference voltage circuit 10 via the source and drain of MOS transistor Q6. Here, the gate and drain of MOS transistor Q5 and the gate of MOS transistor Q6 are connected to each other, and MOS transistors Q5 and Q6 form a current mirror circuit CM1.

[0041] In addition, bipolar transistors Q1 to Q4 are, for example, composed of PNP bipolar transistors, and MOS transistors Q5 and Q6 are, for example, composed of P-channel MOS transistors.

[0042] The operation of the reference voltage generating circuit configured as described above will be explained below.

[0043] Figure 1 The operation of the correction current generating circuit 20 depends on the base voltage Vb4 of the bipolar transistor Q4. The bipolar transistor Q4 in the correction current generating circuit 20 operates when the base voltage Vb4 exceeds its threshold voltage, causing an emitter current to flow into the emitter of the bipolar transistor Q4. Furthermore, the emitter current I4 flowing through the bipolar transistor Q4 is mirrored by the current mirror circuit CM1 of the correction current generating circuit 20, and a correction current Is, corresponding to and proportional to the emitter current I4, flows into the emitter of the bipolar transistor Q1 via the bipolar transistor Q6. Here, for example, when the gate sizes of a pair of MOS transistors Q5 and Q6 in the current mirror circuit CM1 are identical, I4 = Is. For convenience, this will be assumed in the following description. Furthermore, for example, it is preferable to make the first gate sizes of MOS transistors Q1, Q3, and Q4 identical, and to set the gate size of MOS transistor Q2 to be M times the first gate size (M>1).

[0044] Figure 2 It means Figure 1 A graph showing the temperature characteristic of the base voltage Vb4 of the bipolar transistor Q4 in the correction current generation circuit 20. Figure 2It can be seen that the base voltage Vb4 of the bipolar transistor Q4 has a negative slope with respect to temperature.

[0045] Figure 3 It is a circuit diagram showing the currents I1 to I3 flowing when the temperature Temp is less than the temperature threshold Tvth in the reference voltage generation circuit of Figure 1 Figure 4 It is a circuit diagram showing the currents I1 to I4 flowing when the temperature Temp is above the temperature threshold Tvth in the reference voltage generation circuit of Figure 1 Figure 3 In, the components represented by the dotted lines are non-operating. Here, the temperature at which the threshold voltage Vbeth that causes the bipolar transistor Q4 to operate is generated is set as the temperature threshold Tvth. The reference voltage generation circuit configured as described above depends on temperature and operates as follows under the two conditions of less than the temperature threshold Tvth and above the temperature threshold Tvth.

[0046] (1) When Temp < Tvth, as shown in Figure 3 , Is = 0, and the PTAT current Iptat = I1 (only I1).

[0047] (2) When Temp ≥ Tvth, as shown in Figure 4 , Is = I4 and is added to the emitter current I4, becoming the PTAT current Iptat = I1 + I4.

[0048] Figure 5 It is a graph showing the temperature characteristics of the PTAT current Iptat in the reference voltage generation circuit of Figure 1 Figure 5 As shown in, the PTAT current Iptat with respect to temperature is bounded by the temperature threshold Tvth, and two PTAT currents Iptat1 and Iptat2 with different slopes can be realized.

[0049] Next, the operations of the reference voltage generation circuit related to the prior art and the reference voltage generation circuit related to Embodiment 1 are compared as follows.

[0050] Figure 6 It is a circuit diagram showing the structure of the reference voltage generation circuit related to the prior art disclosed in Patent Document 2. Figure 6 The reference voltage generation circuit of

[0051] Figure 6The operation of the calibration current generation circuit 20A depends on the base-emitter voltage Vbe1 of the bipolar transistor Q1. The bipolar transistor Q3 of the calibration current generation circuit 20A operates when the voltage Vbe1 between the base and emitter of the bipolar transistor Q1 exceeds its threshold voltage, and causes the base current of the bipolar transistor Q3 to flow into the bipolar transistor Q1, thereby changing the PTAT current Iptat. At this time, the voltage Vbe1 between the base and emitter of the bipolar transistor Q3 and the bipolar transistor Q1 is uniquely determined by the process characteristics. Therefore, in this prior art, there is a problem that the temperature at which the PTAT current Iptat changes, that is, the temperature for correcting the output voltage, cannot be selected.

[0052] In contrast, in Embodiment 1 according to the present invention, since the operation of the calibration current generation circuit 20 depends on the base voltage Vb4, and the base voltage Vb4 is obtained by dividing the voltage Vbe3 between the base and emitter of the bipolar transistor Q3 by the voltage dividing resistors Rt and Rb of the voltage dividing circuit 31, the temperature at which the PTAT current Iptat changes, that is, the calibration temperature, can be selected by selecting the resistance value ratio of the voltage dividing resistors Rt and Rb.

[0053] Figure 7 (a) shows a graph of the temperature characteristics of the output voltage of the reference voltage generation circuit according to the prior art. Figure 7 (b) shows a graph of the temperature characteristics of the output voltage of the reference voltage generation circuit according to Embodiment 1. In Figure 7 (a) and Figure 7 (b), 101 is the output voltage peak value on the low temperature side, and 102 is the output voltage peak value on the high temperature side.

[0054] In Figure 7 (a) according to the prior art, the output voltage peak value 102 on the high temperature side is around 85°C, while in Figure 7 (b) according to Embodiment 1, it is shown that, for example, by selecting the resistance value ratio of the voltage dividing resistors Rt and Rb, the base voltage Vb4 can be changed, and the position of the output voltage peak value 102 on the high temperature side can be moved toward the output voltage peak value 101 on the low temperature side by the amount of the temperature difference ΔT. Therefore, from Figure 7 (b), for the temperature range from -20°C to 85°C, the temperature deviation of the output voltage is improved (Vh2 < Vh1). As a result, by implementing a circuit with variable calibration temperature, further improvement of the temperature characteristics can be expected. On this basis, the calibration temperature can be set only by switching the resistance value of the voltage dividing circuit 31. Therefore, for example, the calibration temperature can be changed based on trimming in the manufacturing stage, that is, for example, the output voltage corresponding to the temperature range can be set only based on trimming in the manufacturing stage.

[0055] Alternatively, at least one of the voltage divider resistors Rt and Rb in the voltage divider circuit 31 can be constructed using variable resistors or semi-fixed resistors, instead of changing the resistance value setting based on adjustments to at least one of the voltage divider resistors Rt and Rb in the voltage divider circuit 31 (which can be performed during manufacturing, before or after shipment, or after shipment). Here, the resistance value setting can be configured to be changed analogically or digitally, for example, based on a digital indication signal.

[0056] In the reference voltage generating circuit according to Embodiment 1 configured as described above, the correction current generating circuit 20 generates multiple voltage peaks in the output voltage of the bandgap reference voltage circuit 10 by injecting a predetermined correction current Is into the connection point P1 of the bandgap reference voltage circuit 10, thereby generating multiple voltage peaks that vary with temperature. The output voltage characteristic of each of these multiple voltage peaks is configured such that the output voltage changes continuously with temperature. Furthermore, the bipolar transistor Q4 and the voltage divider circuit 31 constitute a temperature setting circuit that allows for the setting of multiple temperatures corresponding to the multiple voltage peaks to be changed.

[0057] As explained above, according to this embodiment, since the output voltage calibration temperature is selective and independent of process characteristics, a more accurate reference voltage can be provided by setting a more suitable calibration temperature based on the temperature range. Furthermore, since the calibration temperature can be set simply by switching the resistance value, selection is easier compared to adjustments made during mass production. In other words, in this embodiment, compared to the prior art, since calibration can be performed at a more suitable temperature corresponding to the temperature range of the target application, a further reduction in the temperature dependence of the output voltage can be expected. Moreover, for example, the calibration temperature can be changed based on adjustments made during the manufacturing stage; that is, an output voltage corresponding to the temperature range of the manufacturing stage can be set.

[0058] (Implementation Method 2)

[0059] Figure 8 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 2. Figure 8 In, with Figure 1 The reference voltage generating circuit in Embodiment 2 differs from that in Embodiment 1 in the following aspects.

[0060] (1) A correction current generating circuit 20B is provided instead of the correction current generating circuit 20. Here, the difference between the correction current generating circuit 20B and the correction current generating circuit 20 is as follows.

[0061] (1A) A voltage divider circuit 32 is provided instead of a voltage divider circuit 31, the voltage divider circuit 32 having three voltage divider resistors Rta, Rtb and Rb connected in series.

[0062] (1B) It also includes a correction current generating circuit 21 having the same structure as the correction current generating circuit, which is composed of a current mirror circuit CM1, a resistor R4 and a bipolar transistor Q4 in the correction current generating circuit 20. Here, the correction current generating circuit 21 is composed of a current mirror circuit CM2 composed of MOS transistors Q7 and Q8, a resistor R21 and a bipolar transistor Q21.

[0063] The differences are explained below.

[0064] exist Figure 8 In this circuit, the voltage at the connection point P6 of the voltage divider resistors Rta and Rtb is applied to the base of the bipolar transistor Q21. Furthermore, in the correction current generation circuit 21, the output voltage terminal 30 is grounded via the source and drain of the MOS transistor Q7, connection point P7, resistor R21, and the emitter and collector of the bipolar transistor Q21. The gate and drain of the MOS transistor Q7 are connected, and the gate of the MOS transistor Q7 is connected to the gate of the MOS transistor Q8. Further, the drain of the MOS transistor Q8 in the current mirror circuit CM2 is connected to connection point P1 of the bandgap reference generation circuit 10. Additionally, the bipolar transistor Q21 is, for example, a PNP type bipolar transistor, and the MOS transistors Q7 and Q8 are, for example, P-channel MOS transistors.

[0065] Alternatively, at least one of the voltage divider resistors Rta, Rtb, and Rb in the voltage divider circuit 32 can be constructed using variable resistors or semi-fixed resistors, instead of changing the resistance value based on the modification of at least one of the voltage divider resistors Rta, Rtb, and Rb in the voltage divider circuit 32.

[0066] According to the reference voltage generating circuit of Embodiment 2 configured as described above, a correction current generating circuit 21 is added to correct the correction current based on the threshold voltage of the bipolar transistor Q21. Here, the operating principle of the correction current generating circuit 21 is the same as in Embodiment 1. Since the base voltage Vb21 of the bipolar transistor Q21 is higher than the base voltage Vb4 of the bipolar transistor Q4, the operating start temperature of the bipolar transistor Q21 is higher. As a result, the correction current Is flowing into the connection point P1 can be corrected in three stages, and the correction of the correction current Is can be corrected in greater detail compared to the reference voltage generating circuit of Embodiment 1.

[0067] In Embodiment 2 described above, a single correction current generating circuit 21 is provided. However, the number of voltage dividing resistors in the voltage divider circuit 32 can be increased, and multiple correction current generating circuits 21 can be provided (hereinafter referred to as variations of Embodiment 2). This allows for additional correction of the correction current Is at multiple stages. As a result, the correction of the correction current Is can be performed in greater detail.

[0068] (Implementation Method 3)

[0069] Figure 9 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 3. Figure 9 In, with Figure 1 The reference voltage generating circuit in Embodiment 3 differs from that in Embodiment 1 in the following aspects.

[0070] (1) A correction current generating circuit 20C is provided to replace the correction current generating circuit 20. Here, the difference between the correction current generating circuit 20C and the correction current generating circuit 20 is as follows.

[0071] (1A) Removed Figure 1 The current correction generation circuit 20C is composed of a current mirror circuit CM1, a voltage divider circuit 31, a resistor R4, a bipolar transistor Q4, and a buffer circuit 33.

[0072] The differences are explained below.

[0073] exist Figure 9 In this circuit, the buffer circuit 33 applies the voltage obtained by buffering (amplifying) the base-emitter voltage Vbe1 of the bipolar transistor Q1 to the voltage divider circuit 31 and utilizes the pull-up voltage of the resistor Rt, thereby achieving a circuit structure that operates in the same way as the reference voltage generation circuit according to Embodiment 1. Here, the buffer circuit 33 can be composed of a source follower circuit or a voltage follower circuit.

[0074] The reference voltage generating circuit of Embodiment 3, configured as described above, has the same effect as that of Embodiment 1.

[0075] Furthermore, similar to the variation of embodiment 2, by increasing the number of voltage divider resistors in the voltage divider circuit 31 and adding one or more correction current generating circuits consisting of the current mirror circuit CM1, the voltage divider circuit 31, the resistor R4, the bipolar transistor Q4, and the buffer circuit 33, the correction current Is can be corrected in multiple stages. As a result, the correction of the correction current Is can be performed in more detail.

[0076] (Implementation Method 4)

[0077] Figure 10 This is a circuit diagram illustrating a structural example of the reference voltage generation circuit according to Embodiment 4. Figure 10 In, with Figure 1 The reference voltage generating circuit in Embodiment 4 differs from that in Embodiment 1 in the following aspects.

[0078] (1) It has a bandgap reference voltage circuit 10A to replace the bandgap reference voltage circuit 10.

[0079] (2) Compared with the bandgap reference voltage circuit 10, the bandgap reference voltage circuit 10A also has a correction current generation circuit 22.

[0080] The differences are explained below.

[0081] exist Figure 10 In this circuit, the correction current generating circuit 22 is configured with a resistor R22 and a bipolar transistor Q22. The output voltage terminal 30 is grounded via the resistor R22 and the emitter and collector of the bipolar transistor Q22, and its base is connected to the connection point P1. Furthermore, the bipolar transistor Q22 is, for example, a PNP type bipolar transistor.

[0082] exist Figure 1 In the correction current generating circuit 20, if the base voltage Vb4 obtained by resistive voltage division of the base-emitter voltage Vbe3 of the bipolar transistor Q3 through the voltage divider circuit 31 exceeds its threshold voltage, then the bipolar transistor Q4 will operate. Conversely, in Figure 10 In the correction current generating circuit 22, if the base-emitter voltage Vbe1 of the bipolar transistor Q1 exceeds its threshold voltage, the bipolar transistor Q22 is turned on and begins to work, and the base current flows into the bipolar transistor Q1 through the connection point P1. Figure 10 In the correction current generating circuit 22, since there is no voltage divider circuit 31, the corresponding base voltage Vb22 is higher than that of the ground. Figure 1 The correction current generating circuit 10 causes the operating temperature of the bipolar transistor Q22 to rise. This results in the following... Figure 11 The peak voltage is 103.

[0083] Figure 11 It means Figure 10 A graph showing the temperature characteristic of the output voltage of the reference voltage generation circuit. Figure 11 It can be seen that, through Figure 1Based on the two output voltage peaks 101 and 102 generated by the correction current generation circuit 10, an output voltage peak 103 based on the correction current generation circuit 22 can be generated. Therefore, as a result, current correction can be performed in three stages, effectively addressing voltage drops at high temperatures. Figure 6 Compared to the reference voltage generation circuit, it can add low-temperature side correction on the basis of three-stage correction, and can provide higher accuracy output voltage.

[0084] (Variation Example 1)

[0085] Figure 12 This is a circuit diagram illustrating the structural example of the reference voltage generation circuit involved in Modification Example 1. Figure 12 In, with Figure 1 Compared with the reference voltage generating circuit of Embodiment 1, the reference voltage generating circuit of Modified Example 1 differs in the following aspects.

[0086] (1) A bandgap reference voltage circuit 10B is provided to replace the bandgap reference voltage circuit 10.

[0087] (2) The bandgap reference voltage circuit 10B is configured to include: a current mirror circuit CM3 including MOS transistors Q11, Q12, and Q13; a current mirror circuit CM4 including MOS transistors Q14 and Q15; resistors R3 and R31; and bipolar transistors Q1, Q2, and Q31. Furthermore, the gate size of the MOS transistor Q31 is preferably set to be the same as the gate size of the bipolar transistor Q1.

[0088] (3) In the correction current generating circuit 20, a MOS transistor Q16 is provided to replace the resistor Rx. Here, the source and drain of the MOS transistor Q16 are connected between the connection point P3 and the power supply voltage VDD, and the gate of the MOS transistor Q16 is connected to the gates of the MOS transistors Q11 and Q12 in the bandgap reference voltage circuit 10B. These MOS transistors Q11, Q12 and Q16 are configured to carry currents that flow through each other.

[0089] The reference voltage generating circuit constructed as described above and Figure 1 The reference voltage generating circuit operates in the same way and has the same effect. Alternatively, the structure of the bandgap reference voltage circuit 10B can also be applied to the second to fourth embodiments.

[0090] (Variation Example 2)

[0091] Figure 13 This is a circuit diagram illustrating the structural example of the reference voltage generation circuit involved in Modification Example 2. Figure 13 In, with Figure 1Compared with the reference voltage generation circuit of Embodiment 1, the reference voltage generation circuit of Modified Example 2 differs in the following aspects.

[0092] (1) It has a bandgap reference voltage circuit 10C to replace the bandgap reference voltage circuit 10.

[0093] (2) The bandgap reference voltage circuit 10C is configured to include: a current mirror circuit CM3 containing MOS transistors Q11, Q12, and Q13; an operational amplifier 12; resistors R3, R21, R22, and R31; and bipolar transistors Q1 and Q2.

[0094] (3) In the correction current generating circuit 20, a MOS transistor Q16 is provided to replace the resistor Rx. Here, the source and drain of the MOS transistor Q16 are connected between the connection point P3 and the power supply voltage VDD, and the gate of the MOS transistor Q16 is connected to the gates of the MOS transistors Q11, Q12, and Q13 in the bandgap reference voltage circuit 10C. These MOS transistors Q11, Q12, Q13, and Q16 are configured to carry corresponding currents.

[0095] The reference voltage generating circuit constructed as described above and Figure 1 The reference voltage generating circuit operates in the same way and has the same effect. Alternatively, the structure of the bandgap reference voltage circuit 10C can also be applied to the second to fourth embodiments.

[0096] Industrial availability

[0097] As detailed above, according to the present invention, a correction current generating circuit 20, 20B, or 20C is provided relative to the bandgap reference voltage circuit 10, 10B, or 10C, or a correction current generating circuit 22 is provided in the bandgap reference voltage circuit 10. Therefore, since the correction temperature of the output voltage is selective and independent of process characteristics, a higher accuracy reference voltage can be provided by setting a more suitable correction temperature according to the temperature range. Furthermore, since the correction temperature can be set simply by switching the resistance value, it can be easily selected through adjustments during mass production. That is, in the present invention, compared to the prior art, since correction can be performed at a more suitable temperature corresponding to the temperature range of the target application, a further reduction in the temperature dependence of the output voltage can be expected. Furthermore, the correction temperature can be changed based on adjustments during the mass production stage, that is, the output voltage can be set according to the temperature range based on the mass production stage. In other words, according to the present invention, compared to the prior art, the temperature dependence of the output voltage can be improved with a simpler circuit.

[0098] Label Explanation

[0099] 10. 10A~10C Bandgap Reference Voltage Circuit

[0100] Operational amplifiers 11 and 12

[0101] 20, 20A~20C, 21, 22 Correction current generation circuits

[0102] 30 Output voltage terminals

[0103] 31, 32 Voltage divider circuit

[0104] 33 Buffer Circuit

[0105] CM1~CM4 Current mirror circuit

[0106] Connection points P1~P12

[0107] Q1~Q4, Q21~Q31 bipolar transistors

[0108] MOS transistors Q5-Q8 and Q11-Q16

[0109] Resistors R1 to R31 and Rx

[0110] Rt, Rb, Rbm, Rta, Rtb voltage divider resistors

Claims

1. A reference voltage generating circuit, comprising: The bandgap reference voltage circuit generates a specified reference voltage; and The first correction current generating circuit generates a first correction current in response to temperature changes. The first correction current generating circuit injects the first correction current into the bandgap reference voltage circuit, thereby generating multiple voltage peaks in the output voltage of the reference voltage generating circuit that vary with temperature, wherein... The output voltage characteristic of each of the plurality of voltage peaks is configured such that the output voltage changes continuously with respect to temperature. The first correction current generating circuit includes a temperature setting circuit that sets multiple temperatures corresponding to the multiple voltage peaks to be changeable. The temperature setting circuit includes: The first bipolar transistor; and A voltage divider circuit includes multiple voltage divider resistors connected in series. The voltage divider circuit applies a predetermined base voltage to the base of the first bipolar transistor. The temperature setting circuit is configured to change at least one temperature corresponding to at least one of the plurality of voltage peak values ​​by changing the resistance value of at least one of the plurality of voltage divider resistors.

2. The reference voltage generating circuit as described in claim 1, wherein, The reference voltage generating circuit includes a buffer circuit that buffers the voltage corresponding to the first correction current from the first correction current generating circuit and outputs it to the voltage divider circuit.

3. The reference voltage generating circuit as described in claim 2, wherein, The buffer circuit is composed of a voltage follower circuit or a source follower circuit.

4. The reference voltage generating circuit as described in claim 1, wherein, The reference voltage generating circuit includes multiple first correction current generating circuits. By injecting multiple first correction currents from multiple first correction current generation circuits into the bandgap reference voltage circuit, more than three voltage peaks relative to temperature changes are generated in the output voltage of the reference voltage generation circuit.

5. The reference voltage generating circuit as described in any one of claims 1 to 4, wherein, The bandgap reference voltage circuit further includes: a second correction current generating circuit, which generates a second correction current in response to temperature changes. The second correction current generating circuit generates additional voltage peaks in the output voltage of the reference voltage generating circuit relative to temperature changes by injecting the second correction current into the bandgap reference voltage circuit.

6. The reference voltage generating circuit as described in claim 5, wherein, The second correction current generating circuit includes a second bipolar transistor and a resistor connected in series. The second correction current generating circuit generates the second correction current from the base of the second bipolar transistor, and generates the other voltage peaks at a temperature higher than the temperature of the voltage peak generated by the first correction current through the first correction current generating circuit.

7. A method for generating a reference voltage, used in a reference voltage generating circuit, the reference voltage generating circuit comprising: The bandgap reference voltage circuit generates a specified reference voltage; and The first correction current generating circuit generates a first correction current in response to temperature changes. In the reference voltage generation method, The first correction current generating circuit injects the first correction current into the bandgap reference voltage circuit, thereby generating multiple voltage peaks in the output voltage of the reference voltage generating circuit that vary with temperature, wherein... The output voltage characteristic of each of the plurality of voltage peaks is configured such that the output voltage changes continuously with respect to temperature. The reference voltage generation method includes the following steps: The temperature setting circuit allows for the setting of multiple temperatures corresponding to the multiple voltage peaks to be changed. The temperature setting circuit includes: The first bipolar transistor; and The voltage divider circuit includes multiple voltage divider resistors connected in series, and applies a predetermined base voltage to the base of the first bipolar transistor. The reference voltage generation method further includes the following steps: By changing the resistance value of at least one of the plurality of voltage divider resistors, at least one temperature corresponding to at least one of the plurality of voltage peaks is changed.

8. The reference voltage generation method as described in claim 7, wherein, The reference voltage generation method further includes the following steps: The voltage corresponding to the first correction current from the first correction current generation circuit is buffered and output to the voltage divider circuit.

9. The reference voltage generation method as described in claim 7, wherein, The reference voltage generation method further includes the following steps: By injecting multiple first correction currents from multiple first correction current generation circuits into the bandgap reference voltage circuit, more than three voltage peaks relative to temperature changes are generated in the output voltage of the reference voltage generation circuit.

10. The reference voltage generation method according to any one of claims 7 to 9, wherein, The bandgap reference voltage circuit further includes: a second correction current generating circuit, which generates a second correction current in response to temperature changes. The reference voltage generation method further includes the following steps: The second correction current generating circuit generates additional voltage peaks in the output voltage of the reference voltage generating circuit relative to temperature changes by injecting the second correction current into the bandgap reference voltage circuit.

11. The reference voltage generation method as described in claim 10, wherein, The second correction current generating circuit includes a second bipolar transistor and a resistor connected in series. The reference voltage generation method further includes the following steps: The second correction current generating circuit generates the second correction current from the base of the second bipolar transistor; and The second correction current generating circuit generates the other voltage peaks at a temperature higher than the temperature of the voltage peak generated by the first correction current through the first correction current generating circuit.

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