Reference voltage circuit

Abstract

The present application relates to a reference voltage circuit, which includes a reference current circuit, a voltage compensation circuit, and a reference voltage output circuit; the first end of the reference current circuit and the first end of the reference voltage output circuit are both connected to a voltage source, and the second end of the reference current circuit and the second end of the reference voltage output circuit are both connected to the voltage compensation circuit; the voltage compensation circuit is used to compensate the voltage at the second end of the reference voltage output circuit so that the error between the voltage at the second end of the reference voltage output circuit and the voltage at the second end of the reference current circuit is less than a preset voltage threshold. The reference voltage circuit has a simple structure, strong PSR capability, and a simple implementation process.

Description

Technical Field

[0001] The present application relates to the field of circuits, and in particular to a reference voltage circuit. Background Art

[0002] A bandgap voltage reference converts the voltage of a voltage source into a reference voltage. However, voltage fluctuations or temperature changes in the voltage source can affect the output reference voltage. For example, to reduce the impact of voltage fluctuations on the output reference voltage, it is necessary to improve the power supply rejection (PSR) capability of the bandgap voltage reference.

[0003] In the related art, the PSR capability of a bandgap reference voltage source can be improved in various ways. For example, the PSR capability can be improved by increasing the gain of the operational amplifier in the bandgap reference voltage source, but this method can only partially reduce the impact of voltage fluctuations on the output reference voltage. Alternatively, a pre-stabilization circuit can be added between the voltage source and the bandgap reference voltage source. This pre-stabilization circuit can reduce the impact of voltage fluctuations on the output reference voltage and improve the PSR capability, but this method has a relatively complex structure. Alternatively, the PSR capability can be improved by adjusting the properties of the current mirror, but this method is limited by the processing accuracy and the implementation process is relatively complex.

[0004] Therefore, there is an urgent need for a reference voltage circuit with a simple structure, strong PSR capability and simple implementation process. Summary of the Invention

[0005] Based on this, it is necessary to provide a reference voltage circuit with a simple structure, strong PSR capability and simple implementation process to address the above technical problems.

[0006] In a first aspect, the present application provides a reference voltage circuit, which includes a reference current circuit, a voltage compensation circuit, and a reference voltage output circuit; a first end of the reference current circuit and a first end of the reference voltage output circuit are both connected to a voltage source, and a second end of the reference current circuit and a second end of the reference voltage output circuit are both connected to the voltage compensation circuit;

[0007] The voltage compensation circuit is used to compensate the voltage of the second end of the reference voltage output circuit so that the error between the voltage of the second end of the reference voltage output circuit and the voltage of the second end of the reference current circuit is less than a preset voltage threshold.

[0008] In one embodiment, the reference current circuit includes a first transistor group, the reference voltage output circuit includes a second transistor group, and the first transistor group and the second transistor group form a current mirror structure;

[0009] The first end of the first transistor group and the first end of the second transistor group are both connected to the voltage source; the second end of the first transistor group and the second end of the second transistor group are both connected to the voltage compensation circuit;

[0010] The voltage compensation circuit is used to compensate the voltage of the second end of the second transistor group so that the error between the voltage of the second end of the second transistor group and the voltage of the second end of the first transistor group is less than a preset voltage threshold.

[0011] In one embodiment, the first transistor group includes a first transistor and a second transistor, the drain of the first transistor and the source of the second transistor are connected to form a first drain-source terminal; the second transistor group includes a third transistor and a fourth transistor, the drain of the third transistor and the source of the fourth transistor are connected to form a second drain-source terminal;

[0012] The gate of the first transistor is connected to the gate of the third transistor; the source of the first transistor and the source of the third transistor are both connected to a voltage source;

[0013] The input end of the voltage compensation circuit is connected to the first drain-source end and the second drain-source end respectively, and the output end of the voltage compensation circuit is connected to the gate of the second transistor and the gate of the fourth transistor respectively.

[0014] In one embodiment, the reference voltage output circuit further includes a voltage output terminal and a first resistor, the first terminal and the voltage output terminal of the first resistor are respectively connected to the drain of the fourth transistor, and the second terminal of the first resistor is grounded.

[0015] In one embodiment, the voltage compensation circuit includes an operation circuit, wherein an input terminal of the operation circuit is connected to the first drain-source terminal and the second drain-source terminal respectively, and an output terminal of the operation circuit is connected to the gate of the second transistor and the gate of the fourth transistor respectively;

[0016] The operation circuit is used to compensate the voltage of the second drain-source terminal so that the error between the voltage of the second drain-source terminal and the voltage of the first drain-source terminal is less than a preset voltage threshold.

[0017] In one embodiment, the arithmetic circuit includes a level shifting circuit and a gain compensation circuit, each of which includes a plurality of transistor groups connected in parallel; each transistor group includes two identical transistors, and the gates of the two identical transistors are connected to each other; a first terminal of the level shifting circuit is connected to a first drain-source terminal and a second drain-source terminal, respectively; a second terminal of the level shifting circuit is connected to the gain compensation circuit, and the gain compensation circuit is connected to the gates of the second transistor and the fourth transistor, respectively;

[0018] A level shift circuit, configured to level shift the voltage input to the first drain-source terminal and the second drain-source terminal;

[0019] The gain compensation circuit is used to provide gain for the operation circuit so that the error between the voltage at the second drain-source terminal and the voltage at the first drain-source terminal is less than a preset voltage threshold.

[0020] In one embodiment, the reference current circuit also includes an original current transistor group, which forms a current mirror structure with the first transistor group; the original current transistor group includes a fifth transistor and a sixth transistor, the gate of the fifth transistor is connected to the gate of the first transistor, the gate of the sixth transistor is connected to the gate of the second transistor, and the source of the fifth transistor is connected to the voltage source.

[0021] In one embodiment, the reference current circuit further includes a temperature compensation circuit, and the temperature compensation circuit is connected to the drain of the sixth transistor and the drain of the second transistor respectively;

[0022] The temperature compensation circuit is used to compensate for the current flowing through the first transistor and the second transistor.

[0023] In one embodiment, the temperature compensation circuit includes an operational amplifier, a seventh transistor, an eighth transistor, a second resistor, and a temperature compensation unit, the second resistor is connected in parallel with the seventh transistor, the collector of the seventh transistor is respectively connected to the drain of the sixth transistor and the input terminal of the operational amplifier, the eighth transistor is connected to one end of the temperature compensation unit, the other end of the temperature compensation unit is respectively connected to the drain of the second transistor and the output terminal of the operational amplifier, and the second end of the second resistor, the emitter and base of the seventh transistor, and the emitter and base of the eighth transistor are grounded;

[0024] an operational amplifier, configured to compensate for a voltage at the drain of the second transistor so that an error between a voltage at the drain of the second transistor and a voltage at the drain of the sixth transistor is less than a preset voltage threshold;

[0025] The temperature compensation unit is used to compensate for the current flowing through the first transistor and the second transistor.

[0026] In one embodiment, the temperature compensation unit includes a third resistor and a fourth resistor, the third resistor is connected in series with the eighth transistor, the third resistor and the eighth transistor are combined to form a branch, and the fourth resistor is connected in parallel with the branch;

[0027] a third resistor, configured to perform forward temperature compensation on the current flowing through the first transistor and the second transistor;

[0028] The fourth resistor is used to perform reverse temperature compensation on the current flowing through the first transistor and the second transistor.

[0029] The above-mentioned reference voltage circuit includes a reference current circuit, a voltage compensation circuit and a reference voltage output circuit; the first end of the reference current circuit and the first end of the reference voltage output circuit are both connected to a voltage source, and the second end of the reference current circuit and the second end of the reference voltage output circuit are both connected to the voltage compensation circuit. The voltage of the second end of the reference voltage output circuit is compensated by the voltage compensation circuit, so that the error between the voltage of the second end of the reference voltage output circuit and the voltage of the second end of the reference current circuit is less than a preset voltage threshold, thereby avoiding the influence of voltage fluctuations on the voltage output of the reference voltage output circuit and improving the PSR capability; at the same time, by adding a voltage compensation circuit to the reference voltage circuit, there is no need to introduce other external circuits, and the structure of the reference voltage circuit is simpler; in addition, the reference voltage circuit also does not need to improve the processing accuracy of the internal components of the circuit, and its implementation process is simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a reference voltage circuit in one embodiment;

[0031] Figure 2 is a schematic diagram of a reference voltage circuit in one embodiment;

[0032] Figure 3 is a schematic diagram of a reference voltage circuit in one embodiment;

[0033] Figure 4 is a schematic diagram of a reference voltage circuit in one embodiment;

[0034] Figure 5 is a schematic diagram of a reference voltage circuit in one embodiment;

[0035] Figure 6 is a schematic diagram of a reference voltage circuit in one embodiment;

[0036] Figure 7 is a schematic diagram of a reference voltage circuit in one embodiment;

[0037] Figure 8 is a schematic diagram of a reference voltage circuit in one embodiment;

[0038] Figure 9 is a schematic diagram of a reference voltage circuit in one embodiment;

[0039] Figure 10 is a schematic diagram of a reference voltage circuit in one embodiment;

[0040] Figure 11 is a schematic diagram of a reference voltage circuit in one embodiment;

[0041] Figure 12 is a schematic diagram of a reference voltage circuit in one embodiment;

[0042] Figure 13 is a schematic diagram of a reference voltage circuit in one embodiment;

[0043] Figure 14 FIG. 1 is a schematic diagram of a reference voltage circuit in one embodiment.

[0044] Description of reference numerals:

[0045] 11: Reference voltage circuit; 12: Reference current circuit;

[0046] 121: a first transistor group; M1: a first transistor;

[0047] M2: second transistor; 122: original current transistor group;

[0048] M5: fifth transistor; M6: sixth transistor;

[0049] 123: temperature compensation circuit; OPA1: operational amplifier;

[0050] Q1: eighth transistor; Q2: seventh transistor;

[0051] R2: second resistor; 1231: temperature compensation unit;

[0052] R3: the third resistor; R4: the fourth resistor;

[0053] 13: voltage compensation circuit; 131: operation circuit;

[0054] 1311: level shift circuit; 1312: gain compensation circuit;

[0055] 14: a reference voltage output circuit; 141: a second transistor group;

[0056] M3: third transistor; M4: fourth transistor;

[0057] R1: first resistor; Vref: voltage output terminal;

[0058] VDD voltage source. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0060] Before introducing the embodiments of the present application, the technical background of the present application is first introduced.

[0061] As integrated circuits (ICs) continue to improve in precision, they all require a more accurate reference voltage source to provide bias voltage to maintain chip performance. When providing voltage reference and bias for ICs, the reference voltage source must have an improved PSR capability to suppress voltage fluctuations generated by the voltage source, thereby ensuring a more stable reference voltage output.

[0062] In the related art, the PSR capability of the reference voltage source can be improved in a variety of ways. For example, the PSR capability can be improved by increasing the open-loop gain of the operational amplifier in the reference voltage source, but the reference voltage obtained in this way can only partially improve the PSR capability. In order to further improve the PSR capability, on the basis of improving the open-loop gain of the operational amplifier, a pre-stabilization circuit is added between the voltage source and the reference voltage source. The pre-stabilization circuit reduces the impact of voltage fluctuations on the output voltage of the reference voltage source. However, after adding the pre-stabilization circuit, the structure of the reference voltage source is more complicated. In addition, the PSR capability can also be improved by adjusting the current mirror property characteristics, but this method is limited by the process processing accuracy and the implementation process is relatively complicated.

[0063] In order to simplify the structure of the reference voltage source and improve the PSR capability, this solution proposes a reference voltage circuit. Next, the technical solution of the reference voltage circuit 11 provided by this application is introduced in detail.

[0064] In one embodiment, Figure 1 A schematic diagram of a reference voltage circuit is provided, wherein the reference voltage circuit 11 includes a reference current circuit 12, a voltage compensation circuit 13, and a reference voltage output circuit 14; a first end of the reference current circuit 12 and a first end of the reference voltage output circuit 14 are both connected to a voltage source VDD, and a second end of the reference current circuit 12 and a second end of the reference voltage output circuit 14 are both connected to the voltage compensation circuit 13; the voltage compensation circuit 13 is used to compensate for the voltage of the second end of the reference voltage output circuit 14, so that the error between the voltage of the second end of the reference voltage output circuit 14 and the voltage of the second end of the reference current circuit 12 is less than a preset voltage threshold.

[0065] In this embodiment, since the voltage source VDD is interfered by various uncontrollable factors when outputting a voltage, the voltage output by the voltage source VDD may be disturbed, thereby affecting the reference voltage output by the reference voltage output circuit 14. Therefore, it is necessary to compensate the output voltage of the voltage source VDD to avoid the influence of the voltage disturbance on the output voltage of the reference voltage output circuit 14.

[0066] The voltage compensation circuit 13 is disposed between the reference current circuit 12 and the reference voltage output circuit 14. When the input voltage of the voltage source VDD fluctuates, the voltage of the reference voltage output circuit 14 will be affected by the voltage fluctuation, resulting in a large error between the output voltages of the reference current circuit 12 and the reference voltage output circuit 14. The voltage compensation circuit 13 can compensate the voltage of the reference voltage output circuit 14 so that the error between the output voltages of the reference voltage output circuit 14 and the reference current circuit 12 is less than a preset voltage threshold, thereby ensuring that the voltage output of the reference voltage output circuit 14 is not affected by the voltage fluctuation. The voltage compensation circuit 13 is a compensation circuit that forcibly reduces the difference between the output voltage of the reference voltage output circuit 14 and the output voltage of the reference current circuit 12. The voltage compensation circuit 13 can be a compensation circuit composed of an operational amplifier and other electronic components.

[0067] The above-mentioned reference voltage circuit includes a reference current circuit, a voltage compensation circuit and a reference voltage output circuit; the first end of the reference current circuit and the first end of the reference voltage output circuit are both connected to a voltage source, and the second end of the reference current circuit and the second end of the reference voltage output circuit are both connected to the voltage compensation circuit. The voltage of the second end of the reference voltage output circuit is compensated by the voltage compensation circuit, so that the error between the voltage of the second end of the reference voltage output circuit and the voltage of the second end of the reference current circuit is less than a preset voltage threshold, thereby avoiding the influence of voltage fluctuations on the voltage output of the reference voltage output circuit and improving the PSR capability; at the same time, by adding a voltage compensation circuit to the reference voltage circuit, there is no need to introduce other external circuits, and the structure of the reference voltage circuit is simpler; in addition, the reference voltage circuit also does not need to improve the processing accuracy of the internal components of the circuit, and its implementation process is simpler.

[0068] In the above Figure 1 Based on the embodiment, this embodiment specifically introduces the contents of the reference current circuit 12 in the above embodiment. Figure 2 A schematic diagram of a reference voltage circuit is provided, wherein the reference current circuit 12 includes a first transistor group 121, and the reference voltage output circuit 14 includes a second transistor group 141, and the first transistor group 121 and the second transistor group 141 form a current mirror structure; the first end of the first transistor group 121 and the first end of the second transistor group 141 are both connected to a voltage source VDD; the second end of the first transistor group 121 and the second end of the second transistor group 141 are both connected to a voltage compensation circuit 13; the voltage compensation circuit 13 is used to compensate for the voltage of the second end of the second transistor group 141, so that the error between the voltage of the second end of the second transistor group 141 and the voltage of the second end of the first transistor group 121 is less than a preset voltage threshold.

[0069] In this embodiment, the current mirror generates a copy of the current flowing through the first transistor group 121 to ensure that the current flowing through the first transistor group 121 and the current flowing through the second transistor group 141 are the same.

[0070] Both the reference current circuit 12 and the reference voltage output circuit 14 include a transistor group, each of which may include at least two transistors. The multiple transistors in the first transistor group 121 and the second transistor group 141 form a current mirror structure. The current mirror structure can replicate the current flowing through the first transistor group 121, with the current flowing through the second transistor group 141 being the replicated current. When the output voltage of the voltage source VDD is disturbed, the voltage on the second transistor group 141 is disturbed, affecting the output voltage of the reference voltage output circuit 14. The voltage compensation circuit 13 can compensate for the voltage at the second terminal of the second transistor group 141. The error between the compensated voltage at the second terminal of the second transistor group 141 and the voltage at the second terminal of the first transistor group 121 is less than a preset voltage threshold. This minimizes the error in the current flowing through the first transistor group 121 and the second transistor group 141, preventing the output voltage of the reference voltage output circuit 14 from being disturbed by voltage and improving the current replication capability.

[0071] The above-mentioned reference current circuit includes a first transistor group, and the reference voltage output circuit includes a second transistor group, and the first transistor group and the second transistor group form a current mirror structure; the first end of the first transistor group and the first end of the second transistor group are both connected to a voltage source; the second end of the first transistor group and the second end of the second transistor group are both connected to a voltage compensation circuit; the voltage of the second end of the second transistor group is compensated by the voltage compensation circuit, so that the error between the voltage of the second end of the second transistor group and the voltage of the second end of the first transistor group is less than a preset voltage threshold, thereby avoiding the influence of voltage fluctuations on the voltage output of the reference voltage output circuit and improving the PSR capability.

[0072] In the above Figure 2 Based on the embodiment, this embodiment specifically introduces the contents of the first transistor group 121 and the second transistor group 141 in the above embodiment. Figure 3A schematic diagram of a reference voltage circuit is provided, wherein the first transistor group 121 includes a first transistor M1 and a second transistor M2, wherein the drain of the first transistor M1 and the source of the second transistor M2 are connected to form a first drain-source terminal; the second transistor group 141 includes a third transistor M3 and a fourth transistor M4, wherein the drain of the third transistor M3 and the source of the fourth transistor M4 are connected to form a second drain-source terminal; the gate of the first transistor M1 is connected to the gate of the third transistor M3; the source of the first transistor M1 and the source of the third transistor M3 are both connected to a voltage source VDD; the input terminal of the voltage compensation circuit 13 is respectively connected to the first drain-source terminal and the second drain-source terminal, and the output terminal of the voltage compensation circuit 13 is respectively connected to the gate of the second transistor 1211 and the gate of the fourth transistor M4.

[0073] In this embodiment, the first transistor group 121 and the second transistor group 141 each include two transistors, the first transistor group 121 includes a first transistor M1 and a second transistor M2, and the second transistor group includes a third transistor M3 and a fourth transistor M4. According to the connection relationship between the first transistor M1, the second transistor M2, the third transistor M3 and the fourth transistor M4, it can be determined that the current mirror structure formed by the first transistor group 121 and the second transistor group 141 is a common-source common-gate current mirror.

[0074] In this embodiment, the PSR capability can be improved by enhancing the current replication capability of the cascode current mirror. When manufacturing transistors using deep submicron and nanometer processes, due to the relatively small channel length of the transistors, their channel length modulation effect is more pronounced. Changes in the drain-source voltage of the transistors have a significant impact on the leakage current, causing the current mirror's current replication accuracy to deteriorate. However, configuring the current mirror as a cascode current mirror can alleviate the problems caused by the channel length modulation effect. The cascode transistors can shield the changes in the drain-source voltage, improving the accuracy of current replication.

[0075] The above-mentioned first transistor group includes a first transistor and a second transistor, and the drain of the first transistor and the source of the second transistor are connected to form a first drain-source terminal; the second transistor group includes a third transistor and a fourth transistor, and the drain of the third transistor and the source of the fourth transistor are connected to form a second drain-source terminal; the gate of the first transistor is connected to the gate of the third transistor; the source of the first transistor and the source of the third transistor are both connected to a voltage source; by connecting the input end of the voltage compensation circuit to the first drain-source terminal and the second drain-source terminal respectively, and connecting the output end of the voltage compensation circuit to the gate of the second transistor and the gate of the fourth transistor respectively, the voltage of the second drain-source terminal is compensated by the voltage compensation circuit, so that the error between the voltage of the second drain-source terminal and the voltage of the first drain-source terminal is less than a preset voltage threshold, thereby improving the PSR capability.

[0076] In the above Figure 3Based on the embodiment, this embodiment specifically introduces the contents of the reference voltage output circuit 14 in the above embodiment. Figure 4 A reference voltage circuit schematic is provided. The reference voltage output circuit 14 further includes a voltage output terminal Vref and a first resistor R1. The first terminal of the first resistor R1 and the voltage output terminal Vref are respectively connected to the drain of the fourth transistor M4. The second terminal of the first resistor R1 is grounded.

[0077] In this embodiment, the reference voltage output circuit 14 includes a second transistor group 141 (a third transistor M3 and a fourth transistor M4), a voltage output terminal Vref and a first resistor R1. By setting a common source and common gate current mirror structure and a voltage compensation circuit 13, it can be ensured that the current flowing through the second transistor group 141 is consistent with that flowing through the first transistor group 121, thereby avoiding the influence of voltage fluctuations in the voltage source VDD on the output voltage of the voltage output terminal Vref.

[0078] Furthermore, the resistance of the first resistor R1 determines the output voltage of the voltage output terminal Vref. The output voltage of the voltage output terminal Vref is the voltage generated when current flows through the first resistor R1. The first resistor R1 can be a fixed-resistance resistor, and the corresponding output voltage of the voltage output terminal Vref is the product of the current flowing through the first resistor R1 and the resistance of the first resistor R1. The first resistor R1 can also be a sliding rheostat, and the resistance of the first resistor R1 can be adjusted according to the desired reference voltage, thereby adjusting the output voltage of the voltage output terminal Vref.

[0079] The above-mentioned reference voltage output circuit also includes a voltage output end and a first resistor. The first end of the first resistor and the voltage output end are respectively connected to the drain of the fourth transistor, and the second end of the first resistor is grounded. The output voltage of the voltage output end can be adjusted through the first resistor to ensure that the output voltage of the voltage output end can meet various voltage requirements.

[0080] In the above Figure 3 Based on the embodiment, this embodiment specifically introduces the contents of the voltage compensation circuit 13 in the above embodiment. Figure 5 A schematic diagram of a reference voltage circuit is provided. The voltage compensation circuit 13 includes an operation circuit 131. The input end of the operation circuit 131 is respectively connected to the first drain-source end and the second drain-source end, and the output end of the operation circuit 131 is respectively connected to the gate of the second transistor M2 and the gate of the fourth transistor M4; the operation circuit 131 is used to compensate the voltage of the second drain-source end so that the error between the voltage of the second drain-source end and the voltage of the first drain-source end is less than a preset voltage threshold.

[0081] The accuracy of current replication can be improved by using a cascode current mirror. However, when the drain-source voltage difference between the first transistor group 121 and the second transistor group 141 is relatively large, the accuracy of current replication will be partially limited.

[0082] To further improve the accuracy of current replication, this embodiment adds an operational circuit 131, which can be an operational amplifier, between the first transistor group 121 and the second transistor group 141. After voltage source VDD generates voltage fluctuations, the voltage difference between the first drain-source terminal and the second drain-source terminal becomes large. Because operational circuit 131 and the cascode current mirror form a feedback loop, the voltages at the first drain-source terminal and the second drain-source terminal are regulated by negative feedback. Based on the "virtual short" characteristic of the operational amplifier, the voltages at the first drain-source terminal and the second drain-source terminal can be made equal. That is, operational circuit 131 can ensure that the voltage difference between the first drain-source terminal and the second drain-source terminal is not affected by voltage fluctuations, noise, process technology, and temperature of voltage source VDD, further improving the current replication capability.

[0083] The above-mentioned voltage compensation circuit includes an operational circuit, the input end of the operational circuit is respectively connected to the first drain-source end and the second drain-source end, and the output end of the operational circuit is respectively connected to the gate of the second transistor and the gate of the fourth transistor. The operational circuit in the circuit can compensate for the voltage of the second drain-source end so that the error between the voltage of the second drain-source end and the voltage of the first drain-source end is less than the preset voltage threshold, so that the current flowing through the first transistor group and the second transistor group can be kept consistent, avoiding the output voltage of the reference voltage output circuit from being affected by voltage fluctuations, thereby improving the PSR capability.

[0084] In the above Figure 3 Based on the embodiment, this embodiment specifically introduces the contents of the operation circuit 131 in the above embodiment. Figure 6 A schematic diagram of a reference voltage circuit is provided. The operation circuit 131 includes a level shifting circuit 1311 and a gain compensation circuit 1312. The level shifting circuit 1311 and the gain compensation circuit 1312 each include multiple transistor groups. The multiple transistor groups are connected in parallel, and their second ends are connected to the gain compensation circuit 1312. The gain compensation circuit 1312 is respectively connected to the gate of the second transistor M2 and the gate of the fourth transistor M4. The level shifting circuit 1311 is used to level shift the voltage input to the first drain-source terminal and the second drain-source terminal. The gain compensation circuit 1312 is used to provide gain for the operation circuit 131 so that the error between the voltage at the second drain-source terminal and the voltage at the first drain-source terminal is less than a preset voltage threshold.

[0085] In this embodiment, the operational circuit 131 may include various types of operational amplifiers. Each type of operational amplifier may include a level shifting circuit 1311 and a gain compensation circuit 1312. Both the level shifting circuit 1311 and the gain compensation circuit 1312 are internal circuits composed of multiple transistor groups. Because the input voltage of the operational circuit 131 is relatively high, the voltage needs to be level shifted before it can be connected to the gain compensation circuit 1312. Gain is provided by the gain compensation circuit 1312. If the gain provided by the gain compensation circuit 1312 is sufficiently large, the error between the two voltages input to the operational circuit 131 through the first drain-source terminal and the second drain-source terminal is less than a preset voltage threshold.

[0086] For example, Figure 7 、 8 9 is a schematic diagram of the internal circuit of the operational amplifier, and the multiple transistors in the level shift circuit 1311 and the gain compensation circuit 1312 are numbered. The multiple transistors can be represented as Mr1, Mr2...MrX. For example, the multiple transistors are MOS tubes. Figure 7 The circuit 131 includes eight MOS transistors. The level shift circuit 1311 of the operation circuit 131 includes Mr3, Mr4, Mr5, and Mr6. The gain compensation circuit 1312 includes Mr1, Mr2, Mr7, and Mr8. The first drain-source terminal is connected to the gate of Mr5, the second drain-source terminal is connected to the gate of Mr6, the gate of the second transistor M2 is connected between Mr1 and Mr8, and the gate of the fourth transistor M4 is connected between Mr2 and Mr7. Figure 8 The circuit 131 includes eight MOS transistors. The level shift circuit 1311 of the operation circuit 131 includes Mr1, Mr2, Mr3, and Mr4. The gain compensation circuit 1312 includes Mr5, Mr6, Mr7, and Mr8. The first drain-source terminal is connected to the gate of Mr1, the second drain-source terminal is connected to the gate of Mr2, the gate of the second transistor M2 is connected between Mr5 and Mr7, and the gate of the fourth transistor M4 is connected between Mr6 and Mr8. Figure 9 11 MOS transistors are included. The level shift circuit 1311 of the arithmetic circuit 131 includes Mr1, Mr2, Mr3, Mr4, Mr5, Mr8, and Mr9. The gain compensation circuit 1312 includes Mr6, Mr7, Mr10, and Mr11. The first drain-source terminal is connected to the gate of Mr2, the second drain-source terminal is connected to the gate of Mr3, the gate of the second transistor M2 is connected between Mr6 and Mr10, and the gate of the fourth transistor M4 is connected between Mr7 and Mr11. This embodiment does not impose any restrictions on the number and connection relationship of the transistors in the level shift circuit 1311 and the gain compensation circuit 1312. The only requirement is to ensure that the gain of the arithmetic circuit 131 is sufficiently large.

[0087] The above-mentioned operation circuit includes a level shifting circuit and a gain compensation circuit. The level shifting circuit and the gain compensation circuit both include multiple transistor groups. The multiple transistor groups are connected in parallel, and the second ends are connected to the gain compensation circuit. The gain compensation circuit is connected to the gate of the second transistor and the gate of the fourth transistor, respectively. The voltage input to the first drain-source end and the second drain-source end is level-shifted by the level shifting circuit to reduce the voltage output by the voltage source and provide the required voltage for the gain compensation circuit. The gain compensation circuit then provides gain for the operation circuit so that the error between the voltage at the second drain-source end and the voltage at the first drain-source end is less than a preset voltage threshold, which can improve the current replication capability and thus improve the PSR capability.

[0088] In the above Figure 3 Based on the embodiment, this embodiment specifically introduces the contents of the reference current circuit 12 in the above embodiment. Figure 10 A schematic diagram of a reference voltage circuit is provided. The reference current circuit 12 also includes an original current transistor group 122, which forms a current mirror structure with the first transistor group 121; the original current transistor group 122 includes a fifth transistor M5 and a sixth transistor M6, the gate of the fifth transistor M5 is connected to the gate of the first transistor M1, the gate of the sixth transistor M6 is connected to the gate of the second transistor M2, and the source of the fifth transistor M5 is connected to the voltage source VDD.

[0089] In this embodiment, the original current transistor group 122 is used to provide an original current. Specifically, after the first transistor group 121 replicates the current of the original current transistor group 122, the second transistor group 141 replicates the current of the first transistor group 121 a second time. The secondary replicated current flows through the first resistor R1 to generate an output voltage. Based on the connection relationship between the fifth transistor M5, the sixth transistor M6, the first transistor M1, and the second transistor M2, the current mirror structure formed by the original current transistor group 122 and the first transistor group 121 can be determined to be a cascode current mirror.

[0090] The above-mentioned reference current circuit also includes an original current transistor group, which forms a current mirror structure with the first transistor group; the original current transistor group includes a fifth transistor and a sixth transistor, the gate of the fifth transistor is connected to the gate of the first transistor, the gate of the sixth transistor is connected to the gate of the second transistor, and the source of the fifth transistor is connected to the voltage source. Through two groups of common source and common gate current mirror structures, the original current can be copied twice, the current copying ability can be improved, thereby improving the PSR capability.

[0091] In the above Figure 10 Based on the embodiment, this embodiment specifically introduces the contents of the reference current circuit 12 in the above embodiment. Figure 11 A reference voltage circuit schematic is provided. The reference current circuit 12 further includes a temperature compensation circuit 123, which is connected to the drain of the sixth transistor M6 and the drain of the second transistor M2 respectively; the temperature compensation circuit 123 is used to compensate for the current flowing through the first transistor M1 and the second transistor M2.

[0092] In this embodiment, temperature changes will affect the voltage across the transistors. When the temperature rises, the voltage across the transistors will decrease, and accordingly, the current flowing through the first transistor M1 and the second transistor M2 will decrease. When the temperature drops, the voltage across the transistors will increase, and accordingly, the current flowing through the first transistor M1 and the second transistor M2 will increase. The temperature compensation circuit 123 compensates for the change in the current flowing through the first transistor M1 and the second transistor M2 so that the current flowing through the first transistor M1 and the second transistor M2 does not change with changes in temperature. The temperature compensation circuit 123 can be a circuit composed of electronic components such as a voltage regulator diode, a thermistor, and an operational amplifier.

[0093] The above-mentioned reference current circuit also includes a temperature compensation circuit, which is connected to the drain of the sixth transistor and the drain of the second transistor respectively; the temperature compensation circuit is used to compensate for the current flowing through the first transistor and the second transistor. The temperature compensation circuit can compensate for the copied current so that the current flowing through the first transistor and the second transistor will not be affected by the temperature, thereby improving the current replication capability.

[0094] In the above Figure 11 Based on the embodiment, this embodiment specifically introduces the contents of the temperature compensation circuit 123 in the above embodiment. Figure 12 A schematic diagram of a reference voltage circuit is provided. The temperature compensation circuit 123 includes an operational amplifier OPA1, a seventh transistor Q2, an eighth transistor Q1, a second resistor R2, and a temperature compensation unit 1231. The second resistor R2 is connected in parallel with the seventh transistor Q2. The collector of the seventh transistor Q2 is connected to the drain of the sixth transistor M6 and the input terminal of the operational amplifier OPA1, respectively. The eighth transistor Q1 is connected to one end of the temperature compensation unit 1231. The other end of the temperature compensation unit 1231 is connected to the drain of the second transistor M2 and the output terminal of the operational amplifier OPA1, respectively. The second end of the second resistor R2, the emitter and base of the seventh transistor Q2, and the emitter and base of the eighth transistor Q1 are grounded. The operational amplifier OPA1 is used to compensate for the voltage of the drain of the second transistor M2 so that the error between the voltage of the drain of the second transistor M2 and the drain of the sixth transistor M6 is less than a preset voltage threshold. The temperature compensation unit 1231 is used to compensate for the current flowing through the first transistor M1 and the second transistor M2.

[0095] In this embodiment, when the temperature in the circuit changes, the voltage across the transistors also changes with the temperature. Due to the different areas of the seventh transistor Q2 and the eighth transistor Q1, the voltage across the seventh transistor Q2 and the eighth transistor Q1 change differently. By utilizing the "virtual short" characteristic of operational amplifier OPA1, the temperature compensation unit 1231 is connected in series with the eighth transistor Q1, ensuring that the sum of the voltages across the eighth transistor Q1 and the temperature compensation unit 1231 is equal to the voltage across the seventh transistor Q2.

[0096] The voltage across the temperature compensation unit 1231 is the difference between the voltage across the seventh transistor Q2 and the voltage across the eighth transistor Q1. When the temperature rises, the voltage across the seventh transistor Q2 and the eighth transistor Q1 decreases with the temperature increase. Correspondingly, the voltage across the temperature compensation unit 1231 increases with the temperature increase. When the voltage increases and the resistance remains unchanged, the current flowing through the first transistor M1 and the second transistor M2 increases. The temperature compensation unit 1231 needs to reduce the current flowing through the first transistor M1 and the second transistor M2 to ensure that the current flowing through the first transistor M1 and the second transistor M2 does not change with changes in temperature. For example, the temperature compensation unit 1231 can shunt the increased current by connecting a parallel resistor to compensate for the current flowing through the first transistor M1 and the second transistor M2.

[0097] The above-mentioned temperature compensation circuit includes an operational amplifier, a seventh transistor, an eighth transistor, a second resistor and a temperature compensation unit. The second resistor is connected in parallel with the seventh transistor, the collector of the seventh transistor is respectively connected to the drain of the sixth transistor and the input end of the operational amplifier, the eighth transistor is connected to one end of the temperature compensation unit, and the other end of the temperature compensation unit is respectively connected to the drain of the second transistor and the output end of the operational amplifier. The second end of the second resistor, the emitter and base of the seventh transistor, and the emitter and base of the eighth transistor are grounded; the voltage of the drain of the second transistor is compensated by the operational amplifier, so that the error between the voltage of the drain of the second transistor and the drain of the sixth transistor is less than a preset voltage threshold, and then the current flowing through the first transistor and the second transistor is compensated by the temperature compensation unit, thereby avoiding the current of the first transistor and the second transistor from changing with temperature, improving the accuracy of current replication, and ensuring that the output voltage does not change with temperature.

[0098] In the above Figure 12 Based on the embodiment, this embodiment specifically introduces the contents of the temperature compensation unit 1231 in the above embodiment. Figure 13A schematic diagram of a reference voltage circuit is provided, in which the temperature compensation unit 1231 includes a third resistor R3 and a fourth resistor R4. The third resistor R3 is connected in series with the eighth transistor Q1. The third resistor R3 and the eighth transistor Q1 are combined into a branch, and the fourth resistor R4 is connected in parallel with the branch. The third resistor R3 is used to perform forward temperature compensation on the current flowing through the first transistor M1 and the second transistor M2. The fourth resistor R4 is used to perform reverse temperature compensation on the current flowing through the first transistor M1 and the second transistor M2.

[0099] In this embodiment, the third resistor R3 in the temperature compensation unit 1231 is connected in series with the eighth transistor Q1, and the fourth resistor R4 is connected in parallel with the branch formed by the third resistor R3 and the eighth transistor Q1. That is, the voltage across the fourth resistor R4 is the same as the voltage across the branch. When the temperature increases, the voltage across the eighth transistor Q1 and the seventh transistor Q2 decreases. Correspondingly, the voltage across the third resistor R3 increases, and the current flowing through the first transistor M1 and the second transistor M2 increases. That is, the third resistor R3 performs positive temperature compensation for the current flowing through the first transistor M1 and the second transistor M2. The fourth resistor R4 is connected in parallel with the branch formed by the third resistor R3 and the eighth transistor Q1, which shunts the increased current and performs reverse temperature compensation for the current flowing through the first transistor M1 and the second transistor M2, so that the current flowing through the first transistor M1 and the second transistor M2 does not change with changes in temperature.

[0100] The above-mentioned temperature compensation unit includes a third resistor and a fourth resistor, the third resistor is connected in series with the eighth transistor, the third resistor and the eighth transistor are combined into a branch, and the fourth resistor is connected in parallel with the branch; the third resistor is used to perform forward temperature compensation on the current flowing through the first transistor and the second transistor; the fourth resistor is used to perform reverse temperature compensation on the current flowing through the first transistor and the second transistor. Through the forward temperature compensation of the third resistor and the reverse temperature compensation of the fourth resistor, the current flowing through the first transistor and the second transistor will not change with changes in temperature, thereby improving the temperature stability of the current.

[0101] Figure 14This is a schematic diagram of a reference voltage circuit. The original transistor group 122, the first transistor group 121, and the second transistor group 141 include two PMOS transistors. The original transistor group 122 includes a fifth transistor M5 and a sixth transistor M6. The first transistor group 121 includes a first transistor M1 and a second transistor M2. The second transistor group 121 includes a third transistor M3 and a fourth transistor M4. This circuit includes two current replication processes. The first is to replicate the current flowing through the original transistor group 122 to the first transistor group 121. The temperature compensation circuit 123 compensates the current flowing through the first transistor group 121 to ensure that the current flowing through the first transistor group 121 is not affected by temperature changes. The second is to replicate the current in the first transistor group 121 to the second transistor group 141. The operation circuit 131 compensates the voltage at the second drain-source terminal to ensure that the difference between the voltage at the second drain-source terminal and the voltage at the first drain-source terminal is within a preset range. By performing two current replication processes, not only can the impact of voltage fluctuations on the output voltage be avoided, but also the impact of temperature changes on the output voltage can be avoided, thereby improving the accuracy of current replication and thus improving the PSR capability. In addition, the operational circuit 131 can be represented by an operational amplifier OPA2, the input terminal of the operational amplifier OPA2 being connected to the first drain-source terminal and the second drain-source terminal respectively, and the output terminal of the operational amplifier OPA2 being connected to the drain of the second transistor M2 and the drain of the fourth transistor M4 respectively.

[0102] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A reference voltage circuit, characterized in that: The reference voltage circuit includes a reference current circuit, a voltage compensation circuit having an operation circuit, and a reference voltage output circuit; The first end of the reference current circuit and the first end of the reference voltage output circuit are both connected to a voltage source, and the second end of the reference current circuit and the second end of the reference voltage output circuit are both connected to the voltage compensation circuit; the operation circuit includes a level shift circuit and a gain compensation circuit, and the level shift circuit and the gain compensation circuit each include a plurality of transistor groups, and the plurality of transistor groups are connected in parallel; each transistor group includes two identical transistors, and the gates of the two identical transistors are connected to each other; The voltage compensation circuit is used to compensate the voltage of the second end of the reference voltage output circuit so that the error between the voltage of the second end of the reference voltage output circuit and the voltage of the second end of the reference current circuit is less than a preset voltage threshold.

2. The circuit according to claim 1, characterized in that The reference current circuit includes a first transistor group, the reference voltage output circuit includes a second transistor group, and the first transistor group and the second transistor group form a current mirror structure; The first end of the first transistor group and the first end of the second transistor group are both connected to the voltage source; the second end of the first transistor group and the second end of the second transistor group are both connected to the voltage compensation circuit; The voltage compensation circuit is used to compensate the voltage of the second end of the second transistor group so that the error between the voltage of the second end of the second transistor group and the voltage of the second end of the first transistor group is less than a preset voltage threshold.

3. The circuit according to claim 2, characterized in that The first transistor group includes a first transistor and a second transistor, the drain of the first transistor and the source of the second transistor are connected to form a first drain-source terminal; the second transistor group includes a third transistor and a fourth transistor, the drain of the third transistor and the source of the fourth transistor are connected to form a second drain-source terminal; The gate of the first transistor is connected to the gate of the third transistor; the source of the first transistor and the source of the third transistor are both connected to the voltage source; The input end of the voltage compensation circuit is connected to the first drain-source end and the second drain-source end respectively, and the output end of the voltage compensation circuit is connected to the gate of the second transistor and the gate of the fourth transistor respectively.

4. The circuit according to claim 3, characterized in that The reference voltage output circuit further includes a voltage output terminal and a first resistor, wherein the first terminal of the first resistor and the voltage output terminal are respectively connected to the drain of the fourth transistor, and the second terminal of the first resistor is grounded.

5. The circuit according to claim 3, characterized in that The input end of the operation circuit is connected to the first drain-source end and the second drain-source end respectively, and the output end of the operation circuit is connected to the gate of the second transistor and the gate of the fourth transistor respectively; The operation circuit is used to compensate the voltage of the second drain-source terminal so that the error between the voltage of the second drain-source terminal and the voltage of the first drain-source terminal is less than a preset voltage threshold.

6. The circuit according to claim 3, characterized in that A first terminal of the level shift circuit is connected to the first drain-source terminal and the second drain-source terminal respectively, a second terminal of the level shift circuit is connected to the gain compensation circuit, and the gain compensation circuit is connected to the gate of the second transistor and the gate of the fourth transistor respectively; The level shift circuit is used to level shift the voltage input to the first drain-source terminal and the second drain-source terminal; The gain compensation circuit is used to provide gain for the operation circuit so that the error between the voltage at the second drain-source terminal and the voltage at the first drain-source terminal is smaller than a preset voltage threshold.

7. The circuit according to any one of claims 3 to 6, characterized in that: The reference current circuit also includes an original current transistor group, which forms a current mirror structure with the first transistor group; the original current transistor group includes a fifth transistor and a sixth transistor, the gate of the fifth transistor is connected to the gate of the first transistor, the gate of the sixth transistor is connected to the gate of the second transistor, and the source of the fifth transistor is connected to the voltage source.

8. The circuit according to claim 7, characterized in that The reference current circuit further includes a temperature compensation circuit, and the temperature compensation circuit is connected to the drain of the sixth transistor and the drain of the second transistor respectively; The temperature compensation circuit is used to compensate for the current flowing through the first transistor and the second transistor.

9. The circuit according to claim 8, characterized in that The temperature compensation circuit includes an operational amplifier, a seventh transistor, an eighth transistor, a second resistor, and a temperature compensation unit, wherein the second resistor is connected in parallel with the seventh transistor, the collector of the seventh transistor is respectively connected to the drain of the sixth transistor and the input terminal of the operational amplifier, the eighth transistor is connected to one end of the temperature compensation unit, the other end of the temperature compensation unit is respectively connected to the drain of the second transistor and the output terminal of the operational amplifier, and the second end of the second resistor, the emitter and base of the seventh transistor, and the emitter and base of the eighth transistor are grounded; the operational amplifier being configured to compensate for the voltage of the drain of the second transistor so that an error between the voltages of the drain of the second transistor and the drain of the sixth transistor is less than a preset voltage threshold; The temperature compensation unit is used to compensate for the current flowing through the first transistor and the second transistor.

10. The circuit according to claim 9, characterized in that The temperature compensation unit includes a third resistor and a fourth resistor, the third resistor is connected in series with the eighth transistor, the third resistor and the eighth transistor are combined into a branch, and the fourth resistor is connected in parallel with the branch; The third resistor is used to perform forward temperature compensation on the current flowing through the first transistor and the second transistor; The fourth resistor is used to perform reverse temperature compensation on the current flowing through the first transistor and the second transistor.

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