Band-gap reference circuit structure with temperature compensation and LDO (Low Dropout Regulator) circuit

Abstract

The utility model discloses a band-gap reference circuit structure with temperature compensation and an LDO (Low Dropout Regulator) circuit, and the circuit structure comprises a band-gap reference circuit which generates reference voltage VA with a zero temperature coefficient; the temperature compensation circuit is used for generating a compensation voltage to compensate the reference voltage VA when the band-gap reference circuit outputs at a high temperature; and a negative feedback circuit for stabilizing the reference voltage VA. According to the circuit structure provided by the utility model, the temperature compensation circuit is configured to compensate the output of the band-gap reference circuit in a high-temperature state, when the compensation is not performed, the output voltage VREF at a high temperature is reduced along with the temperature rise and is in a negative temperature coefficient, and after the compensation, the output voltage VREF at a high temperature is increased along with the temperature rise and is in a positive temperature coefficient; generally speaking, positive temperature coefficient current is filled into the reference voltage for compensation, so that the reference voltage rises along with the temperature.

Description

Technical Field

[0001] The utility model belongs to the field of electronic circuits, and particularly relates to a bandgap reference circuit structure with temperature compensation and an LDO circuit. Background Technique

[0002] A bandgap reference voltage source is a kind of reference source, which has excellent temperature stability and is often used for high-precision voltage reference. This kind of voltage source is very important in both analog and digital circuits because many circuit functions rely on an accurate reference voltage. The bandgap reference voltage source circuit usually combines two voltages with opposite temperature coefficients:

[0003] 1. Positive temperature coefficient voltage: This part of the voltage is usually generated by two diodes or transistors with different current densities; as the temperature increases, this part of the voltage also increases.

[0004] 2. Negative temperature coefficient voltage: This part of the voltage is usually provided by the forward voltage drop (VBE) of a diode, and as the temperature increases, this part of the voltage will decrease.

[0005] By appropriately combining these two parts of the voltage, a total voltage can be obtained, whose temperature coefficient is close to zero, so as to remain stable within a certain temperature range.

[0006] When the bandgap reference voltage source is in a high-temperature state in the bandgap reference voltage source circuit or other circuits (such as LDO circuits) constituted by the bandgap reference voltage source, the output reference voltage V A has a relatively high temperature coefficient, and providing it to other circuits will affect the working stability of other circuits. Content of the Utility Model

[0007] To solve the technical problems existing in the prior art, the utility model provides a bandgap reference circuit structure with temperature compensation here. This circuit compensates the output when the bandgap reference circuit is in a high-temperature state, so as to achieve temperature compensation.

[0008] This circuit structure includes:

[0009] A bandgap reference circuit, which generates a reference voltage V with zero temperature coefficient A ;

[0010] A temperature compensation circuit, which is used to generate a compensation voltage to compensate the reference voltage V A when the bandgap reference circuit outputs at high temperature;

[0011] A negative feedback circuit, which is used to stabilize the reference voltage V A .

[0012] In some embodiments, the bandgap reference circuit includes transistor Q2, transistor Q3, transistor Q10, transistor Q11, resistor R1, and resistor R2; the base and emitter of transistor Q2 are respectively connected to the base and emitter of transistor Q3, the base of transistor Q2 is also shorted to its collector, and the collector of transistor Q2 is connected to the collector of transistor Q10; the base of transistor 10 is connected to the base of transistor Q11, and the emitter is connected to the low power supply of the bandgap reference circuit structure through resistor R1 and resistor R2; the collector of transistor Q3 is connected to the collector of transistor Q11, and the emitter of transistor Q11 is connected to the low power supply of the bandgap reference circuit structure through resistor R2.

[0013] In some embodiments, the temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5; the emitter of transistor Q6 is used for accessing the bias signal, the base is connected to the collector of transistor Q2, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection end of the temperature compensation circuit for connecting to the bandgap reference circuit to enable the reference voltage V A to be accessed; the emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5; the other end of resistor R3 serves as the output + end of the bandgap reference circuit structure.

[0014] In some embodiments, the present circuit structure further includes a mirror circuit, including transistor Q5 and transistor Q8;

[0015] The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5;

[0016] The emitter of transistor Q5 is used for accessing the bias signal, the collector is connected to the collector of transistor Q8, and the base is connected to the base of transistor Q6; the base of transistor Q8 is connected to the collector of transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure;

[0017] The emitter of transistor Q6 is used for accessing the bias signal, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection end of the temperature compensation circuit for connecting to the bandgap reference circuit to enable the reference voltage V A to be accessed; the emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5; the other end of resistor R3 serves as the output + end of the bandgap reference circuit structure.

[0018] In some embodiments, the present circuit structure further includes a mirror circuit, and the mirror circuit includes transistor Q1, transistor Q7, transistor Q5, and transistor Q8;

[0019] The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5;

[0020] The emitter of transistor Q1 is connected to the emitter of transistor Q2, the base is connected to the collector of transistor Q2, and the collector is connected to the collector of transistor Q7; the base of transistor Q7 is connected to the base of transistor Q8 and shorted to its collector, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the collector of transistor Q8 is connected to the collector of transistor Q5, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of transistor Q5 is used for biasing signal access, and the base is connected to the base of transistor Q6;

[0021] The emitter of transistor Q6 is used for biasing signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection end of the temperature compensation circuit for connection to the bandgap reference circuit to access the reference voltage V A ; the emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5; the other end of resistor R3 serves as the output + terminal of the bandgap reference circuit structure.

[0022] In some embodiments, the negative feedback circuit includes transistor Q4 and transistor Q9; the base of transistor Q4 is connected to the collector of transistor Q3, the emitter is connected to the low power supply of the bandgap reference circuit structure through resistors R6 and R7, and the connection end of resistors R6 and R7 is connected to the output + terminal of the bandgap reference circuit structure; the collector of transistor Q4 is connected to the collector of transistor Q9, the base of transistor Q9 is connected to the collector of transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

[0023] In some embodiments, the present circuit structure further includes a mirror circuit, and the mirror circuit includes transistor Q5 and transistor Q8;

[0024] The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5;

[0025] The negative feedback circuit includes transistor Q4 and transistor Q9;

[0026] The emitter of the triode Q5 is used for accessing the bias signal, the collector is connected to the collector of the triode Q8, and the base is connected to the base of the triode Q6; the base of the triode Q8 is connected to the collector of the triode Q2 and the base of the triode Q9, and the emitter is connected to the low power supply of the bandgap reference circuit structure;

[0027] The emitter of the triode Q6 is used for accessing the bias signal, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the triode Q12 is connected to one end of the resistor R3 and serves as the first connection end of the temperature compensation circuit for connecting to the bandgap reference circuit to enable the reference voltage V A to be accessed; the emitter of the triode Q12 is connected to the low power supply of the bandgap reference circuit structure through the resistor R4, and the base is connected to the low power supply of the circuit structure through the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure;

[0028] The base of the triode Q4 is connected to the collector of the triode Q3, the emitter is connected to the low power supply of the bandgap reference circuit structure through the resistors R6 and R7, and the connected end of the resistor R6 and the resistor R7 is connected to the output + end of the bandgap reference circuit structure; the collector of the triode Q4 is connected to the collector of the triode Q9, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

[0029] In some embodiments, the present circuit structure further includes a mirror circuit, including triodes Q1, Q7, Q5 and Q8;

[0030] The temperature compensation circuit includes triodes Q6, Q12, resistor R3, resistor R4 and resistor R5;

[0031] The negative feedback circuit includes triodes Q4 and Q9;

[0032] The emitter of the triode Q1 is connected to the emitter of the triode Q2, the base is connected to the collector of the triode Q2, and the collector is connected to the collector of the triode Q7; the base of the triode Q7 is connected to the base of the triode Q8 and is short-circuited with its collector, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the collector of the triode Q8 is connected to the collector of the triode Q5, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of the triode Q5 is used for accessing the bias signal, and the base is connected to the base of the triode Q6;

[0033] The emitter of the triode Q6 is used for accessing the bias signal, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the triode Q12 is connected to one end of the resistor R3 and serves as the first connection end of the temperature compensation circuit for connecting to the bandgap reference circuit to enable the reference voltage V AAccess; the emitter of the triode Q12 is connected to the low power supply of the bandgap reference circuit structure through the resistor R4, and the base is connected to the low power supply of the circuit structure through the resistor R5; the other end of the resistor R3 serves as the output + terminal of the bandgap reference circuit structure;

[0034] The base of the triode Q4 is connected to the collector of the triode Q3, and the emitter is connected to the low power supply of the bandgap reference circuit structure through the resistors R6 and R7. The connected end of the resistor R6 and the resistor R7 is connected to the output + terminal of the bandgap reference circuit structure; the collector of the triode Q4 is connected to the collector of the triode Q9, the base of the triode Q9 is connected to the base of the triode Q8, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

[0035] In some embodiments, the circuit structure further includes a capacitor C for performing Miller compensation on the negative feedback circuit.

[0036] The present invention also provides an LDO circuit, which includes the bandgap reference circuit structure with temperature compensation provided by the present invention.

[0037] The beneficial effects of the present invention are at least:

[0038] 1) The circuit structure provided by the present invention configures a temperature compensation circuit to compensate the output of the bandgap reference circuit when it is in a high-temperature state. When no compensation is performed, the output voltage V at high temperature REF decreases as the temperature rises, which is a negative temperature coefficient. After compensation, the output voltage V at high temperature REF increases as the temperature rises, which is a positive temperature coefficient; generally speaking, it is to inject a positive temperature coefficient current into the reference voltage for compensation, so that the reference voltage rises with the temperature.

[0039] 2) The circuit structure provided by the present invention configures a feedback circuit to stabilize the reference voltage. Description of the Drawings

[0040] In order to more clearly illustrate the embodiments of the present application, the following will briefly introduce the drawings required to be used or involved in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. Without creative efforts, other drawings can also be obtained based on these drawings:

[0041] Figure 1 It is the circuit schematic diagram of the bandgap reference circuit described by the present invention;

[0042] Figures 2-7 It is the circuit schematic diagram of the circuit structure provided by the present invention. Detailed Embodiments

[0043] This part describes the present utility model more comprehensively with reference to the accompanying drawings, in which illustrative embodiments of the present utility model are shown. However, the present utility model can be embodied in many different forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present utility model to those skilled in the art.

[0044] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the technical field to which this utility model belongs. It will be further understood that terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless specifically defined herein.

[0045] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this utility model will be more thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art.

[0046] A bandgap reference circuit (bandgap reference voltage source circuit) typically combines two voltages with opposite temperature coefficients:

[0047] 1. Positive temperature coefficient voltage: This part of the voltage is typically generated by two diodes or transistors with different current densities. As the temperature increases, this part of the voltage also increases.

[0048] 2. Negative temperature coefficient voltage: This part of the voltage is typically provided by the forward voltage drop (VBE) of a diode. As the temperature increases, this part of the voltage decreases.

[0049] By appropriately combining these two parts of the voltage in a certain ratio, a total voltage can be obtained whose temperature coefficient is close to zero, thus remaining stable within a certain temperature range.

[0050] Please refer to Figure 1 , the bandgap reference circuit includes transistors Q2, Q3, Q10, Q11, resistor R1 and resistor R2. Q10, Q11 and resistors R1, R2 form a Brokaw bandgap reference structure; Q10 and Q11 are transistors with emitter areas in proportion, and the area ratio is configured according to the circuit application, such as 10:1. Q2 and Q3 form a current mirror. By using the current mirror Q2 and Q3, the currents flowing through Q10 and Q11 are made the same. The same current flows through Q10 and Q11, such that the difference in base-emitter voltages ΔV BE across resistor R1 generates a positive temperature coefficient current I C10, the current satisfies the following relationship:

[0051]

[0052] In the formula, V T is the thermoelectric voltage: is the positive temperature coefficient voltage of the circuit, which is the voltage difference between the base and emitter of Q10.

[0053] The positive temperature coefficient voltage and the negative temperature coefficient voltage are generated by the triodes Q2, Q3, Q10, and Q11, so as to obtain the voltage V A with zero temperature coefficient, which can be expressed as:

[0054]

[0055] Formula (2) is the reference voltage without compensation.

[0056] This embodiment is described by taking the ratio of the emitter areas of Q10 and Q11 as 10:1 as an example. However, those skilled in the art can understand that the ratio of the emitter areas of Q10 and Q11 being 10:1 is not the only ratio for the implementation of this circuit structure. According to the application situation of the circuit structure, it can be configured as other ratios, such as 5:1, 8:1, 15:1, 20:1, etc.

[0057] As one of the functional circuits constituting the LDO circuit, since the LDO circuit is entirely composed of triodes, the temperature coefficient of the LDO circuit is too large; one of the functional circuits related to the temperature coefficient in the LDO circuit is the bandgap reference circuit, and the temperature coefficient of the LDO circuit can be reduced by reducing the temperature coefficient of the bandgap reference circuit.

[0058] Therefore, the present invention provides a bandgap reference circuit structure with temperature compensation to reduce the temperature coefficient of the bandgap reference circuit by temperature compensation. Please refer to Figure 2 , the circuit structure includes a bandgap reference circuit that generates a reference voltage V A with zero temperature coefficient, a temperature compensation circuit for generating a compensation voltage to compensate the reference voltage V A when the bandgap reference circuit outputs at a high temperature, and a negative feedback circuit for stabilizing the reference voltage V A .

[0059] When the bandgap reference circuit does not output at a high temperature, the temperature compensation circuit does not work, and the output voltage V REF of the bandgap reference circuit structure is the reference voltage V A ; when the bandgap reference circuit outputs at a high temperature, the temperature compensation circuit generates a compensation voltage for compensating the reference voltage V A to reduce the temperature coefficient of the reference voltage V A .

[0060] Please refer to Figure 2 , including transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5; the emitter of transistor Q6 is used for accessing the bias signal, the base is connected to the collector of transistor Q2, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection end of the temperature compensation circuit for connection to the bandgap reference circuit, so that the reference voltage V A is accessed; the emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5; the other end of resistor R3 serves as the output + end of the bandgap reference circuit structure, and the output voltage V REF .

[0061] When the bandgap reference circuit outputs at high temperature, transistor Q12 conducts, and the current I generated by the reference voltage V A flows into the branch where transistor Q12 is located to form current I 1 and the branch where resistor R3 is located to form current I 2 , and current I 1 and current I 2 are equal; the voltage generated across resistor R3 is the compensation voltage to compensate the reference voltage V A .

[0062] The high-temperature output of the bandgap reference circuit means the reference voltage V A output when the LDO circuit or the circuit structure provided by the present invention is in a high-temperature state; the circuit described in "the circuit temperature is lower" and "the circuit temperature is higher" in this article refers to the LDO circuit or the circuit structure provided by the present invention; the lower or higher temperature is configured according to the application place of the circuit and is realized by configuring different transistors. The temperature characteristic of the transistor is as follows: the higher the temperature, the lower the conduction voltage, and the lower the temperature, the higher the conduction voltage; therefore, configuring different transistors can achieve self-adaptation to lower or higher temperatures. Of course, those skilled in the art can also understand that by configuring a temperature sensing module to sense the working environment temperature of the circuit, comparing the sensed ambient temperature with a preset temperature threshold to judge whether the circuit temperature is low or high, and forming a control signal according to the judgment result to control the conduction and cut-off of transistor Q12 (when the working environment temperature of the circuit is higher than the temperature threshold, Q12 conducts and the compensation circuit starts; when the working environment temperature of the circuit is lower than the temperature threshold, Q12 cuts off and the compensation circuit does not start).

[0063] When the circuit temperature is relatively low, the conduction voltage of Q12 is relatively large. Since the conduction voltage between the base and emitter of Q12 is not reached, the transistor is turned off and the compensation circuit does not work. As the temperature continues to rise, the conduction voltage of Q12 gradually decreases. When the temperature reaches T0, Q12 begins to conduct, and its current is proportional to the temperature. The current flowing into R3 is approximately equal to the current flowing through Q12. At this time, as the temperature increases, the conduction voltage of the triode decreases, and the voltage across R3 is added to finally obtain the compensated output voltage V REF 。

[0064] Please refer to Figure 2 , when conducting, the collector of Q12 is connected to the resistor R3, so the current flowing into R3 is approximately equal to the current flowing through Q12.

[0065] In the circuit structure, the base of Q6 is connected to the collector of Q2, which ensures the synchronization of the current and makes the circuit structure stable.

[0066] Figure 2 As shown in the structure, the current of the Q6 branch is β times that of the Q2 and Q10 branches (β can be an integer from 1, 2, 3... N, or a number greater than 0 and less than 1; it is determined according to the circuit application situation). Here, taking β = 2 as an example, I C6 Satisfies the following conditions:

[0067]

[0068] Therefore, when the high temperature is reached, the compensation circuit starts to work, and the output voltage V of the circuit structure provided by the present invention REF is equal to the voltage at point A plus the voltage of resistor R3, which is:

[0069]

[0070] The output voltage V of the circuit structure provided by the present invention REF is as follows:

[0071]

[0072] In the formula, T is the working environment temperature of the circuit; T 0 is the temperature threshold for turning on the triode Q12; when the current of the Q6 branch is 2 times that of the Q2 and Q10 branches, and T ≥ T 0 , the output voltage V of the circuit structure REF is as shown in the second formula above.

[0073] Please refer to Figure 2, the negative feedback circuit in this circuit structure includes transistor Q4 and transistor Q9; the base of transistor Q4 is connected to the collector of transistor Q3, and the emitter is connected to the low power supply of the bandgap reference circuit structure through resistor R6 and resistor R7. One end where resistor R6 is connected to resistor R7 is connected to the output + terminal of the bandgap reference circuit structure; the collector of transistor Q4 is connected to the collector of transistor Q9, the base of transistor Q9 is connected to the collector of transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

[0074] When the reference voltage V A rises, the current flowing through Q11 increases exponentially, but the current flowing through Q10 only increases linearly due to the limitation of R1. Q3 mirrors the current of Q2 through the current mirror, so the current flowing through Q3 is less than the current of Q11. Thus, the voltage at node B decreases, resulting in a decrease in the voltage across resistors R6 and R7, and finally causing V REF voltage to decrease, achieving the stability of the reference voltage; conversely, when the reference voltage V A decreases, the negative feedback circuit can also make V REF rise, achieving the purpose of stabilizing the reference voltage.

[0075] Transistors Q4 and Q9 in this negative feedback circuit are in the variable resistance region. As the voltage at point B varies, their conduction voltages are different, thereby changing the voltage across resistors R6 and R7. Resistors R6 and R7 form a voltage dividing circuit, realizing the adjustment of V REF . Since V REF satisfies Equation (5), therefore, by adjusting V REF , the reference voltage can be adjusted to achieve the purpose of stabilizing the reference voltage.

[0076] For another implementation of the temperature compensation circuit of this circuit structure, please refer to Figure 3 as shown (to make the circuit structure clear, Figure 3 the negative feedback circuit is omitted). This circuit structure also includes a mirror circuit, which includes transistor Q5 and transistor Q8; the temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4, and resistor R5. The emitter of transistor Q5 is used for accessing the bias signal, the collector is connected to the collector of transistor Q8, and the base is connected to the base of transistor Q6; the base of transistor Q8 is connected to the collector of transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of transistor Q6 is used for accessing the bias signal, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection end of the temperature compensation circuit for connecting to the bandgap reference circuit, enabling the reference voltage V AConnection: The emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5. The other end of resistor R3 serves as the output + terminal of the bandgap reference circuit structure.

[0077] For the third implementation of the temperature compensation circuit of this circuit structure, please refer to Figure 4 as shown (to make the circuit structure clear, Figure 4 the negative feedback circuit is omitted in the figure). This circuit structure also includes a mirror circuit, and the mirror circuit includes transistors Q1, Q7, Q5, and Q8; the temperature compensation circuit includes transistors Q6, Q12, resistor R3, resistor R4, and resistor R5.

[0078] The emitter of transistor Q1 is connected to the emitter of transistor Q2, the base is connected to the collector of transistor Q2, and the collector is connected to the collector of transistor Q7; the base of transistor Q7 is connected to the base of transistor Q8 and shorted to its collector, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the collector of transistor Q8 is connected to the collector of transistor Q5, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of transistor Q5 is used for biasing signal access, and the base is connected to the base of transistor Q6; the emitter of transistor Q6 is used for biasing signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through resistor R5; the collector of transistor Q12 is connected to one end of resistor R3 and serves as the first connection terminal of the temperature compensation circuit for connection with the bandgap reference circuit, so that the reference voltage V A is connected; the emitter of transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through resistor R4, and the base is connected to the low power supply of the circuit structure through resistor R5; the other end of resistor R3 serves as the output + terminal of the bandgap reference circuit structure.

[0079] According to the base - collector current relationship of the transistor, Figure 3 、 4 in the circuit structure shown, the collector current of transistor Q6 is equal to β times the collector current of Q2. The biasing signal is applied to transistor Q6 to make it conduct. The collector current of Q6 is equal to β times the collector current of Q2, and the base voltage of transistor Q12 is clamped at a conduction voltage required by the temperature through resistor R5. When the circuit temperature reaches the temperature at which transistor Q12 conducts, transistor Q12 conducts and the temperature compensation circuit starts to generate a compensation voltage.

[0080] The collector current of transistor Q6 is equal to β times the collector current of transistor Q2, ensuring current synchronization and making the circuit structure stable.

[0081] Figure 4In it, according to the current mirrors Q2 and Q1, the current of Q1 is equal to the current of the Q2 branch. Also, due to the current sinks Q7 and Q8, the current is also equal to that of the Q5 and Q8 branches. Finally, because of the current mirrors Q5 and Q6, and m = β for Q6, the current of the Q6 branch is β times the currents of the Q2 and Q10 branches, that is, I CQ6 = βI CO2 .

[0082] Please refer to Figure 5 , this circuit structure includes a bandgap reference circuit that generates a reference voltage V A with zero temperature coefficient, a temperature compensation circuit for compensating when the bandgap reference circuit outputs at high temperature to reduce the temperature coefficient, a negative feedback circuit for stabilizing the reference voltage V A , and a mirror circuit that makes the collector current I CQ6 of the triode Q6 and the collector current I CQ9 of the triode Q9 be β times the collector current I CQ2 of the triode Q2 respectively, as well as a resistor R6 and a resistor R7. Among them, the bandgap reference circuit includes triodes Q2, Q3, Q10, Q11, a resistor R1, and a resistor R2; the temperature compensation circuit includes a triode Q12 and resistors R3 to R5; the negative feedback circuit includes triodes Q4 and Q9; the mirror circuit includes triodes Q5 and Q8. The connection relationships between the components are as Figure 5 .

[0083] Please refer to Figure 6 , this circuit structure includes a bandgap reference circuit that generates a reference voltage V A with zero temperature coefficient, a temperature compensation circuit for compensating when the bandgap reference circuit outputs at high temperature to reduce the temperature coefficient, a negative feedback circuit for stabilizing the reference voltage V A , and a mirror circuit that makes the collector current I CQ6 of the triode Q6 and the collector current I CQ9 of the triode Q9 be β times the collector current I CQ2 of the triode Q2 respectively, as well as a resistor R6 and a resistor R7. Among them, the bandgap reference circuit includes triodes Q2, Q3, Q10, Q11, a resistor R1, and a resistor R2; the temperature compensation circuit includes a triode Q12 and resistors R3 to R5; the negative feedback circuit includes triodes Q4 and Q9; the mirror circuit includes triodes Q1, Q7, Q5, and Q8. The connection relationships between the components are as Figure 6 .

[0084] This circuit structure is also configured with a capacitor C. The first plate of this capacitor C is connected to the base of the triode Q4, and the second plate is connected to the collector of the triode Q4; the connection relationships between the remaining components are as Figure 7The capacitor C performs Miller compensation on the negative feedback circuit to separate the circuit poles and make the circuit reach a stable state.

[0085] The bias signal involved in this circuit structure makes the triode Q6 in the working state (fully conducting or variable resistance region), generates a current in the branch where Q6 is located, and clamps the base voltage of Q12 at a conduction voltage required by the temperature.

[0086] The bias signal can be generated and accessed by an external circuit or provided by the circuit structure itself; as Figure 7 shown, the emitter of the triode Q6 is directly connected to the emitter of the triode Q4. When the circuit structure is in the working state, Q4 and Q9 are always in the variable resistance region state, and a bias signal is connected to the emitter of the triode Q6.

[0087] This circuit structure adds a temperature compensation circuit to perform positive temperature compensation on the output of the bandgap reference circuit at high temperature (about 100 °C), thereby reducing the temperature coefficient of the bandgap reference voltage. Using this circuit structure to build an LDO circuit can provide a zero-temperature coefficient voltage for the rest of the LDO circuit to reduce the overall temperature coefficient of the LDO circuit.

[0088] Because in the LDO circuit, the zero-temperature coefficient voltage is only generated by the bandgap reference circuit, in order to reduce the temperature coefficient of the LDO output, the temperature coefficient of the bandgap reference circuit can be reduced to provide a zero-temperature coefficient voltage for the rest of the circuit to reduce the overall temperature coefficient of the LDO circuit.

[0089] After this circuit structure is used to build an LDO circuit, the Q1 and Q7 current mirrors also provide mirror currents for other LDO circuits; the Q1 and Q7 current mirrors also provide mirror currents for other LDO circuits.

[0090] Adopting the circuit structure shown in Figure 7 to build an LDO circuit, the capacitor C can be used to separate the circuit poles. Since there are many poles in the LDO, each pole needs to be separated, and the main pole and the secondary pole need to be distinguished to make the circuit reach a stable state. Therefore, a capacitor is introduced for Miller compensation to separate the circuit poles.

[0091] The conduction voltage described in this article is the lowest conduction voltage of the triode. According to the temperature characteristics of the triode, the higher the temperature, the lower the conduction voltage, and the lower the temperature, the higher the conduction voltage.

[0092] This disclosure has been described by the above related embodiments. However, the above embodiments are only examples of implementing this disclosure. It must be pointed out that the disclosed embodiments do not limit the scope of this disclosure. On the contrary, changes and modifications made without departing from the spirit and scope of this disclosure fall within the patent protection scope of this disclosure.

Claims

1. A bandgap reference circuit structure with temperature compensation, characterized in that: The circuit structure includes: Bandgap reference circuit, generating a reference voltage V with zero temperature coefficient A ; The temperature compensation circuit is used to generate a compensation voltage for the reference voltage V when the bandgap reference circuit outputs at high temperature. A to make compensation; Negative feedback circuit is used to make the reference voltage V A Stablize.

2. The bandgap reference circuit structure with temperature compensation according to claim 1, characterized in that: The bandgap reference circuit includes transistors Q2, Q3, Q10, Q11, resistors R1 and R2; the base and emitter of the transistor Q2 are respectively connected to the base and emitter of the transistor Q3, the base of the transistor Q2 is also short-circuited with its collector, and the collector of the transistor Q2 is connected to the collector of the transistor Q10; the base of the transistor Q10 is connected to the base of the transistor Q11, and the emitter of the transistor Q10 is connected to a low power supply of the bandgap reference circuit structure via the resistors R1 and R2; the collector of the transistor Q3 is connected to the collector of the transistor Q11, and the emitter of the transistor Q11 is connected to a low power supply of the bandgap reference circuit structure via the resistor R2.

3. The bandgap reference circuit structure with temperature compensation according to claim 2, characterized in that: The temperature compensation circuit includes a transistor Q6, a transistor Q12, a resistor R3, a resistor R4 and a resistor R5; the emitter of the transistor Q6 is used for bias signal access, the base is connected to the collector of the transistor Q2, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the transistor Q12 is connected to one end of the resistor R3, and is used as the first connection end of the temperature compensation circuit to be connected to the bandgap reference circuit, so that the reference voltage V A The emitter of the transistor Q12 is connected to the low power supply of the bandgap reference circuit structure via the resistor R4, and the base is connected to the low power supply of the circuit structure via the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure.

4. The bandgap reference circuit structure with temperature compensation according to claim 2, characterized in that: Also included is a mirror circuit, including transistor Q5 and transistor Q8; The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4 and resistor R5; The emitter of the transistor Q5 is used for bias signal access, the collector is connected to the collector of the transistor Q8, and the base is connected to the base of the transistor Q6; the base of the transistor Q8 is connected to the collector of the transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure; The emitter of the transistor Q6 is used for bias signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the transistor Q12 is connected to one end of the resistor R3, and is used as the first connection end of the temperature compensation circuit to connect to the bandgap reference circuit, so that the reference voltage V A The emitter of the transistor Q12 is connected to the low power supply of the bandgap reference circuit structure via the resistor R4, and the base is connected to the low power supply of the circuit structure via the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure.

5. The bandgap reference circuit structure with temperature compensation according to claim 2, characterized in that: It also includes a mirror circuit, which includes transistors Q1, Q7, Q5 and Q8; the temperature compensation circuit includes transistors Q6, Q12, resistors R3, R4 and R5; The emitter of the transistor Q1 is connected to the emitter of the transistor Q2, the base is connected to the collector of the transistor Q2, and the collector is connected to the collector of the transistor Q7; the base of the transistor Q7 is connected to the base of the transistor Q8 and short-circuited with its collector, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the collector of the transistor Q8 is connected to the collector of the transistor Q5, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of the transistor Q5 is used for bias signal access, and the base is connected to the base of the transistor Q6; The emitter of the transistor Q6 is used for bias signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the transistor Q12 is connected to one end of the resistor R3, and is used as the first connection end of the temperature compensation circuit to connect to the bandgap reference circuit, so that the reference voltage V A The emitter of the transistor Q12 is connected to the low power supply of the bandgap reference circuit structure via the resistor R4, and the base is connected to the low power supply of the circuit structure via the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure.

6. The bandgap reference circuit structure with temperature compensation according to claim 3, characterized in that: The negative feedback circuit includes a transistor Q4 and a transistor Q9; the base of the transistor Q4 is connected to the collector of the transistor Q3, the emitter is connected to the low power supply of the bandgap reference circuit structure through resistors R6 and R7, and one end of the resistor R6 connected to the resistor R7 is connected to the output + end of the bandgap reference circuit structure; the collector of the transistor Q4 is connected to the collector of the transistor Q9, the base of the transistor Q9 is connected to the collector of the transistor Q2, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

7. The bandgap reference circuit structure with temperature compensation according to claim 2, characterized in that: Also includes a mirror circuit, the mirror circuit includes a transistor Q5 and a transistor Q8; The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4 and resistor R5; The negative feedback circuit includes a transistor Q4 and a transistor Q9; The emitter of the transistor Q5 is used for bias signal access, the collector is connected to the collector of the transistor Q8, and the base is connected to the base of the transistor Q6; the base of the transistor Q8 is connected to the collector of the transistor Q2 and the base of the transistor Q9, and the emitter is connected to the low power supply of the bandgap reference circuit structure; The emitter of the transistor Q6 is used for bias signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the transistor Q12 is connected to one end of the resistor R3, and is used as the first connection end of the temperature compensation circuit to connect to the bandgap reference circuit, so that the reference voltage V A The emitter of the transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through the resistor R4, and the base is connected to the low power supply of the circuit structure through the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure; The base of the transistor Q4 is connected to the collector of the transistor Q3, and the emitter is connected to the low power supply of the bandgap reference circuit structure through resistors R6 and R7. One end of the resistor R6 connected to the resistor R7 is connected to the output + end of the bandgap reference circuit structure; the collector of the transistor Q4 is connected to the collector of the transistor Q9, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

8. The bandgap reference circuit structure with temperature compensation according to claim 2, characterized in that: Also included is a mirror circuit, including transistor Q1, transistor Q7, transistor Q5 and transistor Q8; The temperature compensation circuit includes transistor Q6, transistor Q12, resistor R3, resistor R4 and resistor R5; The negative feedback circuit includes a transistor Q4 and a transistor Q9; The emitter of the transistor Q1 is connected to the emitter of the transistor Q2, the base is connected to the collector of the transistor Q2, and the collector is connected to the collector of the transistor Q7; the base of the transistor Q7 is connected to the base of the transistor Q8 and short-circuited with its collector, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the collector of the transistor Q8 is connected to the collector of the transistor Q5, and the emitter is connected to the low power supply of the bandgap reference circuit structure; the emitter of the transistor Q5 is used for bias signal access, and the base is connected to the base of the transistor Q6; The emitter of the transistor Q6 is used for bias signal access, and the collector is connected to the low power supply of the bandgap reference circuit structure through the resistor R5; the collector of the transistor Q12 is connected to one end of the resistor R3, and is used as the first connection end of the temperature compensation circuit to connect to the bandgap reference circuit, so that the reference voltage V A The emitter of the transistor Q12 is connected to the low power supply of the bandgap reference circuit structure through the resistor R4, and the base is connected to the low power supply of the circuit structure through the resistor R5; the other end of the resistor R3 serves as the output + end of the bandgap reference circuit structure; The base of the transistor Q4 is connected to the collector of the transistor Q3, and the emitter is connected to the low power supply of the bandgap reference circuit structure through resistors R6 and R7, and one end of the resistor R6 connected to the resistor R7 is connected to the output + end of the bandgap reference circuit structure; the collector of the transistor Q4 is connected to the collector of the transistor Q9, the base of the transistor Q9 is connected to the base of the transistor Q8, and the emitter is connected to the low power supply of the bandgap reference circuit structure.

9. The bandgap reference circuit structure with temperature compensation according to claim 1, characterized in that: It also includes a capacitor C for performing Maitreya compensation on the negative feedback circuit.

10. An LDO circuit, characterized in that: The circuit comprises a bandgap reference circuit structure with temperature compensation as claimed in any one of claims 1 to 9.

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