A negative voltage bandgap reference circuit

Abstract

The present invention discloses a negative voltage bandgap reference circuit, belonging to the field of integrated circuit technology. The circuit includes a startup unit, a reference core unit, and a reference detection unit. The startup unit is connected to the reference core unit and the reference detection unit, and the reference core unit is connected to the reference detection unit. The negative voltage bandgap reference circuit of the present invention can meet the requirement of a lower absolute value of the power supply voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a negative voltage bandgap reference circuit. Background Art

[0002] The reference circuit is one of the core parts of the integrated circuit voltage regulator. Its accuracy and stability directly affect the overall performance of the entire system. Common reference circuits are mainly divided into bandgap reference circuits with operational amplifiers and bandgap reference circuits without operational amplifiers.

[0003] There are two common architectures in operational amplifier bandgap reference circuits: the classic Brokaw Cell architecture and the feedback loop architecture. Both architectures have the following disadvantages: large quiescent current, as the operational amplifier itself consumes current; waste of area, as the operational amplifier requires additional compensation circuits to achieve high gain, which is complex in design and occupies a large area; a high minimum power supply voltage, which must meet the common-mode input range and output swing of the operational amplifier; and an offset voltage introduced into the input of the operational amplifier, which directly affects the bandgap reference voltage and makes it impossible to achieve high output voltage accuracy and consistency.

[0004] A self-biased architecture is commonly used in op-amp-less bandgap reference circuits. This architecture replaces the op-amp with a current mirror or negative feedback loop. This architecture eliminates the offset voltage introduced by the op-amp, and the output stage often uses a source-follower output. However, the minimum power supply voltage (VDD) is relatively high, making it unsuitable for low-power-voltage scenarios. Summary of the Invention

[0005] The present invention aims to provide a negative voltage bandgap reference circuit which has low minimum power supply voltage requirement and does not introduce offset voltage.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A negative voltage bandgap reference circuit comprises a startup unit, a reference core unit, and a reference detection unit, wherein the startup unit is connected to the reference core unit and the reference detection unit, and the reference core unit is connected to the reference detection unit;

[0008] The power supply voltage V of the negative voltage bandgap reference circuit in satisfy:

[0009] ,

[0010] in, is the saturation drain-source voltage of the transistor, V BG is the reference voltage.

[0011] More specifically, the startup unit includes a tenth resistor and a plurality of transistors, the first end of the tenth resistor is grounded, the second end of the tenth resistor is connected to the first end of the zeroth transistor, the second end of the zeroth transistor is connected to the second end and the third end of the twentieth transistor and the third end of the twenty-first transistor, and the first end of the twentieth transistor is connected to the power supply voltage.

[0012] More specifically, the startup unit further includes a twenty-second transistor, a first end of the twenty-second transistor is connected to the second end and the third end of the twenty-second transistor, and a first end of the twenty-second transistor is connected to a power supply voltage.

[0013] More specifically, the reference core unit includes a plurality of transistors, a plurality of resistors and a plurality of transistors, wherein the first end of the zeroth transistor is grounded, the second end of the zeroth transistor is connected to the first end of the zeroth resistor, the second end of the zeroth resistor is connected to the first end of the second resistor and the third end of the zeroth transistor, and the second end of the second resistor is connected to the second end of the twenty-first transistor; the first end of the first resistor is grounded, the second end of the first resistor is connected to the first end of the first transistor, the third end of the first transistor is connected to the first end of the zeroth resistor, the second end of the first transistor is connected to the first end of the third resistor, and the second end of the third resistor is connected to the second end of the twenty-first transistor; the first end of the second transistor is grounded, the third end of the second transistor is connected to the first end of the third resistor, the second end of the second transistor is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the third transistor, the third end of the third transistor is connected to the second end of the twenty-first transistor, the second end of the third transistor is connected to the second end of the nineteenth transistor, the first end of the nineteenth transistor is connected to the second end of the eighth transistor, and the first end of the eighth transistor is connected to the power supply voltage; the first end of the fifth resistor is grounded, the second end of the first resistor is connected to the first end of the first transistor, the third end of the first transistor is connected to the first end of the third resistor, and the second end of the third transistor is connected to the second end of the twenty-first transistor. One end is grounded, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the first end of the fourth triode, the third end of the fourth triode is connected to the second end of the twenty-first transistor, the second end of the fourth triode is connected to the second end of the eighteenth transistor and the first end of the twenty-first transistor, the third end of the eighteenth transistor is connected to the third end of the nineteenth transistor, the first end of the eighteenth transistor is connected to the second end of the ninth transistor, the third end of the ninth transistor is connected to the third end of the eighth transistor and the first end of the twenty-first transistor, and the first end of the ninth transistor is connected to the power supply voltage; the third end of the fourth triode is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the second end of the seventeenth transistor, the third end of the seventeenth transistor is connected to the third end of the nineteenth transistor, the first end of the seventeenth transistor is connected to the second end of the tenth transistor, the third end of the tenth transistor is connected to the third end of the eighth transistor, and the first end of the tenth transistor is connected to the power supply voltage; the first end of the eighth resistor is grounded, the second end of the eighth resistor is connected to the second end of the thirteenth transistor, and the first end of the thirteenth transistor is connected to the second end of the seventh resistor.

[0014] More specifically, the reference core unit further includes a plurality of transistors, wherein a first end of the second transistor is grounded, a second end of the second transistor is connected to a third end thereof and the second end of a sixteenth transistor, a third end of the sixteenth transistor is connected to the third end of a nineteenth transistor, a first end of the sixteenth transistor is connected to the second end of the eleventh transistor, a third end of the eleventh transistor is connected to the third end of the eighth transistor, and a first end of the eleventh transistor is connected to a power supply voltage; a first end of the seventh transistor is grounded, a second end of the seventh transistor is connected to a third end thereof and the second end of a fifteenth transistor, a third end of the fifteenth transistor is connected to the third end of the nineteenth transistor, a first end of the fifteenth transistor is connected to the second end of the twelfth transistor, and a third end of the twelfth transistor is connected to the third end of the eighth transistor. The first end of the twelfth transistor is connected to the power supply voltage; the first end of the third transistor is grounded, the third end of the third transistor is connected to the third end of the second transistor, the second end of the third transistor is connected to the second end and the third end of the fourteenth transistor, the third end of the fourteenth transistor is connected to the third end of the nineteenth transistor, and the first end of the fourteenth transistor is connected to the power supply voltage; the first end of the fourth transistor is grounded, the third end of the fourth transistor is connected to the third end of the second transistor, the second end of the fourth transistor is connected to the third end of the thirteenth transistor and the first end of the first transistor, the third end of the first transistor is connected to the second end of the third triode, the second end of the first transistor is connected to the power supply voltage through the ninth resistor, and the zero capacitor is connected between the third end of the second triode and the second end of the third triode.

[0015] More specifically, the reference detection unit includes a first comparator and multiple transistors, the first end of the fifth transistor is grounded, the third end of the fifth transistor is connected to the third end of the second transistor, the second end of the fifth transistor is connected to the first end of the sixth transistor, the third end of the sixth transistor is connected to the third end of the seventh transistor, the second end of the sixth transistor is connected to the first input end of the first comparator, the second input end of the first comparator is connected to the second end of the second transistor, the third input end of the first comparator is connected to the first end of the sixth resistor, and the output end of the first comparator outputs a first signal to the third end of the zeroth transistor.

[0016] More specifically, the reference voltage V BG The expression is:

[0017] ,

[0018] in, , is the emitter-base voltage of the transistor when the parallel number M=1, is the emitter-base voltage of the transistor when the parallel number M=8, R0 is the resistance of the zeroth resistor, R1 is the resistance of the first resistor, R2 is the resistance of the second resistor, and R7 is the resistance of the seventh resistor.

[0019] More specifically, the resistance values ​​of the second resistor and the third resistor are equal.

[0020] More specifically, the resistance of the second resistor is equal to the sum of the resistance of the fifth resistor and the resistance of the sixth resistor.

[0021] More specifically, the resistance of the fourth resistor is equal to four times the resistance of the sixth resistor.

[0022] Beneficial effects: The negative voltage bandgap reference circuit of the present invention can meet the requirement of a lower absolute value of the power supply voltage; no operational amplifier is used to achieve clamping, there is no offset introduced by the operational amplifier, and the output voltage accuracy and consistency are high; the overall circuit occupies a small area; after the reference voltage is established, the startup unit is turned off, thereby reducing the circuit power consumption; the negative feedback loop can ensure the loop stability of the negative voltage bandgap reference circuit.

[0023] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic structural diagram of a negative voltage bandgap reference circuit of the present invention.

[0025] Figure 2 This is a circuit diagram of a first specific embodiment of a negative voltage bandgap reference circuit according to the present invention.

[0026] Figure 3 This is a circuit diagram of a second specific embodiment of a negative voltage bandgap reference circuit of the present invention.

[0027] In the drawings, like reference numerals refer to the same drawing elements. DETAILED DESCRIPTION

[0028] To make the purpose and technical solutions of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Figure 1 FIG. 1 is a schematic diagram of a negative voltage bandgap reference circuit according to the present invention. Figure 1 As shown, a negative voltage bandgap reference circuit includes a startup unit 11 , a reference core unit 12 , and a reference detection unit 13 . The startup unit 11 is connected to the reference core unit 12 and the reference detection unit 13 , and the reference core unit 12 is connected to the reference detection unit 13 .

[0030] More specifically, the startup unit 11 injects current into the reference core unit 12 to generate a reference voltage; the reference detection unit 13 determines whether the reference voltage is established normally. If the reference voltage is successfully established, the startup unit 11 is controlled to be turned off to achieve no additional current consumption; if the reference voltage is not established, the startup unit 11 is controlled to be turned on to inject current into the reference core unit 12.

[0031] Figure 2 FIG. 1 is a circuit diagram of a first specific embodiment of a negative voltage bandgap reference circuit according to the present invention. Figure 2 As shown, a negative voltage bandgap reference circuit includes a startup unit 21 , a reference core unit 22 , and a reference detection unit 23 . The startup unit 21 is connected to the reference core unit 22 and the reference detection unit 23 , and the reference core unit 22 is connected to the reference detection unit 23 .

[0032] Furthermore, the startup unit 21 includes a resistor R10 and a plurality of transistors, wherein a first end of the resistor R10 is grounded GND, a second end of the resistor R10 is connected to a first end of the transistor M0, a second end of the transistor M0 is connected to a second end and a third end of the transistor M20 and a third end of the transistor M21, a first end of the transistor M20 is connected to a second end and a third end of the transistor M22, and a first end of the transistor M22 is connected to a power supply voltage V in .

[0033] Furthermore, the reference core unit 22 includes a plurality of transistors, a plurality of resistors, and a plurality of transistors. The first end of the transistor Q0 is grounded to GND, the second end of the transistor Q0 is connected to the first end of the resistor R0, the second end of the resistor R0 is connected to the first end of the resistor R2 and the third end of the transistor Q0, and the second end of the resistor R2 is connected to the second end of the transistor M21; the first end of the resistor R1 is grounded to GND, the second end of the resistor R1 is connected to the first end of the transistor Q1, the third end of the transistor Q1 is connected to the first end of the resistor R0, and the second end of the transistor Q1 is connected to the resistor R1. The first end of R3 and the second end of the resistor R3 are connected to the second end of the transistor M21; the first end of the transistor Q2 is grounded GND, the third end of the transistor Q2 is connected to the first end of the resistor R3, the second end of the transistor Q2 is connected to the first end of the resistor R4, the second end of the resistor R4 is connected to the first end of the transistor Q3, the third end of the transistor Q3 is connected to the second end of the transistor M21, the second end of the transistor Q3 is connected to the second end of the transistor M19, the first end of the transistor M19 is connected to the second end of the transistor M8, and the first end of the transistor M8 is connected to the power supply voltage V inA first end of the resistor R5 is connected to the ground GND, a second end of the resistor R5 is connected to the first end of the resistor R6, a second end of the resistor R6 is connected to the first end of the transistor Q4, a third end of the transistor Q4 is connected to the second end of the transistor M21, a second end of the transistor Q4 is connected to the second end of the transistor M18 and the first end of the transistor M21, a third end of the transistor M18 is connected to the third end of the transistor M19, a first end of the transistor M18 is connected to the second end of the transistor M9, a third end of the transistor M9 is connected to the third end of the transistor M8 and the first end of the transistor M21, and a first end of the transistor M9 is connected to the power supply voltage V in The third end of the transistor Q4 is connected to the first end of the resistor R7, the second end of the resistor R7 is connected to the second end of the transistor M17, the third end of the transistor M17 is connected to the third end of the transistor M19, the first end of the transistor M17 is connected to the second end of the transistor M10, the third end of the transistor M10 is connected to the third end of the transistor M8, and the first end of the transistor M10 is connected to the power supply voltage V in The first end of the resistor R8 is connected to the ground GND, the second end of the resistor R8 is connected to the second end of the transistor M13, and the first end of the transistor M13 is connected to the second end of the resistor R7; the first end of the transistor M2 is connected to the ground GND, the second end of the transistor M2 is connected to the third end thereof and the second end of the transistor M16, the third end of the transistor M16 is connected to the third end of the transistor M19, the first end of the transistor M16 is connected to the second end of the transistor M11, the third end of the transistor M11 is connected to the third end of the transistor M8, and the first end of the transistor M11 is connected to the power supply voltage V in The first end of the transistor M7 is connected to the ground GND, the second end of the transistor M7 is connected to the third end thereof and the second end of the transistor M15, the third end of the transistor M15 is connected to the third end of the transistor M19, the first end of the transistor M15 is connected to the second end of the transistor M12, the third end of the transistor M12 is connected to the third end of the transistor M8, and the first end of the transistor M12 is connected to the power supply voltage V in The first end of the transistor M3 is connected to the ground GND, the third end of the transistor M3 is connected to the third end of the transistor M2, the second end of the transistor M3 is connected to the second end and the third end of the transistor M14, the third end of the transistor M14 is connected to the third end of the transistor M19, and the first end of the transistor M14 is connected to the power supply voltage V in The first end of the transistor M4 is connected to the ground GND, the third end of the transistor M4 is connected to the third end of the transistor M2, the second end of the transistor M4 is connected to the third end of the transistor M13 and the first end of the transistor M1, the third end of the transistor M1 is connected to the second end of the triode Q3, and the second end of the transistor M1 is connected to the power supply voltage V through the resistor R9. in The capacitor C0 is connected between the third terminal of the transistor Q2 and the second terminal of the transistor Q3. The second terminal of the resistor R7 generates a reference voltage V for generating a negative bandgap reference voltage according to the present invention.BG .

[0034] Furthermore, the reference detection unit 23 includes a comparator COMP1 and a plurality of transistors, a first end of the transistor M5 is grounded GND, a third end of the transistor M5 is connected to the third end of the transistor M2, a second end of the transistor M5 is connected to the first end of the transistor M6, a third end of the transistor M6 is connected to the third end of the transistor M7, a second end of the transistor M6 is connected to the first input end of the comparator COMP1, a second input end of the comparator COMP1 is connected to the second end of the transistor Q2, a third input end of the comparator COMP1 is connected to the first end of the resistor R6, and an output end of the comparator COMP1 outputs a signal V COMP To the third terminal of transistor M0.

[0035] Optionally, the transistors M0 to M22 may be MOSFETs; the first terminal of each transistor is its source, the second terminal of each transistor is its drain, and the third terminal of each transistor is its gate.

[0036] More specifically, transistors M0 to M7 are P-type MOSFETs, and transistors M8 to M22 are N-type MOSFETs.

[0037] Optionally, the transistors Q0 to Q4 are PNP transistors, wherein the first end of each transistor is its emitter, the second end of each transistor is its collector, and the third end of each transistor is its base.

[0038] Next, continue to combine Figure 2 The working principle of a negative voltage bandgap reference circuit of the present invention is introduced. Before the negative voltage bandgap reference circuit is started, the signal V output by the comparator COMP1 is COMP = is low, the startup unit 21 is turned on, at this time the transistor M0, the transistor M20, and the transistor M22 are turned on, and the startup unit 21 injects current into the reference core unit 22 through the transistor M21. Among them, the startup unit 21 needs to normally inject current into the reference core unit 22 if:

[0039]

[0040] In the above formula, is the gate-source voltage of transistor M20, is the gate-source voltage of the transistor M22, and the absolute value of the lowest power supply voltage can be limited according to the above formula.

[0041] Furthermore, after the startup unit 21 injects current into the reference core unit 22 through the transistor M21, the reference core unit 22 establishes a reference voltage V based on the injected current. BGMore specifically, the transistor M21 injects current into the gates of the transistors M8 and M10. If the current in the branch where the transistors M8 and M10 are located can be established normally, the negative voltage bandgap reference circuit of the present invention can operate stably.

[0042] Therefore, for the branch where the transistor M10 is located, the power supply voltage V in Need to meet:

[0043]

[0044] in, is the saturation drain-source voltage of transistor M10, is the saturation drain-source voltage of transistor M17.

[0045] For the branch where transistor M8 is located, the power supply voltage V in Need to meet:

[0046]

[0047] in, is the gate-source voltage of transistor M13, is the gate-source voltage of transistor M1, is the saturation drain-source voltage of transistor M8, is the saturation drain-source voltage of transistor M19.

[0048] In summary, the power supply voltage V of the negative voltage bandgap reference circuit of the present invention is in Need to meet:

[0049] ,

[0050] in, is the saturation drain-source voltage of the transistor, and 100mV is the threshold voltage difference between N-type MOSFET and P-type MOSFET.

[0051] The power supply voltage requirement of a common negative voltage bandgap reference circuit without an op amp architecture is:

[0052] ,

[0053] in, is the threshold voltage of the transistor.

[0054] In a specific embodiment, The default value is 100mV. The default value is 700mV. Therefore, the power supply voltage V in Need to meet:

[0055] ;

[0056] The power supply voltage requirement of a common negative voltage bandgap reference circuit without an op amp architecture is:

[0057] .

[0058] It can be seen that the absolute value of the lowest power supply voltage of the negative voltage bandgap reference circuit of the present invention is much lower than the absolute value of the lowest power supply voltage of the common negative voltage bandgap reference circuit without operational amplifier architecture. Therefore, the negative voltage bandgap reference circuit of the present invention is suitable for more application scenarios of negative voltage regulators.

[0059] More specifically, transistors Q0 and Q2 are of the same type and are connected in parallel in number M=1. Therefore, the voltage V1 at the third terminal of transistor Q0 and the voltage V2 at the third terminal of transistor Q2 are expressed as follows:

[0060]

[0061] in, is the emitter-base voltage of the transistor when the parallel number M=1.

[0062] More specifically, resistors R2 and R3 satisfy , combined with the above formula, the current I flowing through the resistor R2 is R2 The current I flowing through resistor R3 R3 for:

[0063] ,

[0064] Among them, VCOM is the node where the third terminal of transistor Q3 is located, V COM is the voltage of the node VCOM.

[0065] More specifically, transistor Q1 is of the same type as transistor Q0 and transistor Q2, and the number of transistors connected in parallel is M=8. Then the voltage V1 can also be expressed as:

[0066] ,

[0067] in, is the emitter-base voltage of the transistor when the parallel number M=8.

[0068] From this we can get the current I flowing through resistor R2 R2 The current I flowing through resistor R3 R3 for:

[0069]

[0070] in, .

[0071] More specifically, transistors Q3 and Q4 are of the same type as transistors Q1, Q0, and Q2, and the number of parallel connections M=1, then the current of the self-bias branch where transistor M9 is located is for:

[0072] ,

[0073] Combined It can be seen that:

[0074] .

[0075] More specifically, let the resistor R2 satisfy , you can guarantee: .

[0076] More specifically, since the transistor M9 and the transistor M8 form a current mirror structure with a width-to-length ratio of 1:1, the current I flowing through the transistor Q3 is Q3 , the current I flowing through transistor Q4 Q4 Satisfies the following relationship:

[0077] .

[0078] In summary, the reference voltage V BG The expression is:

[0079] .

[0080] More specifically, the reference voltage V BG It also has low temperature drift characteristics.

[0081] In addition, the reference voltage V BG After the resistor divider reaches the node VCOM, the reference voltage V BG The node where it is located, node VCOM, node VBN0, node VSTR_FB, node VSTR, reference voltage V BG The node where the reference voltage V BG The node where it is located, node VCOM, node VSTR_FB, node VSTR, reference voltage V BG A negative feedback loop is formed at the node where the voltage is applied. In both feedback loops, since the AC impedance of node VSTR_FB is much greater than that of node VBN0, and the remaining loop paths are consistent, the gain of the negative feedback loop is ensured to be much greater than the gain of the positive feedback loop, thereby obtaining a stable negative voltage bandgap reference circuit. Node VBN0 is the node where the first terminal of transistor M21 is located, node VSTR_FB is the node where the third terminal of transistor M1 is located, and node VSTR is the node where the third terminal of transistor M13 is located.

[0082] Furthermore, transistors M2, M3, M4, and M5 form a current mirror. Transistor M2 is self-biased for the current mirror; transistor M3 is the output of the current mirror, providing operating current for transistor M14; transistor M4 is the output of the current mirror, providing operating current for transistor M1; and transistor M5 is the output of the current mirror, providing operating current for comparator COMP1.

[0083] Furthermore, the transistor M7 provides a voltage to the transistor M6 ; the transistor M6 and the transistor M5 form a cascode architecture, providing a current with strong anti-interference capability to the comparator COMP1 .

[0084] Furthermore, the transistor M11 and the transistor M12 are both outputs of the current mirror, providing operating current to the transistor M2 and the transistor M7 respectively.

[0085] Furthermore, transistor M14 provides voltage to transistors M15, M16, M17, M18, and M19, so that the current mirror forms a cascode architecture to increase the reference voltage V BG The ability to resist power supply interference at equal voltage points.

[0086] Furthermore, the reference detection unit 23 compares the voltage V3 of the second terminal of the transistor Q2 with the voltage V4 of the second terminal of the resistor R5, thereby determining the reference voltage V BG Is it established normally?

[0087] When the reference voltage V BG Normally, the expression of the second terminal voltage V3 of the transistor Q2 is:

[0088] ,

[0089] The expression of the voltage V4 at the second terminal of the resistor R5 is:

[0090] .

[0091] Furthermore, the resistor R4 satisfies the relationship: ,because , so the reference voltage V BG When the current I M9 When generated, , at this time the comparator COMP1 outputs the signal V comp is high, turning off the transistor M0 and thus turning off the startup unit 21, so that the startup unit 21 does not consume additional current.

[0092] However, when the reference voltage V BG , current IM9 When not established, , at this time the comparator COMP1 outputs the signal V comp The driving transistor M0 is turned on, thereby turning on the startup unit 21. The startup unit 21 injects current into the node VBN0, thereby allowing the entire circuit to break away from the merging point and thus establish the reference voltage V BG .

[0093] In summary, the negative voltage bandgap reference circuit of the present invention can meet the requirement of a lower absolute value of the power supply voltage; no operational amplifier is used to achieve clamping, there is no offset introduced by the operational amplifier, and the output voltage accuracy and consistency are high; the overall circuit occupies a small area; after the reference voltage is established, the startup unit is turned off, thereby reducing circuit power consumption; and the negative feedback loop can ensure the loop stability of the negative voltage bandgap reference circuit.

[0094] Figure 3 FIG. 1 is a circuit diagram of a second specific embodiment of a negative voltage bandgap reference circuit according to the present invention. Figure 3 As shown, a negative voltage bandgap reference circuit includes a startup unit 31 , a reference core unit 32 , and a reference detection unit 33 . The startup unit 31 is connected to the reference core unit 32 and the reference detection unit 33 , and the reference core unit 32 is connected to the reference detection unit 33 .

[0095] Figure 3 Specific embodiments and Figure 2 The only difference between the specific embodiment and the embodiment is that the transistor M22 is omitted, and the first end of the transistor M20 is directly connected to the power supply voltage V in .

[0096] Therefore, in order for the startup unit 31 to normally inject current into the reference core unit 32, the following conditions must be met:

[0097] ,

[0098] Therefore, a lower absolute value of the power supply voltage can be achieved.

[0099] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary skill in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

Claims

1. A negative voltage bandgap reference circuit, characterized in that: The system comprises a startup unit, a reference core unit, and a reference detection unit, wherein the startup unit is connected to the reference core unit and the reference detection unit, and the reference core unit is connected to the reference detection unit; The power supply voltage V of the negative voltage bandgap reference circuit in satisfy: ， in, is the saturation drain-source voltage of the transistor, V BG is the reference voltage; The startup unit includes a tenth resistor and a plurality of transistors, wherein a first end of the tenth resistor is grounded, a second end of the tenth resistor is connected to a first end of a zeroth transistor, a second end of the zeroth transistor is connected to a second end and a third end of a twentieth transistor and a third end of a twenty-first transistor, and a first end of the twentieth transistor is connected to a power supply voltage; The reference core unit includes multiple transistors, multiple resistors and multiple transistors, the first end of the zeroth transistor is grounded, the second end of the zeroth transistor is connected to the first end of the zeroth resistor, the second end of the zeroth resistor is connected to the first end of the second resistor and the third end of the zeroth transistor, and the second end of the second resistor is connected to the second end of the twenty-first transistor; the first end of the first resistor is grounded, the second end of the first resistor is connected to the first end of the first transistor, the third end of the first transistor is connected to the first end of the zeroth resistor, the second end of the first transistor is connected to the first end of the third resistor, and the second end of the third resistor is connected to the second end of the twenty-first transistor; the first end of the second transistor is grounded, the third end of the second transistor is connected to the first end of the third resistor, and the second end of the second transistor is connected to the a first end of the fourth resistor is connected to the first end of the third transistor, a second end of the fourth resistor is connected to the first end of the third triode, a third end of the third triode is connected to the second end of the twenty-first transistor, a second end of the third triode is connected to the second end of the nineteenth transistor, a first end of the nineteenth transistor is connected to the second end of the eighth transistor, and a first end of the eighth transistor is connected to the power supply voltage; a first end of the fifth resistor is grounded, a second end of the fifth resistor is connected to the first end of the sixth resistor, a second end of the sixth resistor is connected to the first end of the fourth triode, a third end of the fourth triode is connected to the second end of the twenty-first transistor, a second end of the fourth triode is connected to the second end of the eighteenth transistor and the first end of the twenty-first transistor, a third end of the eighteenth transistor is connected to the third end of the nineteenth transistor, and a first end of the eighteenth transistor is connected to the third end of the The first end of the transistor is connected to the second end of the ninth transistor, the third end of the ninth transistor is connected to the third end of the eighth transistor and the first end of the twenty-first transistor, and the first end of the ninth transistor is connected to the power supply voltage; the third end of the fourth transistor is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the second end of the seventeenth transistor, the third end of the seventeenth transistor is connected to the third end of the nineteenth transistor, the first end of the seventeenth transistor is connected to the second end of the tenth transistor, the third end of the tenth transistor is connected to the third end of the eighth transistor, and the first end of the tenth transistor is connected to the power supply voltage; the first end of the eighth resistor is grounded, the second end of the eighth resistor is connected to the second end of the thirteenth transistor, and the first end of the thirteenth transistor is connected to the second end of the seventh resistor; the second A first terminal of the transistor is grounded, a second terminal of the second transistor is connected to a third terminal thereof and the second terminal of a sixteenth transistor, the third terminal of the sixteenth transistor is connected to the third terminal of the nineteenth transistor, the first terminal of the sixteenth transistor is connected to the second terminal of the eleventh transistor, the third terminal of the eleventh transistor is connected to the third terminal of the eighth transistor, and the first terminal of the eleventh transistor is connected to a power supply voltage; a first terminal of the seventh transistor is grounded, a second terminal of the seventh transistor is connected to a third terminal thereof and the second terminal of the fifteenth transistor, the third terminal of the fifteenth transistor is connected to the third terminal of the nineteenth transistor, the first terminal of the fifteenth transistor is connected to the second terminal of the twelfth transistor, the third terminal of the twelfth transistor is connected to the third terminal of the eighth transistor, and the first terminal of the twelfth transistor is connected to the power supply voltage;A first end of the third transistor is grounded, a third end of the third transistor is connected to the third end of the second transistor, a second end of the third transistor is connected to the second end and the third end of the fourteenth transistor, the third end of the fourteenth transistor is connected to the third end of the nineteenth transistor, and the first end of the fourteenth transistor is connected to a power supply voltage; a first end of the fourth transistor is grounded, a third end of the fourth transistor is connected to the third end of the second transistor, a second end of the fourth transistor is connected to the third end of the thirteenth transistor and the first end of the first transistor, a third end of the first transistor is connected to the second end of the third triode, a second end of the first transistor is connected to the power supply voltage via a ninth resistor, and a zero capacitor is connected between the third end of the second triode and the second end of the third triode; The reference detection unit includes a first comparator and multiple transistors, the first end of the fifth transistor is grounded, the third end of the fifth transistor is connected to the third end of the second transistor, the second end of the fifth transistor is connected to the first end of the sixth transistor, the third end of the sixth transistor is connected to the third end of the seventh transistor, the second end of the sixth transistor is connected to the first input end of the first comparator, the second input end of the first comparator is connected to the second end of the second transistor, the third input end of the first comparator is connected to the first end of the sixth resistor, and the output end of the first comparator outputs a first signal to the third end of the zeroth transistor.

2. A negative voltage bandgap reference circuit as claimed in claim 1, characterized in that: The startup unit further includes a twenty-second transistor, a first end of the twenty-second transistor is connected to the second end and the third end of the twenty-second transistor, and a first end of the twenty-second transistor is connected to a power supply voltage.

3. A negative voltage bandgap reference circuit as claimed in claim 1, characterized in that: Reference voltage V BG The expression is: ， in, , is the emitter-base voltage of the transistor when the parallel number M=1, is the emitter-base voltage of the transistor when the parallel number M=8, R0 is the resistance of the zeroth resistor, R1 is the resistance of the first resistor, R2 is the resistance of the second resistor, and R7 is the resistance of the seventh resistor.

4. A negative voltage bandgap reference circuit as claimed in claim 3, characterized in that: The resistance values ​​of the second resistor and the third resistor are equal.

5. A negative voltage bandgap reference circuit as claimed in claim 4, characterized in that: The resistance of the second resistor is equal to the sum of the resistance of the fifth resistor and the resistance of the sixth resistor.

6. A negative voltage bandgap reference circuit as claimed in claim 5, characterized in that: The resistance of the fourth resistor is equal to four times the resistance of the sixth resistor.

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