High-order temperature compensation band-gap reference circuit

Abstract

The invention discloses a high-order temperature compensation band-gap reference circuit, and relates to the technical field of electronic circuits. The circuit comprises a reference generation module, a current source module, a first operational amplifier, a first transistor and a capacitor. The current output port is connected with the current input port, the non-inverting input end of the first operational amplifier is connected with the first voltage port, the inverting input end of the first operational amplifier is connected with the second voltage port, the output end of the first operational amplifier is connected with the grid electrode of the first transistor, and the source electrode of the first transistor is connected with the reference output port. The drain electrode of the first transistor is connected with a first voltage. The capacitor is connected in parallel between the output end and the inverting input end of the first operational amplifier. The reference output port is used for outputting reference voltage according to the output current. According to the high-order temperature compensation band-gap reference circuit, temperature compensation is carried out through the output current and the first resistor, and the reference voltage precision is improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a high-order temperature-compensated bandgap reference circuit. Background Technology

[0002] A bandgap reference circuit is a circuit that utilizes the base-emitter voltage change ΔV of a transistor with a positive temperature coefficient. BE And the base-emitter voltage V of a transistor with a negative temperature coefficient BE A circuit that performs linear summation to obtain a reference voltage that is approximately independent of temperature within a certain temperature range. Due to the temperature drift coefficient of electronic components, the reference voltage output by conventional bandgap reference circuits has low accuracy; furthermore, the accuracy of the generated reference voltage varies with the circuit's operating temperature, both in low and high temperature ranges, with temperature having a more severe impact on the accuracy of the reference voltage. Summary of the Invention

[0003] To address the problems mentioned in the background section, this application provides the following technical solutions:

[0004] A high-order temperature-compensated bandgap reference circuit is provided, comprising: a reference generation module, a current source module, a first operational amplifier, a first transistor, and a capacitor.

[0005] The reference generation module has: a current input port, a first voltage port, a second voltage port, and a reference output port.

[0006] The current source module has a current output port.

[0007] The current output port is connected to the current input port and is used to feed the output current of the current source module into the reference generation module.

[0008] The non-inverting input of the first operational amplifier is connected to the first voltage port, and the inverting input of the first operational amplifier is connected to the second voltage port to clamp the voltage between the first voltage port and the second voltage port.

[0009] The output of the first operational amplifier is connected to the gate of the first transistor, the source of the first transistor is connected to the reference output port, the drain of the first transistor is connected to the first voltage, and a capacitor is connected in parallel between the output of the first operational amplifier and its inverting input.

[0010] The reference output port is used to output a reference voltage based on the output current.

[0011] Furthermore, the reference generation module includes: a first transistor, a second transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a base resistor.

[0012] The emitter of the first transistor is connected to one end of the first resistor and one end of the second resistor to serve as the current input port. The other end of the first resistor is grounded, and the other end of the second resistor is connected to the emitter of the second transistor. The base of the first transistor is connected to one end of the third resistor and one end of the fourth resistor to serve as the first voltage port. The collector of the first transistor is connected to the other end of the third resistor and one end of the base resistor. The other end of the base resistor is connected to the base of the second transistor. The collector of the second transistor is connected to one end of the fifth resistor to serve as the second voltage port. The other end of the fourth resistor is connected to the other end of the fifth resistor and one end of the sixth resistor. The other end of the sixth resistor serves as the reference output port.

[0013] Furthermore, the current source module includes: a current source generating unit, a temperature drift voltage generating unit, and a threshold voltage generating unit.

[0014] The temperature drift voltage generating unit is used to generate temperature drift voltage.

[0015] The threshold voltage generation unit is used to generate a first threshold voltage, a second threshold voltage, and a third threshold voltage.

[0016] The current source generation unit is used to generate output current based on the generated temperature drift voltage, first threshold voltage, second threshold voltage and third threshold voltage.

[0017] Furthermore, the current source generating unit includes: a second operational amplifier, a third operational amplifier, a first comparator, a second comparator, a third comparator, and a NAND gate.

[0018] The inverting input of the first comparator is connected to the inverting input of the second operational amplifier to receive the first threshold voltage.

[0019] The non-inverting input of the second comparator is connected to the non-inverting input of the third operational amplifier to receive the second threshold voltage.

[0020] The inverting input of the third comparator is used to receive the third threshold voltage.

[0021] The non-inverting input of the second operational amplifier is connected to the inverting input of the third operational amplifier, the non-inverting input of the first comparator, the inverting input of the second comparator, and the non-inverting input of the third comparator to receive temperature drift voltage.

[0022] The output of the second comparator is connected to one input of the NAND gate, the output of the third comparator is connected to the other input of the NAND gate, the output of the NAND gate is connected to the first enable terminal of the third operational amplifier, and the output of the first comparator is connected to the second enable terminal of the second operational amplifier.

[0023] The output of the second operational amplifier is connected to the output of the third operational amplifier to generate output current.

[0024] Furthermore, the second and third operational amplifiers are operational transconductance amplifiers.

[0025] The operational transconductance amplifier includes: a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, and a bias current source.

[0026] The gate of the sixth transistor serves as the non-inverting input of the operational transconductance amplifier, and the gate of the seventh transistor serves as the inverting input. The source of the sixth transistor is connected to the source of the seventh transistor. The drain of the sixth transistor is connected to the drain of the eighth transistor, the gate of the eighth transistor, and the gate of the tenth transistor. The drain of the seventh transistor is connected to the drain of the ninth transistor, the gate of the ninth transistor, and the gate of the eleventh transistor. The sources of the eighth, ninth, tenth, and eleventh transistors are connected and then grounded. The drain of the tenth transistor is connected to the drain of the third transistor and serves as the output of the operational transconductance amplifier. The source of the third transistor is connected to the drain of the second transistor. The drain of the eleventh transistor is connected to the drain of the fifth transistor, the gate of the fourth transistor, and the gate of the second transistor. The source of the fifth transistor is connected to the drain of the fourth transistor, and the gate of the fifth transistor is connected to the gate of the third transistor. The source of the second transistor is connected to the source of the fourth transistor and then connected to the first voltage. The bias current source is connected between the source of the second transistor and the source of the sixth transistor.

[0027] Furthermore, the temperature drift voltage generating unit includes a temperature-dependent current source and a seventh resistor.

[0028] One end of the seventh resistor is connected to a temperature-dependent current source to output the temperature drift voltage.

[0029] The other end of the seventh resistor is grounded.

[0030] Furthermore, the threshold voltage generating unit includes: an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor.

[0031] One end of the eleventh resistor is connected to the reference voltage, and the other end of the eleventh resistor is connected to one end of the tenth resistor to output the third threshold voltage.

[0032] The other end of the tenth resistor is connected to one end of the ninth resistor to output the second threshold voltage.

[0033] The other end of the ninth resistor is connected to one end of the eighth resistor to output the first threshold voltage.

[0034] The other end of the eighth resistor is grounded.

[0035] Furthermore, the amplitude of the reference voltage generated by the reference output port is expressed as:

[0036] V BG =V BE +[(R4+2·R6+2·R1) / (R2+R3)]·ΔV BE +I0·R1.

[0037] Among them, V BG The voltage represents the amplitude of the reference voltage. R1, R2, R3, R4, and R6 respectively represent the resistance values ​​of the first, second, third, fourth, and sixth resistors in the reference generation module 100. BE This represents the base-emitter voltage amplitude of the transistor in the reference generation module, ΔV. BE I0 represents the change in the base-emitter voltage amplitude of the transistor in the reference generation module with temperature, and I0 represents the output current value.

[0038] Furthermore, the high-order temperature-compensated bandgap reference circuit also includes at least one third transistor and at least one fourth transistor.

[0039] The base and emitter of the third transistor are connected to one end of the first resistor, and the collector of the third transistor is connected to the collector of the first transistor.

[0040] The base and emitter of the fourth transistor are connected to one end of the first resistor, and the collector of the fourth transistor is connected to the collector of the second transistor.

[0041] Furthermore, the ratio of the number of third transistors to the number of fourth transistors is N:1, where N is an integer.

[0042] By implementing the high-order temperature-compensated bandgap reference circuit described in the embodiments of this application, the accuracy of the reference voltage is improved by temperature compensation through the output current and the first resistor. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of a traditional bandgap reference circuit;

[0045] Figure 2 This is a schematic diagram showing the relationship between the reference voltage generated by a traditional bandgap reference circuit and temperature.

[0046] Figure 3 This is a schematic diagram of a high-order temperature-compensated bandgap reference circuit module provided in an embodiment of this application;

[0047] Figure 4 This is a schematic diagram of the reference generation module circuit provided in an embodiment of this application;

[0048] Figure 5 This is a schematic diagram illustrating the change of output current with temperature provided in an embodiment of this application;

[0049] Figure 6 This is a schematic diagram of the reference voltage changing with temperature provided in an embodiment of this application;

[0050] Figure 7 This is a schematic diagram of the current source module provided in an embodiment of this application;

[0051] Figure 8 This is a schematic diagram of the operational transconductance amplifier circuit provided in an embodiment of this application;

[0052] Figure 9 This is a schematic diagram illustrating the change of electrical quantities with temperature provided in an embodiment of this application;

[0053] Figure 10 This is a schematic diagram of a preferred high-order temperature-compensated bandgap reference circuit provided in an embodiment of this application;

[0054] Figure 11 This is a schematic diagram illustrating the variation of a preferred reference voltage with temperature, provided in an embodiment of this application. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0056] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The numbers in the accompanying drawings are only used to distinguish individual functional parts or modules and do not indicate logical relationships between parts or modules. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. “Above,” “below,” “left,” “right,” etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0057] The various embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are assigned to components having substantially the same or similar structure and function, and repeated descriptions of them will be omitted.

[0058] Traditional bandgap reference circuits, such as Figure 1 As shown, due to the clamping effect of the non-inverting and inverting inputs of the operational amplifier OP, the resistor R on the left... L With collector resistance R C The connection point (point X) and the resistor R on the right side. R The potential at the junction with the collector of the transistor (point Y) is equal, i.e., V X =V Y And because the resistor R on the left side... L and the resistor R on the right side R Connected at the top, resistor R on the left. L and the resistor R on the right side R The potential at the top is also the same. This causes current to flow through the left resistor R. L and the resistor R on the right side R The currents are equal. Since the input current flowing through the operational amplifier OP and the base current of the transistors are small, they can be ignored in the calculation. Therefore, the currents flowing through the two transistors are equal. At the collector resistor R... C This generates a voltage change ΔV with a positive temperature coefficient. BE This generates a current I that is positively correlated with temperature. PATA =ΔV BE / R2. The temperature-dependent current I. PATA On the left resistor RL and variable resistor R V A voltage positively correlated with temperature is generated on the base-emitter voltage V, which has a negative temperature coefficient. BE After linear superposition, a reference voltage V' that is approximately temperature-independent can be obtained within a certain temperature range. BG The expression for this reference voltage is: V' BG =V BE +I PATA ·R L +2·I PATA ·R V =V BE +[(R L +2·R V ) / R C ]·ΔV BE , where V' BG This indicates the amplitude of the reference voltage, V. BE I represents the base-emitter voltage of a transistor. PATA R represents the magnitude of the current that is positively correlated with temperature. L R represents the resistance value of the resistor on the left. V R represents the resistance value of the variable resistor. C The value of the collector resistor is represented by ΔV. BE It represents the change in base-emitter voltage.

[0059] The actual dimensions and performance of the devices obtained in production deviate from the specifications. This can be addressed by adjusting the variable resistor R. V This is to ensure the output accuracy of the reference voltage.

[0060] The reference voltage V' generated by the bandgap reference circuit BG As temperature changes Figure 2 As shown. Its temperature drift coefficient is relatively large, and when the temperature is above 150 degrees Celsius, the reference voltage V' it generates... BG It increased dramatically.

[0061] To address the problems raised in the background art, this application provides the following technical solutions. It should be noted that: in this application, V' BG and V BG This distinguishes between the reference voltage generated by a traditional bandgap reference circuit and the reference voltage generated by the high-order temperature-compensated bandgap reference circuit described in the embodiments of this application. BG V represents the reference voltage generated by a traditional bandgap reference circuit. BG This indicates the reference voltage generated by the high-order temperature-compensated bandgap reference circuit described in the embodiments of this application.

[0062] In some embodiments, such as Figure 3As shown, a high-order temperature-compensated bandgap reference circuit includes: a reference generation module 100, a current source module 200, a first operational amplifier OP1, a first transistor T1, and a capacitor C.

[0063] The reference generation module 100 has: a current input port 100a, a first voltage port 100b, a second voltage port 100c, and a reference output port 100d.

[0064] The current source module 200 has a current output port 200a.

[0065] The current output port 200a is connected to the current input port 100a and is used to inject the output current I0 of the current source module 200 into the reference generation module 100.

[0066] The non-inverting input of the first operational amplifier OP1 is connected to the first voltage port 100b, and the inverting input of the first operational amplifier OP1 is connected to the second voltage port 100c, so as to clamp the voltage between the first voltage port 100b and the second voltage port 100c.

[0067] The output of the first operational amplifier OP1 is connected to the gate of the first transistor T1, the source of the first transistor T1 is connected to the reference output port 100d, and the drain of the first transistor T1 is connected to the first voltage V. DD The capacitor C is connected in parallel between the output terminal of the first operational amplifier OP1 and the inverting input terminal of the first operational amplifier OP1.

[0068] Reference output port 100d is used to output a reference voltage V based on the output current I0. BG .

[0069] The first transistor is an N-channel metal-oxide-semiconductor field-effect transistor.

[0070] The capacitor C connected in parallel between the output terminal of the first operational amplifier OP1 and the inverting input terminal of the first operational amplifier OP1 is used to optimize system stability and response speed.

[0071] First voltage V DD Used to provide operating voltage to electronic components in a circuit.

[0072] Preferably, the high-order temperature-compensated bandgap reference circuit further includes a startup circuit 300. The startup circuit 300 is used to send an excitation signal to the gate of the first transistor T1 after the high-order temperature-compensated bandgap reference circuit is powered on, causing the high-order temperature-compensated bandgap reference circuit to exit the degenerate state and thus be able to operate normally. The reason for the degenerate state is briefly described as follows: solving the circuit equation yields two solutions, one of which is "0". In the case of this solution, the circuit cannot operate normally and output the reference voltage V.BG Yes. After the circuit is powered on, its operating state may be in a state where the solution is "0". Therefore, it is necessary to start the circuit 300 to apply excitation to the gate of the first transistor T1 to ensure that the circuit works normally and outputs the reference voltage V. BG This application does not limit the structure of the startup circuit.

[0073] like Figure 4 As shown, the reference generation module 100 includes: a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a base resistor R. b .

[0074] The emitter of the first transistor Q1 is connected to one end of the first resistor R1 and one end of the second resistor R2, forming a current input port 100a. The other end of the first resistor R1 is grounded, and the other end of the second resistor R2 is connected to the emitter of the second transistor Q2. The base of the first transistor Q1 is connected to one end of the third resistor R3 and one end of the fourth resistor R4, forming a first voltage port 100b. The collector of the first transistor Q1 is connected to the other end of the third resistor R3 and the base resistor R4. b One end is connected to the base resistor R. b The other end is connected to the base of the second transistor Q2. The collector of the second transistor Q2 is connected to one end of the fifth resistor R5 to serve as the second voltage port 100c. The other end of the fourth resistor R4 is connected to the other end of the fifth resistor R5 and one end of the sixth resistor R6. The other end of the sixth resistor R6 serves as the reference output port 100d.

[0075] like Figure 4 As shown, in this invention, a first resistor R1 is provided between the emitter of the first transistor Q1 and ground potential. The current source module 200 injects its output current I0 into the first resistor R1. The first resistor R1 and the output current I0 form a temperature compensation circuit. The output current I0 is at room temperature (T... L <T<T H1 ) or high temperature (T>T) H2 The value is 0 in the region; when the temperature is below T... L or higher than T H1 The change trend is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] Figure 5 As shown. The compensated reference voltage is as follows. Figure 6 As shown, compared to the reference voltage generated by a traditional bandgap reference circuit, at temperature T <T L , and T H1 <T<T H2 Within this range, the stability of the reference voltage is significantly improved. Figure 6The solid line represents the curve of the reference voltage generated in the embodiments of this application as a function of temperature. Figure 6 The dashed line represents the temperature-dependent curve of the reference voltage generated by a traditional bandgap reference circuit. The method for generating the output current I0 will be described in detail below.

[0076] also, Figure 4 The second resistor R2 and the third resistor R3 in the circuit improve the circuit matching, which can improve the product yield during production. The base resistor R is connected in series with the base of the second transistor Q2. b This can reduce the impact of the transistor's base current on the reference voltage.

[0077] like Figure 7 As shown, the current source module 200 includes: a current source generating unit 210, a temperature drift voltage generating unit 220, and a threshold voltage generating unit 230.

[0078] Temperature drift voltage generating unit 220 is used to generate temperature drift voltage V PATA .

[0079] Threshold voltage generation unit 230 is used to generate a first threshold voltage V L Second threshold voltage V H1 and the third threshold voltage V H2 .

[0080] The current source generation unit 210 is used to generate the temperature drift voltage V. PATA First threshold voltage V L Second threshold voltage V H1 and the third threshold voltage V H2 It generates an output current I0.

[0081] Specifically, the current source generating unit 210 includes: a second operational amplifier OP2, a third operational amplifier OP3, a first comparator A1, a second comparator A2, a third comparator A3, and a NAND gate.

[0082] After the inverting input of the first comparator A1 is connected to the inverting input of the second operational amplifier OP2, it is used to receive the first threshold voltage V. L .

[0083] The non-inverting input of the second comparator A2 is connected to the non-inverting input of the third operational amplifier OP3 to receive the second threshold voltage V. H1 .

[0084] The inverting input of the third comparator A3 is used to receive the third threshold voltage V. H2 .

[0085] The non-inverting input of the second operational amplifier OP2 is connected to the inverting input of the third operational amplifier OP3, the non-inverting input of the first comparator A1, the inverting input of the second comparator A2, and the non-inverting input of the third comparator A3 to receive the temperature drift voltage V. PATA .

[0086] The output of the second comparator A2 is connected to one input of the NAND gate, the output of the third comparator A3 is connected to the other input of the NAND gate, the output of the NAND gate is connected to the first enable terminal ENP of the third operational amplifier OP3, and the output of the first comparator A1 is connected to the second enable terminal ENN of the second operational amplifier OP2.

[0087] The output of the second operational amplifier OP2 is connected to the output of the third operational amplifier OP3 to generate the output current I0.

[0088] like Figure 7 As shown, the output current I0 is obtained by summing the output currents of the second operational amplifier OP2 and the third operational amplifier OP3.

[0089] The second operational amplifier OP2 operates at the first threshold voltage V. L Greater than temperature drift voltage V PATA When the first threshold voltage V is reached, the output sink current is activated; when the first threshold voltage V is reached... L Less than temperature drift voltage V PATA At that time, the second operational amplifier OP2 is turned off.

[0090] The third operational amplifier OP3 is affected by the temperature drift voltage V. PATA Greater than the second threshold voltage V H1 And temperature drift voltage V PATA Less than the third threshold voltage V H2 When the output sink current is reached, the temperature drift voltage V is also reached. PATA Less than the second threshold voltage V H1 Or temperature drift voltage V PATA Greater than the third threshold voltage V H2 At that time, the third operational amplifier OP3 is turned off.

[0091] Preferably, the second operational amplifier OP2 and the third operational amplifier OP3 are operational transconductance amplifiers to realize the function of converting the input voltage difference into current output by comparing the input voltages at the two input terminals.

[0092] like Figure 8 As shown, the operational transconductance amplifier includes: second transistor T2, third transistor T3, fourth transistor T4, fifth transistor T5, sixth transistor T6, seventh transistor T7, eighth transistor T8, ninth transistor T9, and tenth transistor T1.10 11th transistor T 11 and bias current source I B .

[0093] The gate of the sixth transistor T6 serves as the non-inverting input "+" of the operational transconductance amplifier, and the gate of the seventh transistor T7 serves as the inverting input "-" of the operational transconductance amplifier. The source of the sixth transistor T6 is connected to the source of the seventh transistor T7. The drain of the sixth transistor T6 is connected to the drain of the eighth transistor T8, the gate of the eighth transistor T8, and the tenth transistor T1. 10 The gate connection of the seventh transistor T7 is such that the drain of the seventh transistor T7 is connected to the drain of the ninth transistor T9, the gate of the ninth transistor T9, and the eleventh transistor T... 11 The gate connection is the source of the eighth transistor T8, the source of the ninth transistor T9, and the tenth transistor T... 10 The source and the eleventh transistor T 11 After the source is connected to ground, the tenth transistor T 10 The drain of transistor T1 is connected to the drain of transistor T3, serving as the output of the operational transconductance amplifier. The source of transistor T3 is connected to the drain of transistor T2. The eleventh transistor T1... 11 The drain of transistor T5 is connected to the drain of transistor T5, the gate of transistor T4, and the gate of transistor T2. The source of transistor T5 is connected to the drain of transistor T4. The gate of transistor T5 is connected to the gate of transistor T3. The source of transistor T2 is connected to the source of transistor T4 and then connected to the first voltage V. DD Bias current source I B It is connected between the source of the second transistor T2 and the source of the sixth transistor T6.

[0094] Among them, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, and the seventh transistor T7 are P-channel metal-oxide-semiconductor field-effect transistors; the eighth transistor T8, the ninth transistor T9, and the tenth transistor T1 are P-channel metal-oxide-semiconductor field-effect transistors. 10 And the eleventh transistor T 11 It is an N-channel metal-oxide-semiconductor field-effect transistor.

[0095] The operational transconductance amplifier converts the difference between the input voltages at the non-inverting and inverting input terminals into a current for output. The proportional gain is adjusted by varying the aspect ratio of the ninth transistor T9 with that of the eleventh transistor T1. 11 The aspect ratio, and adjusting the aspect ratio of the eighth transistor T8 with that of the tenth transistor T 10 The aspect ratio is determined.

[0096] Preferably, the gates of the second transistor, the third transistor, the fourth transistor, and the fifth transistor are connected together to form the first enable terminal. Figure 8 (Not shown in the image); the gates of the eighth transistor, the ninth transistor, the tenth transistor, and the eleventh transistor are connected together to form the second enable terminal. Figure 8 (Not shown in the image).

[0097] The second enable signal ENN is generated by the first comparator A1. The first comparator A1 is at the first threshold voltage V. L Greater than temperature drift voltage V PATA When the second enable signal ENN is high, the second operational amplifier OP2 is turned on. At this time, the current output by the second operational amplifier OP2 is related to the first threshold voltage V. L and temperature drift voltage V PATA The difference is proportional, and the scaling factor is adjusted by changing the aspect ratio of the ninth transistor T9 to that of the eleventh transistor T. 11 The aspect ratio, and adjusting the aspect ratio of the eighth transistor T8 with that of the tenth transistor T 10 The aspect ratio is determined. The first comparator A1 is used at the first threshold voltage V. L Less than temperature drift voltage V PATA When the second enable signal ENN is low, the second operational amplifier OP2 is turned off, and the current output by the second operational amplifier OP2 is 0.

[0098] The first enable signal ENP is generated by a NAND gate, when the temperature drift voltage V PATA Greater than the second threshold voltage V H1 And temperature drift voltage V PATA Less than the third threshold voltage V H2 When the first enable signal ENP is high, the third operational amplifier OP3 is turned on. At this time, the current output by the third operational amplifier OP3 is related to the second threshold voltage V. H1 and temperature drift voltage V PATA The difference is proportional, and the scaling factor is adjusted by changing the aspect ratio of the ninth transistor T9 to that of the eleventh transistor T. 11 The aspect ratio, and adjusting the aspect ratio of the eighth transistor T8 with that of the tenth transistor T 10 The aspect ratio is determined. When the temperature drift voltage V PATA Less than the second threshold voltage V H1 Or temperature drift voltage V PATA Greater than the third threshold voltage V H2 When the first enable signal ENP is low, the current output by the third operational amplifier OP3 is 0.

[0099] Specifically, such as Figure 7As shown, the temperature drift voltage generating unit 220 includes: a temperature-dependent current source I PATA And the seventh resistor R7.

[0100] One end of the seventh resistor R7 is connected to the temperature-dependent current source I. PATA Connection for outputting temperature drift voltage V PATA .

[0101] The other end of the seventh resistor R7 is grounded.

[0102] Temperature drift voltage V PATA It is a voltage that is positively correlated with temperature, used to detect temperature changes, and is generated by a temperature-dependent current source I. PATA The temperature drift voltage V is obtained by flowing through the seventh resistor R7. PATA The expression is: V PATA =I PATA ·R7, where V PATA I represents the amplitude of the temperature drift voltage. PATA R7 represents the current magnitude of the temperature-dependent current source, and R7 represents the resistance value of the seventh resistor.

[0103] Specifically, the threshold voltage generating unit 230 includes: an eighth resistor R8, a ninth resistor R9, and a tenth resistor R 10 And the eleventh resistor R 11 .

[0104] Eleventh resistor R 11 One end is connected to the reference voltage V BG Eleventh resistor R 11 The other end is connected to the tenth resistor R 10 One end is connected to output the third threshold voltage V. H2 .

[0105] The tenth resistor R 10 The other end is connected to one end of the ninth resistor R9, and is used to output the second threshold voltage V. H1 .

[0106] The other end of the ninth resistor R9 is connected to one end of the eighth resistor R8, and is used to output the first threshold voltage V. L .

[0107] The other end of the eighth resistor R8 is grounded.

[0108] First threshold voltage V L Second threshold voltage V H1 and the third threshold voltage V H2 This is an approximately temperature-independent constant voltage used to set the first temperature point T for the corresponding temperature comparison point. L Second temperature point T H1and the third temperature point T H2 This is to achieve temperature compensation for the bandgap reference circuit.

[0109] Figure 9 The first threshold voltage V is shown. L Second threshold voltage V H1 Third threshold voltage V H2 Temperature drift voltage V PATA The relationship between the first enable signal ENP, the second enable signal ENN, and the output current I0 as a function of temperature. When the first threshold voltage V... L Greater than temperature drift voltage V PATA or temperature drift voltage V PATA Greater than the second threshold voltage V H1 And temperature drift voltage V PATA Less than the third threshold voltage V H2 At this time, the output current I0 of the current source module 200 serves as the sink current, flowing to the first resistor R1 to achieve temperature compensation. For example... Figure 6 As shown, within a certain temperature range (T) <T H2 The reference voltage V was reduced. BG The temperature drift coefficient improves the reference voltage V. BG The accuracy.

[0110] The reference output port 100d generates the reference voltage V. BG The amplitude is expressed as:

[0111] V BG =V BE +[(R4+2·R6+2·R1) / (R2+R3)]·ΔV BE +I0·R1.

[0112] Among them, V BG The voltage represents the amplitude of the reference voltage. R1, R2, R3, R4, and R6 respectively represent the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the sixth resistor R6 in the reference generation module 100. BE ΔV represents the base-emitter voltage amplitude of the transistor in the reference generation module 100. BE I0 represents the change in the base-emitter voltage amplitude of the transistor in the reference generation module 100 with temperature, and I0 represents the current value of the output current I0.

[0113] The derivation of the amplitude expression for the reference voltage is as follows:

[0114] V BG =V BEQ1 +I PATA ·R4+2·I PATA ·R6+(2·IPATA +I0)·R1;

[0115] By V BEQ1 =I PATA ·R2+V BEQ2 +I b ·R b +I PATA ·R3, due to base current I b If we can ignore this, then we get:

[0116] I PATA =(V BEQ1 –V BEQ2 ) / (R2+R3)=ΔV BE / (R2+R3);

[0117] Combining the above equations, we get:

[0118] V BG =V BE +[(R4+2·R6+2·R1) / (R2+R3)]·ΔV BE +I0·R1.

[0119] Compared to traditional bandgap reference circuits, the high-order temperature-compensated bandgap reference circuit proposed in this application adds temperature compensation. By adjusting the parameters of the output current I0 and the first resistor R1, the reference voltage V is adjusted. BG At low temperature (T < T) L ) and high temperature (T) H1 <T<T H2 The increase is slight at certain temperatures (T < T), and remains within a certain temperature range. H2 The reference voltage V was reduced. BG The temperature drift coefficient improves the accuracy of the reference voltage.

[0120] Preferably, such as Figure 10 As shown, the high-order temperature-compensated bandgap reference circuit also includes at least one third transistor Q3 and at least one fourth transistor Q4.

[0121] In a preferred reference generation module 100', the base of the third transistor Q3 is connected to the emitter of the third transistor Q3 and then connected to one end of the first resistor R1, and the collector of the third transistor Q3 is connected to the collector of the first transistor Q1.

[0122] The base of the fourth transistor Q4 is connected to the emitter of the fourth transistor Q4 and then connected to one end of the first resistor R1. The collector of the fourth transistor Q4 is connected to the collector of the second transistor Q2.

[0123] Optionally, the ratio of the number of the third transistor Q3 to the number of the fourth transistor Q4 is N:1, where N is an integer.

[0124] When temperature T > T H2 (Illustratively, T) H2 At approximately 150℃, the leakage current of the transistor's parasitic diode increases dramatically at higher temperatures, causing the magnitude of the temperature-dependent current source I to increase. PATA The voltage increases sharply, according to the reference voltage V. BG The expression makes V BG The temperature increased sharply, worsening the situation above the third temperature point (T > T). H2 The temperature drift characteristics of the reference voltage at that time. To address this issue, the temperature drift of the reference voltage V is reduced after the temperature exceeds the third temperature point. BG To improve the temperature drift coefficient and enhance the accuracy of the reference voltage across the entire temperature range, based on the invention described above, at least one third transistor Q3 and at least one fourth transistor Q4 are added, such as... Figure 10 As shown. At temperatures below the third temperature point (T... <T H2 At this time, transistors Q3 and Q4 are turned off and do not participate in the circuit's operation. It should be noted that the specific value of the third temperature point is determined by the manufacturing process. H2 ≈150℃ is for illustrative purposes only.

[0125] When the temperature is higher than the third temperature point (T > T) H2 After that, the collector currents of transistors Q1 and Q2 increase sharply. Transistors Q3 and Q4 will then draw current from the branches containing resistors R4 and R5, respectively, causing the magnitude I of the temperature-dependent current source to increase. PATA The current decreases, thereby suppressing the reference voltage V. BG When the temperature exceeds the third temperature point (T) H2 Then it increases sharply. Reference voltage V BG The diagram showing the change with temperature is shown below. Figure 11 As shown. Figure 11 The solid line represents the curve of the reference voltage generated by the preferred embodiment of this application as a function of temperature; Figure 11 The dashed line represents the temperature-dependent curve of the reference voltage generated by a conventional bandgap reference circuit. Implementing the preferred embodiment of this application enables a reduction in the reference voltage V across the entire temperature range. BG The temperature drift coefficient is reduced, thus improving the accuracy of the reference voltage.

[0126] By implementing the high-order temperature-compensated bandgap reference circuit described in the embodiments of this application, the accuracy of the reference voltage is improved by temperature compensation through the output current and the first resistor; by utilizing the phenomenon that the reference voltage rises sharply after the temperature exceeds the third temperature point by drawing currents through the fourth and fifth resistors respectively after the third and fourth transistors are above the third temperature point, the accuracy of the reference voltage V is reduced across the entire temperature range. BG The temperature drift coefficient improves the accuracy of the reference voltage across the entire temperature range.

[0127] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0128] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A high-order temperature compensated bandgap reference circuit, characterized by, include: The system includes a reference generation module (100), a current source module (200), a first operational amplifier (OP1), a first transistor (T1), and a capacitor (C); The reference generation module (100) has: a current input port (100a), a first voltage port (100b), a second voltage port (100c), and a reference output port (100d); The current source module (200) has a current output port (200a); The current output port (200a) is connected to the current input port (100a) and is used to inject the output current (I0) of the current source module (200) into the reference generation module (100); The non-inverting input of the first operational amplifier (OP1) is connected to the first voltage port (100b), and the inverting input of the first operational amplifier (OP1) is connected to the second voltage port (100c) to clamp the voltage between the first voltage port (100b) and the second voltage port (100c). The output end of the first operational amplifier (OP1) is connected with the gate of the first transistor (T1), the source of the first transistor (T1) is connected with the reference output port (100d), the drain of the first transistor (T1) is connected with the first voltage (V DD ), and the capacitor (C) is connected in parallel between the output end of the first operational amplifier (OP1) and the inverting input end thereof. The reference output port (100d) is configured to output a reference voltage (V BG ) in dependence of the output current (I0).

2. The high-order temperature compensated bandgap reference circuit of claim 1, wherein, The reference generation module (100) comprises a first transistor (Q1), a second transistor (Q2), a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), and a base resistor (R b ). The emitter of the first transistor (Q1) is connected to one end of the first resistor (R1) and one end of the second resistor (R2) to serve as the current input port (100a), the other end of the first resistor (R1) is grounded, the other end of the second resistor (R2) is connected to the emitter of the second transistor (Q2), the base of the first transistor (Q1) is connected to one end of the third resistor (R3) and one end of the fourth resistor (R4) to serve as the first voltage port (100b), the collector of the first transistor (Q1) is connected to the other end of the third resistor (R3) and one end of the base resistor (R b ), the other end of the base resistor (R b ) is connected to the base of the second transistor (Q2), the collector of the second transistor (Q2) is connected to one end of the fifth resistor (R5) to serve as the second voltage port (100c), the other end of the fourth resistor (R4) is connected to the other end of the fifth resistor (R5) and one end of the sixth resistor (R6), the other end of the sixth resistor (R6) serves as the reference output port (100d).

3. The high-order temperature compensated bandgap reference circuit of claim 1, wherein, The current source module (200) includes: a current source generating unit (210), a temperature drift voltage generating unit (220), and a threshold voltage generating unit (230); The temperature drift voltage generating unit (220) is configured to generate a temperature drift voltage (V PATA ) The threshold voltage generating unit (230) is configured to generate a first threshold voltage (V L ), a second threshold voltage (V H1 ), and a third threshold voltage (V H2 ). The current source generation unit (210) is configured to generate the output current (I0) according to the generation temperature drift voltage (V PATA ), the first threshold voltage (V L ), the second threshold voltage (V H1 ), and the third threshold voltage (V H2 ).

4. The high-order temperature compensated bandgap reference circuit of claim 3, wherein, The current source generating unit (210) includes: a second operational amplifier (OP2), a third operational amplifier (OP3), a first comparator (A1), a second comparator (A2), a third comparator (A3), and a NAND gate; The inverting input terminal of the first comparator (A1) is connected to the inverting input terminal of the second operational amplifier (OP2) for receiving the first threshold voltage (V L ) The non-inverting input terminal of the second comparator (A2) is connected with the non-inverting input terminal of the third operational amplifier (OP3), and is used for receiving the second threshold voltage (V H1 ) after the non-inverting input terminal of the third operational amplifier (OP3) is connected with the non-inverting input terminal of the second comparator (A2). the inverting input of the third comparator (A3) is configured to receive the third threshold voltage (V H2 ); The noninverting input terminal of the second operational amplifier (OP2) is connected with the inverting input terminal of the third operational amplifier (OP3), the noninverting input terminal of the first comparator (A1), the inverting input terminal of the second comparator (A2) and the noninverting input terminal of the third comparator (A3), and is used for receiving the temperature drift voltage (V PATA ) after the noninverting input terminal of the second operational amplifier (OP2) is connected with the inverting input terminal of the third operational amplifier (OP3), the noninverting input terminal of the first comparator (A1), the inverting input terminal of the second comparator (A2) and the noninverting input terminal of the third comparator (A3), and is used for receiving the temperature drift voltage (V The output of the second comparator (A2) is connected to one input of the NAND gate, the output of the third comparator (A3) is connected to the other input of the NAND gate, the output of the NAND gate is connected to the first enable terminal (ENP) of the third operational amplifier (OP3), and the output of the first comparator (A1) is connected to the second enable terminal (ENN) of the second operational amplifier (OP2). The output terminal of the second operational amplifier (OP2) is connected to the output terminal of the third operational amplifier (OP3) to generate the output current (I0).

5. The high-order temperature compensated bandgap reference circuit of claim 4, wherein, The second operational amplifier (OP2) and the third operational amplifier (OP3) are operational transconductance amplifiers; The operational transconductance amplifier includes a second transistor (T2), a third transistor (T3), a fourth transistor (T4), a fifth transistor (T5), a sixth transistor (T6), a seventh transistor (T7), an eighth transistor (T8), a ninth transistor (T9), a tenth transistor (T 10 ), an eleventh transistor (T 11 ), and a bias current source (I B ). The gate of the sixth transistor (T6) serves as the non-inverting input of the operational transconductance amplifier, and the gate of the seventh transistor (T7) serves as the inverting input of the operational transconductance amplifier. The source of the sixth transistor (T6) is connected to the source of the seventh transistor (T7). The drain of the sixth transistor (T6) is connected to the drain of the eighth transistor (T8), the gate of the eighth transistor (T8), and the tenth transistor (T1). 10 The gate of the seventh transistor (T7) is connected to the gate of the ninth transistor (T9), the drain of the seventh transistor (T7) is connected to the drain of the ninth transistor (T9), the gate of the ninth transistor (T9), and the eleventh transistor (T1). 11 The gate of the eighth transistor (T8), the source of the ninth transistor (T9), and the tenth transistor (T) are connected. 10 The source of the eleventh transistor (T) and the source of the eleventh transistor (T) 11 The source of the tenth transistor (T) is connected to ground. 10 The drain of the eleventh transistor (T1) is connected to the drain of the third transistor (T3) and serves as the output terminal of the operational transconductance amplifier. The source of the third transistor (T3) is connected to the drain of the second transistor (T2). 11 The drain of the fifth transistor (T5) is connected to the drain of the fifth transistor (T5), the gate of the fourth transistor (T4), and the gate of the second transistor (T2). The source of the fifth transistor (T5) is connected to the drain of the fourth transistor (T4). The gate of the fifth transistor (T5) is connected to the gate of the third transistor (T3). The source of the second transistor (T2) is connected to the source of the fourth transistor (T4) and then connected to a first voltage (V). DD The bias current source (I) B It is connected between the source of the second transistor (T2) and the source of the sixth transistor (T6).

6. The high-order temperature compensated bandgap reference circuit of claim 3, wherein, The temperature drift voltage generating unit (220) comprises a temperature related current source (I PATA ) and a seventh resistance (R7). One end of the seventh resistor (R7) is connected with the temperature related current source (I PATA ), for outputting the temperature drift voltage (V PATA ); The other end of the seventh resistor (R7) is grounded.

7. The high-order temperature compensated bandgap reference circuit of claim 3, wherein, The threshold voltage generating unit (230) comprises an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R 10 ) and an eleventh resistor (R 11 ). one end of the eleventh resistor (R 11 ) is connected with the reference voltage (V BG ), the other end of the eleventh resistor (R 11 ) is connected with one end of the tenth resistor (R 10 ), for outputting the third threshold voltage (V H2 ); The other end of the tenth resistor (R 10 ) is connected with one end of the ninth resistor (R9) for outputting the second threshold voltage (V H1 ). The other end of the ninth resistor (R9) is connected with one end of the eighth resistor (R8) for outputting the first threshold voltage (V L ); The other end of the eighth resistor (R8) is grounded.

8. The high-order temperature compensated bandgap reference circuit of claim 1, wherein, The reference output port (100d) generates a reference voltage (V BG ) whose amplitude is expressed as: V BG = V BE + [(R4 + 2-R6 + 2-R1) / (R2 + R3)] - AV BE + I0-R1; Wherein, the V BG represents the amplitude of the reference voltage, R1, R2, R3, R4 and R6 respectively correspond to the resistance value of the first resistance (R1), the second resistance (R2), the third resistance (R3), the fourth resistance (R4) and the sixth resistance (R6) in the reference generation module (100), the V BE represents the base-emitter voltage amplitude of the transistor in the reference generation module (100), the ΔV BE represents the change amount of the base-emitter voltage amplitude of the transistor in the reference generation module (100) with temperature, and the I0 represents the current value of the output current (I0).

9. The high-order temperature compensated bandgap reference circuit of any of claims 2-8, wherein, The high-order temperature-compensated bandgap reference circuit also includes at least one third transistor (Q3) and at least one fourth transistor (Q4); The base of the third transistor (Q3) is connected to its emitter and then to one end of the first resistor (R1). The collector of the third transistor (Q3) is connected to the collector of the first transistor (Q1). The base of the fourth transistor (Q4) is connected to its emitter and then to one end of the first resistor (R1). The collector of the fourth transistor (Q4) is connected to the collector of the second transistor (Q2).

10. The high-order temperature compensated bandgap reference circuit of claim 9, wherein, The ratio of the number of the third transistor (Q3) to the fourth transistor (Q4) is N:1, where N is an integer. The ratio of the number of the third transistor (Q3) to the fourth transistor (Q4) is N:1, where N is an integer.

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