Bandgap reference circuit, electronic chip and electronic device

Abstract

The application belongs to the technical field of electronic circuits, and provides a band gap reference circuit, an electronic chip and an electronic device. The band gap reference circuit comprises a first pre-adjustment module, a second pre-adjustment module and a band gap reference module, the first pre-adjustment module is connected with the second pre-adjustment module and the band gap reference module respectively, and the first pre-adjustment module is used for receiving a power supply voltage. The application only needs to realize the suppression of the power supply voltage fluctuation through the loop feedback between the first pre-adjustment module and the second pre-adjustment module, and guarantees the stability of the reference voltage. Compared with the band gap reference circuit adopting an LDO pre-adjuster, the implementation structure of the application is simple, which can not only reduce the area, power consumption and cost of the circuit, but also enable the band gap reference circuit to have a high PSR.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic circuits, and particularly relates to a bandgap reference circuit, an electronic chip and an electronic device. BACKGROUND

[0002] The bandgap reference circuit is widely applied in power management chips and analog / digital converters, and the signal precision of the bandgap reference circuit has a significant influence on the system precision, so it is necessary to design a high-precision bandgap reference circuit. However, the precision of the bandgap reference circuit is easily affected by power voltage fluctuation, so it is necessary to improve the precision by improving the PSR (Power Supply Rejection) of the bandgap reference circuit.

[0003] In order to improve the PSR of the bandgap reference circuit, a pre-regulator is currently used: the principle is to add a low-dropout linear regulator (LDO) in front of the power input path of the bandgap reference circuit, the LDO itself has high PSR in the medium-low frequency band, can significantly attenuate the ripple and noise of the input power supply, and provides a cleaner local power supply for the bandgap reference; but this structure increases the area, power consumption and cost.

[0004] Therefore, it is an urgent problem to be solved to provide a bandgap reference circuit with small area, low power consumption, low cost and high PSR. SUMMARY

[0005] The embodiments of the application provide a bandgap reference circuit, an electronic chip and an electronic device, which can solve the problem that the bandgap reference circuit using the LDO pre-regulator can realize high PSR but has large area, high power consumption and high cost.

[0006] In a first aspect, the embodiments of the application provide a bandgap reference circuit, which comprises a first pre-regulation module, a second pre-regulation module and a bandgap reference module, the first pre-regulation module is connected with the second pre-regulation module and the bandgap reference module respectively, and the first pre-regulation module is used for receiving a power voltage.

[0007] The first pre-regulation module is used for outputting a first voltage according to the power voltage; the bandgap reference module is used for outputting a reference voltage according to the first voltage; when the power voltage fluctuates, the first voltage and the reference voltage both fluctuate, the first pre-regulation module is further used for outputting a first feedback voltage to the second pre-regulation module; and the second pre-regulation module is used for outputting a second feedback voltage according to the first feedback voltage, so that the first pre-regulation module suppresses the fluctuation of the power voltage according to the second feedback voltage.

[0008] In a possible implementation manner of the first aspect, the first pre-adjustment module comprises a first current source, a second current source, a first field effect transistor, a second field effect transistor and a first capacitor, a first end of the first current source and a drain of the first field effect transistor are configured to receive the power supply voltage, a second end of the first current source is connected with a first end of the first capacitor, a gate of the first field effect transistor and the second pre-adjustment module respectively, a second end of the first capacitor is connected with a drain of the second field effect transistor, a first end of the second current source and the second pre-adjustment module respectively, a source of the first field effect transistor is connected with a source of the second field effect transistor and the bandgap reference module respectively, a gate of the second field effect transistor is connected with the bandgap reference module, and a second end of the second current source is grounded.

[0009] In a possible implementation manner of the first aspect, the second pre-adjustment module comprises a third field effect transistor, a gate of the third field effect transistor is connected with the first pre-adjustment module, a drain of the third field effect transistor is connected with the first pre-adjustment module, and a source of the third field effect transistor is grounded.

[0010] In a possible implementation manner of the first aspect, the bandgap reference module comprises a current mirror unit, a feedback adjustment unit, a differential pair unit and an output unit, a first end of the current mirror unit is configured to receive a first voltage, a second end of the current mirror unit is connected with a first end of the feedback adjustment unit and a first end of the differential pair unit respectively, a third end of the current mirror unit is connected with a second end of the feedback adjustment unit and a second end of the differential pair unit respectively, a fourth end of the current mirror unit is connected with the output unit and the first pre-adjustment module respectively, and a third end of the feedback adjustment unit is connected with a fifth end of the current mirror unit.

[0011] The current mirror unit is configured to output equal first and second currents according to the first voltage, the differential pair unit is configured to generate a third current according to the first and second currents, the current mirror unit is further configured to mirror the third current to obtain a fourth current, the output unit is configured to output the reference voltage according to the fourth current, and the feedback adjustment unit is configured to output an adjustment signal according to first and second voltages, so that the current mirror unit adjusts the first or second voltage according to the adjustment signal, so that the first voltage is equal to the second voltage, wherein the first voltage is a voltage at the first end of the feedback adjustment unit, and the second voltage is a voltage at the second end of the feedback adjustment unit.

[0012] In a possible implementation manner of the first aspect, the current mirror unit includes a fourth field effect transistor, a fifth field effect transistor, a sixth field effect transistor, a seventh field effect transistor, an eighth field effect transistor and a second capacitor, a source of the fourth field effect transistor is connected with a source of the fifth field effect transistor, a source of the sixth field effect transistor, a source of the seventh field effect transistor and the first pre-adjustment module respectively, a gate of the fourth field effect transistor is connected with a drain of the fourth field effect transistor, a drain of the eighth field effect transistor, a gate of the fifth field effect transistor, a gate of the sixth field effect transistor and a gate of the seventh field effect transistor respectively, a gate of the eighth field effect transistor is connected with a first end of the second capacitor and a third end of the feedback adjustment unit respectively, a drain of the fifth field effect transistor is connected with a first end of the feedback adjustment unit and a first end of the differential pair unit respectively, a drain of the sixth field effect transistor is connected with a second end of the feedback adjustment unit and a second end of the differential pair unit respectively, a drain of the seventh field effect transistor is connected with the output unit and the first pre-adjustment module respectively, and the source of the eighth field effect transistor and a second end of the second capacitor are grounded.

[0013] In a possible implementation manner of the first aspect, the feedback adjustment unit includes an operational amplifier, a first input end of the operational amplifier is connected with a second end of the current mirror unit and a first end of the differential pair unit respectively, a second input end of the operational amplifier is connected with a third end of the current mirror unit and a second end of the differential pair unit respectively, and an output end of the operational amplifier is connected with a fifth end of the current mirror unit.

[0014] In a possible implementation manner of the first aspect, the differential pair unit includes a first resistor, a first triode and a second triode, a first end of the first resistor is connected with a second end of the feedback adjustment unit and a third end of the current mirror unit respectively, a second end of the first resistor is connected with an emitter of the second triode, an emitter of the first triode is connected with a first end of the feedback adjustment unit and a second end of the current mirror unit respectively, and a base of the first triode, a collector of the first triode, a base of the second triode and a collector of the second triode are grounded.

[0015] In a possible implementation manner of the first aspect, the output unit includes a third triode and a resistance trimming subunit, the resistance trimming subunit is connected with a fourth end of the current mirror unit, the first pre-adjustment module and an emitter of the third triode respectively, and a base of the third triode and a collector of the third triode are grounded.

[0016] In the second aspect, the embodiments of the present application provide an electronic chip including the bandgap reference circuit in any of the first aspect.

[0017] In a third aspect, the embodiments of the present application provide an electronic device comprising the bandgap reference circuit of any one of the second aspect.

[0018] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0019] The embodiments of the present application provide a bandgap reference circuit, comprising a first pre-adjustment module, a second pre-adjustment module and a bandgap reference module, the first pre-adjustment module is connected with the second pre-adjustment module and the bandgap reference module respectively, and the first pre-adjustment module is configured to receive a power supply voltage.

[0020] The first pre-adjustment module is configured to output a first voltage according to the power supply voltage. The bandgap reference module is configured to output a reference voltage according to the first voltage. When the power supply voltage fluctuates, the first voltage and the reference voltage both fluctuate, and the first pre-adjustment module is further configured to output a first feedback voltage to the second pre-adjustment module. The second pre-adjustment module is configured to output a second feedback voltage according to the first feedback voltage, so that the first pre-adjustment module suppresses the fluctuation of the power supply voltage according to the second feedback voltage, thereby suppressing the fluctuation of the first voltage and the reference voltage, and finally improving the PSR of the bandgap reference circuit.

[0021] The present application only realizes the suppression of the fluctuation of the power supply voltage through the loop feedback between the first pre-adjustment module and the second pre-adjustment module, and ensures the stability of the reference voltage VBG. Compared with the bandgap reference circuit using the LDO pre-adjuster, the implementation of the present application is simple, which not only can reduce the area, power consumption and cost of the circuit, but also can make the bandgap reference circuit have high PSR.

[0022] It can be understood that the beneficial effects of the above-mentioned second aspect to the third aspect can be referred to the related description in the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is a principle block diagram of the bandgap reference circuit provided by an embodiment of the present application;

[0025] Figure 2 is a principle block diagram of the bandgap reference circuit provided by another embodiment of the present application;

[0026] Figure 3 is a circuit connection schematic diagram of the bandgap reference circuit provided by an embodiment of the present application;

[0027] Figure 4 is a circuit connection diagram of a bandgap reference circuit provided by another embodiment of the present application;

[0028] Figure 5 is a small signal model diagram of a bandgap reference module in the present application;

[0029] Figure 6 is a small signal model diagram of a bandgap reference circuit provided by an embodiment of the present application;

[0030] Figure 7 is a simulation waveform diagram of a bandgap reference circuit provided by an embodiment of the present application.

[0031] In the figure: 10, first pre-adjustment module; 20, second pre-adjustment module; 30, bandgap reference module; 31, current mirror unit; 32, feedback adjustment unit; 33, differential pair unit; 34, output unit; 341, resistance trimming sub-unit; 40, power supply. DETAILED DESCRIPTION

[0032] In the following description, for the purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the application. However, it will be apparent to those skilled in the art that the application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the application with unnecessary detail.

[0033] It should be understood that the term "includes" when used in the specification and the appended claims herein, specifies the presence of stated features, integers, steps, operations, elements, and / or components but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0034] It should also be understood that the term "and / or" when used in the specification and the appended claims herein, means any one or more of the associated listed items can be present, and includes multiples of those items when the context allows.

[0035] As used in the description and the appended claims herein, the term "if' can be interpreted as meaning "when" or "once" or "in response to a determination" or "in response to a detection" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted as meaning "once determined" or "in response to a determination" or "once detected [the described condition or event]" or "in response to a detection [the described condition or event]" depending on the context.

[0036] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are used only to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0037] In the present application, the reference to "one embodiment" or "some embodiments" means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in further some embodiments" and the like appearing in the present specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "including but not limited to", unless otherwise specifically emphasized.

[0038] In order to improve the PSR of the bandgap reference circuit, the following methods can be used:

[0039] (1) Using a common-source common-gate current mirror: because it has high output impedance, the influence of power supply voltage change on the output current of the current mirror is minimal, but this method not only consumes voltage margin, but also increases design complexity.

[0040] (2) Adding a filter capacitor at the output of the bandgap reference circuit: this method has a significant effect on the suppression of high-frequency power supply noise, but the effect on the suppression of low-frequency power supply noise is limited.

[0041] (3) Using a pre-regulator: the principle is to add an LDO in front of the power input path of the bandgap reference circuit, which itself has high PSR in the medium and low frequency band, can significantly attenuate the ripple and noise of the input power supply, and provide a "cleaner" local power supply for the bandgap reference; but this structure will increase the area, power consumption and cost.

[0042] Based on this, the present application proposes a bandgap reference circuit, which not only has the same suppression effect on power voltage fluctuations as the bandgap reference circuit using an LDO pre-regulator, i.e. high PSR, but also has smaller area, lower power consumption and cost. As shown in Figure 1 The bandgap reference circuit includes a first pre-regulation module 10, a second pre-regulation module 20 and a bandgap reference module 30, the first pre-regulation module 10 is connected with the second pre-regulation module 20 and the bandgap reference module 30 respectively, the first pre-regulation module 10 is used to be connected with the positive electrode of a power supply 40, receive a power supply voltage VPP, and the negative electrode of the power supply 40 is grounded.

[0043] Specifically, the first pre-regulator 10 is configured to output a first voltage VLL according to the power supply voltage VPP. The bandgap reference module 30 is configured to output a reference voltage VBG according to the first voltage VLL. When the power supply voltage VPP fluctuates, both the first voltage VLL and the reference voltage VBG fluctuate. The first pre-regulator 10 is further configured to output a first feedback voltage to the second pre-regulator 20. The second pre-regulator 20 is configured to output a second feedback voltage according to the first feedback voltage, so that the first pre-regulator 10 suppresses the fluctuation of the power supply voltage VPP according to the second feedback voltage, thereby suppressing the fluctuation of the first voltage VLL and the reference voltage VBG, and finally improving the PSR of the bandgap reference circuit. More specifically, when the power supply voltage VPP fluctuates and becomes larger, both the first voltage VLL and the reference voltage VBG will become larger. At this time, the first feedback voltage output by the first pre-regulator 10 will also become larger. After receiving the larger first feedback voltage, the second pre-regulator 20 will make the second feedback voltage output by it smaller. Finally, the first pre-regulator 10 suppresses the trend of the power supply voltage VPP becoming larger according to the smaller second feedback voltage, thereby suppressing the fluctuation of the first voltage VLL and the reference voltage VBG, and finally improving the PSR of the bandgap reference circuit. Similarly, when the power supply voltage VPP fluctuates and becomes smaller, both the first voltage VLL and the reference voltage VBG will become smaller. At this time, the first feedback voltage output by the first pre-regulator 10 will also become smaller. After receiving the smaller first feedback voltage, the second pre-regulator 20 will make the second feedback voltage output by it larger. Finally, the first pre-regulator 10 suppresses the trend of the power supply voltage VPP becoming smaller according to the larger second feedback voltage, thereby suppressing the fluctuation of the first voltage VLL and the reference voltage VBG, and finally improving the PSR of the bandgap reference circuit.

[0044] In summary, by the loop feedback between the first pre-regulator 10 and the second pre-regulator 20, the fluctuation of the power supply voltage VPP is suppressed, and the stability of the reference voltage VBG is ensured. Compared with the bandgap reference circuit using the LDO pre-regulator, the implementation of the present application is simple, which not only can reduce the area, power consumption and cost of the circuit, but also can make the bandgap reference circuit have high PSR.

[0045] It should be noted that the bandgap reference circuit provided by the embodiments of the present application can be applied to power management systems, high-precision comparators, digital-analog hybrid circuits, phase-locked loops and other circuits.

[0046] In some embodiments, as Figure 2As shown, the bandgap reference module 30 includes a current mirror unit 31, a feedback adjustment unit 32, a differential pair unit 33, and an output unit 34. The first terminal of the current mirror unit 31 is used to receive a first voltage VLL. The second terminal of the current mirror unit 31 is connected to the first terminal of the feedback adjustment unit 32 and the first terminal of the differential pair unit 33, respectively. The third terminal of the current mirror unit 31 is connected to the second terminal of the feedback adjustment unit 32 and the second terminal of the differential pair unit 33, respectively. The fourth terminal of the current mirror unit 31 is connected to the output unit 34 and the first pre-adjustment module 10, respectively. The third terminal of the feedback adjustment unit 32 is connected to the fifth terminal of the current mirror unit 31.

[0047] Specifically, the current mirror unit 31 outputs a first current and a second current equal to the first voltage VLL. The differential pair unit 33 generates a third current based on the first and second currents. The current mirror unit 31 also mirrors the third current to obtain a fourth current. The output unit 34 outputs a reference voltage VBG based on the fourth current. The feedback adjustment unit 32 outputs an adjustment signal based on the first voltage VX and the second voltage VY, causing the current mirror unit 31 to adjust either the first voltage VX or the second voltage VY according to the adjustment signal, thereby making the first voltage VX equal to the second voltage VY to ensure the stability of the reference voltage VBG. Here, the first voltage VX is the voltage at the first terminal of the feedback adjustment unit 32, and the second voltage VY is the voltage at the second terminal of the feedback adjustment unit 32.

[0048] In some embodiments, such as Figure 3 As shown, the current mirror unit 31 includes a fourth field-effect transistor M4, a fifth field-effect transistor M5, a sixth field-effect transistor M6, a seventh field-effect transistor M7, an eighth field-effect transistor M8, and a second capacitor C2. The source of the fourth field-effect transistor M4 is connected to the sources of the fifth field-effect transistor M5, the sixth field-effect transistor M6, the seventh field-effect transistor M7, and the first pre-adjustment module 10, respectively. The gate of the fourth field-effect transistor M4 is connected to the drain of the fourth field-effect transistor M4, the drain of the eighth field-effect transistor M8, the gate of the fifth field-effect transistor M5, the gate of the sixth field-effect transistor M6, and the seventh field-effect transistor M8, respectively. The gate of the eighth field-effect transistor M7 is connected to the first terminal of the second capacitor C2 and the third terminal of the feedback adjustment unit 32, respectively. The drain of the fifth field-effect transistor M5 is connected to the first terminal of the feedback adjustment unit 32 and the first terminal of the differential pair unit 33, respectively. The drain of the sixth field-effect transistor M6 is connected to the second terminal of the feedback adjustment unit 32 and the second terminal of the differential pair unit 33, respectively. The drain of the seventh field-effect transistor M7 is connected to the output unit 34 and the first pre-adjustment module 10, respectively. The source of the eighth field-effect transistor M8 and the second terminal of the second capacitor C2 are both grounded. The second capacitor C2 is used for filtering.

[0049] Specifically, the fourth field-effect transistor M4, the fifth field-effect transistor M5, the sixth field-effect transistor M6, and the seventh field-effect transistor M7 form a current mirror structure, with equal current in each branch. The fourth field-effect transistor M4, the fifth field-effect transistor M5, the eighth field-effect transistor M8, and the first voltage VX form positive feedback, while the fourth field-effect transistor M4, the sixth field-effect transistor M6, the eighth field-effect transistor M8, and the second voltage VY form negative feedback. The negative feedback gain is greater than the positive feedback gain, making the bandgap reference module 30 a negative feedback circuit.

[0050] In some embodiments, such as Figure 3 As shown, the feedback adjustment unit 32 includes an operational amplifier OP. The first input terminal of the operational amplifier OP is connected to the second terminal of the current mirror unit 31 and the first terminal of the differential pair unit 33, respectively. The second input terminal of the operational amplifier OP is connected to the third terminal of the current mirror unit 31 and the second terminal of the differential pair unit 33, respectively. The output terminal of the operational amplifier OP is connected to the fifth terminal of the current mirror unit 31.

[0051] Specifically, the operational amplifier (OP) is the core device for feedback regulation, used to ensure that the first voltage VX is equal to the second voltage VY. If the first voltage VX increases, the output of the operational amplifier OP will increase, meaning the gate voltage of the eighth field-effect transistor (FET) M8 will increase. After the gate voltage of FET M8 increases, the current in its branch increases, and the drain voltage of FET M8 decreases, meaning the gate voltage of the fifth field-effect transistor (FET) M5 decreases. The current in the branch of FET M5 increases, and the drain voltage of FET M5 also increases, thus forming positive feedback. If the second voltage VY increases, the output of the operational amplifier OP will decrease, meaning the gate voltage of the eighth field-effect transistor (FET) M8 will decrease. When the gate voltage of the eighth field-effect transistor M8 decreases, the current in its branch decreases, and the drain voltage of the eighth field-effect transistor M8 increases. This means the gate voltage of the fifth field-effect transistor M5 increases, the current in its branch decreases, and the drain voltage of the fifth field-effect transistor M5 also decreases, thus forming negative feedback. The ultimate purpose of the operational amplifier OP is to adjust either the first voltage VX or the second voltage VY to ensure that the first voltage VX is equal to the second voltage VY.

[0052] In some embodiments, such as Figure 3As shown, the differential pair unit 33 includes a first resistor R1, a first transistor Q1, and a second transistor Q2. The first end of the first resistor R1 is connected to the second end of the feedback adjustment unit 32 and the third end of the current mirror unit 31, respectively. The second end of the first resistor R1 is connected to the emitter of the second transistor Q2. The emitter of the first transistor Q1 is connected to the first end of the feedback adjustment unit 32 and the second end of the current mirror unit 31, respectively. The base and collector of the first transistor Q1, the base and collector of the second transistor Q2 are all grounded.

[0053] Specifically, under the action of the current mirror unit 31, the first transistor Q1 and the second transistor Q2 are used to generate a positive temperature coefficient voltage difference, which will generate a positive temperature coefficient third current across the first resistor R1.

[0054] In some embodiments, such as Figure 3 As shown, the output unit 34 includes a third transistor Q3 and a resistor adjustment unit 341. The resistor adjustment unit 341 is connected to the fourth terminal of the current mirror unit 31, the first pre-adjustment module 10, and the emitter of the third transistor Q3, respectively. The base and collector of the third transistor Q3 are both grounded. Figure 4 As shown, the resistor adjustment unit 341 can be equivalent to a second resistor R2 that can change its resistance value.

[0055] Specifically, the fourth current is derived from the mirror image of the third current. Since the third current has a positive temperature coefficient, the fourth current also has a positive temperature coefficient. The third transistor Q3 generates a negative temperature coefficient voltage based on the fourth current. The fourth current will generate a positive temperature coefficient voltage difference across the second resistor R2. The positive temperature coefficient voltage difference and the negative temperature coefficient voltage are superimposed. By adjusting their coefficients, a zero temperature coefficient reference voltage VBG can be obtained.

[0056] Combination Figure 4 This explains the working principle of the bandgap reference module 30.

[0057] After the bandgap reference module 30 enters a stable operating state, under the action of the current mirror unit 31, the first transistor Q1 and the second transistor Q2 will generate a first voltage difference ΔV1 with a positive temperature coefficient, as shown in equation (1). The first voltage difference ΔV1 generates a third current I3 with a positive temperature coefficient across the first resistor R1, as shown in equation (2). The third current I3 is mirrored through the current mirror to obtain a fourth current I4 with a positive temperature coefficient. The fourth current I4 generates a negative temperature coefficient voltage V through the third transistor Q3. BE3, a second voltage difference ΔV2 with a positive temperature coefficient is generated by the fourth current I4 passing through the second resistor R2, and the expression is shown in equation (3). The second voltage difference ΔV2 with a positive temperature coefficient is superimposed on a negative temperature coefficient voltage V BE3 By adjusting the coefficients, a reference voltage VBG with a zero temperature coefficient can be obtained, and the expression is shown in equation (4).

[0058] (1);

[0059] where ΔV1 represents the first voltage difference, V BE1 represents the emitter junction voltage of the first transistor Q1, V BE2 represents the emitter junction voltage of the second transistor Q2, K represents the Boltzmann function, T represents the thermodynamic temperature, q represents the electronic charge, and N represents the quantity ratio of the first transistor Q1 to the second transistor Q2.

[0060] (2);

[0061] where I3 represents the third current, and r1 represents the resistance value of the first resistor R1.

[0062] (3);

[0063] where ΔV2 represents the second voltage difference, and r2 represents the resistance value of the second resistor R2.

[0064] (4);

[0065] where V BE3 represents the negative temperature coefficient voltage, and VBG represents the reference voltage.

[0066] Figure 5 A small signal model of the bandgap reference module 30 is shown in FIG. 3, Figure 5 where r 05 represents the small signal impedance of the seventh field effect transistor M7, r b3 represents the small signal impedance of the third transistor Q3, vpp represents the small signal voltage of the power supply voltage VPP, vbg represents the small signal voltage of the reference voltage VBG, r2 represents the resistance value of the second resistor R2, and k represents the proportion of the resistance value of the second resistor R2. Then the expression of the PSR of the bandgap reference module 30 is shown in equation (5);

[0067] (5).

[0068] In some embodiments, as Figure 3As shown, the first pre-adjustment module 10 includes a first current source IB1, a second current source IB2, a first field-effect transistor M1, a second field-effect transistor M2, and a first capacitor C1. The first terminal of the first current source IB1 and the drain of the first field-effect transistor M1 are both connected to the positive terminal of the power supply 40 to receive the power supply voltage VPP. The second terminal of the first current source IB1 is connected to the first terminal of the first capacitor C1, the gate of the first field-effect transistor M1, and the second pre-adjustment module 20. The second terminal of the first capacitor C1 is connected to the drain of the second field-effect transistor M2, the first terminal of the second current source IB2, and the second pre-adjustment module 20. The source of the first field-effect transistor M1 is connected to the source of the second field-effect transistor M2 and the bandgap reference module 30. The gate of the second field-effect transistor M2 is connected to the bandgap reference module 30. The second terminal of the second current source IB2 is grounded.

[0069] Specifically, when the power supply voltage VPP fluctuates significantly, the gate voltage of the first field-effect transistor M1 increases accordingly, leading to an increase in the first voltage VLL. After the first voltage VLL increases, the reference voltage VBG also increases accordingly. Because the gate voltage of the first field-effect transistor M1 increases, the current flowing through it will be greater than the current from the second current source IB2. Therefore, the drain voltage of the second field-effect transistor M2 will increase, meaning the output first feedback voltage will increase.

[0070] Similarly, when the power supply voltage VPP fluctuates and decreases, the gate voltage of the first field-effect transistor M1 decreases accordingly, which in turn causes the first voltage VLL to decrease. After the first voltage VLL decreases, the reference voltage VBG will also decrease accordingly. Since the gate voltage of the first field-effect transistor M1 decreases, the current flowing through the first field-effect transistor M1 will be less than the current of the second current source IB2. Therefore, the drain voltage of the second field-effect transistor M2 will decrease, that is, the output first feedback voltage will decrease.

[0071] The function of the second field-effect transistor M2 is to ensure that the first voltage VLL is always higher than the reference voltage VBG by a value of Vgs2 (Vgs2 is the gate-source voltage of the second field-effect transistor M2).

[0072] The function of the first capacitor C1 is to provide compensation to ensure that the negative feedback loop of the bandgap reference module 30 is more stable.

[0073] In some embodiments, such as Figure 3 As shown, the second pre-adjustment module 20 includes a third field-effect transistor M3. The gate of the third field-effect transistor M3 is connected to the first pre-adjustment module 10, the drain of the third field-effect transistor M3 is connected to the first pre-adjustment module 10, and the source of the third field-effect transistor M3 is grounded.

[0074] Specifically, when the power supply voltage VPP fluctuates and becomes larger, the gate voltage of the first field effect transistor M1 becomes larger, and then the first voltage VLL becomes larger. After the first voltage VLL becomes larger, the reference voltage VBG also becomes larger. Since the gate voltage of the first field effect transistor M1 becomes larger, the current flowing through the first field effect transistor M1 is larger than the current of the second current source IB2, and thus the drain voltage of the second field effect transistor M2 becomes larger, i.e., the output first feedback voltage becomes larger, and thus the gate voltage of the third field effect transistor M3 becomes larger. After the gate voltage of the third field effect transistor M3 becomes larger, the drain voltage of the third field effect transistor M3 becomes smaller, i.e., the output second feedback voltage becomes smaller, and thus the gate voltage of the first field effect transistor M1 becomes smaller, which can inhibit the trend of the power supply voltage VPP becoming larger, thereby inhibiting the fluctuation of the first voltage VLL and the reference voltage VBG, and finally improving the PSR of the bandgap reference circuit.

[0075] Similarly, when the power supply voltage VPP fluctuates and becomes smaller, the gate voltage of the first field effect transistor M1 becomes smaller, and then the first voltage VLL becomes smaller. After the first voltage VLL becomes smaller, the reference voltage VBG also becomes smaller. Since the gate voltage of the first field effect transistor M1 becomes smaller, the current flowing through the first field effect transistor M1 is smaller than the current of the second current source IB2, and thus the drain voltage of the second field effect transistor M2 becomes smaller, i.e., the output first feedback voltage becomes smaller, and thus the gate voltage of the third field effect transistor M3 becomes smaller. After the gate voltage of the third field effect transistor M3 becomes smaller, the drain voltage of the third field effect transistor M3 becomes larger, i.e., the output second feedback voltage becomes larger, and thus the gate voltage of the first field effect transistor M1 becomes larger, which can inhibit the trend of the power supply voltage VPP becoming smaller, thereby inhibiting the fluctuation of the first voltage VLL and the reference voltage VBG, and finally improving the PSR of the bandgap reference circuit.

[0076] Figure 6 A small signal model of the bandgap reference circuit is shown. The KCL (Kirchhoff's Current Law) equation of the A node is shown in expression (6),

[0077] (6);

[0078] wherein, gm3 represents the transconductance of the third field effect transistor M3, v B2 vg3 represents the gate small signal voltage of the third field effect transistor M3, r ds2 rm3 represents the small signal impedance of the third field effect transistor M3, vpp vp represents the small signal voltage of the power supply voltage VPP, v B1 vg1 represents the gate small signal voltage of the first field effect transistor M1, r on1represents the impedance of the first current source IB1, s = jw, j represents the imaginary unit, w represents the angular frequency, and c1 represents the capacitance value of the first capacitor C1.

[0079] The KCL equation for the B node is expressed as shown in Equation (7),

[0080] (7);

[0081] wherein, vll represents the small-signal voltage of the first voltage VLL, r on2 represents the impedance of the second current source IB2, represents the transconductance of the second field effect transistor M2, r ds3 represents the small-signal impedance of the second field effect transistor M2, vx represents the small-signal voltage of the gate of the second field effect transistor M2.

[0082] The KCL equation for the C node is expressed as shown in Equation (8),

[0083] (8);

[0084] wherein, ds1 represents the small-signal impedance of the first field effect transistor M1, represents the transconductance of the first field effect transistor M1, r 05 represents the small-signal impedance of the seventh field effect transistor M7, r b3 represents the small-signal impedance of the third diode Q3.

[0085] The small-signal voltage of the reference voltage VBG vbg is expressed as shown in Equation (9),

[0086] (9);

[0087] The small-signal voltage of the gate of the second field effect transistor M2 vx is expressed as shown in Equation (10),

[0088] (10);

[0089] Based on the above formula, the PSR of the bandgap reference circuit at low frequency can be obtained, as shown in Equation (11),

[0090] (11).

[0091] Figure 7 The simulation waveforms of the bandgap reference circuit are shown in FIG. 6, Figure 7 PSR1 represents the PSR of the bandgap reference module 30, and PSR2 represents the PSR of the bandgap reference circuit, according to Figure 7It can be seen that the bandgap reference circuit provided by the embodiment of the present application greatly improves the PSR, and has a simple implementation structure, and can not only achieve the same suppression effect on the power supply voltage fluctuation as the bandgap reference circuit using the LDO pre-regulator, but also has a smaller area, lower power consumption and cost.

[0092] In summary, the bandgap reference circuit provided by the embodiment of the present application realizes the suppression of the power supply voltage VPP fluctuation through the loop feedback between the first pre-regulation module 10 and the second pre-regulation module 20, and ensures the stability of the reference voltage VBG. Compared with the bandgap reference circuit using the LDO pre-regulator, the implementation structure of the present application is simple, which can not only reduce the area, power consumption and cost of the circuit, but also enable the bandgap reference circuit to have high PSR in a wide range.

[0093] The embodiment of the present application also provides an electronic chip comprising the bandgap reference circuit described above. Since the electronic chip provided by the embodiment of the present application comprises the bandgap reference circuit described above, the electronic chip provided by the embodiment of the present application has the advantages of high PSR, small area, low power consumption and low cost.

[0094] For example, the electronic chip comprises a power management chip, a digital-to-analog conversion chip, an analog-to-digital conversion chip, etc.

[0095] The embodiment of the present application also provides an electronic device comprising the electronic chip described above. Since the electronic device provided by the embodiment of the present application comprises the electronic chip described above, the electronic device provided by the embodiment of the present application has the advantages of small overall volume, high cost performance, high running stability and strong anti-interference capability.

[0096] For example, the electronic device comprises a smart phone, a smart tablet, a wearable device, etc.

[0097] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0098] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A bandgap reference circuit, characterized by, The first pre-adjustment module, the second pre-adjustment module and the bandgap reference module are connected with each other, the first pre-adjustment module is used for receiving a power supply voltage; The first pre-adjustment module is used for outputting a first voltage according to the power supply voltage, the bandgap reference module is used for outputting a reference voltage according to the first voltage, when the power supply voltage fluctuates, the first voltage and the reference voltage both fluctuate, the first pre-adjustment module is further used for outputting a first feedback voltage to the second pre-adjustment module, and the second pre-adjustment module is used for outputting a second feedback voltage according to the first feedback voltage, so that the first pre-adjustment module suppresses the fluctuation of the power supply voltage according to the second feedback voltage; The first pre-adjustment module comprises a first current source, a second current source, a first field effect tube, a second field effect tube and a first capacitor, the first end of the first current source and the drain of the first field effect tube are both used for receiving the power supply voltage, the second end of the first current source is connected with the first end of the first capacitor, the gate of the first field effect tube and the second pre-adjustment module respectively, the second end of the first capacitor is connected with the drain of the second field effect tube, the first end of the second current source and the second pre-adjustment module respectively, the source of the first field effect tube is connected with the source of the second field effect tube and the bandgap reference module respectively, the gate of the second field effect tube is connected with the bandgap reference module, and the second end of the second current source is grounded; The second pre-adjustment module comprises a third field effect tube, the gate of the third field effect tube is connected with the first pre-adjustment module, the drain of the third field effect tube is connected with the first pre-adjustment module, and the source of the third field effect tube is grounded.

2. The bandgap reference circuit of claim 1, wherein, The bandgap reference module comprises a current mirror unit, a feedback adjustment unit, a differential pair unit and an output unit, the first end of the current mirror unit is used for receiving a first voltage, the second end of the current mirror unit is connected with the first end of the feedback adjustment unit and the first end of the differential pair unit respectively, the third end of the current mirror unit is connected with the second end of the feedback adjustment unit and the second end of the differential pair unit respectively, the fourth end of the current mirror unit is connected with the output unit and the first pre-adjustment module respectively, and the third end of the feedback adjustment unit is connected with the fifth end of the current mirror unit; The current mirror unit is used for outputting equal first current and second current according to the first voltage, the differential pair unit is used for generating third current according to the first current and the second current, the current mirror unit is further used for mirroring the third current to obtain fourth current, and the output unit is used for outputting the reference voltage according to the fourth current; The first pre-adjustment module, the second pre-adjustment module and the bandgap reference module are connected with each other, the first pre-adjustment module is used for receiving a power supply voltage; The first pre-adjustment module is used for outputting a first voltage according to the power supply voltage, the bandgap reference module is used for outputting a reference voltage according to the first voltage, when the power supply voltage fluctuates, the first voltage and the reference voltage both fluctuate, the first pre-adjustment module is further used for outputting a first feedback voltage to the second pre-adjustment module, and the second pre-adjustment module is used for outputting a second feedback voltage according to the first feedback voltage, so that the first pre-adjustment module suppresses the fluctuation of the power supply voltage according to the second feedback voltage; The first pre-adjustment module comprises a first current source, a second current source, a first field effect tube, a second field effect tube and a first capacitor, the first end of the first current source and the drain of the first field effect tube are both used for receiving the power supply voltage, the second end of the first current source is connected with the first end of the first capacitor, the gate of the first field effect tube and the second pre-adjustment module respectively, the second end of the first capacitor is connected with the drain of the second field effect tube, the first end of the second current source and the second pre-adjustment module respectively, the source of the first field effect tube is connected with the source of the second field effect tube and the bandgap reference module respectively, the gate of the second field effect tube is connected with the bandgap reference module, and the second end of the second current source is grounded; The second pre-adjustment module comprises a third field effect tube, the gate of the third field effect tube is connected with the first pre-adjustment module, the drain of the third field effect tube is connected with the first pre-adjustment module, and the source of the third field effect tube is grounded. The bandgap reference module comprises a current mirror unit, a feedback adjustment unit, a differential pair unit and an output unit, the first end of the current mirror unit is used for receiving a first voltage, the second end of the current mirror unit is connected with the first end of the feedback adjustment unit and the first end of the differential pair unit respectively, the third end of the current mirror unit is connected with the second end of the feedback adjustment unit and the second end of the differential pair unit respectively, the fourth end of the current mirror unit is connected with the output unit and the first pre-adjustment module respectively, and the third end of the feedback adjustment unit is connected with the fifth end of the current mirror unit; The current mirror unit is used for outputting equal first current and second current according to the first voltage, the differential pair unit is used for generating third current according to the first current and the second current, the current mirror unit is further used for mirroring the third current to obtain fourth current, and the output unit is used for outputting the reference voltage according to the fourth current; The feedback adjusting unit is configured to output an adjusting signal according to the first voltage and the second voltage, and the current mirror unit is configured to adjust the first voltage or the second voltage according to the adjusting signal, so that the first voltage is equal to the second voltage; wherein the first voltage is a voltage at a first end of the feedback adjusting unit, and the second voltage is a voltage at a second end of the feedback adjusting unit.

3. The bandgap reference circuit of claim 2, wherein, The current mirror unit comprises a fourth field effect transistor, a fifth field effect transistor, a sixth field effect transistor, a seventh field effect transistor, an eighth field effect transistor and a second capacitor, a source of the fourth field effect transistor is connected with a source of the fifth field effect transistor, a source of the sixth field effect transistor, a source of the seventh field effect transistor and the first pre-adjustment module respectively, a gate of the fourth field effect transistor is connected with a drain of the fourth field effect transistor, a drain of the eighth field effect transistor, a gate of the fifth field effect transistor, a gate of the sixth field effect transistor and a gate of the seventh field effect transistor respectively, a gate of the eighth field effect transistor is connected with a first end of the second capacitor and a third end of the feedback adjusting unit respectively, a drain of the fifth field effect transistor is connected with the first end of the feedback adjusting unit and a first end of the differential pair unit respectively, a drain of the sixth field effect transistor is connected with a second end of the feedback adjusting unit and a second end of the differential pair unit respectively, a drain of the seventh field effect transistor is connected with the output unit and the first pre-adjustment module respectively, and a source of the eighth field effect transistor and a second end of the second capacitor are grounded.

4. The bandgap reference circuit of claim 2, wherein, The feedback adjusting unit comprises an operational amplifier, a first input end of the operational amplifier is connected with the second end of the current mirror unit and the first end of the differential pair unit respectively, a second input end of the operational amplifier is connected with the third end of the current mirror unit and the second end of the differential pair unit respectively, and an output end of the operational amplifier is connected with a fifth end of the current mirror unit.

5. The bandgap reference circuit of claim 2, wherein, The differential pair unit comprises a first resistor, a first triode and a second triode, a first end of the first resistor is connected with the second end of the feedback adjusting unit and the third end of the current mirror unit respectively, a second end of the first resistor is connected with an emitter of the second triode, an emitter of the first triode is connected with the first end of the feedback adjusting unit and the second end of the current mirror unit respectively, and a base of the first triode, a collector of the first triode, a base of the second triode and a collector of the second triode are grounded.

6. The bandgap reference circuit of claim 2, wherein, The output unit comprises a third triode and a resistance trimming subunit, the resistance trimming subunit is connected with a fourth end of the current mirror unit, the first pre-adjustment module and an emitter of the third triode respectively, and a base of the third triode and a collector of the third triode are grounded.

7. An electronic chip, characterized by The bandgap reference circuit comprises any one of claims 1-6.

8. An electronic device, comprising: The electronic chip comprises claim 7.

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