A high-voltage bandgap reference structure

Abstract

This application provides a high-voltage bandgap reference structure, which includes a reference module, a start-stop module, and a feedback module. The reference module has a reference voltage node and a reference module power supply node. The start-stop module includes a first branch, a second branch, a start-up voltage structure, and a start-up switch. The first branch includes a first PNP transistor, a second PNP transistor, and a first resistor connected in series between the power supply and ground. The second branch includes a second resistor, a third PNP transistor, and a fourth PNP transistor connected in series between the power supply and the start-up voltage node. The start-up voltage structure is connected in series between the start-up voltage node and the ground. The base of the start-up switch is connected to the start-up voltage node, the collector is connected to the power supply, and the emitter is connected to the reference voltage node, used to pull up the reference voltage under the drive of the start-up voltage. The feedback module includes a positive feedback structure. Its advantage is that when the power supply voltage changes, the output voltage of the reference module and the start-up voltage provided by the start-stop module can have better power supply suppression.

Description

Technical Field

[0001] This application relates to the field of electronic systems, and more specifically, to a high-voltage bandgap reference structure. Background Technology

[0002] In the field of electronic systems, core devices such as measuring instruments and power management chips place extremely stringent requirements on the performance of reference voltage sources. Taking measuring instruments as an example, even a slight deviation in the reference voltage source can lead to significant errors in the final output during the multi-stage signal processing and amplification.

[0003] Under low supply voltage conditions, a simple bandgap reference circuit can effectively suppress the influence of temperature on the output voltage. However, as the supply voltage increases, the bandgap voltage may fluctuate drastically. This is because some key components in the bandgap reference source, such as the threshold voltage of the transistor and the voltage divider characteristics of the resistor, undergo nonlinear changes under high voltage environments. Such drastic fluctuations can have extremely adverse effects on subsequent circuits, leading to output signal distortion; in analog-to-digital conversion circuits, an unstable reference voltage directly affects conversion accuracy, causing errors in the digital signal output. Therefore, there is a need in the existing technology for a more stable bandgap reference circuit under voltage variations. Utility Model Content

[0004] To address or improve the aforementioned problems in the existing technology, this application provides a high-voltage bandgap reference structure, which includes a reference module, a start-stop module, and a feedback module.

[0005] The reference module includes a reference voltage node and a reference module power supply node.

[0006] The start-stop module includes a first branch, a second branch, a start-up voltage structure, and a start-up switch transistor. The first branch includes a first PNP transistor, a second PNP transistor, and a first resistor connected in series between the power supply and the ground terminal. The second branch includes a second resistor, a third PNP transistor, and a fourth PNP transistor connected in series between the power supply and the start-up voltage node. The bases of the first PNP transistor and the third PNP transistor are connected, and the bases of the second PNP transistor and the fourth PNP transistor are connected. The start-up voltage structure is connected in series between the start-up voltage node and the ground terminal.

[0007] The start-up switch is an NPN transistor, with its base connected to the start-up voltage node, its collector connected to the power supply, and its emitter connected to the reference voltage node. It is used to pull up the reference voltage under the drive of the start-up voltage.

[0008] The feedback module includes a positive feedback structure;

[0009] The positive feedback structure is used to accelerate the establishment of the reference voltage. It includes a first NPN transistor, a second NPN transistor, and a fifth PNP transistor. The base of the first NPN transistor is connected to the reference voltage node, the emitter is grounded via a resistor, and the collector is connected to the base of the fifth PNP transistor. The collector of the fifth PNP transistor is connected to the power supply node of the reference module. The base of the second NPN transistor is connected to the power supply node of the reference module, the collector is connected to the power supply, and the emitter is connected to the reference voltage node.

[0010] In the aforementioned scheme, when the power supply is turned on, the current flows to ground through the first branch, establishing an initial current. The third PNP transistor in the second branch is interconnected with the base of the first PNP transistor in the first branch, forming a current mirror. However, because the emitter of the third PNP transistor is connected in series with a second resistor, under the same base voltage, the collector current of the third PNP transistor will be much smaller than that of the first PNP transistor. This significantly reduces the power consumption of the startup circuit.

[0011] In the aforementioned scheme, a small current flows through the fourth PNP transistor. The collector voltage of the fourth PNP transistor is used to control the startup switch. The base voltage of the second PNP transistor fluctuates with the power supply voltage, and this fluctuation is transmitted to the base of the fourth PNP transistor. When the base voltage and emitter voltage of the fourth PNP transistor increase equally, its impedance increases, thereby suppressing voltage fluctuations at its collector (startup voltage node). This makes the startup voltage in the aforementioned scheme insensitive to changes in the power supply voltage, i.e., it has a high PSRR (Power Supply Rejection Ratio, which is the ratio of the change in input power supply to the change in circuit output).

[0012] In the aforementioned scheme, when the startup voltage is high enough, the startup switch is turned on, injecting the charge from the power supply into the base of the third NPN transistor in the reference circuit, thus starting the reference module.

[0013] In the aforementioned scheme, the startup voltage structure is used to raise the startup voltage to a level sufficient to turn on the startup switch transistor.

[0014] The positive feedback structure in the aforementioned scheme is used to accelerate the startup of the high-voltage bandgap reference structure. Specifically, when the startup switch begins charging the reference voltage node, the reference voltage is very low. As the reference voltage rises, the base voltage of the first NPN transistor increases, the collector current increases, and the voltage decreases. Subsequently, the base voltage of the fifth PNP transistor decreases, the collector current decreases, and the voltage (i.e., the base voltage of the second NPN transistor and the voltage of the reference module power node) rises. The emitter voltage of the second NPN transistor (i.e., the reference voltage) rises further. It is evident that this structure forms a positive feedback process, enabling the reference voltage to quickly establish itself near the operating point.

[0015] Optionally, the reference module includes a sixth PNP transistor, a seventh PNP transistor, a third NPN transistor, a fourth NPN transistor, a third resistor, and a fourth resistor; wherein,

[0016] The base and emitter of the sixth PNP transistor are connected to the power supply node of the reference module, and the base and collector of the sixth PNP transistor are connected.

[0017] The collectors of the third NPN transistor and the sixth PNP transistor are connected, and the collectors of the fourth NPN transistor and the seventh PNP transistor are connected.

[0018] The bases of the third and fourth NPN transistors are both connected to the reference voltage node;

[0019] One end of the third resistor is connected to the emitter of the third NPN transistor, and the other end is connected to the emitter of the fourth NPN transistor.

[0020] One end of the fourth resistor is connected to the emitter of the fourth NPN transistor, and the other end is grounded.

[0021] Optionally, the feedback module may include a negative feedback structure;

[0022] The negative feedback structure is used to suppress fluctuations in the reference voltage and includes an eighth PNP transistor, a second NPN transistor, and a first capacitor.

[0023] The base of the eighth PNP transistor is connected to the collector of the fourth NPN transistor and grounded via the first capacitor. The collector of the eighth PNP transistor is grounded, and the emitter is connected to the power node of the reference module.

[0024] In the aforementioned scheme, the negative feedback structure is used to maintain the stability of the reference voltage. When the reference voltage continues to rise above the design value for some reason (such as interference), the collector current of the fourth NPN transistor increases, and the voltage drops. The emitter voltage of the eighth PNP transistor then drops, and the emitter voltage of the second NPN transistor (i.e., the reference voltage) also drops. This structure forms a negative feedback process that pulls the reference voltage back to a stable value.

[0025] Optionally, the start / stop module also includes: a charge discharge tube, which is a PNP tube, with its base connected to the power supply, its emitter connected to the reference module power node, and its collector grounded.

[0026] In the aforementioned scheme, when the power is off, the charge discharge tube is turned on, quickly discharging the charge from the power node of the reference module to ground, preventing charge accumulation from causing abnormal circuit conditions.

[0027] Optionally, the base and collector of the first PNP transistor are connected, and the base and collector of the second PNP transistor are connected.

[0028] The startup voltage structure includes a fifth NPN transistor and a sixth NPN transistor. The collector and base of the fifth NPN transistor are connected to the startup voltage node, and the emitter is connected to the base and collector of the sixth NPN transistor. The emitter of the sixth NPN transistor is grounded.

[0029] In the aforementioned scheme, the fifth and sixth NPN transistors raise the VBE voltage of these two transistors to ensure that the startup switching transistors can be fully turned on.

[0030] Optionally, the feedback module includes a voltage regulator structure for providing a stable voltage to the power nodes of the reference module.

[0031] Optionally, the voltage regulator structure includes a ninth PNP tube, a tenth PNP tube, an eleventh PNP tube, and a fifth PNP tube;

[0032] The base and collector of the ninth PNP transistor are connected to the base of the fifth PNP transistor.

[0033] The base and collector of the tenth PNP transistor are connected to the emitter of the ninth PNP transistor and the base of the eleventh PNP transistor, and the emitter is connected to the power supply.

[0034] The emitter of the eleventh PNP transistor is connected to the power supply, and the collector is connected to the emitter of the fifth PNP transistor.

[0035] In the aforementioned scheme, the ninth, tenth, eleventh, and fifth PNP transistors constitute a high output impedance voltage regulator structure, which can improve the PSRR between the power supply and the power node of the reference module.

[0036] Optionally, the feedback module may also include: a seventh NPN transistor, a fifth resistor, and a sixth resistor;

[0037] The base and collector of the seventh NPN transistor are connected to the reference voltage node, and the emitter is grounded via the sixth resistor;

[0038] One end of the fifth resistor is connected to the emitter of the first NPN transistor, and the other end is grounded.

[0039] Optionally, the resistance values ​​R3 of the third resistor and R4 of the fourth resistor satisfy the following:

[0040] V REF = V BEN04 +2×V T lnN ×R4 / R3

[0041] Among them, V REF The reference voltage value, V BEN04 V is the base-emitter voltage of the fourth NPN transistor. T is the thermal voltage, and N is the ratio of the operating currents of the third NPN transistor and the fourth NPN transistor.

[0042] Optionally, the reference voltage changes at a rate of less than or equal to 0.12 mV / ℃ and the power supply rejection ratio is greater than or equal to 110 dB in the range of -55℃ to 125℃.

[0043] In summary, the high-voltage bandgap reference structure provided in this application has the advantage of better power supply rejection for the output voltage of the reference module and the start-up voltage provided by the start-stop module when the power supply voltage changes. Experimental results show that the rate of change of the start-up voltage with the power supply voltage does not exceed 50uV, and the rate of change of the reference voltage does not exceed 51.5uV. Under conditions of -55℃ to 125℃, the rate of change of the output reference voltage with temperature does not exceed 0.12mV / ℃, and the power supply rejection ratio is greater than or equal to 110dB. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0045] Figure 1 This is a functional logic diagram of the high-voltage bandgap reference structure provided in the embodiments of this application;

[0046] Figure 2 This is a schematic diagram of the circuit structure of the high-voltage bandgap reference structure provided in the embodiments of this application;

[0047] Figure 3 This is a schematic diagram of the circuit structure of the start-stop module in the high-voltage bandgap reference structure provided in this application embodiment;

[0048] Figure 4 This is a schematic diagram of the circuit structure of the reference module in the high-voltage bandgap reference structure provided in this application embodiment;

[0049] Figure 5 This is a schematic diagram of the circuit structure of the feedback module in the high-voltage bandgap reference structure provided in this application embodiment.

[0050] The image is labeled as follows:

[0051] 100: Baseline module, 200: Start-stop module, 300: Feedback module;

[0052] 210: First branch, 220: Second branch, 230: Start-up voltage structure;

[0053] 310: Voltage stabilizing structure;

[0054] VREF is the reference voltage node, BG_VDD is the reference module power node, and VST is the startup voltage node;

[0055] P01 to P11 are the first to eleventh PNP tubes;

[0056] N01 to N07 are the first to seventh NPN transistors;

[0057] M10 is the start-up switch transistor, and M20 is the charge discharge transistor. Detailed Implementation

[0058] In this specification, it will also be understood that when a component is referred to as being "connected to" other components relative to them, such as "connected to" other components, the component may be directly connected to or directly coupled to the component, or there may be an intermediary third component; in addition, in the embodiments of this application, "connection" mainly refers to electrical connection.

[0059] This application will now be described more fully below with reference to the accompanying drawings. However, this application can be implemented in many different ways and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided herein to make this application more detailed and complete, and to fully convey the scope of this application to those skilled in the art. The same reference numerals denote the same objects throughout the drawings.

[0060] In view of the problem that in the prior art, the reference voltage (VREF) output by the bandgap reference circuit drifts with changes in the power supply voltage (VCC), leading to circuit malfunction, this application proposes a high-voltage bandgap reference structure, the functional logic block diagram of which is as follows: Figure 1 As shown, the circuit structure mainly consists of three key modules (sub-circuits): a reference module, a start / stop module, and a feedback module.

[0061] In this application, the influence of the power supply voltage on the reference voltage is reduced mainly from two key aspects, thereby improving the overall stability of the circuit.

[0062] First, this application focuses on reducing the sensitivity of the startup voltage (VST) to changes in the power supply voltage, in order to ensure the startup of the switching transistor M10 (such as...). Figure 2 or Figure 3 As shown, it can still operate normally under changes in power supply voltage. That is, when the power supply voltage rises, the start-stop module responds quickly and outputs a start-up voltage that is insensitive to changes in power supply voltage. This start-up voltage pulls the reference voltage through the aforementioned start-up switch M10.

[0063] Secondly, this application aims to reduce the influence of power supply voltage VCC on the reference module power supply voltage (BG_VDD) of the reference circuit, thereby reducing the impact of power supply voltage changes on the reference voltage.

[0064] Verification has shown that the high-voltage bandgap reference structure provided in this application can significantly suppress the variation of the startup voltage (VST) with the power supply voltage, as well as the sensitivity of the reference voltage to power supply voltage variations. The overall circuit's PSRR is significantly improved, providing a stable and reliable bandgap reference structure for high-voltage applications and effectively solving the problem of traditional reference voltages being greatly affected by power supply voltage.

[0065] In a specific embodiment, the overall circuit schematic of the high-voltage bandgap reference structure provided in this application is as follows: Figure 2 As shown, this circuit structure can both suppress the influence of high supply voltage (VCC) on the reference voltage (VREF) and improve the response speed of the reference circuit.

[0066] like Figure 2 As shown, the high-voltage bandgap reference structure provided in this application includes a reference module 100, a start / stop module 200, and a feedback module 300; wherein, as Figure 4 As shown, the reference module 100 has a reference voltage node VREF and a reference module power node BG_VDD. The voltage input to the reference module power node BG_VDD serves as the local power supply of the reference module 100.

[0067] like Figure 3 As shown, the start-stop module 200 includes a first branch 210, a second branch 220, a start-up voltage structure 230, and a start-up switch transistor M10. The first branch 210 includes a first PNP transistor P01, a second PNP transistor P02, and a first resistor R1 connected in series between the power supply VCC and the ground terminal GND. The second branch 220 includes a second resistor R2, a third PNP transistor P03, and a fourth PNP transistor P04 connected in series between the power supply VCC and the start-up voltage node VST. The bases of the first PNP transistor P01 and the third PNP transistor P03 are connected, and the bases of the second PNP transistor P02 and the fourth PNP transistor P04 are connected. The start-up voltage structure 230 is connected in series between the start-up voltage node VST and the ground terminal GND.

[0068] The start-up switch M10 is an NPN transistor. Its base is connected to the start-up voltage node VST, its collector is connected to the power supply VCC, and its emitter is connected to the reference voltage node VREF. It is used to pull up the reference voltage under the drive of the start-up voltage. The aforementioned start-up switch M10 can be regarded as the start-up switch of the high-voltage bandgap reference structure, providing a pre-charge channel for the reference voltage node VREF.

[0069] Regarding the connection method of the components in the aforementioned first branch 210 and second branch 220, more specifically, as follows: Figure 3As shown, the emitter of the first PNP transistor P01 is connected to the power supply, and its base and collector are connected to the emitter of the second PNP transistor P02; the base and collector of the second PNP transistor P02 are connected to one end of the first resistor R1; the emitter of the third PNP transistor P03 is connected to the second resistor R2, and its collector is connected to the emitter of the fourth PNP transistor P04; the collector of the fourth PNP transistor P04 is connected to the start-up voltage node VST.

[0070] Explained, when the power supply voltage increases, current begins to flow in the first branch. The third PNP transistor P03 and the fourth PNP transistor P04 will replicate a smaller current due to the presence of the second resistor R2. When the power supply voltage VCC fluctuates, the base of the second PNP transistor P02 will experience the same fluctuation, but this will suppress the collector voltage (i.e., the startup voltage node VST) of the fourth PNP transistor P04, thus enhancing the startup voltage's immunity to power supply voltage interference.

[0071] For example, when the power supply voltage VCC increases, the current in the first branch increases. (Refer to...) Figure 2 It can be seen that the collector and base voltages of the second PNP transistor P02 and the base voltage of the fourth PNP transistor P04 (the three are connected) all increase. Based on the characteristics of the fourth PNP transistor P04, its collector output current will decrease. Therefore, the voltage of the startup voltage node VST tends to decrease, which plays a role in suppressing the startup voltage node VST.

[0072] While ensuring the startup circuit functions properly, adjusting the resistance value of the second resistor R2 can effectively reduce the power consumption of the startup circuit.

[0073] The feedback module 300 includes a positive feedback structure; the positive feedback structure is used to accelerate the establishment of the reference voltage, such as... Figure 5 As shown, the positive feedback structure includes at least a first NPN transistor N01, a second NPN transistor N02, and a fifth PNP transistor P05. The base of the first NPN transistor N01 is connected to the reference voltage node VREF, the emitter is grounded via a resistor, and the collector is connected to the base of the fifth PNP transistor P05. The collector of the fifth PNP transistor P05 is connected to the reference module power supply node BG_VDD. The base of the second NPN transistor N02 is connected to the reference module power supply node BG_VDD, the collector is connected to the power supply, and the emitter is connected to the reference voltage node VREF.

[0074] When the start-up switch M10 is turned on, the voltage at the reference voltage node VREF rises, causing the collector voltage of the first NPN transistor N01 to drop, the collector voltage of the fifth PNP transistor P05 to rise, and the emitter voltage of the second NPN transistor N02 to rise. That is, the voltage generates a small superposition of voltages at the reference voltage node VREF through this positive feedback branch.

[0075] It is evident that the aforementioned positive feedback branch can accelerate the establishment of the reference voltage node VREF voltage at the start-up, or accelerate the start-up of the negative feedback circuit described in subsequent embodiments when the reference voltage is slightly affected by external factors.

[0076] In a preferred embodiment, such as Figure 4 As shown, the reference module 100 includes a sixth PNP transistor P06, a seventh PNP transistor P07, a third NPN transistor N03, a fourth NPN transistor N04, a third resistor R3, and a fourth resistor R4.

[0077] Among them, the base of the sixth PNP transistor P06 and the seventh PNP transistor P07 are connected, and the emitter is connected to the reference module power node BG_VDD. The base and collector of the sixth PNP transistor P06 are connected.

[0078] The collectors of the third NPN transistor N03 and the sixth PNP transistor P06 are connected, and the collectors of the fourth NPN transistor N04 and the seventh PNP transistor P07 are connected.

[0079] The bases of the third NPN transistor N03 and the fourth NPN transistor N04 are both connected to the reference voltage node VREF.

[0080] One end of the third resistor R3 is connected to the emitter of the third NPN transistor N03, and the other end is connected to the emitter of the fourth NPN transistor N04.

[0081] One end of the fourth resistor R4 is connected to the emitter of the fourth NPN transistor N04, and the other end is grounded.

[0082] In the aforementioned embodiment, due to the base-emitter voltage (V) of the fourth NPN transistor N04 BEN04 It has a negative temperature coefficient, and its current (I) N04 Satisfies the equation:

[0083]

[0084] in, Here are the process parameters, q is the electron charge, and D is the process parameter. n n is the electron diffusion coefficient. p0 Where W is the base region minority carrier concentration, A is the base region width, and V is the emitter junction area. T =kT / q is the thermal voltage.

[0085] In formula V T In the equation =kT / q, k is the Boltzmann constant, with a value of 1.38 × 10⁻⁶. -23 J / K, T is absolute temperature, and q is the electron charge, with a value of 1.602 × 10⁻⁶. -19 C. Typically, under an environment of T=300K, V TIt is approximately 0.026V.

[0086] When the bases of the third NPN transistor N03 and the fourth NPN transistor N04 are interconnected, the base-emitter voltage of the fourth NPN transistor N04 is equal to the base-emitter voltage of the third NPN transistor N03 plus the voltage across the third resistor R3. That is, V R3 =V BEN04 -V BEN03 , where V BEN04 V is the base-emitter voltage of the fourth NPN transistor N04. BEN03 V is the base-emitter voltage of the third NPN transistor N03. R3 This is the voltage across the third resistor R3.

[0087] When the fourth NPN transistor N04 and the third NPN transistor N03 operate at a current ratio of 1:N, the difference between their base-emitter voltages is proportional to the absolute temperature. Ignoring the small current injected by the eighth PNP transistor P08, and maintaining the current ratio of the sixth PNP transistor P06 and the seventh PNP transistor P07 at 1:1, the base voltage of the second NPN transistor N02, i.e., the reference voltage value V... REF satisfy:

[0088] V REF =V BEN04 +R4*(V BEN04 -V BEN03 ) / R3

[0089] That is, V REF = V BEN04 +2×V T lnN ×R4 / R3

[0090] As can be seen from the formula, selecting an appropriate resistance ratio or current ratio can reduce the negative temperature coefficient voltage between the base and emitter of the fourth NPN transistor N04 relative to the reference voltage value V. REF The impact.

[0091] In an optional embodiment, the resistance values ​​R3 of the third resistor and R4 of the fourth resistor can be based on the relationship: V REF =V BEN04 +2×V T Set using lnN ×R4 / R3.

[0092] While positive feedback can speed up the response, adding only positive feedback may affect the stability of the circuit. Therefore, a negative feedback branch needs to be introduced into the circuit to keep the circuit in a negative feedback state to maintain stability.

[0093] In a typical embodiment, the negative feedback structure is used to suppress fluctuations in the reference voltage, such as... Figure 5As shown, the negative feedback structure includes an eighth PNP transistor P08, a second NPN transistor N02, and a first capacitor C1.

[0094] The base of the eighth PNP transistor P08 is connected to the collector of the fourth NPN transistor N04, and is grounded via the first capacitor C1. The collector is grounded, and the emitter is connected to the reference module power node BG_VDD.

[0095] When the reference voltage increases, the collector voltage of the fourth NPN transistor N04 decreases, the emitter voltage of the eighth PNP transistor P08 decreases, and the emitter voltage of the second NPN transistor N02 decreases. At this time, the voltage signal generated through this negative feedback branch will be superimposed on the reference voltage, which has the effect of suppressing the voltage rise.

[0096] During the process of the aforementioned reference voltage node VREF gradually increasing through the positive feedback branch, both the positive and negative feedback branches play a role. It should be understood that the positive feedback branch plays a dominant role at this time, while the negative feedback branch plays a dominant role during the voltage holding phase and the voltage fluctuation phase of the reference voltage node VREF.

[0097] In a preferred embodiment, such as Figure 3 As shown, the start / stop module 200 also includes a charge discharge tube M20, which is a PNP transistor. Its base is connected to the power supply VCC, its emitter is connected to the power node BG_VDD of the reference module, and its collector is grounded GND. When the power supply voltage VCC is turned off, the charge discharge tube M20 can quickly discharge the inter-line accumulated charge at the power node BG_VDD of the reference module.

[0098] In a typical embodiment, such as Figure 3 As shown, the base and collector of the first PNP transistor P01 are connected, and the base and collector of the second PNP transistor P02 are connected.

[0099] The startup voltage structure 230 includes a fifth NPN transistor N05 and a sixth NPN transistor N06. The collector and base of the fifth NPN transistor N05 are connected to the startup voltage node VST, and the emitter is connected to the base and collector of the sixth NPN transistor N06. The emitter of the sixth NPN transistor N06 is grounded to GND.

[0100] In the aforementioned embodiment, the base and collector of the fifth NPN transistor N05 and the sixth NPN transistor N06 are each connected together, so that the startup voltage node VST can generate the BE junction voltage of these two NPN transistors, thereby ensuring that the startup switch transistor M10 can start and stop normally.

[0101] In a preferred embodiment, the feedback module 300 includes a voltage regulator structure 310 for providing a stable voltage to the power node of the reference module. Typically, as... Figure 5As shown, the voltage regulator structure 310 includes a ninth PNP tube P09, a tenth PNP tube P10, an eleventh PNP tube P11, and a fifth PNP tube P05.

[0102] The base and collector of the ninth PNP transistor P09 are connected to the base of the fifth PNP transistor P05.

[0103] The base and collector of the tenth PNP transistor P10 are connected to the emitter of the ninth PNP transistor P09 and the base of the eleventh PNP transistor P11, and the emitter is connected to the power supply VCC.

[0104] The emitter of the eleventh PNP transistor P11 is connected to the power supply VCC, and the collector is connected to the emitter of the fifth PNP transistor P05.

[0105] The aforementioned voltage regulator structure 310 is used to continuously provide a stable voltage to the reference module power node BG_VDD after the start-up switch M10 is turned off, thereby avoiding or reducing the impact of power supply voltage VCC fluctuations on the reference module power node BG_VDD voltage.

[0106] Furthermore, such as Figure 5 As shown, the feedback module 300 also includes: a seventh NPN transistor N07, a fifth resistor R5, and a sixth resistor R6.

[0107] The base and collector of the seventh NPN transistor N07 are connected to the reference voltage node VREF, and the emitter is grounded through the sixth resistor R6;

[0108] One end of the fifth resistor R5 is connected to the emitter of the first NPN transistor N1, and the other end is grounded to GND.

[0109] In the aforementioned embodiments, the ninth PNP transistor P09, the tenth PNP transistor P10, the eleventh PNP transistor P11, and the fifth PNP transistor P05 can reduce the impact of the power supply voltage on the power node BG_VDD of the reference module.

[0110] from Figure 5 As can be seen from the circuit structure shown, the reference voltage is equal to the base voltage of the second NPN transistor N02 (i.e., the reference module power node BG_VDD voltage) minus the base-emitter voltage of the second NPN transistor N02. That is, this structure can reduce the impact of excessive power supply voltage changes on the reference module power node BG_VDD.

[0111] In the aforementioned embodiment, the current flows through the seventh NPN transistor N07 and the sixth resistor R6 to ground, forming a fixed voltage drop between the base and emitter of the seventh NPN transistor N07. This voltage drop, plus the voltage across the sixth resistor R6, constitutes a stable bias voltage. This bias voltage is provided to the base of the first NPN transistor N01 to prevent the base voltage of the first NPN transistor N01 from changing with the power supply voltage VCC, thus making the positive feedback loop more stable.

[0112] Adjusting the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 in the circuit can reduce the current in their respective branches. However, excessively large values ​​may cause the branch to shut down. Appropriate selection can reduce power consumption. This circuit achieves a relatively high power supply rejection ratio, while the first capacitor C1 can be appropriately reduced to maintain circuit stability.

[0113] In a preferred embodiment, the reference voltage changes at a rate of less than or equal to 0.12 mV / ℃ between -55°C and 125°C, and the power supply rejection ratio is greater than or equal to 110 dB.

[0114] In the high-voltage bandgap reference structure provided by this invention, the overall operation of the circuit is as follows: When the power supply voltage increases, the bases of the first PNP transistor P01 and the second PNP transistor P02 begin to rise, and the third PNP transistor P03 and the fourth PNP transistor P04 begin to conduct, generating a startup voltage (i.e., the voltage at the VTS node). This startup voltage has a certain anti-interference capability against the power supply voltage. When the startup voltage reaches the turn-on voltage of the startup switch transistor M10, the startup switch transistor M10 provides a charging channel to charge the reference voltage node VREF until the first NPN transistor N01 is turned on. Then, through the positive feedback loop of the ninth PNP transistor P09, the tenth PNP transistor P10, the fifth PNP transistor P05, the eleventh PNP transistor P11, the second NPN transistor N02, and the seventh NPN transistor N07, a voltage superposition is generated at the reference voltage node VREF, which accelerates the startup speed of the reference circuit.

[0115] As the reference voltage node VREF gradually increases through the positive feedback branch, the fourth NPN transistor N04, the eighth PNP transistor P08, and the second NPN transistor N02 in the negative feedback branch also operate successively, suppressing the reference voltage node VREF. Finally, the third NPN transistor N03 and the fourth NPN transistor N04 are fully turned on, and the reference voltage node VREF is limited to V. BEN04 Apply the voltage across the fourth resistor R4.

[0116] At this time, the base-emitter voltage of the start-up switch M10 is less than the turn-on voltage of the start-up switch M10, and the start-up switch M10 is turned off.

[0117] By introducing the eleventh PNP transistor P11, the tenth PNP transistor P10, the ninth PNP transistor P09, and the fifth PNP transistor P05 into the feedback circuit, the equivalent output resistance can be increased, thereby enhancing the suppression of the reference voltage node VREF. At the same time, connecting the reference power supply voltage together with the base of the second NPN transistor N02 can further enhance the anti-interference capability of the collector voltage of the seventh PNP transistor P07 and the sixth PNP transistor P06 against the power supply voltage, making the current flowing through the fourth resistor R4 more stable, and thus reducing the influence of the power supply voltage on the reference voltage node VREF.

[0118] Because of the addition of the ninth PNP transistor P09 and the fifth PNP transistor P05, the equivalent resistance increases. Therefore, to maintain the stability of the negative feedback loop, a first capacitor C1 is added between the base of the eighth PNP transistor P08 and ground GND. Finally, when the power supply VCC is turned off, the charge discharge transistor M20 acts as a fast discharge path, pulling down the voltage of the reference module power node BG_VDD and shutting down the reference circuit.

[0119] In the high-voltage bandgap reference structure provided by this invention, the advantage of this circuit is that when the power supply voltage changes, the output voltage of the reference and the output voltage of its startup circuit can have better power supply rejection. Results show that the startup output voltage changes no more than 50µV with the power supply voltage, and the reference voltage changes no more than 51.5µV. Under conditions of -55℃ to 125℃, the reference voltage node VREF changes no more than 0.12mV / ℃ with temperature, and the power supply rejection ratio is greater than or equal to 110dB.

[0120] By adding a second PNP transistor P02 between the first PNP transistor P01 and the first resistor R1, the power consumption and area of ​​this branch can be reduced. This is because without the second PNP transistor P02, the area of ​​the first resistor R1 required to achieve the same power consumption is larger than the area required using the PNP transistor.

[0121] By adding a second resistor R2 between the power supply VCC and the third PNP transistor P03, the current generated by the third PNP transistor P03 can be made less than the current of the first PNP transistor P01, thereby further reducing the power consumption of the startup circuit and increasing the equivalent resistance between the third PNP transistor P03 and VCC.

[0122] By adding a fourth PNP transistor P04 between the third PNP transistor P03 and the fifth NPN transistor N05, the resistance between the startup voltage node VST and VCC can be increased, thereby improving the power supply interference immunity of the startup voltage node VST.

[0123] By adding a fifth PNP transistor P05 between the eleventh PNP transistor P11 and the eighth PNP transistor P08, and adding a ninth PNP transistor P09 between the tenth PNP transistor P10 and the first NPN transistor N01, the equivalent resistance between the base of the second NPN transistor N02 and VCC can be increased, thereby reducing the impact of the power supply voltage on the power node BG_VDD of the reference module.

[0124] Meanwhile, when the power supply node BG_VDD of the reference module increases due to the increase in the power supply voltage VCC, it will cause the collector voltage of the seventh NPN transistor N07 to increase, thereby suppressing the effect of the increase in the collector voltage of the fourth NPN transistor N04 caused by the increase in BG_VDD voltage. At the same time, connecting the emitters of the sixth PNP transistor P06 and the eighth PNP transistor P08 together with the base of the second NPN transistor N02 can reduce the influence of the power supply voltage on the collector voltage of the third NPN transistor N03, thereby enhancing the anti-interference capability of the current of the third NPN transistor N03 and the fourth NPN transistor N04 on BG_VDD, and increasing the anti-interference capability of the reference voltage node VREF on the power supply.

[0125] In summary, the high-voltage bandgap reference structure provided in this application, through an innovative startup module design, generates a startup voltage insensitive to the power supply voltage VCC, ensuring reliable circuit startup under varying power supply voltage conditions. Furthermore, the voltage regulation structure in the feedback module provides a stable power supply to the reference module (i.e., the BG_VDD node), significantly attenuating fluctuations in the power supply voltage VCC. The positive feedback structure in the feedback module ensures rapid startup, while the negative feedback structure ensures precise voltage stability, and capacitor C1 eliminates potential stability issues. In addition, the current mirror loads, the seventh PNP transistor P07 and the eighth PNP transistor P08, are also connected to the stable BG_VDD node, rather than the unstable power supply voltage VCC, thus reducing the impact of VCC variations from an architectural perspective.

[0126] The above description is only a partial embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-voltage bandgap reference structure, characterized in that, It includes a reference module (100), a start / stop module (200), and a feedback module (300); among which, The reference module (100) has a reference voltage node and a reference module power node; The start-stop module (200) includes a first branch (210), a second branch (220), a start-up voltage structure (230), and a start-up switch. The first branch (210) includes a first PNP transistor, a second PNP transistor, and a first resistor connected in series between the power supply and the ground terminal. The second branch (220) includes a second resistor, a third PNP transistor, and a fourth PNP transistor connected in series between the power supply and the start-up voltage node. The bases of the first PNP transistor and the third PNP transistor are connected, and the bases of the second PNP transistor and the fourth PNP transistor are connected. The start-up voltage structure is connected in series between the start-up voltage node and the ground terminal. The start-up switch is an NPN transistor, with its base connected to the start-up voltage node, its collector connected to the power supply, and its emitter connected to the reference voltage node, used to pull up the reference voltage under the drive of the start-up voltage; The feedback module (300) includes a positive feedback structure; The positive feedback structure is used to accelerate the establishment of the reference voltage and includes a first NPN transistor, a second NPN transistor, and a fifth PNP transistor. The base of the first NPN transistor is connected to the reference voltage node, the emitter is grounded via a resistor, and the collector is connected to the base of the fifth PNP transistor. The collector of the fifth PNP transistor is connected to the power supply node of the reference module. The base of the second NPN transistor is connected to the power supply node of the reference module, the collector is connected to the power supply, and the emitter is connected to the reference voltage node.

2. The high-voltage bandgap reference structure according to claim 1, characterized in that, The reference module (100) includes a sixth PNP transistor, a seventh PNP transistor, a third NPN transistor, a fourth NPN transistor, a third resistor, and a fourth resistor; wherein, The base and emitter of the sixth PNP transistor are connected to the power supply node of the reference module, and the base and collector of the sixth PNP transistor are connected. The collectors of the third NPN transistor and the sixth PNP transistor are connected, and the collectors of the fourth NPN transistor and the seventh PNP transistor are connected. The bases of the third NPN transistor and the fourth NPN transistor are both connected to the reference voltage node; One end of the third resistor is connected to the emitter of the third NPN transistor, and the other end is connected to the emitter of the fourth NPN transistor. One end of the fourth resistor is connected to the emitter of the fourth NPN transistor, and the other end is grounded.

3. The high-voltage bandgap reference structure according to claim 2, characterized in that, The feedback module (300) includes a negative feedback structure; The negative feedback structure is used to suppress fluctuations in the reference voltage and includes an eighth PNP transistor, a second NPN transistor, and a first capacitor. The base of the eighth PNP transistor is connected to the collector of the fourth NPN transistor and grounded via the first capacitor. The collector is grounded and the emitter is connected to the power node of the reference module.

4. The high-voltage bandgap reference structure according to claim 1, characterized in that, The start / stop module (200) also includes: The charge discharge tube is a PNP transistor, with its base connected to the power supply, its emitter connected to the power node of the reference module, and its collector grounded.

5. The high-voltage bandgap reference structure according to claim 1 or 4, characterized in that, The base and collector of the first PNP transistor are connected, and the base and collector of the second PNP transistor are connected. The startup voltage structure includes a fifth NPN transistor and a sixth NPN transistor. The collector and base of the fifth NPN transistor are connected to the startup voltage node, and the emitter is connected to the base and collector of the sixth NPN transistor. The emitter of the sixth NPN transistor is grounded.

6. The high-voltage bandgap reference structure according to claim 3, characterized in that, The feedback module (300) includes a voltage regulator structure (310) for providing a stable voltage to the power node of the reference module after the start-up switch is turned off.

7. The high-voltage bandgap reference structure according to claim 6, characterized in that, The voltage regulator structure (310) includes a ninth PNP tube, a tenth PNP tube, an eleventh PNP tube, and the fifth PNP tube; The base and collector of the ninth PNP transistor are connected to the base of the fifth PNP transistor. The base and collector of the tenth PNP transistor are connected to the emitter of the ninth PNP transistor and the base of the eleventh PNP transistor, and the emitter is connected to the power supply. The emitter of the eleventh PNP transistor is connected to the power supply, and the collector is connected to the emitter of the fifth PNP transistor.

8. The high-voltage bandgap reference structure according to claim 7, characterized in that, The feedback module (300) further includes: a seventh NPN transistor, a fifth resistor, and a sixth resistor; The base and collector of the seventh NPN transistor are connected to the reference voltage node, and the emitter is grounded via the sixth resistor; One end of the fifth resistor is connected to the emitter of the first NPN transistor, and the other end is grounded.

9. The high-voltage bandgap reference structure according to claim 2, characterized in that, The resistance values ​​R3 of the third resistor and R4 of the fourth resistor satisfy the following: V REF = V BEN04 +2×V T lnN ×R4 / R3 Among them, V REF The reference voltage value, V BEN04 V is the base-emitter voltage of the fourth NPN transistor. T is the thermal voltage, and N is the ratio of the operating currents of the third NPN transistor and the fourth NPN transistor.

10. The high-voltage bandgap reference structure according to claim 9, characterized in that, The reference voltage changes at a rate of less than or equal to 0.12 mV / ℃ between -55℃ and 125℃, and the power supply rejection ratio is greater than or equal to 110 dB.

Images