Reference voltage circuit and chip

Abstract

The application discloses a reference voltage circuit and a chip. The reference voltage circuit comprises a first bandgap reference voltage circuit, a second bandgap reference voltage circuit and a trimming circuit. The first bandgap reference voltage circuit is used for providing a first bandgap reference voltage. The second bandgap reference voltage circuit is used for providing a second bandgap reference voltage. The trimming circuit is used for converting the first bandgap reference voltage into the reference voltage and performing temperature compensation on the reference voltage according to the second bandgap reference voltage when the predetermined condition is met. The second bandgap reference circuit is not started when the predetermined condition is not met. The second bandgap reference circuit is started when the predetermined condition is met, so that the trimming circuit performs temperature compensation on the reference voltage. The reference voltage circuit reduces or eliminates the influence of the ambient temperature on the reference voltage while considering the low power consumption and cost, and does not affect the overall accuracy of the reference voltage.

Description

Technical Field

[0001] This application relates to the field of power supply circuit technology, and more specifically, to a reference voltage circuit and chip. Background Technology

[0002] Inside the chip, a reference voltage circuit is used to generate a reference voltage to provide as the operating voltage for subsequent circuits. Specifically, the bandgap reference voltage circuit can generate a 1.2V bandgap reference voltage, and then different reference voltage circuits can generate target reference voltages of different magnitudes based on the bandgap reference voltage.

[0003] During the operation of a bandgap voltage reference circuit, the ambient temperature may change. These temperature variations can cause changes in the threshold voltage of the transistors within the bandgap voltage reference circuit, preventing the circuit from generating a stable bandgap voltage and consequently affecting the chip's performance. While temperature compensation circuits can be used to eliminate the effect of temperature on the reference voltage, these circuits increase the chip's power consumption. Utility Model Content

[0004] This application provides a reference voltage circuit and chip.

[0005] The reference voltage circuit provided in this application is used to provide a reference voltage. The reference voltage circuit includes a first bandgap reference voltage circuit, a second bandgap reference voltage circuit, and a trimming circuit. The first bandgap reference voltage circuit provides a first bandgap reference voltage. The second bandgap reference voltage circuit provides a second bandgap reference voltage. The trimming circuit converts the first bandgap reference voltage into the reference voltage and, under predetermined conditions, performs temperature compensation on the reference voltage based on the second bandgap reference voltage.

[0006] In some implementations, the predetermined condition is a predetermined time interval.

[0007] In some embodiments, the reference voltage circuit further includes a temperature detection circuit. The temperature detection circuit detects the ambient temperature, and the predetermined condition is that the change in the ambient temperature exceeds a preset temperature value.

[0008] In some embodiments, the reference voltage circuit further includes a voltage detection circuit. The voltage detection circuit is also used to detect the system power supply voltage of the first bandgap reference voltage circuit, wherein the predetermined condition is that the change in the system power supply voltage is greater than a predetermined voltage change value.

[0009] In some embodiments, the adjustment circuit, when the predetermined conditions are met, acquires the second bandgap reference voltage and performs temperature compensation on the reference voltage based on the difference between the second bandgap reference voltage and the reference voltage.

[0010] In some embodiments, the adjustment circuit includes a control circuit and a voltage conversion circuit. The control circuit provides a control signal to the voltage conversion circuit based on the voltage difference to control the voltage conversion circuit to convert the first bandgap reference voltage into the reference voltage.

[0011] In some embodiments, the voltage conversion circuit includes a first operational amplifier and multiple feedback lines. A first input terminal of the first operational amplifier is used to connect to the first bandgap reference voltage, and an output terminal of the first operational amplifier is used to provide the reference voltage. A second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier through the feedback lines. Each feedback line includes a control switch and a voltage divider resistor. The control circuit is used to control any one of the control switches to be turned on or off, thereby controlling the voltage ratio of the reference voltage to the first bandgap reference voltage.

[0012] In some embodiments, the first bandgap reference voltage circuit includes a first transistor unit, a first reference current circuit, and a first resistor unit. The first transistor unit includes at least one transistor, and the first reference current circuit is used to provide a first reference current based on the threshold voltage of the transistor in the first transistor unit. The first reference current flows through the first resistor unit to generate the first bandgap reference voltage.

[0013] In some embodiments, the first transistor unit includes a first transistor and a second transistor. The first reference current circuit includes a first resistor and a second operational amplifier. The reference voltage circuit further includes a first current mirror circuit. The first input terminal of the second operational amplifier is grounded through the first resistor and the second transistor, the second input terminal of the second operational amplifier is grounded through the first transistor, and the output terminal of the second operational amplifier is connected to the first and second input terminals. The first current mirror circuit is used to replicate the current flowing through the first transistor as the first reference current. The first bandgap reference voltage circuit further includes a first bandgap reference voltage source, which is grounded through the first resistor unit and is used to provide a first bandgap reference voltage.

[0014] In some embodiments, the first reference current circuit further includes a second resistor and a third resistor, with the second input terminal of the second operational amplifier grounded through the second resistor and the first input terminal of the second operational amplifier grounded through the third resistor.

[0015] In some embodiments, the first bandgap reference voltage circuit includes a third operational amplifier, a third transistor, a fourth transistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first input terminal of the third operational amplifier is grounded through the third transistor, and the first input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier through the fourth resistor. The second input terminal of the third operational amplifier is grounded through the fifth resistor and the fourth transistor, and the second input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier through the sixth resistor. The fifth resistor and / or the sixth resistor includes a variable resistor.

[0016] In some embodiments, the adjustment circuit, when the predetermined conditions are met, acquires the second bandgap reference voltage and adjusts the resistance values ​​of the fifth resistor and / or the sixth resistor according to the difference between the second bandgap reference voltage and the reference voltage, so as to perform temperature compensation on the reference voltage.

[0017] In some embodiments, the second bandgap reference voltage circuit includes a second transistor unit, a second reference current circuit, a temperature compensation circuit, and a second resistor unit. The second transistor unit includes at least one transistor, and the second reference current circuit provides a second reference current based on the threshold voltage of the transistor in the second transistor unit. The temperature compensation circuit provides a compensation current. The compensation current and the second reference current flow through the second resistor unit to generate the second bandgap reference voltage.

[0018] In some embodiments, the second transistor unit includes a fifth transistor and a sixth transistor, and the second reference current circuit includes a seventh resistor, a fourth operational amplifier, and a second current mirror circuit. The second input terminal of the fourth operational amplifier is grounded through the fifth transistor, and the first input terminal of the fourth operational amplifier is grounded through the seventh resistor and the sixth transistor. The output terminal of the fourth operational amplifier is connected to both its first and second input terminals. The second current mirror circuit is used to replicate the current flowing through the fifth transistor as the second reference current. The temperature compensation circuit includes a seventh transistor, an eighth resistor, and a ninth resistor. The second input terminal of the fourth operational amplifier is grounded through the eighth resistor and the seventh transistor, and the first input terminal of the fourth operational amplifier is grounded through the ninth resistor and the sixth transistor. The second bandgap reference voltage circuit includes a second bandgap reference voltage source, which is grounded through the second resistor unit. The second bandgap reference voltage source is used to provide a second bandgap reference voltage.

[0019] In some embodiments, the second reference current circuit further includes a tenth resistor and an eleventh resistor, with the second input terminal of the fourth operational amplifier grounded through the tenth resistor and the first input terminal of the fourth operational amplifier grounded through the eleventh resistor.

[0020] This application also provides a chip that includes the reference voltage circuit of any of the above embodiments.

[0021] In the reference voltage circuit and chip provided in this application embodiment, the first bandgap reference voltage circuit can provide a first bandgap reference voltage, the voltage value of which is significantly affected by temperature. The second bandgap reference voltage circuit can provide a temperature-compensated second bandgap reference voltage. Compared with the first bandgap reference voltage, the second bandgap reference voltage has better stability, but its power consumption is higher. The second bandgap reference circuit does not turn on when a predetermined condition is not met, but turns on and provides the second bandgap reference voltage when the predetermined condition is met, so that the adjustment circuit performs temperature compensation on the reference voltage based on the second bandgap reference voltage. The reference voltage circuit reduces or eliminates the influence of ambient temperature on the reference voltage while also considering low power consumption and cost, without affecting the overall accuracy of the reference voltage.

[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:

[0024] Figure 1 This is a schematic diagram of the reference voltage circuit according to an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the adjustment circuit according to an embodiment of this application;

[0026] Figure 3 This is another schematic diagram of the adjustment circuit according to an embodiment of this application;

[0027] Figure 4 This is a circuit diagram of the first bandgap reference voltage according to the first embodiment of this application;

[0028] Figure 5 This is a circuit diagram of the first bandgap reference voltage according to the second embodiment of this application;

[0029] Figure 6 This is a circuit diagram of the first bandgap reference voltage according to the third embodiment of this application;

[0030] Figure 7 This is a circuit diagram of the second bandgap reference voltage according to the first embodiment of this application;

[0031] Figure 8 This is a schematic diagram of a chip according to an embodiment of this application. Detailed Implementation

[0032] The embodiments of this application are described in detail below. These embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0033] Inside the chip, a reference voltage circuit is used to generate a reference voltage to provide as the operating voltage for subsequent circuits. Specifically, the bandgap reference voltage circuit can generate a 1.2V bandgap reference voltage, and then different reference voltage circuits can generate target reference voltages of different magnitudes based on the bandgap reference voltage.

[0034] During the operation of a bandgap voltage reference circuit, the ambient temperature may change. These temperature variations can cause changes in the threshold voltage of the transistors within the bandgap voltage reference circuit, preventing the circuit from generating a stable bandgap voltage and consequently affecting the chip's performance. While temperature compensation circuits can be used to eliminate the effect of temperature on the reference voltage, these circuits increase the chip's power consumption.

[0035] Please see Figure 1 This application provides a reference voltage circuit 100, which can provide a reference voltage Vout. The reference voltage circuit 100 includes a first bandgap reference voltage circuit 10, a second bandgap reference voltage circuit 20, and a trimming circuit 30.

[0036] The first bandgap reference voltage circuit 10 can provide a first bandgap reference voltage Vref1, the voltage value of which is significantly affected by temperature. The second bandgap reference voltage circuit 20 can provide a temperature-compensated second bandgap reference voltage Vref2. Compared to the first bandgap reference voltage Vref1, the second bandgap reference voltage Vref2 has better stability, but the power consumption of the second bandgap reference voltage circuit 20 is higher. Therefore, the first bandgap reference voltage circuit 10 can be a low-power, high-temperature drift reference voltage source, while the second bandgap reference voltage circuit 20 can be a low-temperature drift, high-power reference voltage source.

[0037] Reference Figure 2During the operation of the reference voltage circuit 100, the first bandgap reference voltage circuit 10 remains in the ON state for an extended period, providing the first bandgap reference voltage Vref1. The adjustment circuit 30 can serve as a downstream circuit of the first bandgap reference voltage circuit 10. The adjustment circuit 30 can convert the first bandgap reference voltage Vref1 into a reference voltage Vout for external output.

[0038] Reference Figure 3 The second bandgap reference circuit is activated and provides a second bandgap reference voltage Vref2 when predetermined conditions are met. Under the same conditions, the adjustment circuit 30 can perform temperature compensation on the reference voltage Vout based on the second bandgap reference voltage Vref2, thereby reducing or eliminating the influence of ambient temperature on the reference voltage Vout.

[0039] If the predetermined conditions are not met, the second bandgap reference circuit can be in the off state, which can prevent the high-power second bandgap reference voltage circuit 20 from being turned on for a long time, and also prevent the reference voltage circuit 100 from consuming too much power.

[0040] In summary, the second bandgap reference circuit remains off when predetermined conditions are not met, but turns on and provides a second bandgap reference voltage Vref2 when the predetermined conditions are met. This allows the adjustment circuit 30 to perform temperature compensation on the reference voltage Vout based on the second bandgap reference voltage Vref2. The reference voltage circuit 100 reduces or eliminates the influence of ambient temperature on the reference voltage Vout while also maintaining low power consumption and cost, without affecting the overall accuracy of the reference voltage.

[0041] Furthermore, in some implementations, the predetermined condition may be a predetermined time interval.

[0042] The reference voltage circuit 100 may include an enable circuit that can provide an enable signal to the second bandgap reference voltage circuit 20 to control the second bandgap reference voltage circuit 20 to turn on or off. The enable circuit can provide an enable signal to the second bandgap reference voltage circuit 20 at predetermined time intervals to control the second bandgap reference voltage circuit 20 to turn on at predetermined time intervals.

[0043] The second bandgap reference voltage circuit 20 can also be connected to a power supply via a corresponding switching device. The switching device can be controlled to turn on or off, thereby controlling the second bandgap reference voltage circuit 20 to start or stop operating. The corresponding switching device can be controlled to turn on at predetermined time intervals to control the second bandgap reference voltage circuit 20 to start at predetermined time intervals.

[0044] Reference Figure 2During the operation of the reference voltage circuit 100, the first bandgap reference voltage circuit 10 is in the on state for a long time. The voltage value of the first bandgap reference voltage Vref1 may change with the change of ambient temperature, which in turn leads to the instability of the reference voltage Vout.

[0045] Reference Figure 3 The second bandgap reference voltage circuit 20 can be turned on at a predetermined time interval, so that the adjustment circuit 30 can correct the voltage value of the reference voltage Vout at the predetermined time interval, thereby stabilizing the voltage value of the reference voltage Vout.

[0046] For example, the predetermined time interval can be set to Δt. At time t1, the second bandgap reference voltage circuit 20 is turned on and provides the second bandgap reference voltage Vref2a, so that the trimming circuit 30 provides a reference voltage of Vout1 according to the second bandgap reference voltage Vref2a. Between time t1 and time t1+Δt, the reference voltage provided by the trimming circuit 30 is Vout1. At time t1+Δt, the second bandgap reference voltage circuit 20 is turned on and provides the second bandgap reference voltage Vref2b, so that the trimming circuit 30 provides a reference voltage of Vout2 according to the second bandgap reference voltage Vref2b.

[0047] The predetermined time interval Δt can be determined according to actual usage requirements. In applications where the stability requirements of the reference voltage are low, the predetermined time interval Δt can be set to be relatively large. Under the premise of satisfying the stability of the reference voltage, the larger the predetermined time interval Δt, the shorter the turn-on time of the second bandgap reference voltage circuit 20 and the lower the power consumption of the reference voltage circuit 100.

[0048] In applications requiring high reference voltage stability, the predetermined time interval Δt can be set relatively small to ensure the stability of the reference voltage. The smaller the predetermined time interval Δt, the longer the on-time of the second bandgap reference voltage circuit 20, the higher the frequency at which the adjustment circuit 30 corrects the reference voltage, and the higher the stability of the reference voltage.

[0049] In some implementations, the predetermined condition may be that the change in ambient temperature is greater than a preset temperature value.

[0050] The reference voltage circuit 100 may further include a temperature detection circuit, which may include a thermistor, thermocouple, or other element whose physical properties change with temperature. The temperature detection circuit can detect the ambient temperature at different points in time. Based on the ambient temperature detected by the temperature detection circuit at these different points in time, the change in ambient temperature can be determined.

[0051] Reference Figure 2When the ambient temperature changes, the voltage value of the first bandgap reference voltage Vref1 may change with the ambient temperature, which in turn leads to the instability of the reference voltage Vout.

[0052] Reference Figure 3 The second bandgap reference voltage circuit 20 can be turned on when the ambient temperature changes significantly. The second bandgap reference voltage Vref2 is less affected by the ambient temperature. The adjustment circuit 30 can adjust the reference voltage Vout value according to the second bandgap reference voltage Vref2 to eliminate or reduce the influence of ambient temperature on the reference voltage Vout.

[0053] The preset temperature value can be a temperature threshold. For example, the preset temperature value is the temperature threshold Ta. At time t3, the ambient temperature detected by the temperature detection circuit is T0, and at time t4, the ambient temperature detected by the temperature detection circuit is T1. If T1-T0 is greater than Ta, or T0-T1 is greater than Ta, the predetermined condition can be considered met, and the second reference bandgap voltage circuit is turned on.

[0054] The preset temperature value can also be a temperature change rate threshold. For example, the preset temperature value is the temperature change threshold Tb / tb. At time t5, the ambient temperature detected by the temperature detection circuit is T2, and at time t6, the ambient temperature detected by the temperature detection circuit is T3. If (T3-T2) / (t6-t5) is greater than Tb / tb, or if T2-T3 / t6-t5 is greater than Tb / tb, the predetermined condition can be considered met, and the second reference bandgap voltage circuit will be turned on.

[0055] The preset temperature value can be determined according to actual usage requirements. In applications where the stability requirements of the reference voltage are low, the preset temperature value can be set relatively high. Under the premise of satisfying the stability of the reference voltage, the higher the preset temperature value, the shorter the turn-on time of the second bandgap reference voltage circuit 20 and the lower the power consumption of the reference voltage circuit 100.

[0056] In applications where high reference voltage stability is required, the preset temperature value can be set relatively low to ensure the stability of the reference voltage. The lower the preset temperature value, the higher the frequency at which the second bandgap reference voltage circuit 20 is turned on, the higher the frequency at which the adjustment circuit 30 corrects the reference voltage, and the higher the stability of the reference voltage.

[0057] In some embodiments, the predetermined condition may be that the change in system power supply voltage is greater than a predetermined voltage change. The reference voltage circuit 100 may also include a voltage detection circuit that can detect the system power supply voltage of the first bandgap reference voltage circuit 10.

[0058] Reference Figure 2The first bandgap reference voltage circuit 10 can generate a first bandgap reference voltage based on the input system power supply voltage. When the system power supply voltage of the first bandgap reference voltage circuit 10 changes, the first bandgap reference voltage Vref1 will also change, resulting in instability of the reference voltage Vout value.

[0059] by Figure 4 For example, the voltage of the voltage source Vdd1 can be the system power supply voltage of the first bandgap reference voltage circuit 10. When the voltage of the voltage source Vdd changes, the first bandgap reference voltage Vref1 will also change, thus making the reference voltage Vout unstable.

[0060] Reference Figure 3 The second bandgap reference voltage circuit 20 can be turned on when the system power supply voltage of the first bandgap reference voltage circuit 10 changes significantly. The adjustment circuit 30 can correct the voltage value of the reference voltage Vout according to the second bandgap reference voltage Vref2, thereby eliminating or reducing the influence of the system power supply voltage of the first bandgap reference voltage circuit 10 on the reference voltage Vout.

[0061] The preset voltage value can be a voltage threshold. For example, the preset voltage value is the voltage threshold Ua. The initial value of the system power supply voltage of the first bandgap reference voltage circuit 10 can be Udd. When the voltage detection circuit detects that the system power supply voltage of the first bandgap reference voltage circuit 10 is less than Udd-Ua, or detects that the system power supply voltage of the first bandgap reference voltage circuit 10 is greater than Udd+Ua, it can be considered that the predetermined condition is met, and at this time the second reference bandgap voltage circuit is turned on.

[0062] The preset voltage value can be determined according to actual usage requirements. In applications where the stability requirements of the reference voltage are low, the preset voltage value can be set relatively large. Under the premise of satisfying the stability of the reference voltage, the larger the preset voltage value, the shorter the turn-on time of the second bandgap reference voltage circuit 20 and the lower the power consumption of the reference voltage circuit 100.

[0063] In applications where high reference voltage stability is required, the preset voltage value can be set relatively small to ensure the stability of the reference voltage. The smaller the preset voltage value, the higher the frequency at which the second bandgap reference voltage circuit 20 is turned on, the higher the frequency at which the adjustment circuit 30 corrects the reference voltage, and the higher the stability of the reference voltage.

[0064] In some embodiments, the adjustment circuit 30 acquires a second bandgap reference voltage when predetermined conditions are met, and performs temperature compensation on the reference voltage based on the difference between the second bandgap reference voltage and the reference voltage.

[0065] The adjustment circuit 30 can acquire the voltage value of the reference voltage Vout in real time. Under predetermined conditions, the second bandgap reference voltage circuit 20 is turned on, and the adjustment circuit 30 can acquire the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout.

[0066] The adjustment circuit 30 can adjust the voltage value of the reference voltage Vout to be close to the voltage value of the second bandgap reference voltage Vref2, so as to achieve temperature compensation for the reference voltage Vout.

[0067] When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is positive, meaning the voltage value of the second bandgap reference voltage Vref2 is greater than the voltage value of the reference voltage Vout, the adjustment circuit 30 can increase the voltage value of the reference voltage Vout. When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is negative, meaning the voltage value of the second bandgap reference voltage Vref2 is less than the voltage value of the reference voltage Vout, the adjustment circuit 30 can decrease the voltage value of the reference voltage Vout.

[0068] Reference Figure 2 In some embodiments, the trimming circuit 30 may include a control circuit 31 and a voltage conversion circuit 32. The control circuit 31 may provide a control signal to the voltage conversion circuit 32 based on the voltage difference. The voltage conversion circuit 32 may convert the first bandgap reference voltage Vref1 into a reference voltage Vout.

[0069] The input terminal of the voltage conversion circuit 32 can be connected to the first bandgap reference voltage Vref1, and the output terminal of the voltage conversion circuit 32 can provide a reference voltage Vout. The voltage conversion circuit 32 has a corresponding voltage conversion ratio Ka. The voltage value of the reference voltage Vout can be Ka*Vref1. The larger the voltage conversion ratio Ka is, the larger the voltage value of the reference voltage Vout is; the smaller the voltage conversion ratio Ka is, the smaller the voltage value of the reference voltage Vout is.

[0070] In some embodiments, the voltage conversion circuit 32 may include a first operational amplifier and multiple feedback lines. The first input terminal of the first operational amplifier is used to connect to a first bandgap reference voltage, the output terminal of the first operational amplifier is used to provide the reference voltage, and the second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier via feedback lines. Each feedback line includes a control switch and a voltage divider resistor. The control circuit 31 is used to control any one of the control switches to be turned on or off, thereby controlling the voltage ratio between the reference voltage and the first bandgap reference voltage.

[0071] Optionally, with Figure 2For example, the first operational amplifier may include operational amplifier A1, the voltage conversion circuit 32 may include n feedback lines, the voltage divider resistors may include resistors Ra1 to Ran, and the control switches may include switching elements SW1 to SWn. Resistor Ram and switching element SWm can form a feedback line, where m can be any positive integer from 1 to n.

[0072] Control circuit 31 can control a control switch to be turned on. For example, control circuit 31 can control switching element SWm to be turned on and other switching elements to be turned off, so that the amplification factor of operational amplifier A1 is Ram / Ra0, that is, the voltage ratio of the reference voltage to the first bandgap reference voltage is Ram / Ra0.

[0073] The control circuit 31 can also control multiple control switches to be turned on. For example, the control circuit 31 can control all switching elements SW1 to SWm to be turned on, while other switching elements are turned off. The parallel equivalent resistance of resistors Ra1 to Ram is RAm, so that the amplification factor of operational amplifier A1 is RAm / Ra0, that is, the voltage ratio of the reference voltage to the first bandgap reference voltage is RAm / Ra0.

[0074] The control circuit 31 can provide a control signal to the voltage conversion circuit 32 based on the voltage difference to control the voltage conversion ratio Ka, thereby adjusting the magnitude of the reference voltage Vout. When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is positive, meaning the voltage value of the second bandgap reference voltage Vref2 is greater than the voltage value of the reference voltage Vout, the control circuit 31 can control the voltage conversion ratio Ka to increase, thus increasing the voltage value of the reference voltage Vout. When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is negative, meaning the voltage value of the second bandgap reference voltage Vref2 is less than the voltage value of the reference voltage Vout, the control circuit 31 can control the voltage conversion ratio Ka to decrease, thus decreasing the voltage value of the reference voltage Vout.

[0075] Reference Figure 3 The reference voltage circuit 100 may also include an analog-to-digital converter (ADC), which can convert the acquired analog voltage difference signal into a corresponding digital signal for the control circuit 31.

[0076] Furthermore, an incremental (delta-sigma) modulator can be used to convert the acquired analog voltage difference signal into a corresponding digital signal. A delta-sigma modulator may include a comparator, a digital-to-analog converter (DAC), an ADC, and an integrator.

[0077] The comparator's positive input can be connected to a second bandgap reference voltage, Vref2. The ADC's output is connected to the comparator's negative input via a DAC, and the comparator's output is connected to the ADC's input via an integrator circuit. The digital signal converted by the ADC can then be converted into an analog signal by the DAC and fed to the comparator's negative input.

[0078] The delta-sigma modulator can provide differential signals to the integrator circuit, which can accumulate multiple differential signals and provide them to the ADC, which then converts them into corresponding digital signals for the control circuit 31.

[0079] Furthermore, the delta-sigma modulator may also include a digital filter circuit, which can filter out noise in the digital signal provided by the ADC and improve the modulation accuracy of the delta-sigma modulator.

[0080] Reference Figure 4 In some embodiments, the first bandgap reference voltage circuit 10 includes a first transistor unit 11, a first reference current circuit 12, and a first resistor unit 13.

[0081] When the ambient temperature changes, the threshold voltage of the transistor in the first transistor unit 11 will also change, causing the reference current flowing through the first resistor unit 13 to change, which in turn causes the first bandgap reference voltage to change.

[0082] In some embodiments, the first transistor unit 11 may include a first transistor 111 and a second transistor 112. The first reference current circuit 12 may include a first resistor 121 and a second operational amplifier. The reference voltage circuit 100 may include a first current mirror circuit 14, which is used to replicate the current flowing through the first transistor 111 as a first reference current. The first bandgap reference voltage circuit 10 may include a first bandgap reference voltage source 15, which is used to provide a first bandgap reference voltage.

[0083] The first transistor 111 can be transistor Q1, and the second transistor 112 can be transistor Q2. Transistors Q1 and Q2 are in the on state.

[0084] The first resistor 121 can be resistor R1, and the second operational amplifier can be operational amplifier A2. The negative input terminal of operational amplifier A2 can be grounded through transistor Q1, and the positive input terminal of operational amplifier A2 can be grounded through resistor R1 and transistor Q2. Transistors M1, M2, and M3 are all turned on, so that the output terminal of operational amplifier A2 is shorted to the positive and negative input terminals of operational amplifier A2, respectively.

[0085] The voltage drop across resistor R1 is UR1, the threshold voltage of transistor Q1 is ΔVBE1, and the threshold voltage of transistor Q2 is ΔVBE2. When the ambient temperature changes, the threshold voltage ΔVBE1 of transistor Q1 changes, causing a change in the current flowing through transistor Q1, which in turn changes the current flowing through transistor M1.

[0086] Transistors M1, M2, and M3 can form a first current mirror circuit 14. When the current flowing through transistor M1 changes, the current flowing through transistor M3 will also change, that is, the current flowing through resistor Rb1 will change.

[0087] The first resistor unit 13 can be a resistor Rb1. The first bandgap reference voltage source 15 can be grounded through the resistor Rb1. Changes in the current flowing through the resistor Rb1 will cause changes in the first bandgap reference voltage Vref1.

[0088] Reference Figure 5 In some embodiments, the first reference current circuit 12 may include a second resistor 123 and a third resistor 124, the second input terminal of the second operational amplifier is grounded through the second resistor 123, and the first input terminal of the second operational amplifier is grounded through the third resistor 124.

[0089] The second resistor 123 can be resistor R2, and the third resistor 124 can be resistor R3. The negative input terminal of op-amp A2 can be grounded through resistor R2, and the positive input terminal of op-amp A2 can be grounded through resistor R3. Resistors R2 and R3 can be used as grounding resistors for op-amp A2, improving the noise voltage at the input of op-amp A2.

[0090] Reference Figure 6 In some embodiments, the first bandgap reference voltage circuit 10 may include a third operational amplifier 166, a third transistor 161, a fourth transistor 162, a fourth resistor 163, a fifth resistor 164, and a sixth resistor 165.

[0091] The third op-amp 166 can be op-amp A3, the third transistor 161 can be transistor Q3, the fourth transistor 162 can be transistor Q4, the fourth resistor 163 can be resistor R4, the fifth resistor 164 can be resistor R5, and the sixth resistor 165 can be resistor R6.

[0092] The voltage drop across resistor R5 is UR5, the threshold voltage of transistor Q3 is ΔVBE3, and the threshold voltage of transistor Q4 is ΔVBE4. Since the voltage at the positive input terminal and the voltage at the negative input terminal of op-amp A2 are the same, we can determine that ΔVBE3 = UR5 + ΔVBE4, and UR5 = ΔVBE3 - ΔVBE4.

[0093] Since the current flowing through resistor R5 is the same as the current flowing through resistor R6, the voltage drop across resistor R6 is UR6, where UR6 = (ΔVBE3 - ΔVBE4) * R6 / R5.

[0094] Furthermore, the voltage drop across resistor R4 is UR4, where UR4 = UR6 = (ΔVBE3 - ΔVBE4) * R6 / R5. Therefore, Vref1 = UR4 + ΔVBE3. When the specifications of transistors Q3 and Q4 are determined, ΔVBE3 - ΔVBE4 can be a constant T, and R6 / R5 can be denoted as K. Therefore, Vref1 = K * T + ΔVBE3.

[0095] If the specifications of transistors Q3 and Q4 are fixed and resistors R5 and R6 remain unchanged, a change in ambient temperature that causes the threshold voltage ΔVBE3 of the third transistor 161 will result in a change in the first bandgap reference voltage Vref1.

[0096] In some implementations, the fifth resistor 164 and / or the sixth resistor 165 may include variable resistors.

[0097] When the predetermined conditions are met, the adjustment circuit 30 acquires the second bandgap reference voltage and adjusts the resistance values ​​of the fifth resistor 164 and / or the sixth resistor 165 according to the difference between the second bandgap reference voltage and the reference voltage to perform temperature compensation on the reference voltage.

[0098] The control circuit 31 can provide a control signal based on the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout to adjust the resistance values ​​of resistors R5 and R6, thereby adjusting the value of K.

[0099] When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is positive, that is, when the voltage value of the second bandgap reference voltage Vref2 is greater than the voltage value of the reference voltage Vout, the control circuit 31 can reduce the resistor R5 or increase the resistor R6 to make K larger, thereby increasing the first bandgap reference voltage Vref1, so as to achieve temperature compensation for the reference voltage Vout.

[0100] When the difference between the second bandgap reference voltage Vref2 and the reference voltage Vout is negative, that is, when the voltage value of the second bandgap reference voltage Vref2 is less than the voltage value of the reference voltage Vout, the control circuit 31 can increase the resistor R5 or decrease the resistor R6 to make K smaller, thereby making the first bandgap reference voltage Vref1 smaller, so as to achieve temperature compensation for the reference voltage Vout.

[0101] Reference Figure 7In some embodiments, the second bandgap reference voltage circuit 20 may include a second transistor unit 21, a second reference current circuit 22, a temperature compensation circuit 23, and a second resistor unit 24. The second transistor unit 21 includes at least one transistor. The second reference current circuit 22 provides a second reference current based on the threshold voltage of the transistor in the second transistor unit 21. The temperature compensation circuit 23 provides a compensation current. The compensation current and the second reference current flow through the second resistor unit 24 to generate the second bandgap reference voltage.

[0102] The second transistor unit 21 includes a fifth transistor 211 and a sixth transistor 212, and the second reference current circuit 22 includes a seventh resistor 221, a fourth operational amplifier 222, and a second current mirror circuit 25.

[0103] The fifth transistor 211 can be transistor Q5, and the sixth transistor 212 can be transistor Q6. Transistors Q5 and Q6 are in the on state.

[0104] The seventh resistor 221 can be resistor R7, and the fourth operational amplifier 222 can be operational amplifier A4. The negative input terminal of operational amplifier A4 can be grounded through transistor Q5, and the positive input terminal of operational amplifier A4 can be grounded through resistor R7 and transistor Q6. Transistors M1, M2, and M3 are all turned on, causing the output terminal of operational amplifier A4 to be shorted to the positive and negative input terminals of operational amplifier A4, respectively.

[0105] The voltage drop across resistor R7 is UR7, and the threshold voltage of transistor Q5 is ΔVBE5. When the ambient temperature changes, the threshold voltage ΔVBE5 of transistor Q5 changes, causing a change in the current flowing through transistor Q5, which in turn changes the current flowing through transistor M1.

[0106] Transistors M1, M2, and M3 can form a second current mirror circuit 25. When the current flowing through transistor M1 changes, the current flowing through transistor M3 will also change, that is, the current flowing through resistor Rb2 will change.

[0107] The second resistor unit 24 can be a resistor Rb2. The second bandgap reference voltage source 26 can be grounded through the resistor Rb2. Changes in the current flowing through the resistor Rb2 will cause changes in the second bandgap reference voltage Vref2.

[0108] The temperature compensation circuit 23 may include a seventh transistor 231, an eighth resistor 232, and a ninth resistor 233. The seventh transistor 231 may be transistor Q7, the eighth resistor 232 may be resistor R8, and the ninth resistor 233 may be resistor R9. The positive input terminal of operational amplifier A4 can be grounded through resistor R9 and transistor Q7, and the negative input terminal of operational amplifier A4 can be grounded through resistor R8 and transistor Q7.

[0109] When the ambient temperature changes, the threshold voltage ΔVBE5 of transistor Q5 changes, and the current flowing through transistor Q5 changes. Temperature compensation current is provided to transistor Q5 through resistor R8. By adjusting the resistance values ​​of resistors R7, R8, and R9, the temperature offset current flowing through transistor Q5 can be offset, thereby achieving temperature compensation for the second bandgap reference voltage Vref2.

[0110] Reference Figure 7 In some embodiments, the first reference current circuit 12 may include a tenth resistor 223 and an eleventh resistor 224. The tenth resistor 223 may be resistor R10, and the eleventh resistor 224 may be resistor R11. The negative input terminal of operational amplifier A4 can be grounded through resistor R10, and the positive input terminal of operational amplifier A2 can be grounded through resistor R11. Resistors R10 and R11 can serve as grounding resistors for operational amplifier A4, improving the noise voltage at the input of operational amplifier A4.

[0111] Reference Figure 8 This application also provides a chip 1000, which includes the reference voltage circuit 100 of any of the above embodiments. The beneficial effects of the chip 1000 include all the beneficial effects of the reference voltage circuit 100, which will not be elaborated here.

[0112] In the description of this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in this specification, as well as features of different embodiments or examples.

[0113] Furthermore, the term "connection" should be interpreted broadly. For example, it can include fixed connections, detachable connections, or integral connections; it can include direct connections or indirect connections through an intermediate medium; and it can also include internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0114] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0115] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0116] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A reference voltage circuit for providing a reference voltage, characterized in that, The reference voltage circuit includes: A first bandgap reference voltage circuit is used to provide a first bandgap reference voltage; The second bandgap reference voltage circuit is used to turn on and provide a temperature-compensated second bandgap reference voltage when predetermined conditions are met. The adjustment circuit is used to convert the first bandgap reference voltage into the reference voltage, and, under the condition that the predetermined condition is met, to perform temperature compensation on the reference voltage based on the second bandgap reference voltage.

2. The reference voltage circuit according to claim 1, characterized in that, The predetermined condition is a predetermined time interval.

3. The reference voltage circuit according to claim 1, characterized in that, The reference voltage circuit also includes a temperature detection circuit, which is used to detect the ambient temperature. The predetermined condition is when the change in the ambient temperature is greater than a preset temperature value.

4. The reference voltage circuit according to claim 1, characterized in that, The reference voltage circuit further includes a voltage detection circuit, which is also used to detect the system power supply voltage of the first bandgap reference voltage circuit. The predetermined condition is that the change in the system power supply voltage is greater than a predetermined voltage change value.

5. The reference voltage circuit according to any one of claims 1-4, characterized in that, When the predetermined conditions are met, the adjustment circuit acquires the second bandgap reference voltage and performs temperature compensation on the reference voltage based on the difference between the second bandgap reference voltage and the reference voltage.

6. The reference voltage circuit according to claim 5, characterized in that, The adjustment circuit includes a control circuit and a voltage conversion circuit. The control circuit provides a control signal to the voltage conversion circuit based on the voltage difference to control the voltage conversion circuit to convert the first bandgap reference voltage into the reference voltage.

7. The reference voltage circuit according to claim 6, characterized in that, The voltage conversion circuit includes a first operational amplifier and multiple feedback lines. The first input terminal of the first operational amplifier is used to connect to the first bandgap reference voltage, and the output terminal of the first operational amplifier is used to provide the reference voltage. The second input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier through the feedback lines. Each feedback line includes a control switch and a voltage divider resistor. The control circuit is used to control any one of the control switches to be turned on or off, so as to control the voltage ratio of the reference voltage to the first bandgap reference voltage.

8. The reference voltage circuit according to claim 1, characterized in that, The first bandgap reference voltage circuit includes: The first transistor unit includes at least one transistor; A first reference current circuit is configured to provide a first reference current based on the threshold voltage of the transistor in the first transistor unit. The first resistor unit is through which the first reference current flows to generate the first bandgap reference voltage.

9. The reference voltage circuit according to claim 8, characterized in that, The first transistor unit includes a first transistor and a second transistor. The first reference current circuit includes a first resistor and a second operational amplifier. The reference voltage circuit further includes a first current mirror circuit. The first input terminal of the second operational amplifier is grounded through the first resistor and the second transistor. The second input terminal of the second operational amplifier is grounded through the first transistor. The output terminal of the second operational amplifier is connected to the first input terminal and the second input terminal of the second operational amplifier. The first current mirror circuit is used to replicate the current flowing through the first transistor as the first reference current. The first bandgap reference voltage circuit further includes a first bandgap reference voltage source, which is grounded through the first resistor unit and is used to provide a first bandgap reference voltage.

10. The reference voltage circuit according to claim 9, characterized in that, The first reference current circuit also includes a second resistor and a third resistor. The second input terminal of the second operational amplifier is grounded through the second resistor, and the first input terminal of the second operational amplifier is grounded through the third resistor.

11. The reference voltage circuit according to claim 1, characterized in that, The first bandgap reference voltage circuit includes a third operational amplifier, a third transistor, a fourth transistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first input terminal of the third operational amplifier is grounded through the third transistor. The first input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier through the fourth resistor. The second input terminal of the third operational amplifier is grounded through the fifth resistor and the fourth transistor. The second input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier through the sixth resistor. The fifth resistor and / or the sixth resistor includes a variable resistor.

12. The reference voltage circuit according to claim 11, characterized in that, When the predetermined conditions are met, the adjustment circuit acquires the second bandgap reference voltage and adjusts the resistance values ​​of the fifth resistor and / or the sixth resistor according to the difference between the second bandgap reference voltage and the reference voltage to perform temperature compensation on the reference voltage.

13. The reference voltage circuit according to claim 1, characterized in that, The second bandgap reference voltage circuit includes: The second transistor unit includes at least one transistor; The second reference current circuit is used to provide a second reference current based on the threshold voltage of the transistor in the second transistor unit; Temperature compensation circuit, used to provide compensation current; The second resistor unit, through which the compensation current and the second reference current flow, generate the second bandgap reference voltage.

14. The reference voltage circuit according to claim 13, characterized in that, The second transistor unit includes a fifth transistor and a sixth transistor. The second reference current circuit includes a seventh resistor, a fourth operational amplifier, and a second current mirror circuit. The second input terminal of the fourth operational amplifier is grounded through the fifth transistor. The first input terminal of the fourth operational amplifier is grounded through the seventh resistor and the sixth transistor. The output terminal of the fourth operational amplifier is connected to the first and second input terminals of the fourth operational amplifier. The second current mirror circuit is used to replicate the current flowing through the fifth transistor as the second reference current. The temperature compensation circuit includes a seventh transistor, an eighth resistor, and a ninth resistor. The second input terminal of the fourth operational amplifier is grounded through the eighth resistor and the seventh transistor, and the first input terminal of the fourth operational amplifier is grounded through the ninth resistor and the sixth transistor. The second bandgap reference voltage circuit includes a second bandgap reference voltage source, which is grounded through the second resistor unit and is used to provide a second bandgap reference voltage.

15. The reference voltage circuit according to claim 14, characterized in that, The second reference current circuit also includes a tenth resistor and an eleventh resistor. The second input terminal of the fourth operational amplifier is grounded through the tenth resistor, and the first input terminal of the fourth operational amplifier is grounded through the eleventh resistor.

16. A chip, characterized in that, The chip includes the reference voltage circuit according to any one of claims 1-15.

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