Bandgap reference circuit and bandgap reference voltage calibration method

Abstract

The present application provides a bandgap reference circuit and a bandgap reference voltage calibration method, relating to the field of circuit technology. In the bandgap reference circuit, the two input terminals of a first voltage sampling circuit and the input terminal of a second calibration circuit are connected to the first voltage input terminal, and the output terminals of the first voltage sampling circuit and the first calibration circuit are connected to the positive input terminal of a proportional integration circuit; the first input terminal of the second voltage sampling circuit is connected to a preset ground terminal, the input terminal and the input terminal of the first calibration circuit are connected to the second voltage input terminal, and the output terminals of the second voltage sampling circuit and the second calibration circuit are connected to the negative input terminal of the proportional integration circuit; the two input terminals of the comparison circuit are connected to the positive output terminal and the negative output terminal of the proportional integration circuit, the output terminal is connected to the input terminal of a control circuit, and the output terminal of the control circuit is connected to the control terminals of the two voltage sampling circuits. The present application can calibrate both the absolute value and temperature coefficient of the bandgap reference voltage.

Description

Technical Field

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

[0002] A bandgap reference circuit is an analog circuit that generates a bandgap reference voltage that is independent of power supply voltage and temperature. Since the bandgap reference voltage varies little with temperature, it is widely used in various analog circuits.

[0003] In related technologies, a bandgap reference circuit obtains a temperature-independent bandgap reference voltage by adding a voltage that is positively correlated with absolute temperature (Proporational To Absolute Temperature, PTAT) and a voltage that is negatively correlated with absolute temperature (Complementary To Absolute Temperature, CTAT).

[0004] However, the bandgap reference voltage may vary due to process fluctuations, which is manifested in that the absolute value and temperature coefficient of the bandgap reference voltage deviate from expectations. Summary of the Invention

[0005] The purpose of this application is to address the deficiencies in the above-mentioned prior art and provide a bandgap reference circuit and a bandgap reference voltage calibration method, so as to adjust the positive temperature coefficient voltage and the negative temperature coefficient voltage of the bandgap reference voltage through a circuit with a self-calibration function, and simultaneously realize the calibration of the absolute value and temperature coefficient of the bandgap reference voltage.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a bandgap reference circuit, the bandgap reference circuit comprising: a first calibration circuit, a second calibration circuit, a comparison circuit, a control circuit, and a bandgap reference voltage source; the bandgap reference voltage source comprising: a first voltage sampling circuit, a second voltage sampling circuit, and a proportional-integral circuit;

[0008] The first input terminal and the second input terminal of the first voltage sampling circuit are connected to the first voltage input terminal, the output terminal of the first voltage sampling circuit is connected to the positive input terminal of the proportional integration circuit, the input terminal of the first calibration circuit is connected to the second voltage input terminal, and the output terminal of the first calibration circuit is connected to the positive input terminal of the proportional integration circuit;

[0009] A first input terminal of the second voltage sampling circuit is connected to a preset ground terminal, a second input terminal of the second voltage sampling circuit is connected to the second voltage input terminal, an output terminal of the second voltage sampling circuit is connected to the negative input terminal of the proportional-integral circuit, an input terminal of the second calibration circuit is connected to the first voltage input terminal, and an output terminal of the second calibration circuit is connected to the negative input terminal of the proportional-integral circuit;

[0010] The positive output terminal and the negative output terminal of the proportional integral circuit are respectively connected to the two input terminals of the comparison circuit, the output terminal of the comparison circuit is connected to the input terminal of the control circuit, and the output terminal of the control circuit is connected to the control terminals of the first voltage sampling circuit and the second voltage sampling circuit.

[0011] Optionally, the first voltage sampling circuit includes: a first charge-discharge electronic circuit and a second charge-discharge electronic circuit;

[0012] The input end of the first charge-discharge electronic circuit serves as the first input end of the first voltage sampling circuit, the input end of the second charge-discharge electronic circuit serves as the second input end of the first voltage sampling circuit, and the output end of the first charge-discharge electronic circuit and the output end of the second charge-discharge electronic circuit are connected to serve as the output end of the first voltage sampling circuit;

[0013] The control end of the first charge-discharge electronic circuit and the control end of the second charge-discharge electronic circuit serve as the control end of the first voltage sampling circuit.

[0014] Optionally, the first charge-discharge electronic circuit includes: a first switch group, a second switch group and a first sampling capacitor;

[0015] One switch unit in the first switch group is connected between the input terminal of the first charge-discharge electronic circuit and one end of the first sampling capacitor, and another switch unit in the first switch group is connected between the common mode voltage input terminal and the other end of the first sampling capacitor;

[0016] One switch unit in the second switch group is connected between the common-mode voltage input terminal and one end of the first sampling capacitor, and another switch unit in the second switch group is connected between the other end of the first sampling capacitor and the output end of the first charge-discharge electronic circuit;

[0017] The second charge-discharge electronic circuit includes: a third switch group, a fourth switch group and a second sampling capacitor;

[0018] One switch unit in the third switch group is connected between the input terminal of the second charge-discharge electronic circuit and one end of the second sampling capacitor, and another switch unit in the third switch group is connected between the common-mode voltage input terminal and the other end of the second sampling capacitor;

[0019] One switch unit in the fourth switch group is connected between the common-mode voltage input terminal and one end of the second sampling capacitor, and another switch unit in the fourth switch group is connected between the other end of the second sampling capacitor and the output end of the second charge-discharge electronic circuit;

[0020] The first sampling capacitor and the second sampling capacitor are adjustable capacitors. The control end of the first sampling capacitor serves as the control end of the first charge-discharge electronic circuit, and the control end of the second sampling capacitor serves as the control end of the second charge-discharge electronic circuit.

[0021] Optionally, the second voltage sampling circuit includes: a third charge-discharge electronic circuit and a fourth charge-discharge electronic circuit;

[0022] The input end of the third charge-discharge electronic circuit serves as the first input end of the second voltage sampling circuit, the input end of the fourth charge-discharge electronic circuit serves as the second input end of the second voltage sampling circuit, and the output end of the third charge-discharge electronic circuit and the output end of the fourth charge-discharge electronic circuit are connected as the output end of the second voltage sampling circuit;

[0023] The control end of the third charge-discharge electronic circuit and the control end of the fourth charge-discharge electronic circuit serve as the control end of the second voltage sampling circuit.

[0024] Optionally, the third charge-discharge electronic circuit includes: a fifth switch group, a sixth switch group and a third sampling capacitor;

[0025] One switch unit in the fifth switch group is connected between the input terminal of the third charge-discharge electronic circuit and one end of the third sampling capacitor, and another switch unit in the fifth switch group is connected between the common mode voltage input terminal and the other end of the third sampling capacitor;

[0026] One switch unit in the sixth switch group is connected between the common-mode voltage input terminal and one end of the third sampling capacitor, and another switch unit in the sixth switch group is connected between the other end of the third sampling capacitor and the output end of the third charge-discharge electronic circuit;

[0027] The fourth charge-discharge electronic circuit includes: a seventh switch group, an eighth switch group and a fourth sampling capacitor;

[0028] One switch unit in the seventh switch group is connected between the input terminal of the fourth charge-discharge electronic circuit and one end of the fourth sampling capacitor, and another switch unit in the seventh switch group is connected between the common-mode voltage input terminal and the other end of the fourth sampling capacitor;

[0029] One switch unit in the eighth switch group is connected between the common-mode voltage input terminal and one end of the fourth sampling capacitor, and another switch unit in the eighth switch group is connected between the other end of the fourth sampling capacitor and the output end of the fourth charge-discharge electronic circuit;

[0030] The third sampling capacitor and the fourth sampling capacitor are adjustable capacitors. The control end of the third sampling capacitor serves as the control end of the third charge-discharge electronic circuit, and the control end of the fourth sampling capacitor serves as the control end of the fourth charge-discharge electronic circuit.

[0031] Optionally, the first calibration circuit includes: a ninth switch group, a tenth switch group, and a fifth sampling capacitor;

[0032] One switch unit in the ninth switch group is connected between the input terminal of the first calibration circuit and one end of the fifth sampling capacitor, and another switch unit in the ninth switch group is connected between the common mode voltage input terminal and the other end of the fifth sampling capacitor;

[0033] One switch unit in the tenth switch group is connected between the common-mode voltage input terminal and one end of the fifth sampling capacitor, and another switch unit in the tenth switch group is connected between the other end of the fifth sampling capacitor and the output terminal of the first calibration circuit.

[0034] Optionally, the second calibration circuit includes: an eleventh switch group, a twelfth switch group and a sixth sampling capacitor;

[0035] One switch unit in the eleventh switch group is connected between the input terminal of the second calibration circuit and one end of the sixth sampling capacitor, and another switch unit in the eleventh switch group is connected between the common mode voltage input terminal and the other end of the sixth sampling capacitor;

[0036] One switch unit in the twelfth switch group is connected between the common-mode voltage input terminal and one end of the sixth sampling capacitor, and another switch unit in the twelfth switch group is connected between the other end of the sixth sampling capacitor and the output end of the second calibration circuit.

[0037] Optionally, the proportional-integral circuit includes: a first switching capacitor unit, a second switching capacitor unit and an amplifier;

[0038] The first switch capacitor unit is connected between the positive input terminal and the negative output terminal of the amplifier, and the second switch capacitor unit is connected between the negative input terminal and the positive output terminal of the amplifier.

[0039] In a second aspect, an embodiment of the present application further provides a bandgap reference voltage calibration method, which is applied to the bandgap reference circuit according to any one of the first aspects, the method comprising:

[0040] When the bandgap reference voltage source is in a calibration mode, a first integrated voltage and a second integrated voltage are generated by a first voltage sampling circuit and a proportional integral circuit, and a third integrated voltage is generated by a second voltage sampling circuit and the proportional integral circuit;

[0041] generating a first calibration voltage through a first calibration circuit and the proportional-integral circuit, and generating a second calibration voltage through a second calibration circuit and the discharge circuit;

[0042] calculating an output voltage difference based on the first integrated voltage, the second integrated voltage, the third integrated voltage, the first calibration voltage, and the second calibration voltage;

[0043] Outputting a comparison result according to the output voltage difference through a comparison circuit;

[0044] generating, by a control circuit, control signals for the first voltage sampling circuit and the second voltage sampling circuit according to the comparison result and a preset trimming ratio, so as to adjust the positive temperature coefficient and the negative temperature coefficient of the bandgap reference voltage source by adjusting the voltage sampling coefficients of the first voltage sampling circuit and the second voltage sampling circuit;

[0045] After the calibration is completed, the bandgap reference voltage source exits the calibration mode and outputs the bandgap reference voltage in the output mode.

[0046] Optionally, the process of calculating the preset adjustment ratio is as follows:

[0047] Determining a bandgap reference voltage of the bandgap reference voltage source in a current state;

[0048] Adjusting the temperature coefficient of the bandgap reference voltage to determine a first voltage change amount of the positive temperature coefficient and a first voltage change amount of the negative temperature coefficient;

[0049] Adjusting the absolute value of the bandgap reference voltage to determine a second voltage change amount of the positive temperature coefficient and a second voltage change amount of the negative temperature coefficient;

[0050] The preset trim ratio of the bandgap reference voltage source in the current state is determined according to the first voltage change of the positive temperature coefficient, the first voltage change of the negative temperature coefficient, the second voltage change of the positive temperature coefficient, and the second voltage change of the negative temperature coefficient.

[0051] In a third aspect, an embodiment of the present application further provides a chip, which includes the bandgap reference circuit described in any one of the first aspects above, and executes the bandgap reference voltage calibration method described in any one of the second aspects above.

[0052] In a fourth aspect, an embodiment of the present application further provides an electronic device, which includes the chip and functional circuit as described in the third aspect, wherein the chip is connected to the functional circuit to provide a bandgap reference voltage for the functional circuit.

[0053] The beneficial effects of this application are:

[0054] The bandgap reference circuit and bandgap reference voltage calibration method provided in the present application calibrate the sampling voltages of the first voltage sampling circuit and the second voltage sampling circuit based on the calibration voltages generated by the first calibration circuit and the second calibration circuit in a calibration mode. By calibrating both the first voltage sampling circuit and the second voltage sampling circuit, the positive temperature coefficient voltage and the negative temperature coefficient voltage of the bandgap reference voltage source are adjusted, and the absolute value and temperature coefficient of the bandgap reference voltage are calibrated at the same time, so that the bandgap reference voltage is not affected by temperature and process fluctuations. Based on the first calibration circuit, the second calibration circuit, the comparison circuit and the control circuit, no manual intervention is required for calibration, and self-calibration of the bandgap reference voltage source can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 Schematic diagram of the structure of the bandgap reference circuit provided in the embodiment of the present application Figure 1 ;

[0057] Figure 2 Schematic diagram of the structure of the bandgap reference circuit provided in the embodiment of the present application Figure 2 ;

[0058] Figure 3 A circuit schematic diagram of a bandgap reference circuit provided in an embodiment of the present application;

[0059] Figure 4 A circuit schematic diagram of a bandgap reference voltage source in output mode provided by an embodiment of the present application;

[0060] Figure 5 Schematic diagram of the process of the bandgap reference voltage calibration method provided in the embodiment of the present application Figure 1 ;

[0061] Figure 6 A flowchart of the calibration process provided in an embodiment of the present application;

[0062] Figure 7 is a schematic diagram of a circuit for generating voltage;

[0063] Figure 8 Schematic diagram of the process of the bandgap reference voltage calibration method provided in the embodiment of the present application Figure 2 . DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0065] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0066] In addition, the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0067] It should be noted that, in the absence of conflict, the features in the embodiments of this application can be combined with each other.

[0068] Figure 1 Schematic diagram of the structure of the bandgap reference circuit provided in the embodiment of the present application Figure 1 ,like Figure 1 As shown, the bandgap reference circuit includes: a first calibration circuit 10, a second calibration circuit 20, a comparison circuit 30, a control circuit 40 and a bandgap reference voltage source 50; the bandgap reference voltage source 50 includes: a first voltage sampling circuit 501, a second voltage sampling circuit 502 and a proportional integration circuit 503.

[0069] Among them, the first input terminal and the second input terminal of the first voltage sampling circuit 501 are connected to the first voltage input terminal, the output terminal of the first voltage sampling circuit 501 is connected to the positive input terminal of the proportional integration circuit 503, the input terminal of the first calibration circuit 10 is connected to the second voltage input terminal, and the output terminal of the first calibration circuit 10 is connected to the positive input terminal of the proportional integration circuit 503.

[0070] The first input terminal of the second voltage sampling circuit 502 is connected to the preset ground terminal GND, the second input terminal of the second voltage sampling circuit 502 is connected to the second voltage input terminal, the output terminal of the second voltage sampling circuit 502 is connected to the negative input terminal of the proportional integration circuit 503, the input terminal of the second calibration circuit 20 is connected to the first voltage input terminal, and the output terminal of the second calibration circuit 20 is connected to the negative input terminal of the proportional integration circuit 503.

[0071] The positive output terminal and the negative output terminal of the proportional integral circuit 503 are respectively connected to the two input terminals of the comparison circuit 30, the output terminal of the comparison circuit 30 is connected to the input terminal of the control circuit 40, and the output terminal of the control circuit 40 is connected to the control terminals of the first voltage sampling circuit 501 and the second voltage sampling circuit 502.

[0072] In this embodiment, the first input terminal of the first voltage sampling circuit 501 is connected to the first voltage input terminal for sampling the first input voltage VEB1. The first input terminal of the first voltage sampling circuit 501 has a first sampling coefficient. According to the first sampling coefficient, the first voltage sampling circuit 501 samples the first input voltage VEB1 to obtain a first sampled voltage.

[0073] The second input terminal of the first voltage sampling circuit 501 is connected to the first voltage input terminal for sampling the first input voltage VEB1. The second input terminal of the first voltage sampling circuit 501 has a second sampling coefficient. According to the second sampling coefficient, the first voltage sampling circuit 501 samples the first input voltage VEB1 to obtain a second sampled voltage.

[0074] An input terminal of the first calibration circuit 10 is connected to the second voltage input terminal, and is used to obtain a second input voltage VEB2 and generate a second calibration voltage.

[0075] The output end of the first voltage sampling circuit 501 and the output end of the first calibration circuit 10 are both connected to the positive input end of the proportional integration circuit 503. The proportional integration circuit 503 performs proportional integration on the first sampling voltage and the second sampling voltage to generate a first output voltage. At the same time, the proportional integration circuit 503 also performs proportional integration on the second calibration voltage to generate a second output calibration voltage.

[0076] Similarly, the second input terminal of the second voltage sampling circuit 502 is connected to the second voltage input terminal for sampling the second input voltage VEB2. The second input terminal of the second voltage sampling circuit 502 has a second sampling coefficient. Based on the second sampling coefficient, the second voltage sampling circuit 502 samples the second input voltage VEB2 to obtain a third sampled voltage. In addition, the first output terminal of the second voltage sampling circuit 502 also has the first sampling coefficient.

[0077] An input terminal of the second calibration circuit 20 is connected to the first voltage input terminal, and is used to obtain a first input voltage VBE1 and generate a first calibration voltage.

[0078] The output end of the second voltage sampling circuit 502 and the output end of the second calibration circuit 20 are both connected to the negative input end of the proportional integration circuit 503. The proportional integration circuit 503 performs proportional integration on the third sampling voltage to generate a second output voltage. At the same time, the proportional integration circuit 503 also performs proportional integration on the first calibration voltage to generate a first output calibration voltage.

[0079] A calibration reference voltage is obtained based on the first output calibration voltage and the second output calibration voltage. The output voltage of the bandgap reference voltage source is calculated based on the difference between the first output voltage and the second output voltage. The output voltage difference is calculated based on the output voltage and the calibration reference voltage as the input voltage of the comparison circuit. The comparison circuit determines the output level based on the magnitude of the output voltage difference.

[0080] Among them, if the output voltage is greater than the calibration reference voltage, that is, the output voltage difference is greater than 0, the comparison circuit outputs a high level, and the control circuit generates control signals for the first voltage sampling circuit 501 and the second voltage sampling circuit 502 respectively according to the high-level signal. The control signal lowers the voltage sampling coefficients of the first voltage sampling circuit 501 and the second voltage sampling circuit 502 according to the preset adjustment ratio, that is, lowers the first sampling coefficient and the second sampling coefficient.

[0081] If the output voltage is less than the calibration reference voltage, that is, the output voltage difference is less than 0, the comparison circuit outputs a low level, and the control circuit generates control signals for the first voltage sampling circuit 501 and the second voltage sampling circuit 502 respectively according to the low level signal. The control signals increase the voltage sampling coefficients of the first voltage sampling circuit 501 and the second voltage sampling circuit 502 according to a preset adjustment ratio, that is, increase the first sampling coefficient and the second sampling coefficient.

[0082] The preset adjustment ratio is the ratio of the change in the PTAT voltage of the bandgap reference voltage source to the change in the CTAT voltage. By adjusting the voltage sampling coefficients of the first voltage sampling circuit 501 and the second voltage sampling circuit 502, the positive temperature coefficient and the negative temperature coefficient of the bandgap reference voltage source are actually adjusted, thereby achieving adjustment of the PTAT voltage and the CTAT voltage of the bandgap reference voltage source, thereby simultaneously adjusting the absolute value and the temperature coefficient of the bandgap reference voltage.

[0083] In one possible implementation, Figure 2 Schematic diagram of the structure of the bandgap reference circuit provided in the embodiment of the present application Figure 2 ,like Figure 2 As shown, the first voltage sampling circuit 501 includes: a first charge-discharge electronic circuit 511 and a second charge-discharge electronic circuit 512 .

[0084] The input end of the first charge-discharge electronic circuit 511 serves as the first input end of the first voltage sampling circuit 501, the input end of the second charge-discharge electronic circuit 512 serves as the second input end of the first voltage sampling circuit 501, the output end of the first charge-discharge electronic circuit 511 and the output end of the second charge-discharge electronic circuit 512 are connected as the output end of the first voltage sampling circuit 501; the control end of the first charge-discharge electronic circuit 511 and the control end of the second charge-discharge electronic circuit 512 serve as the control end of the first voltage sampling circuit 501.

[0085] In this embodiment, the first charge-discharge electronic circuit 511 has a first sampling coefficient. The input of the first charge-discharge electronic circuit 511 is connected to the first voltage input. During the charging process of the first charge-discharge electronic circuit 511, the first input voltage VEB1 is sampled to obtain a first sampled voltage. The output of the first charge-discharge electronic circuit 511 is connected to the proportional-integrator circuit 503. During the discharging process of the first charge-discharge electronic circuit 511, the proportional-integrator circuit 503 integrates the first sampled voltage to obtain a first integrated voltage.

[0086] The second electronic charge / discharge circuit 512 has a second sampling coefficient. The input of the second electronic charge / discharge circuit 512 is connected to the first voltage input. During charging, the second electronic charge / discharge circuit 512 samples the first input voltage VEB1 to obtain a second sampled voltage. The output of the second electronic charge / discharge circuit 512 is connected to the proportional-integrator circuit 503. During discharging, the proportional-integrator circuit 503 integrates the second sampled voltage to obtain a second integrated voltage. The proportional-integrator circuit 503 outputs a first output voltage based on the first and second integrated voltages.

[0087] In one possible implementation, Figure 2As shown, the second voltage sampling circuit 502 includes: a third charge-discharge electronic circuit 521 and a fourth charge-discharge electronic circuit 522 .

[0088] The input end of the third charge-discharge electronic circuit 521 serves as the first input end of the second voltage sampling circuit 502, the input end of the fourth charge-discharge electronic circuit 522 serves as the second input end of the second voltage sampling circuit 502, the output end of the third charge-discharge electronic circuit 521 and the output end of the fourth charge-discharge electronic circuit 522 are connected as the output end of the second voltage sampling circuit 502; the control end of the third charge-discharge electronic circuit 521 and the control end of the fourth charge-discharge electronic circuit 522 serve as the control end of the second voltage sampling circuit.

[0089] In this embodiment, the third charge-discharge electronic circuit 521 has a first sampling coefficient, and an input terminal of the third charge-discharge electronic circuit 521 is grounded GND.

[0090] The fourth charge-discharge electronic circuit 522 has a second sampling coefficient. The input of the fourth charge-discharge electronic circuit 522 is connected to the second voltage input. During the charging process of the fourth charge-discharge electronic circuit 522, the second input voltage VEB2 is sampled to obtain a third sampled voltage. The output of the fourth charge-discharge electronic circuit 522 is connected to the proportional-integrator circuit 503. During the discharging process of the fourth charge-discharge electronic circuit 522, the proportional-integrator circuit 503 integrates the third sampled voltage to output a second output voltage.

[0091] Furthermore, if Figure 2 As shown, the first calibration circuit 10 includes: a fifth charge and discharge electronic circuit 101, the input end of the fifth charge and discharge electronic circuit 101 serves as the input end of the first calibration circuit 10, connected to the second voltage input end, and the output end of the fifth charge and discharge electronic circuit 101 serves as the output end of the first calibration circuit 10, connected to the positive input end of the proportional integral circuit 503.

[0092] During the charging process of the fifth charge-discharge electronic circuit 101, a second calibration voltage is generated according to the second input voltage VEB2. During the discharging process of the fifth charge-discharge electronic circuit 101, the proportional-integral circuit 503 integrates the second calibration voltage to generate a second output calibration voltage.

[0093] Furthermore, if Figure 2 As shown, the second calibration circuit 20 includes: a sixth charge and discharge electronic circuit 201, the input end of the sixth charge and discharge electronic circuit 201 serves as the input end of the second calibration circuit 20, connected to the first voltage input end, and the output end of the sixth charge and discharge electronic circuit 201 serves as the output end of the second calibration circuit 20, connected to the negative input end of the proportional integral circuit 503.

[0094] During the charging process of the sixth charge-discharge electronic circuit 201 , a first calibration voltage is generated according to the first input voltage VEB1 . During the discharging process of the sixth charge-discharge electronic circuit 201 , the proportional-integral circuit 503 integrates the first calibration voltage to generate a first output calibration voltage.

[0095] In one possible implementation, Figure 3 The circuit schematic diagram of the bandgap reference circuit provided in the embodiment of the present application is as follows: Figure 3 As shown, the first charge and discharge electronic circuit 511 includes: a first switch group, a second switch group and a first sampling capacitor C S11 .

[0096] A switch unit S11 in the first switch group is connected to the input end of the first charge and discharge electronic circuit 511 and the first sampling capacitor C S11 Another switch unit S12 in the first switch group is connected between the common mode voltage input terminal VCM and the first sampling capacitor C S11 between the other ends.

[0097] A switch unit S21 in the second switch group is connected to the common mode voltage input terminal VCM and the first sampling capacitor C S11 Another switch unit S22 in the second switch group is connected to the first sampling capacitor C S11 between the other end and the output end of the first charging and discharging electronic circuit 511.

[0098] The second charge and discharge electronic circuit 512 includes: a third switch group, a fourth switch group and a second sampling capacitor C S21 .

[0099] A switch unit S13 in the third switch group is connected to the input end of the second charge and discharge electronic circuit 512 and the second sampling capacitor C S21 Another switch S14 unit in the third switch group is connected between the common mode voltage input terminal VCM and the second sampling capacitor C S21 between the other ends.

[0100] A switch unit S23 in the fourth switch group is connected between the common mode voltage input terminal VCM and the second sampling capacitor C S21 Another switch unit S24 in the fourth switch group is connected to the second sampling capacitor C S21 between the other end and the output end of the second charge and discharge electronic circuit 512.

[0101] The first sampling capacitor C S11 and the second sampling capacitor C S21 is an adjustable capacitor, the first sampling capacitor C S11The control end of the first charge and discharge electronic circuit 511 is used as the control end of the second sampling capacitor C S21 The control end of serves as the control end of the second charging and discharging electronic circuit 512.

[0102] In this embodiment, when the switch units S1n in each switch group are closed at the same time and the switch units S2n are opened at the same time, the first voltage input terminal and the first sampling capacitor C S11 A first charging loop is formed between the common mode voltage input terminal and the first sampling capacitor C S11 To charge, the first voltage input terminal and the second sampling capacitor C S21 A second charging loop is formed between the common mode voltage input terminal and the second sampling capacitor C S21 Charge.

[0103] When the switch units S1n in each switch group are disconnected at the same time and the switch units S2n are closed at the same time, the common mode voltage input terminal and the first sampling capacitor C S11 A first discharge loop is formed between the positive input terminal of the proportional-integral circuit 503 and the first sampling capacitor C S11 Discharge, common mode voltage input terminal, second sampling capacitor C S21 A second discharge loop is formed between the positive input terminal of the proportional-integral circuit 503 and the second sampling capacitor C S21 discharge.

[0104] The control circuit adjusts the first sampling capacitor C S11 and the second sampling capacitor C S21 The capacitance value is set to adjust the sampling coefficient.

[0105] Furthermore, if Figure 3 As shown, the third charge and discharge electronic circuit 521 includes: a fifth switch group, a sixth switch group and a third sampling capacitor C S12 .

[0106] A switch unit S15 in the fifth switch group is connected between the input end of the third charge and discharge electronic circuit 521 and the third sampling capacitor C S12 Another switch unit S16 in the fifth switch group is connected between the common mode voltage input terminal VCM and the third sampling capacitor C S12 between the other ends.

[0107] A switch unit S25 in the sixth switch group is connected between the common mode voltage input terminal VCM and the third sampling capacitor C S12 Another switch unit S26 in the sixth switch group is connected to the third sampling capacitor C S12 between the other end and the output end of the third charging and discharging electronic circuit 521.

[0108] The fourth charge-discharge electronic circuit 522 includes: a seventh switch group, an eighth switch group and a fourth sampling capacitor C S22 .

[0109] A switch unit S17 in the seventh switch group is connected between the input end of the fourth charge-discharge electronic circuit 522 and the fourth sampling capacitor C S22 Another switch unit S18 in the seventh switch group is connected between the common mode voltage input terminal VCM and the fourth sampling capacitor C S22 between the other ends.

[0110] A switch unit S27 in the eighth switch group is connected between the common mode voltage input terminal and the fourth sampling capacitor C S22 Another switch unit S28 in the eighth switch group is connected to the fourth sampling capacitor C S22 between the other end and the output end of the fourth charge and discharge electronic circuit 522.

[0111] The third sampling capacitor C S12 and the fourth sampling capacitor C S22 is an adjustable capacitor, the third sampling capacitor C S12 The control end of the third charge and discharge electronic circuit 521 is used as the control end of the fourth sampling capacitor C S22 The control end of serves as the control end of the fourth charge-discharge electronic circuit 522.

[0112] In this embodiment, when the switch units S1n in each switch group are closed at the same time and the switch units S2n are opened at the same time, the second voltage input terminal and the fourth sampling capacitor C S22 A third charging loop is formed between the common mode voltage input terminal and the fourth sampling capacitor C S22 Charge.

[0113] When the switch units S1n in each switch group are disconnected at the same time and the switch units S2n are closed at the same time, the common mode voltage input terminal and the fourth sampling capacitor C S22 A third discharge loop is formed between the negative input terminal of the proportional integral circuit 503 and the fourth sampling capacitor C S22 discharge.

[0114] The control circuit adjusts the third sampling capacitor C S12 and the fourth sampling capacitor C S22 The capacitance value is set to adjust the sampling coefficient.

[0115] Furthermore, if Figure 3 As shown, the first calibration circuit 10 includes: a ninth switch group, a tenth switch group and a fifth sampling capacitor C S31 .

[0116] A switch unit S11′ in the ninth switch group is connected to the input terminal of the first calibration circuit 10 and the fifth sampling capacitor C S31 Another switch unit S12′ in the ninth switch group is connected between the common mode voltage input terminal VCM and the fifth sampling capacitor C S31 between the other ends.

[0117] A switch unit S21′ in the tenth switch group is connected between the common mode voltage input terminal VCM and the fifth sampling capacitor C S31 Another switch unit S22′ of the tenth switch group is connected to the fifth sampling capacitor C S31 between the other end of the first calibration circuit 10 and the output end of the first calibration circuit 10.

[0118] In this embodiment, when the switch units S1n in each switch group are closed at the same time and the switch units S2n are opened at the same time, the second voltage input terminal and the fifth sampling capacitor C S31 A fifth charging loop is formed between the common mode voltage input terminal and the fifth sampling capacitor C S31 Charge.

[0119] When the switch units S1n in each switch group are disconnected at the same time and the switch units S2n are closed at the same time, the common mode voltage input terminal and the fifth sampling capacitor C S31 A fifth discharge loop is formed between the positive input terminal of the proportional-integral circuit 503 and the fifth sampling capacitor C S31 discharge.

[0120] Furthermore, if Figure 3 As shown, the second calibration circuit 20 includes: an eleventh switch group, a twelfth switch group and a sixth sampling capacitor C S32 .

[0121] A switch unit S13′ in the eleventh switch group is connected to the input end of the second calibration circuit 20 and the sixth sampling capacitor C S32 Another switch unit S14′ in the eleventh switch group is connected between the common mode voltage input terminal VCM and the sixth sampling capacitor C S32 between the other ends.

[0122] A switch unit S23′ in the twelfth switch group is connected to the common mode voltage input terminal VCM and the sixth sampling capacitor C S32 Another switch unit S24′ of the twelfth switch group is connected to the sixth sampling capacitor C S32 between the other end of the calibration circuit and the output end of the second calibration circuit 20.

[0123] In this embodiment, when the switch units S1n' in each switch group are closed at the same time and the switch units S2n' are opened at the same time, the first voltage input terminal and the sixth sampling capacitor C S32 A sixth charging loop is formed between the common mode voltage input terminal and the sixth sampling capacitor C S32 Charge.

[0124] When the switch units S1n' in each switch group are disconnected at the same time and the switch units S2n' are closed at the same time, the common mode voltage input terminal and the sixth sampling capacitor C S32 A sixth discharge loop is formed between the negative input terminal of the proportional-integral circuit 503 and the sixth sampling capacitor C S32 discharge.

[0125] Furthermore, if Figure 3 As shown, the proportional-integral circuit 503 includes: a first switching capacitor unit, a second switching capacitor unit and an amplifier.

[0126] The first switch capacitor unit is connected between the positive input terminal and the negative output terminal of the amplifier, and the second switch capacitor unit is connected between the negative input terminal and the positive output terminal of the amplifier.

[0127] In this embodiment, the first switch capacitor unit includes: a first switch unit S I1 and the first integrating capacitor C I1 , the first switch unit S I1 and the first integrating capacitor C I1 The second switch capacitor unit is connected in parallel between the positive input terminal and the negative output terminal of the amplifier, and includes: a second switch unit S I2 and the second integrating capacitor C I2 , the second switch unit S I2 and the second integrating capacitor C I2 Connected in parallel between the negative input and positive output of the amplifier.

[0128] When the switch units S1n and S1n' in each switch group are closed, the first switch unit S I1 and the second switch unit S I2 Also closed, the first integrating capacitor C I1 and the second integrating capacitor C I2 The charge on the first switch unit S1n is cleared, and when the switch units S1n and S1n' in each switch group are disconnected, the first switch unit S1n is disconnected. I1 and the second switch unit S I2 The sampling capacitors in each charging and discharging electronic circuit are discharged, and the charge is transferred to the first integrating capacitor C I1 and the second integrating capacitor C I2 , to integrate the sampling voltage of each sampling capacitor.

[0129] Figure 3 The bandgap reference circuit shown is a circuit schematic diagram of a bandgap reference voltage source operating in calibration mode, for example. Figure 4 The circuit schematic diagram of the bandgap reference voltage source in the output mode provided by the embodiment of the present application is as follows: Figure 4 As shown, when the bandgap reference voltage source exits the calibration mode and enters the output mode, ie, the working mode, the first calibration circuit, the second calibration circuit, the comparison circuit, and the control circuit no longer participate in the calibration and control of the bandgap reference voltage source.

[0130] Among them, the calibration mode can be triggered under preset conditions or timed triggering. The triggering under preset conditions can be, for example, triggered when the chip where the bandgap reference circuit is located is powered on or when the working environment fluctuates greatly. The timed triggering can be, for example, triggered by using a clock signal. This embodiment does not impose any restrictions on this.

[0131] The bandgap reference circuit provided in the above embodiment calibrates the sampling voltages of the first voltage sampling circuit and the second voltage sampling circuit in a calibration mode based on the calibration voltages generated by the first calibration circuit and the second calibration circuit. By calibrating both the first voltage sampling circuit and the second voltage sampling circuit, the positive temperature coefficient voltage and the negative temperature coefficient voltage of the bandgap reference voltage source are adjusted, and the absolute value and temperature coefficient of the bandgap reference voltage are calibrated at the same time, so that the bandgap reference voltage is not affected by temperature and process fluctuations. Based on the first calibration circuit, the second calibration circuit, the comparison circuit, and the control circuit, self-calibration of the bandgap reference voltage source can be achieved without manual intervention in the calibration.

[0132] In a possible implementation, the embodiment of the present application further provides a bandgap reference voltage calibration method, which is applied to the above-mentioned bandgap reference voltage. Figure 5 Schematic diagram of the process of the bandgap reference voltage calibration method provided in the embodiment of the present application Figure 1 ,like Figure 5 As shown, the method may include:

[0133] S101 : When a bandgap reference voltage source is in a calibration mode, a first integrated voltage and a second integrated voltage are generated by a first voltage sampling circuit and a proportional integral circuit, and a third integrated voltage is generated by a second voltage sampling circuit and a proportional integral circuit.

[0134] S102 : Generate a first calibration voltage through a first calibration circuit and a proportional-integral circuit, and generate a second calibration voltage through a second calibration circuit and a discharge circuit.

[0135] S103: Calculating an output voltage difference according to the first integrated voltage, the second integrated voltage, the third integrated voltage, the first calibration voltage, and the second calibration voltage.

[0136] S104: Outputting a comparison result according to the output voltage difference through the comparison circuit.

[0137] S105: Generate control signals for the first voltage sampling circuit and the second voltage sampling circuit according to the comparison result and the preset adjustment ratio through the control circuit, so as to adjust the positive temperature coefficient and the negative temperature coefficient of the bandgap reference voltage source by adjusting the voltage sampling coefficients of the first voltage sampling circuit and the second voltage sampling circuit.

[0138] S106: After the calibration is completed, the bandgap reference voltage source exits the calibration mode and outputs the bandgap reference voltage in the output mode.

[0139] In this embodiment, if Figure 1 As shown, when the bandgap reference voltage source is in the calibration mode, the first voltage sampling circuit samples the first input voltage VEB1 according to the first sampling coefficient to obtain a first sampled voltage. The first voltage sampling circuit also samples the first input voltage VEB1 according to the second sampling coefficient to obtain a second sampled voltage. The first sampled voltage is integrated by the proportional integration circuit to obtain a first integrated voltage. The second sampled voltage is integrated by the proportional integration circuit to obtain a second integrated voltage. The proportional integration circuit outputs a first output voltage VOUT1 according to the first integrated voltage and the second integrated voltage.

[0140] The second voltage sampling circuit samples the second input voltage VEB2 according to the second sampling coefficient to obtain a third sampling voltage. The third sampling voltage is integrated by the proportional integration circuit to obtain a third integrated voltage. The proportional integration circuit outputs a second output voltage VOUT2 according to the third integrated voltage.

[0141] The first calibration circuit generates a second calibration voltage based on the second input voltage VEB2, and the proportional-integral circuit also performs proportional integration on the second calibration voltage to generate a second output calibration voltage; the second calibration circuit generates a first calibration voltage based on the first input voltage VBE1, and the proportional-integral circuit also performs proportional integration on the first calibration voltage to generate a first output calibration voltage.

[0142] A calibration reference voltage is obtained based on the first output calibration voltage and the second output calibration voltage. The output voltage of the bandgap reference voltage source is determined based on the difference between the first output voltage VOUT1 and the second output voltage VOUT2. The output voltage difference is calculated based on the output voltage and the calibration reference voltage as the input voltage of the comparison circuit. The comparison circuit determines the output level based on the magnitude of the output voltage difference.

[0143] Among them, if the output voltage is greater than the calibration reference voltage, that is, the output voltage difference is greater than 0, the comparison circuit outputs a high level, and the control circuit generates control signals for the first voltage sampling circuit and the second voltage sampling circuit respectively according to the high-level signal. The control signal lowers the voltage sampling coefficients of the first voltage sampling circuit and the second voltage sampling circuit according to a preset adjustment ratio, that is, lowers the first sampling coefficient and the second sampling coefficient.

[0144] If the output voltage is less than the calibration reference voltage, that is, the output voltage difference is less than 0, the comparison circuit outputs a low level, and the control circuit generates control signals for the first voltage sampling circuit and the second voltage sampling circuit respectively according to the low level signal. The control signals increase the voltage sampling coefficients of the first voltage sampling circuit and the second voltage sampling circuit according to a preset adjustment ratio, that is, increase the first sampling coefficient and the second sampling coefficient.

[0145] Among them, the preset adjustment ratio is the ratio of the change in the PTAT voltage of the bandgap reference voltage source to the change in the CTAT voltage. By adjusting the voltage sampling coefficients of the first voltage sampling circuit and the second sampling voltage, what is actually adjusted is the positive temperature coefficient and the negative temperature coefficient of the bandgap reference voltage source, thereby achieving the adjustment of the PTAT voltage and the CTAT voltage of the bandgap reference voltage source, so as to simultaneously adjust the absolute value and temperature coefficient of the bandgap reference voltage.

[0146] For example, Figure 6 The calibration flow chart provided in the embodiment of the present application is as follows: Figure 6 As shown, set the preset calibration times. After the calibration is triggered, the calibration times are cleared. During a calibration process, each time a calibration is performed, the calibration times are increased by 1, and the calibration times are compared with the preset calibration times. If the calibration times are less than the preset calibration times, continue to perform the above process for calibration. If the calibration times are greater than or equal to the preset calibration times, exit the calibration mode and switch to the output mode.

[0147] The following combination Figure 3 、 Figure 4 The specific working principle of the bandgap reference circuit in calibration mode and output mode is explained.

[0148] For a general bandgap reference voltage, its expression is:

[0149] VREF=VBE+k*ΔVBE (1)

[0150] Wherein, VBE is the CTAT voltage, ΔVBE is the PTAT voltage, and the prior art adjusts the absolute value or temperature drift of the bandgap reference voltage by adjusting the coefficient k of the PTAT voltage.

[0151] Figure 7 is a circuit schematic diagram for generating voltage, such as Figure 7As shown, the area ratio of Q2 and Q1 is SQ2:SQ1=N1, I1:I2=N2.

[0152] In calibration mode, if Figure 3 As shown, first, the switch units S1n, S1n' and the first switch unit S1n in each switch group are I1 and the second switch unit S I2 At the same time, the switch units S2n and S2n' in each switch group are opened at the same time, and the first integral capacitor C I1 and the second integrating capacitor C I2 The charge on the capacitors is cleared, and each sampling capacitor is charged. Then, the switch units S1n, S1n' and the first switch unit S1n in each switch group are charged. I1 and the second switch unit S I2 At the same time, the switch units S2n and S2n' in each switch group are closed at the same time, and the charges stored on each sampling capacitor are transferred to the first integrating capacitor C I1 and the second integrating capacitor C I2 Transfer is performed, and according to the charge conservation law, the output voltage is:

[0153]

[0154] Among them, VBE1 is the CTAT voltage, ΔVBE=VBE1-VBE2 is the PTAT voltage, where This is the coefficient k of the PTAT voltage.

[0155] Since ΔVBE is not sensitive to temperature and process fluctuations, it can be used as a reference source for calibrating the absolute value of the bandgap reference voltage. A standard calibration reference voltage is constructed using ΔVBE, so CS3 meets the following conditions:

[0156]

[0157] Then, the input voltage of the comparison circuit can be:

[0158]

[0159] When the comparison circuit outputs a high level, the control circuit adjusts C according to the preset adjustment ratio. S11 、C S12 and C S21 、C S22 When the comparison circuit outputs a low level, the control circuit adjusts the C S11 、C S12 and C S21 、C S22 Increase proportionally.

[0160] Among them, the first sampling capacitor C S11 and the third sampling capacitor C S12 The capacitance values ​​are equal, both are C S1 , the second sampling capacitor C S21 and the fourth sampling capacitor C S22 The capacitance values ​​are equal, both are C S2 , the fifth sampling capacitor CS 31 and the sixth sampling capacitor C S32 The capacitance values ​​are equal, both are C S3 , the first integrating capacitor C I1 and the second integrating capacitor C I2 The capacitance values ​​are equal, both are C I .

[0161] After completing the calibration, the calibration mode can be switched to the output mode. Figure 4 As shown, the process of output mode is as follows:

[0162] First, the switch units S1n and the first switch unit S1n in each switch group I1 and the second switch unit S I2 At the same time, the switch units S2n in each switch group are opened at the same time, and the first sampling capacitor C S11 , the second sampling capacitor CS21 , the third sampling capacitor C S12 and the fourth sampling capacitor C S22 Charging, taking VOUT1 as an example:

[0163] Q1=(VCM-VBE1)C S1 +(VCM-VBE1)C S2 (5)

[0164] Secondly, the switch units S1n and the first switch unit S1n in each switch group I1 and the second switch unit S I2 At the same time, the switch units S2n in each switch group are closed at the same time to redistribute the charge:

[0165] (VCM-VBE1)C S1 +(VCM-VBE1)C S2 =(VCM-VOUT1)C I (6)

[0166]

[0167] Similarly, VOUT2 is:

[0168]

[0169] The final output voltage is:

[0170]

[0171] By adjusting CS1 and CS2 through the above adjustment process, the CTAT voltage VBE1 and the PTAT voltage ΔVBE are adjusted.

[0172] The bandgap reference voltage calibration method provided in the above embodiment calibrates the sampling voltages of the first voltage sampling circuit and the second voltage sampling circuit in a calibration mode based on the calibration voltages generated by the first calibration circuit and the second calibration circuit. By calibrating both the first voltage sampling circuit and the second voltage sampling circuit, the positive temperature coefficient voltage and the negative temperature coefficient voltage of the bandgap reference voltage source are adjusted, and the absolute value and temperature coefficient of the bandgap reference voltage are calibrated at the same time, so that the bandgap reference voltage is not affected by temperature and process fluctuations. Based on the first calibration circuit, the second calibration circuit, the comparison circuit, and the control circuit, self-calibration of the bandgap reference voltage source can be achieved without manual intervention in the calibration.

[0173] Figure 8 Schematic diagram of the process of the bandgap reference voltage calibration method provided in the embodiment of the present application Figure 2 ,like Figure 8 As shown in the figure, the process of calculating the preset adjustment ratio is:

[0174] S201: Determine a bandgap reference voltage of a bandgap reference voltage source in a current state.

[0175] S202: Adjust the temperature coefficient of the bandgap reference voltage to determine a first voltage change amount of a positive temperature coefficient and a first voltage change amount of a negative temperature coefficient.

[0176] S203: Adjust the absolute value of the bandgap reference voltage to determine a second voltage change amount with a positive temperature coefficient and a second voltage change amount with a negative temperature coefficient.

[0177] S204 : Determine a preset trimming ratio of the bandgap reference voltage source in a current state according to the first voltage variation of the positive temperature coefficient, the first voltage variation of the negative temperature coefficient, the second voltage variation of the positive temperature coefficient, and the second voltage variation of the negative temperature coefficient.

[0178] In this embodiment, according to the BSIM model, it can be obtained that:

[0179]

[0180] Among them, η F is the forward emission coefficient of the transistor, I E is the collector current, β Fis the common emitter current gain, I S is the reverse saturation current of the transistor. S0 ,η F0 and β F0 , respectively I S ,η F and β F Value under TT process angle; as well as It is related to the selected process and is insensitive to temperature and process angle; σ changes with different process angles; T r is the reference temperature, and Xti is the temperature index of the reverse saturation current. G (T) Band gap energy V at temperature T T (T) Thermovoltage at temperature T.

[0181] If we assume that the output voltage at the TT process angle is:

[0182] VREF=VBE+k*ΔVBE (13)

[0183] Then, by using the bandgap reference voltage to find the partial derivative of the process angle σ, we can finally get the bandgap reference voltage with process fluctuations:

[0184]

[0185] The VBE1 and ΔVBE mentioned above are the values ​​at the TT process angle, and Δσ is the change of σ relative to σ at the TT process angle. F greater than 0, To be greater than Therefore, it can be analyzed that is a PTAT voltage.

[0186] Furthermore, in order to take into account the absolute value and temperature coefficient of the bandgap reference voltage, both the PTAT voltage and the CTAT voltage need to be adjusted. The above formula (25) can be expressed as:

[0187]

[0188] After trimming with the temperature coefficient as the target:

[0189] VREF 2，TC = VREF2 + k3 * ΔVBE + t1 * VBE (27)

[0190] At this time, VREF 2，TC The temperature derivative needs to be zero, that is:

[0191] VREF2'+k3*ΔVBE'+t1*VBE'=0 (28)

[0192] Wherein, k3 represents the change in PTAT voltage when the temperature coefficient is trimmed, and t1 represents the change in CTAT voltage when the temperature coefficient is trimmed.

[0193] After adjusting with absolute value as target:

[0194] VREF 2,value = VREF2 + k4 * ΔVBE + t2 * VBE (29)

[0195] At this time, VREF 2,value It needs to be equal to VREF under the TT angle, that is:

[0196] VREF2+k4*ΔVBE+t2*VBE-VBE-k*ΔVBE=0 (30)

[0197] Here, k4 represents the change in the PTAT voltage when the absolute value is trimmed, and t2 represents the change in the CTAT voltage when the absolute value is trimmed.

[0198] To take both absolute value and temperature drift into account during adjustment, the following conditions must be met:

[0199] k3=k4 (31)

[0200] t1=t2 (32)

[0201] Combining the formula in the BMIS model, we can get:

[0202]

[0203] t1=t2=k ηF Δσ (34)

[0204] From the above formula, we can get the preset adjustment ratio:

[0205]

[0206] When the process is selected, k, η F and k Is Insensitive to temperature and process angle, N1 and N2 are not sensitive to temperature and process, due to β F In advanced processes, the ratio of the two voltages is weakly correlated with process and temperature, so while the temperature fluctuation is small, it can be seen that by proportionally adjusting the PTAT and CTAT voltages, both the absolute value and the temperature coefficient of the bandgap reference voltage can be adjusted.

[0207] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited to them. Any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A bandgap reference circuit, characterized in that: The bandgap reference circuit includes: a first calibration circuit, a second calibration circuit, a comparison circuit, a control circuit and a bandgap reference voltage source; the bandgap reference voltage source includes: a first voltage sampling circuit, a second voltage sampling circuit and a proportional integration circuit; The first input terminal and the second input terminal of the first voltage sampling circuit are connected to the first voltage input terminal, the output terminal of the first voltage sampling circuit is connected to the positive input terminal of the proportional integration circuit, the input terminal of the first calibration circuit is connected to the second voltage input terminal, and the output terminal of the first calibration circuit is connected to the positive input terminal of the proportional integration circuit; A first input terminal of the second voltage sampling circuit is connected to a preset ground terminal, a second input terminal of the second voltage sampling circuit is connected to the second voltage input terminal, an output terminal of the second voltage sampling circuit is connected to the negative input terminal of the proportional-integral circuit, an input terminal of the second calibration circuit is connected to the first voltage input terminal, and an output terminal of the second calibration circuit is connected to the negative input terminal of the proportional-integral circuit; The positive output terminal and the negative output terminal of the proportional-integral circuit are respectively connected to the two input terminals of the comparison circuit, the output terminal of the comparison circuit is connected to the input terminal of the control circuit, and the output terminal of the control circuit is connected to the control terminals of the first voltage sampling circuit and the second voltage sampling circuit, so as to adjust the first sampling coefficient of the first voltage sampling circuit and the second sampling coefficient of the second voltage sampling circuit according to the comparison result of the comparison circuit and a preset adjustment ratio; Among them, the first input voltage of the first voltage input terminal is the base-emitter voltage generated in the first transistor according to the first current, the second input voltage of the second voltage input terminal is the base-emitter voltage generated in the second transistor according to the second current, the area ratio of the second transistor to the first transistor is N1, and the ratio of the first current to the second current is N2.

2. The bandgap reference circuit according to claim 1, wherein: The first voltage sampling circuit includes: a first charge-discharge electronic circuit and a second charge-discharge electronic circuit; The input end of the first charge-discharge electronic circuit serves as the first input end of the first voltage sampling circuit, the input end of the second charge-discharge electronic circuit serves as the second input end of the first voltage sampling circuit, and the output end of the first charge-discharge electronic circuit and the output end of the second charge-discharge electronic circuit are connected to serve as the output end of the first voltage sampling circuit; The control end of the first charge-discharge electronic circuit and the control end of the second charge-discharge electronic circuit serve as the control end of the first voltage sampling circuit.

3. The bandgap reference circuit according to claim 2, wherein: The first charge-discharge electronic circuit includes: a first switch group, a second switch group and a first sampling capacitor; One switch unit in the first switch group is connected between the input terminal of the first charge-discharge electronic circuit and one end of the first sampling capacitor, and another switch unit in the first switch group is connected between the common mode voltage input terminal and the other end of the first sampling capacitor; One switch unit in the second switch group is connected between the common-mode voltage input terminal and one end of the first sampling capacitor, and another switch unit in the second switch group is connected between the other end of the first sampling capacitor and the output end of the first charge-discharge electronic circuit; The second charge-discharge electronic circuit includes: a third switch group, a fourth switch group and a second sampling capacitor; One switch unit in the third switch group is connected between the input terminal of the second charge-discharge electronic circuit and one end of the second sampling capacitor, and another switch unit in the third switch group is connected between the common-mode voltage input terminal and the other end of the second sampling capacitor; One switch unit in the fourth switch group is connected between the common-mode voltage input terminal and one end of the second sampling capacitor, and another switch unit in the fourth switch group is connected between the other end of the second sampling capacitor and the output end of the second charge-discharge electronic circuit; The first sampling capacitor and the second sampling capacitor are adjustable capacitors. The control end of the first sampling capacitor serves as the control end of the first charge-discharge electronic circuit, and the control end of the second sampling capacitor serves as the control end of the second charge-discharge electronic circuit.

4. The bandgap reference circuit according to claim 1, wherein: The second voltage sampling circuit includes: a third charge-discharge electronic circuit and a fourth charge-discharge electronic circuit; The input end of the third charge-discharge electronic circuit serves as the first input end of the second voltage sampling circuit, the input end of the fourth charge-discharge electronic circuit serves as the second input end of the second voltage sampling circuit, and the output end of the third charge-discharge electronic circuit and the output end of the fourth charge-discharge electronic circuit are connected as the output end of the second voltage sampling circuit; The control end of the third charge-discharge electronic circuit and the control end of the fourth charge-discharge electronic circuit serve as the control end of the second voltage sampling circuit.

5. The bandgap reference circuit according to claim 4, wherein: The third charge-discharge electronic circuit includes: a fifth switch group, a sixth switch group and a third sampling capacitor; One switch unit in the fifth switch group is connected between the input terminal of the third charge-discharge electronic circuit and one end of the third sampling capacitor, and another switch unit in the fifth switch group is connected between the common mode voltage input terminal and the other end of the third sampling capacitor; One switch unit in the sixth switch group is connected between the common-mode voltage input terminal and one end of the third sampling capacitor, and another switch unit in the sixth switch group is connected between the other end of the third sampling capacitor and the output end of the third charge-discharge electronic circuit; The fourth charge-discharge electronic circuit includes: a seventh switch group, an eighth switch group and a fourth sampling capacitor; One switch unit in the seventh switch group is connected between the input terminal of the fourth charge-discharge electronic circuit and one end of the fourth sampling capacitor, and another switch unit in the seventh switch group is connected between the common-mode voltage input terminal and the other end of the fourth sampling capacitor; One switch unit in the eighth switch group is connected between the common-mode voltage input terminal and one end of the fourth sampling capacitor, and another switch unit in the eighth switch group is connected between the other end of the fourth sampling capacitor and the output end of the fourth charge-discharge electronic circuit; The third sampling capacitor and the fourth sampling capacitor are adjustable capacitors. The control end of the third sampling capacitor serves as the control end of the third charge-discharge electronic circuit, and the control end of the fourth sampling capacitor serves as the control end of the fourth charge-discharge electronic circuit.

6. The bandgap reference circuit according to claim 1, wherein: The first calibration circuit includes: a ninth switch group, a tenth switch group, and a fifth sampling capacitor; One switch unit in the ninth switch group is connected between the input terminal of the first calibration circuit and one end of the fifth sampling capacitor, and another switch unit in the ninth switch group is connected between the common mode voltage input terminal and the other end of the fifth sampling capacitor; One switch unit in the tenth switch group is connected between the common-mode voltage input terminal and one end of the fifth sampling capacitor, and another switch unit in the tenth switch group is connected between the other end of the fifth sampling capacitor and the output terminal of the first calibration circuit.

7. The bandgap reference circuit according to claim 1, wherein: The second calibration circuit includes: an eleventh switch group, a twelfth switch group and a sixth sampling capacitor; One switch unit in the eleventh switch group is connected between the input terminal of the second calibration circuit and one end of the sixth sampling capacitor, and another switch unit in the eleventh switch group is connected between the common mode voltage input terminal and the other end of the sixth sampling capacitor; One switch unit in the twelfth switch group is connected between the common-mode voltage input terminal and one end of the sixth sampling capacitor, and another switch unit in the twelfth switch group is connected between the other end of the sixth sampling capacitor and the output end of the second calibration circuit.

8. The bandgap reference circuit according to claim 1, wherein: The proportional integral circuit includes: a first switching capacitor unit, a second switching capacitor unit and an amplifier; The first switch capacitor unit is connected between the positive input terminal and the negative output terminal of the amplifier, and the second switch capacitor unit is connected between the negative input terminal and the positive output terminal of the amplifier.

9. A bandgap reference voltage calibration method, characterized in that: Applied to the bandgap reference circuit according to any one of claims 1 to 8, the method comprising: When the bandgap reference voltage source is in a calibration mode, a first integrated voltage and a second integrated voltage are generated by a first voltage sampling circuit and a proportional integral circuit, and a third integrated voltage is generated by a second voltage sampling circuit and the proportional integral circuit; generating a second calibration voltage through a first calibration circuit and the proportional-integral circuit, and generating a first calibration voltage through a second calibration circuit and the proportional-integral circuit; calculating an output voltage difference according to the first integrated voltage, the second integrated voltage, the third integrated voltage, the first calibration voltage, and the second calibration voltage; Outputting a comparison result according to the output voltage difference through a comparison circuit; generating, by a control circuit, control signals for the first voltage sampling circuit and the second voltage sampling circuit according to the comparison result and a preset trimming ratio, so as to adjust the positive temperature coefficient and the negative temperature coefficient of the bandgap reference voltage source by adjusting the voltage sampling coefficients of the first voltage sampling circuit and the second voltage sampling circuit; After the calibration is completed, the bandgap reference voltage source exits the calibration mode and outputs the bandgap reference voltage in the output mode.

10. The bandgap reference voltage calibration method according to claim 9, wherein: The process of calculating the preset adjustment ratio is as follows: Determining a bandgap reference voltage of the bandgap reference voltage source in a current state; Adjusting the temperature coefficient of the bandgap reference voltage to determine a first voltage change amount of the positive temperature coefficient and a first voltage change amount of the negative temperature coefficient; Adjusting the absolute value of the bandgap reference voltage to determine a second voltage change amount of the positive temperature coefficient and a second voltage change amount of the negative temperature coefficient; The preset trim ratio of the bandgap reference voltage source in the current state is determined according to the first voltage change of the positive temperature coefficient, the first voltage change of the negative temperature coefficient, the second voltage change of the positive temperature coefficient, and the second voltage change of the negative temperature coefficient.

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