Band-gap reference starting circuit and electronic device

Abstract

The embodiment of the invention provides a band-gap reference starting circuit and an electronic device. The band-gap reference starting circuit comprises a band-gap reference voltage source and a starting control module, the starting control module comprises a first control branch and a second control branch, the first control branch is connected between a bias high voltage and a second bias low voltage, and the second bias low voltage is larger than the first bias low voltage. A first switching voltage threshold value of the first control branch is positively correlated with the bias high voltage, and the second control branch is connected between the current injection end of the temperature compensation branch and the preset bias low voltage. And when the reference voltage is greater than the sum of the first switching voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the preset bias low voltage, so that the second control branch is switched off.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electrical technology, and in particular to a bandgap reference startup circuit and an electronic device. Background Art

[0002] Bandgap reference voltage sources are widely used in various high-performance analog circuits to provide accurate and stable reference voltages for various sensor circuits, power management circuits, etc. On the one hand, when the power supply module provides the supply voltage, the bandgap reference voltage source will experience environmental changes such as temperature fluctuations, power supply voltage fluctuations, and manufacturing process deviations. Therefore, the bandgap reference voltage source needs to be robust when the above-mentioned various environmental changes occur, that is, to stably output the reference voltage within a larger power supply voltage range. On the other hand, when the battery module is used as a power supply module, it is necessary to ensure the low power consumption of the bandgap reference voltage source. The bandgap reference voltage source usually does not contain an op amp, and lacks the amplification and negative feedback effects of the op amp.

[0003] With the demand for low power consumption and a larger power supply voltage range, abnormal operating points such as a zero current operating point or a weak current operating point are more likely to appear in the bandgap reference voltage source, and the startup circuit will not be able to reliably drive the bandgap reference voltage source out of the abnormal operating point. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a bandgap reference startup circuit and an electronic device to solve the above problems.

[0005] According to a first aspect of an embodiment of the present invention, a bandgap reference startup circuit is provided, comprising a bandgap reference voltage source and a startup control module. The bandgap reference voltage source comprises a temperature compensation branch and a load branch, wherein the temperature compensation branch and the load branch are connected between a bias high voltage and a first bias low voltage, and the bandgap reference voltage source provides a reference voltage from the output end of the load branch according to the voltage stability state of the current injection end of the temperature compensation branch. The startup control module comprises a first control branch and a second control branch. The first control branch is connected between the bias high voltage and the second bias low voltage, and the control end of the first control branch is connected to the output end of the load branch for receiving the reference voltage, wherein the second bias low voltage is greater than the first bias low voltage, and the first switch voltage threshold of the first control branch is positively correlated with the bias high voltage. The second control branch is connected between the current injection end of the temperature compensation branch and a preset bias low voltage, and the control end of the second control branch is connected to the output end of the first control branch. When the reference voltage is greater than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the preset bias low voltage to turn off the second control branch.

[0006] In another implementation of the present invention, when the reference voltage is less than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the bias high voltage to turn on the second control branch.

[0007] In another implementation of the present invention, the startup control module also includes a first equivalent diode, one end of the first control branch is connected to the bias high voltage, the other end of the first control branch is connected to the anode of the first equivalent diode, and the cathode of the first equivalent diode is connected to the first bias low voltage.

[0008] In another implementation of the present invention, the first equivalent diode includes a first transistor, the other end of the first control branch is connected to the emitter of the first transistor, and the collector and base of the first transistor are connected to the first bias low voltage.

[0009] In another implementation of the present invention, the first control branch includes a first equivalent resistor and a first MOS transistor, the first equivalent resistor is connected between the drain of the first MOS transistor and the bias high voltage, the source of the first MOS transistor is connected to the anode of the first equivalent diode, and the gate of the first MOS transistor is connected to the output end of the load branch.

[0010] In another implementation of the present invention, the preset bias low voltage is the third bias low voltage, the second control branch includes a second MOS tube, the source of the second MOS tube is connected to the third bias low voltage, the drain of the second MOS tube is connected to the current injection end of the temperature compensation branch, and the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube, wherein the second bias low voltage is less than the sum of the second switching voltage threshold of the second MOS tube and the third bias low voltage.

[0011] In another implementation of the present invention, the second control branch also includes a second equivalent diode, the anode of the second equivalent diode is connected to the source of the second MOS tube, the cathode of the second equivalent diode is connected to the first bias low voltage, and the reverse turn-off voltage of the second equivalent diode is the third bias low voltage.

[0012] In another implementation of the present invention, the second equivalent diode includes a second triode, the emitter of the second triode is connected to the source of the second MOS tube, and the collector and the base of the second triode are connected to the first bias low voltage.

[0013] In another implementation of the present invention, the preset bias low voltage is the bias high voltage, the second control branch includes a second MOS tube, a third MOS tube and a second equivalent resistor, the source of the second MOS tube is connected to the first bias low voltage, the second equivalent resistor is connected between the drain of the second MOS tube and the bias high voltage, the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube. The gate of the third MOS tube is connected between the second equivalent resistor and the drain of the second MOS tube, the source of the third MOS tube is connected to the bias high voltage, and the drain of the third MOS tube is connected to the current injection terminal of the temperature compensation branch.

[0014] In another implementation of the present invention, the startup control module further includes a third control branch, the third control branch, the third control branch is connected between the control end of the first control branch and the output end of the load branch. When the reference voltage is less than a third switch voltage threshold of the third control branch, the third control branch is turned off, and when the reference voltage is greater than a third switch voltage threshold of the third control branch, the third control branch is turned on, wherein the third switch voltage threshold is less than the sum of the first switch voltage threshold and the second bias low voltage.

[0015] In another implementation of the present invention, the third control branch includes a series of MOS tubes formed by multiple fourth MOS tubes, the gate of each fourth MOS tube is connected to the first bias low voltage, the source of the series MOS tube is connected to the output end of the load branch, and the drain of the series MOS tube is connected to the control end of the first control branch.

[0016] In another implementation of the present invention, the third control branch further includes a capacitor, one end of which is connected to the first bias low voltage, and the other end of which is connected between the drain of the series MOS tube and the control end of the first control branch.

[0017] According to a second aspect of an embodiment of the present invention, there is provided an electronic device, comprising: the bandgap reference startup circuit according to the first aspect.

[0018] In the scheme of the embodiment of the present invention, since the first switch voltage threshold becomes smaller when the bias high voltage becomes smaller, the second bias low voltage that is greater than the first bias low voltage is set, and only when the reference voltage is greater than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the preset bias low voltage, so that the second control branch is turned off to stop the start-up of the bandgap reference voltage source, that is, the smaller reference voltage under abnormal working conditions such as weak current working conditions cannot turn off the second control branch to stop the start-up of the bandgap reference voltage source, so that the bandgap reference voltage source can reliably leave the abnormal working state and reach the normal working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is a schematic circuit diagram of a bandgap reference startup circuit according to some examples.

[0021] Figure 2 Schematic diagram of the structure of a bandgap reference startup circuit according to some embodiments of the present invention.

[0022] Figure 3 for Figure 2 Schematic circuit diagram of a bandgap reference startup circuit of some examples of embodiments.

[0023] Figure 4 for Figure 2 Schematic circuit diagrams of bandgap reference startup circuits according to other examples of the embodiments.

[0024] Figure 5 for Figure 2 Schematic circuit diagrams of bandgap reference startup circuits according to other examples of the embodiments.

[0025] Figure 6 Schematic diagrams of structures of electronic devices according to other embodiments of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in the field based on the embodiments in the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0027] The specific implementation of the embodiment of the present invention is further described below in conjunction with the accompanying drawings of the embodiment of the present invention. Figure 1 A bandgap reference startup circuit according to some examples is shown. Figure 1 As shown, the bandgap reference startup circuit 100 includes a bandgap reference voltage source 110 and a startup control module 120. The startup control module 120 includes a first control branch 121 and a second control branch 122.

[0028] Specifically, the bandgap reference voltage source 110 includes a temperature compensation branch 111 and a load branch 112. The temperature compensation branch 111 and the load branch 112 are connected between a bias high voltage (e.g., a power supply terminal VDD) and a bias low voltage (e.g., a ground terminal GND), and the bandgap reference voltage source 110 provides a reference voltage from an output terminal of the load branch 112 according to a voltage stable state at a current injection terminal of the temperature compensation branch 111.

[0029] With the demand for low power consumption and a larger power supply voltage range, abnormal operating points such as zero current operating point or weak current operating point are more likely to appear in the bandgap reference voltage source, and the startup circuit will not be able to reliably drive the bandgap reference voltage source out of the abnormal operating point, especially the weak current normal operating point.

[0030] For example, in some cases, when the bandgap reference voltage source is at a weak current operating point, or when the power supply voltage of the bandgap reference voltage source is high, the pull-down capability of the first control branch 121 is weak, causing the startup control module 120 to be disconnected, thereby failing to make the bandgap reference voltage source escape from the weak current operating point, resulting in startup failure. In other words, the startup circuit will not be able to reliably make the bandgap reference voltage source escape from an abnormal operating point. For this reason, the present invention provides a series of embodiments that can reliably make the bandgap reference voltage source escape from an abnormal operating point.

[0031] Figure 2 The bandgap reference startup circuit of some embodiments of the present invention is shown. The bandgap reference startup circuit 200 includes a bandgap reference voltage source 210 and a startup control module 220. Specifically, the bandgap reference voltage source 210 includes a temperature compensation branch 211 and a load branch 212. The startup control module 220 includes a first control branch 221 and a second control branch 222.

[0032] Specifically, the temperature compensation branch 211 and the load branch 212 are connected between the bias high voltage and the first bias low voltage VSS1 , and the bandgap reference voltage source 210 provides a reference voltage from the output end of the load branch 212 according to the voltage stability state of the current injection end of the temperature compensation branch 211 .

[0033] In some examples, the temperature compensation branch 211 and the load branch 212 may be Figure 1 The temperature compensation branch 111 and the load branch 112 in the example. The current injection terminal may include Figure 1 A first selectable current injection terminal and a second selectable current injection terminal are shown.

[0034] In addition, the first control branch 221 is connected between the bias high voltage and the second bias low voltage VSS2, and the control end of the first control branch 221 is connected to the output end of the load branch for receiving the reference voltage, wherein the second bias low voltage VSS2 is greater than the first bias low voltage VSS1, and the first switch voltage threshold of the first control branch 221 is positively correlated with the bias high voltage. The second control branch 222 is connected between the current injection end of the temperature compensation branch and the preset bias low voltage, and the control end of the second control branch 222 is connected to the output end of the first control branch 221.

[0035] In addition, when the reference voltage is greater than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch 221 can connect the control end of the second control branch 222 to the preset bias low voltage to turn off the second control branch 222.

[0036] In addition, when the reference voltage is less than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch 221 can connect the control end of the second control branch 222 to the bias high voltage to turn on the second control branch 222.

[0037] In the scheme of the embodiment of the present invention, since the first switch voltage threshold becomes smaller when the bias high voltage becomes smaller, the second bias low voltage VSS2 that is greater than the first bias low voltage VSS1 is set, only when the reference voltage is greater than the sum of the first switch voltage threshold and the second bias low voltage VSS2, the first control branch connects the control end of the second control branch to the preset bias low voltage, so that the second control branch is turned off to stop the start-up of the bandgap reference voltage source, that is, the smaller reference voltage under abnormal working conditions such as weak current working conditions cannot turn off the second control branch to stop the start-up of the bandgap reference voltage source, so that the bandgap reference voltage source can reliably leave the abnormal working state and reach the normal working state.

[0038] In other embodiments, the first control branch includes a first equivalent resistor and a first MOS tube, the first equivalent resistor is connected between the drain of the first MOS tube and the bias high voltage, the source of the first MOS tube is connected to the anode of the first equivalent diode, and the gate of the first MOS tube is connected to the output end of the load branch. In other words, the first equivalent resistor connected to the bias high voltage avoids excessive current in the first control branch, and the first MOS tube simply implements the switch of the first control branch. In addition, by turning off the first MOS tube, the first equivalent resistor pulls the control end of the second control branch to the bias high voltage, and by turning on the first MOS tube, the control end of the second control branch is pulled down to the preset bias low voltage.

[0039] In addition, the second control branch includes a second MOS tube, the source of the second MOS tube is connected to the third bias low voltage VSS3, the drain of the second MOS tube is connected to the current injection end of the temperature compensation branch, and the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube, wherein the second bias low voltage VSS2 is less than the sum of the second switch voltage threshold of the second MOS tube and the third bias low voltage VSS3. In other words, the gate of the second MOS tube is used as the control end of the second control branch, and the simple switch control of the second control branch by the first control branch is realized, so that when the second control branch is turned on, the current injection end of the temperature compensation branch is injected through the third bias low voltage VSS3, so that the bandgap reference voltage source is separated from the abnormal normal working point. In addition, the second bias low voltage VSS2 is less than the sum of the second switch voltage threshold of the second MOS tube and the third bias low voltage VSS3, which avoids the situation that when the reference voltage at the normal working point turns on the first control branch, the corresponding second bias low voltage VSS2 turns on the second MOS tube, thereby causing the startup control module to be unable to turn off.

[0040] Specifically, Figure 3 As shown, transistor Q4 is a PNP transistor, as an example of a first transistor. The base-to-emitter voltage of transistor Q4 is VBE. Switching tube MN3 is an N-type MOS tube, as an example of a first MOS tube. Switching tube MN4 is an N-type MOS tube, as an example of a second MOS tube. Switching tube MP1 and switching tube MP2 are P-type MOS tubes. The power supply terminal VDD provides a bias high voltage, and the ground terminal GND provides a first bias low voltage.

[0041] In addition, the anode of the second equivalent diode is connected to the source of the second MOS tube, the cathode of the second equivalent diode is connected to the first bias low voltage, and the reverse turn-off voltage of the second equivalent diode is the third bias low voltage. That is, by using the reverse turn-off voltage of the second equivalent diode as the third bias low voltage, the first bias low voltage is used to reliably obtain a third bias low voltage higher than the first bias low voltage. In some examples, the second equivalent diode includes a second triode, the emitter of the second triode is connected to the source of the second MOS tube, and the collector and base of the second triode are connected to the first bias low voltage. As a further example, the triode Q5 is a PNP type triode as an example of the second triode. That is, the collector and base of the second triode are short-circuited and connected to the first bias low voltage, which improves the stability of the reverse turn-off low voltage and provides a stable third bias low voltage.

[0042] Optionally, the first equivalent resistor or the second equivalent resistor can be implemented as a resistor or an analog device that acts as a resistor. In some examples, the first equivalent resistor is a series switch tube formed by multiple switch tubes MP11, and the switch tube MP11 is a P-type MOS tube; the second equivalent resistor is a series switch tube formed by multiple switch tubes MP12, and the switch tube MP12 is a P-type MOS tube.

[0043] In some examples, when the bandgap reference voltage source is at a weak current operating point, the reference voltage VBG=VBE, the switch tube MN3 is still in the off state, so that V4 is pulled up to the bias high voltage VDD, and then the switch tube MN4 is turned on. When the switch tube MN4 is in the on state, V5 is pulled to a low level, so that the switch tubes MP1 and MP2 are turned on, thereby injecting current into the current input terminal to make the bandgap reference voltage source out of the weak current operating point.

[0044] In other examples, when the bandgap reference voltage source is at a normal operating point, the reference voltage VBG=1.2V, so that the switch tube MN3 is turned on, and V4 is pulled down to VBE. Since the source end of the switch tube MN4 is connected in series with the transistor Q5, the gate-source voltage VGSN4≈0 of the switch tube MN4 turns off the switch tube MN4, thereby starting the control module to disconnect, which does not affect the normal operation of the bandgap reference voltage source. It should be connected. In this embodiment, the preset bias low voltage is the third bias low voltage, and the source of the second MOS tube is connected to the first optional current injection terminal. The third bias low voltage can be equal to the second bias low voltage, for example, the VBE of the transistor Q4 is equal to the VBE of the transistor Q5.

[0045] That is, the first equivalent diode includes a first triode, the other end of the first control branch is connected to the emitter of the first triode, and the collector and base of the first triode are connected to the first bias low voltage. That is, the collector and base of the first triode are short-circuited and connected to the first bias low voltage, which improves the stability of the reverse turn-off low voltage and provides a stable second bias low voltage.

[0046] In some examples, when the bandgap reference voltage source is at a normal operating point, the reference voltage is less than the sum of the first switching voltage threshold and the second bias low voltage, for example, VTHN3 (i.e., an example of the first switching voltage threshold of the switch tube MN3) + VBE4 (i.e., the second bias low voltage) > 1.2V. In this case, the startup control module cannot be shut down at the normal operating point. Therefore, the switch tube MN3 adopts an N-type MOS tube with a lower switching threshold voltage to make the reference voltage greater than the sum of the first switching voltage threshold and the second bias low voltage.

[0047] Without loss of generality, one end of the first control branch is connected to the bias high voltage, the other end of the first control branch is connected to the anode of the first equivalent diode, and the cathode of the first equivalent diode is connected to the first bias low voltage. That is, the reverse turn-off voltage of the first equivalent diode is used as the second bias low voltage, and the first bias low voltage is used to reliably obtain a second bias low voltage higher than the first bias low voltage.

[0048] In other embodiments, the second control branch includes a second MOS tube, a third MOS tube, and a second equivalent resistor, the source of the second MOS tube is connected to the first bias low voltage, the second equivalent resistor is connected between the drain of the second MOS tube and the bias high voltage, and the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube. Among them, the gate of the third MOS tube is connected between the second equivalent resistor and the drain of the second MOS tube, the source of the third MOS tube is connected to the bias high voltage, and the drain of the third MOS tube is connected to the current injection end of the temperature compensation branch. In other words, the gate of the second MOS tube is used as the control end of the second control branch. When the source of the second MOS tube is connected to the first bias low voltage, the reliable switch control of the second control branch by the first control branch is realized through the cascade of the second MOS tube and the third MOS tube, so that when the second control branch is turned on, the current injection end of the temperature compensation branch is injected with current through the bias high voltage, so that the bandgap reference voltage source is separated from the abnormal operating point.

[0049] Specifically, Figure 4As shown, transistor Q4 is a PNP transistor, which is used as an example of a first transistor. The base-to-emitter voltage of transistor Q4 is VBE. Switching tube MN3 is an N-type MOS tube, which is used as an example of a first MOS tube. Switching tube MN4 is an N-type MOS tube, which is used as an example of a second MOS tube. Switching tube MP4 is a P-type MOS tube, which is used as an example of a third MOS tube. Switching tube MP1 and switching tube MP2 are P-type MOS tubes. The power supply terminal VDD provides a bias high voltage, and the ground terminal GND provides a first bias low voltage.

[0050] exist Figure 3 In the example, the setting of transistor Q5 is actually not conducive to reducing the circuit area of ​​the bandgap reference startup circuit. In this example, the source end of the switch tube MN4 is directly connected to the first bias low voltage which is lower than the second bias low voltage, and compared with Figure 3 The embodiment adds a pull-up branch formed by a second equivalent resistor of V5 and a switch tube MP4.

[0051] In some examples, when the bandgap reference voltage source is at a weak current operating point, the reference voltage VBG=VBE, the switch tube MN3 is still turned off, so that V4 is pulled up to the bias high voltage VDD, and then the switch tube MN4 is turned on. When the switch tube MN4 is in the on state, V5 is pulled down to the first bias low voltage GND, so that the switch tube MP4 is turned on, thereby injecting current into the current injection terminal to break away from the weak current operating point. It should be understood that in this embodiment, the preset bias low voltage is the bias high voltage, and the source of the third MOS tube is connected to the second optional current injection terminal.

[0052] In another example, when the bandgap reference voltage source is at a normal operating point, the reference voltage VBG=1.2V, which turns on the switch tube MN3, thereby pulling V4 down to VBE. Due to the existence of the second equivalent resistor, the switch tube MN4 is turned on but has a weak pull-down capability, causing V5 to be pulled up to the bias high voltage VDD, thereby turning off the switch tube MP4, causing the startup control module to be disconnected, which does not affect the normal operation of the bandgap reference voltage source.

[0053] In some examples, when the bandgap reference voltage source is at a normal operating point, the reference voltage is less than the sum of the first switching voltage threshold and the second bias low voltage, for example, VTHN3 (i.e., an example of the first switching voltage threshold of the switch tube MN3) + VBE4 (i.e., the second bias low voltage) > 1.2V. In this case, the startup control module cannot be shut down at the normal operating point. Therefore, the switch tube MN3 adopts an N-type MOS tube with a lower switching threshold voltage to make the reference voltage greater than the sum of the first switching voltage threshold and the second bias low voltage.

[0054] In some other embodiments, the startup control module further includes a first control circuit, a second control circuit and a third control branch. The third control branch is connected between the control end of the first control branch and the output end of the load branch.

[0055] Specifically, Figure 5 As shown, transistor Q4 is a PNP transistor, as an example of a first transistor. The base-to-emitter voltage of transistor Q4 is VBE. Switch tube MN3 is an N-type MOS tube, as an example of a first MOS tube. Switch tube MN4 is an N-type MOS tube, as an example of a second MOS tube. Switch tube MP4 is a P-type MOS tube, as an example of a third MOS tube. Switch tube MP5 is a P-type MOS tube, as an example of a fourth MOS tube. Switch tube MP1 and switch tube MP2 are P-type MOS tubes. The power supply terminal VDD provides a bias high voltage, and the ground terminal GND provides a first bias low voltage.

[0056] In some examples, when the bandgap reference voltage source is at a weak current operating point, the reference voltage VBG=VBE, the switch tube MN3 is still turned off, so that V4 is pulled up to the bias high voltage VDD, and then the switch tube MN4 is turned on. When the switch tube MN4 is in the on state, V5 is pulled down to the first bias low voltage GND, so that the switch tube MP4 is turned on, thereby injecting current into the current injection terminal to break away from the weak current operating point. It should be understood that in this embodiment, the preset bias low voltage is the bias high voltage, and the source of the third MOS tube is connected to the second optional current injection terminal.

[0057] In another example, when the bandgap reference voltage source is at a normal operating point, the reference voltage VBG=1.2V, which turns on the switch tube MN3, thereby pulling V4 down to VBE. Due to the existence of the second equivalent resistor, the switch tube MN4 is turned on but has a weak pull-down capability, causing V5 to be pulled up to the bias high voltage VDD, thereby turning off the switch tube MP4, causing the startup control module to be disconnected, which does not affect the normal operation of the bandgap reference voltage source.

[0058] In other examples, when the bandgap reference voltage source is at a weak current operating point, VBG is between 300mV and 600mV. If VBG < the third switch voltage threshold VTHP5, the switch tube MP5 is turned off, V6 = 0, so that the startup control module injects current into the current injection end to make the bandgap reference voltage source leave the weak current operating point. If VBG > the third switch voltage threshold VTHP5, V6 = VBG = VBE, since the source end of the switch tube MN3 is connected in series with the transistor Q4, the first switch voltage threshold VGSN3 of the switch tube MN3 is ≈ 0, the switch tube MN3 is turned off, V4 is pulled up to the bias high voltage VDD, so that the switch tube MN4 is turned on, and then V5 is pulled down to the first bias low voltage GND, so that the switch tube MP4 is turned on, and the current is injected into the current injection point to leave the weak current operating point of the bandgap reference voltage source.

[0059] It should be understood that the third control branch includes a series of MOS tubes formed by a plurality of fourth MOS tubes, the gate of each fourth MOS tube is connected to the first bias low voltage, the source of the series MOS tube is connected to the output end of the load branch, and the drain of the series MOS tube is connected to the control end of the first control branch. In other words, the series of MOS tubes formed by the plurality of fourth MOS tubes ensures the safety of the third control branch when turned off, and ensures the reliability of the third control branch when turned on.

[0060] Without loss of generality, when the reference voltage is less than the third switch voltage threshold of the third control branch, the third control branch is turned off, and when the reference voltage is greater than the third switch voltage threshold of the third control branch, the third control branch is turned on, wherein the third switch voltage threshold is less than the sum of the first switch voltage threshold and the second bias low voltage. In other words, the third switch voltage threshold is less than the sum of the first switch voltage threshold and the second bias low voltage, and when the reference voltage is less than the third switch voltage threshold of the third control branch, the third control branch is turned off, thereby further avoiding the first control branch from being turned on by mistake. That is, the robustness of the bandgap reference startup circuit is further enhanced by using the third control branch as an auxiliary branch.

[0061] Furthermore, the third control branch also includes a capacitor C1, one end of the capacitor C1 is connected to the first bias low voltage, and the other end of the capacitor C1 is connected between the drain of the series MOS tube and the control end of the first control branch. For example, the capacitance of the capacitor C1 is in the order of hundreds of fF, and the residual current between the third control branch and the first control branch of the bandgap reference startup circuit during the current startup process is discharged through the capacitor, thereby avoiding the residual current from affecting the accuracy of the next startup process, for example, the initial voltage of V6 is almost 0.

[0062] The following will be combined Figure 6 Electronic devices according to other embodiments of the present invention are described. The electronic device 600 includes a bandgap reference startup circuit 200. The electronic device includes, but is not limited to, a sensor circuit, a power management circuit, and the like. The reference voltage provided by the bandgap reference startup circuit can be used as a reference for a sensor signal, a reference level for an analog-to-digital converter (ADC), or as a stable voltage source in a power management circuit. In practical applications, designers will select a suitable bandgap reference circuit based on the specific needs of the circuit and integrate it into a larger system to achieve the desired functions and performance. For example, a high-precision operational amplifier can be built with a bandgap reference startup circuit to ensure that the input and output of the operational amplifier maintain precise voltages under different temperatures and power supply voltage changes.

[0063] Thus far, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired results. Additionally, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing may be advantageous.

[0064] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0065] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0066] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0067] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A bandgap reference startup circuit, characterized in that: include: A bandgap reference voltage source, comprising a temperature compensation branch and a load branch, wherein the temperature compensation branch and the load branch are connected between a bias high voltage and a first bias low voltage, and the bandgap reference voltage source provides a reference voltage from an output end of the load branch according to a voltage stability state of a current injection end of the temperature compensation branch; Start control module, including: A first control branch is connected between a bias high voltage and a second bias low voltage, a control end of the first control branch is connected to an output end of the load branch, and is used to receive the reference voltage, wherein the second bias low voltage is greater than the first bias low voltage, and a first switch voltage threshold of the first control branch is positively correlated with the bias high voltage; A second control branch connected between the current injection terminal of the temperature compensation branch and a preset bias low voltage, wherein the control terminal of the second control branch is connected to the output terminal of the first control branch; When the reference voltage is greater than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the preset bias low voltage to turn off the second control branch.

2. The circuit according to claim 1, characterized in that When the reference voltage is less than the sum of the first switch voltage threshold and the second bias low voltage, the first control branch connects the control end of the second control branch to the bias high voltage to turn on the second control branch.

3. The circuit according to claim 2, characterized in that The startup control module further includes a first equivalent diode, one end of the first control branch is connected to the bias high voltage, the other end of the first control branch is connected to the anode of the first equivalent diode, and the cathode of the first equivalent diode is connected to the first bias low voltage.

4. The circuit according to claim 3, characterized in that The first equivalent diode includes a first transistor, the other end of the first control branch is connected to the emitter of the first transistor, and the collector and the base of the first transistor are connected to the first bias low voltage.

5. The circuit according to claim 3, characterized in that The first control branch includes a first equivalent resistor and a first MOS tube, the first equivalent resistor is connected between the drain of the first MOS tube and the bias high voltage, the source of the first MOS tube is connected to the anode of the first equivalent diode, and the gate of the first MOS tube is connected to the output end of the load branch.

6. The circuit according to claim 5, characterized in that The preset bias low voltage is the third bias low voltage, the second control branch includes a second MOS tube, the source of the second MOS tube is connected to the third bias low voltage, the drain of the second MOS tube is connected to the current injection end of the temperature compensation branch, and the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube, wherein the second bias low voltage is less than the sum of the second switch voltage threshold of the second MOS tube and the third bias low voltage.

7. The circuit according to claim 6, characterized in that The second control branch also includes a second equivalent diode, the anode of the second equivalent diode is connected to the source of the second MOS tube, the cathode of the second equivalent diode is connected to the first bias low voltage, and the reverse turn-off voltage of the second equivalent diode is the third bias low voltage.

8. The circuit according to claim 7, characterized in that The second equivalent diode comprises a second triode, the emitter of the second triode is connected to the source of the second MOS tube, and the collector and the base of the second triode are connected to the first bias low voltage.

9. The circuit according to claim 5, characterized in that The preset bias low voltage is the bias high voltage, the second control branch includes a second MOS tube, a third MOS tube and a second equivalent resistor, the source of the second MOS tube is connected to the first bias low voltage, the second equivalent resistor is connected between the drain of the second MOS tube and the bias high voltage, and the gate of the second MOS tube is connected between the first equivalent resistor and the drain of the first MOS tube; Among them, the gate of the third MOS tube is connected between the second equivalent resistor and the drain of the second MOS tube, the source of the third MOS tube is connected to the bias high voltage, and the drain of the third MOS tube is connected to the current injection end of the temperature compensation branch.

10. The circuit according to claim 2, characterized in that The startup control module further includes a third control branch, wherein the third control branch is connected between the control end of the first control branch and the output end of the load branch. When the reference voltage is less than a third switch voltage threshold of the third control branch, the third control branch is turned off, and when the reference voltage is greater than a third switch voltage threshold of the third control branch, the third control branch is turned on, wherein the third switch voltage threshold is less than the sum of the first switch voltage threshold and the second bias low voltage.

11. The circuit according to claim 10, characterized in that The third control branch includes a series of MOS tubes formed by multiple fourth MOS tubes, the gate of each fourth MOS tube is connected to the first bias low voltage, the source of the series MOS tube is connected to the output end of the load branch, and the drain of the series MOS tube is connected to the control end of the first control branch.

12. The circuit according to claim 11, characterized in that The third control branch further includes a capacitor, one end of which is connected to the first bias low voltage, and the other end of which is connected between the drain of the series MOS tube and the control end of the first control branch.

13. An electronic device, characterized in that: include: A bandgap reference startup circuit according to any one of claims 1 to 12.

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