Second-order temperature compensation circuit, band-gap reference circuit structure and integrated circuit

Abstract

The utility model discloses a second-order temperature compensating circuit, a band-gap reference circuit structure and an integrated circuit. The second-order temperature compensating circuit comprises a triode Q4, a triode Q5 and a resistor R5, when the temperature T reaches T1, the triode Q5 is conducted, so that first compensation voltage is generated at the two ends of the resistor R5 to compensate the compensated voltage; and when the temperature T reaches T2, the triode Q4 and the triode Q5 are conducted at the same time, so that second compensation voltage is generated at the two ends of the resistor R5 to compensate the compensated voltage. The compensating circuit provided by the utility model is provided with the triode, when the temperature reaches the temperature which enables the triode to be conducted, the triode is conducted to realize the compensation of the compensated voltage, when the compensation is not carried out, the compensated voltage is reduced along with the temperature rise and is in a negative temperature coefficient, and after the compensation, the compensated voltage is increased along with the temperature rise and is in a positive temperature coefficient.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of electronic circuit, especially is involved in a two order temperature compensation circuit, band gap reference circuit structure and integrated circuit. BACKGROUND

[0002] Bandgap reference is a kind of reference source, it has excellent temperature stability, commonly used in high-precision voltage reference.This voltage source is very important in analog and digital circuits, because many circuit functions depend on a precise reference voltage.Bandgap reference circuit usually combines two kinds of temperature coefficient opposite voltage:

[0003] 1. Positive temperature coefficient voltage: this part of voltage is usually generated by two different current density diodes or transistors;With temperature rising, this part of voltage also increases.

[0004] 2. Negative temperature coefficient voltage: this part of voltage is usually provided by a diode forward voltage drop (VBE), with temperature rising, this part of voltage will decrease.

[0005] By proper proportion combination of the two parts of voltage, a total voltage can be obtained, and its temperature coefficient is close to zero, so as to keep stable within a certain temperature range.

[0006] Bandgap reference voltage source outputs reference voltage V A Temperature coefficient is higher, and the working stability of other circuits will be affected when providing other circuits. SUMMARY

[0007] To solve the technical problems existing in the prior art, the utility model provides a two order temperature compensation circuit.

[0008] The circuit is configured to include triode Q4, triode Q5 and resistance R5;When temperature T reaches T1, the triode Q5 is turned on to generate a first compensation voltage across the resistance R5 to compensate the compensated voltage;When temperature T reaches T2, the triode Q4 and the triode Q5 are turned on simultaneously to generate a second compensation voltage across the resistance R5 to compensate the compensated voltage.

[0009] Further, the temperature compensation circuit is also configured to include an over-temperature detection circuit.

[0010] Further, the over-temperature detection circuit includes triode Q3, the base of the triode Q3 is used for biasing signal access, the collector is used as the first connection end of temperature compensation, and the emitter is connected to circuit ground.

[0011] In some embodiments, the base of the transistor Q3 is connected to the circuit ground through the resistor R3;

[0012] The base of the transistor Q4 is connected to the circuit ground through the series connection of the resistor R2 and the resistor R3, and the collector is used as the first connection end of the compensation circuit for outputting the voltage V REF One end of the resistor R5 is connected to the circuit ground, and the emitter is connected to the circuit ground.

[0013] Further, the base of the transistor Q5 is connected to the circuit ground through the series connection of the resistor R1, the resistor R2 and the resistor R3, the collector is connected to the collector of the transistor Q4, and the emitter is connected to the circuit ground.

[0014] Further, the temperature compensation circuit is further configured to include a power supply circuit for providing a working voltage for an electrical device.

[0015] Further, the power supply circuit includes a transistor Q1 and a transistor Q2, the emitter and the base of the transistor Q1 are respectively connected to the emitter and the base of the transistor Q2, the collector of the transistor Q1 is used as the second connection end of the compensation circuit and is short-circuited with the base, and the collector of the transistor Q2 is used as the output of the power supply circuit.

[0016] The utility model also provides a band gap reference circuit structure, the circuit structure includes:

[0017] The band gap reference circuit is used for generating a reference voltage V REF with zero temperature coefficient.

[0018] The temperature compensation circuit is used for compensating the reference voltage V REF .

[0019] The temperature compensation circuit is the temperature compensation circuit provided by the utility model.

[0020] Further, the band gap reference circuit includes a transistor Q6, a transistor Q7, a transistor Q8, a transistor Q9, a resistor R7 and a resistor R8, the base and the emitter of the transistor Q6 are respectively connected to the base and the emitter of the transistor Q7, the base of the transistor Q6 is also short-circuited with the collector, and the collector of the transistor Q6 is connected to the collector of the transistor Q8, the base of the transistor Q8 is connected to the base of the transistor Q9, and the emitter is connected to the circuit ground of the band gap reference circuit structure through the resistor R7 and the resistor R8, the collector of the transistor Q7 is connected to the collector of the transistor Q9, and the emitter of the transistor Q9 is connected to the circuit ground through the resistor R8.

[0021] The third aspect of the utility model provides an integrated circuit, and the circuit includes the second-order temperature compensation circuit provided by the utility model.

[0022] The utility model discloses the beneficial effect has:

[0023] The utility model discloses a compensation circuit configuration triode, when the temperature reaches the temperature of making triode conduction, triode conduction realizes the compensation of the compensated voltage, when not carrying out compensation, the compensated voltage drops with the temperature rise voltage, is negative temperature coefficient, after compensation, the compensated voltage rises with the temperature rise voltage, is positive temperature coefficient.

[0024] The utility model discloses a compensation circuit configuration two triodes, and its conduction temperature is different, realized two order temperature compensation, and two order temperature compensation makes the compensated voltage have lower temperature drift coefficient.

[0025] The utility model discloses a compensation circuit configuration overtemperature detection circuit makes the circuit have overtemperature detection function, and overtemperature detection circuit and temperature compensation circuit share temperature detection resistance, simplified the circuit structure, reduced the circuit area. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the embodiment of the present application, the drawings needed to be used or referred to in the embodiment will be simply introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor:

[0027] Figure 1 The circuit structure diagram of the band gap reference circuit described in the utility model is shown in the figure:

[0028] Figure 2 The circuit structure diagram of the temperature compensation circuit provided by the utility model is shown in the figure:

[0029] Figure 3 The circuit structure diagram of the band gap reference circuit structure provided by the utility model is shown in the figure. DETAILED DESCRIPTION

[0030] This part describes the utility model more fully with reference to the drawings, and the illustrative embodiments of the utility model are shown in the drawings. However, the utility model also embodies in many different forms and should not be understood as limiting to the embodiments described here. On the contrary, these embodiments are provided in order to make the disclosure sufficient and complete, and to fully convey the scope of the utility model to the person skilled in the art.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0032] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the implementations set forth in this disclosure; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the inventive aspects of the example implementations to those skilled in the art. Like reference numerals may refer to like elements throughout the figures.

[0033] Bandgap reference circuits (bandgap reference voltage source circuits) typically combine two voltages with opposite temperature coefficients:

[0034] 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.

[0035] 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.

[0036] By combining these two parts of the voltage in the appropriate proportions, a total voltage can be obtained that has a temperature coefficient close to zero, thus remaining stable over a certain temperature range.

[0037] Referring to Figure 1 , the bandgap reference circuit includes a transistor Q6, a transistor Q7, a transistor Q8, a transistor Q9, a resistor R7, and a resistor R8; the base and the emitter of the transistor Q6 are connected to the base and the emitter of the transistor Q7, respectively, and the base of the transistor Q6 is also short-circuited to the collector thereof, and the collector thereof is connected to the collector of the transistor Q8; the base of the transistor Q8 is connected to the base of the transistor Q9, and the emitter thereof is connected to the circuit ground of the bandgap reference circuit through the resistor R7 and the resistor R8; the collector of the transistor Q7 is connected to the collector of the transistor Q9, and the emitter of the transistor Q9 is connected to the circuit ground through the resistor R8.

[0038] Figure 1 As shown in the circuit, Q8, Q9 and resistors R7, R8 constitute a Brokaw bandgap reference structure; Q8, Q9 are transistors with proportional emitter areas, and the area ratio is configured according to the application of the circuit, such as 10:1. Q6, Q7 constitute a current mirror, and the current mirror Q6 and Q7 are used to make the current flowing through Q8 and Q9 the same, and the same current flows through Q8 and Q9, so that the difference ΔV BEThe current acting on the resistor R7 generates a positive temperature coefficient current I C8 The current satisfies the following relationship:

[0039]

[0040] In the formula, V T is the thermal voltage: is the positive temperature coefficient voltage of the circuit, which is the voltage difference between the base and the emitter of Q8.

[0041] The positive temperature coefficient voltage and the negative temperature coefficient voltage are generated by the triode Q6, the triode Q7, the triode Q8, and the triode Q9, so that the zero-temperature coefficient voltage V REF at point A can be expressed as:

[0042]

[0043] Formula (2) is the reference voltage without compensation.

[0044] This embodiment is described by taking the proportion of the emitter areas of Q8 and Q9 as 10:1 as an example, but those skilled in the art can understand that the proportion of the emitter areas of Q8 and Q9 as 10:1 is not the only proportion for realizing the circuit structure, and according to the application situation of the circuit structure, other proportions such as 5:1, 8:1, 15:1, 20:1, etc.

[0045] The bandgap reference circuit is one of the functional circuits constituting the LDO circuit, and 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.

[0046] Therefore, the utility model provides a kind of second-order temperature compensation circuit, utilize the reference voltage V REF of the output of bandgap reference circuit is compensated, and the temperature coefficient of bandgap reference circuit can be effectively reduced. Please refer to Figure 2 The temperature compensation circuit is configured to include triode Q4, triode Q5 and resistor R5;The base of triode Q4 is used for bias signal access, and the collector is used as the connection end of compensation for being accessed by compensated voltage (reference voltage V REF );The emitter is connected to low power supply;The collector of triode Q5 is connected to the collector of triode Q4, and the base is used for bias signal access, and the emitter is connected to low power supply;One end of resistor R5 is connected to the collector of triode Q4 and Q5, and the other end is used as the output of compensation circuit, and outputs V OUT .

[0047] The bases of the transistors Q4 and Q5 are connected to bias signals, and the compensated voltage is connected. When the temperature is low, the on-voltage of Q4 and Q5 is large, and the base-emitter voltage of Q4 and Q5 is not large enough, so Q4 and Q5 are both off, and the compensation circuit does not work. As the temperature rises, the on-voltage of Q4 and Q5 decreases. When the temperature rises to T1, Q5 starts to conduct, and the current of Q5 is proportional to the temperature. The output voltage V OUT The compensated voltage is the voltage across the resistor R5 plus the voltage across the resistor R5, where the current flowing through R5 is approximately equal to the current flowing through Q4. At this time, the compensated voltage is temperature-compensated. When the temperature continues to rise to T2, Q4 also starts to conduct, and the current flowing through R5 is the sum of the currents flowing through Q4 and Q5, and the compensated voltage increases. The output voltage V OUT satisfies the following relationship:

[0048]

[0049] where T is the operating temperature, V REF is the compensated voltage; V1 is the first compensation voltage; and V2 is the second compensation voltage.

[0050] The temperature compensation circuit also includes an over-temperature detection circuit. Please refer to Figure 2 The over-temperature detection circuit includes a transistor Q3, the base of the transistor Q3 is connected to a bias signal, the collector is connected to the first connection terminal of the temperature compensation, and the emitter is connected to the circuit ground. The over-temperature detection circuit of the compensation circuit realizes over-temperature detection. The collector of the transistor Q3 is connected to the key point, and the base is connected to the bias signal. When the temperature reaches the on-voltage of the transistor Q3, the transistor Q3 is turned on, which lowers the voltage of the key point and achieves the purpose of turning off, thereby realizing over-temperature protection.

[0051] The key point described herein refers to a point that needs to be lowered in voltage in an over-temperature state, such as the base of the transistors Q4 and Q5, so that the temperature compensation circuit has no output and achieves the purpose of over-temperature protection; or the output terminal of a functional circuit composed of the temperature compensation circuit, such as the output of an LDO circuit composed of the temperature compensation circuit. When the circuit is in an over-temperature state, the transistor Q3 is turned on to lower the output of the circuit and achieve the purpose of over-temperature protection.

[0052] The temperature compensation circuit also includes a power supply circuit for providing operating voltage to the circuit devices. The power supply circuit can be composed of any existing voltage stabilizing circuit, and provides stable voltage to the transistors Q3-Q5 as the bias signal of the transistors. Please refer to Figure 2The power supply circuit of the temperature compensation circuit is configured to include a transistor Q1 and a transistor Q2, the emitter and the base of the transistor Q1 are connected to the emitter and the base of the transistor Q2 respectively, the collector of the transistor Q1 is connected to the second connection end of the compensation circuit and is used for connecting the mirror power supply, and the collector of the transistor Q1 is short-circuited to the base of the transistor Q1; and the collector of the transistor Q2 is used as the output of the power supply circuit. The mirror power supply is connected to the collector of the transistor Q1, and the mirror current is provided to the electrical device by the mirror circuit composed of the transistors Q1 and Q2. The mirror power supply mode reduces the influence of the voltage fluctuation of the voltage source and ensures the stability of the circuit.

[0053] It should be understood that the collector of the transistor Q1 can also be connected to a constant current source to reduce the fluctuation of the power supply and ensure the stability of the circuit.

[0054] Please refer to Figure 2 The base of the transistor Q3 is connected to the circuit ground through the resistor R3; the base of the transistor Q4 is connected to the circuit ground through the resistor R2 and the resistor R3 in series; and the base of the transistor Q5 is connected to the circuit ground through the resistor R1, the resistor R2 and the resistor R3 in series. The output provided by the power supply circuit is divided by the resistor R1, the resistor R2 and the resistor R3 to form different voltages which are provided to the transistors Q3, Q4 and Q5 to provide different base bias. The resistor R3 is the conduction resistor of the transistor Q3, the resistor R2 and the resistor R3 are the conduction resistors of the transistor Q4, and the resistor R1, the resistor R2 and the resistor R3 are the conduction resistors of the transistor Q5.

[0055] In addition, the emitter of the transistor Q4 and the emitter of the transistor Q5 are connected to the circuit ground through the resistor R4 and the resistor R6 respectively. The size of the compensation voltage can be adjusted by configuring the resistors R4 and R6 with different resistance values.

[0056] The "lower temperature" and "higher temperature" described in the present text refer to the temperature of the circuit, and the circuit refers to the circuit structure provided by the present application or the integrated circuit including the circuit structure, such as the bandgap reference circuit structure with temperature compensation (as shown in Figure 3 ) or the LDO circuit (integrated circuit), the driving integrated circuit (output V OUT as the driving voltage), and the temperature compensation integrated circuit with independent over-temperature detection.

[0057] The temperature is lower or the temperature is higher according to the place where the circuit is applied, and different triodes are configured to achieve the temperature characteristics of the triode, that is, the higher the temperature, the lower the on-voltage, and the lower the temperature, the higher the on-voltage; therefore, different triodes can be configured to achieve the self-adaptation of low or high temperature. Of course, those skilled in the art can also understand that the temperature sensing module is configured to sense the working environment temperature of the circuit, the sensed environment temperature is compared with the preset temperature threshold to determine the low / high temperature of the circuit, and the control signal is formed according to the determination result to control the conduction and cutoff of the triodes Q4 and Q5 (when the working environment temperature of the circuit is higher than the temperature threshold, the triodes Q4 and Q5 are turned on, and the compensation circuit is started; when the working environment temperature of the circuit is lower than the temperature threshold, the triodes Q4 and Q5 are turned off, and the compensation circuit is not started).

[0058] The on-voltage described herein is the minimum on-voltage of the triode, and according to the temperature characteristics of the triode, the higher the temperature, the lower the on-voltage, and the lower the temperature, the higher the on-voltage.

[0059] The disclosure has been described by the above related embodiments, however, the above embodiments are only examples for implementing the disclosure. It must be pointed out that the disclosed embodiments do not limit the scope of the disclosure. On the contrary, changes and modifications made without departing from the spirit and scope of the disclosure are within the scope of the patent protection of the disclosure.

Claims

1. A second order temperature compensation circuit, characterized by, The circuit is configured to include a transistor Q4, a transistor Q5 and a resistor R5; when the temperature T reaches T1, the transistor Q5 is turned on to generate a first compensation voltage across the resistor R5 to compensate the compensated voltage; when the temperature T reaches T2, the transistor Q4 and the transistor Q5 are turned on at the same time to generate a second compensation voltage across the resistor R5 to compensate the compensated voltage.

2. The second order temperature compensation circuit of claim 1, wherein, It is also configured to include an over-temperature detection circuit.

3. The second order temperature compensation circuit of claim 2, wherein, The over-temperature detection circuit includes a transistor Q3, the base of the transistor Q3 is used for biasing signal access, the collector is used as a first connection end of temperature compensation, and the emitter is connected to the circuit ground.

4. The second order temperature compensation circuit of claim 3, wherein, The base of the transistor Q3 is connected to the circuit ground through a resistor R3; The base of the triode Q4 is connected to the circuit ground through the series connection of the resistor R2 and the resistor R3, and the collector is used as the first connection end of the compensation circuit for outputting the voltage V REF One end of the resistor R5 is connected to the circuit ground, and the emitter is connected to the circuit ground.

5. The second order temperature compensation circuit of claim 4, wherein, The base of the transistor Q5 is connected to the circuit ground through a resistor R1, a resistor R2 and a resistor R3 in series, the collector is connected to the collector of the transistor Q4, and the emitter is connected to the circuit ground.

6. The second order temperature compensation circuit of claim 1, wherein, It is also configured to include a power supply circuit for providing operating voltage for the electrical device.

7. The second order temperature compensation circuit of claim 6, wherein, The power supply circuit includes a transistor Q1 and a transistor Q2, the emitter and the base of the transistor Q1 are connected to the emitter and the base of the transistor Q2 respectively, the collector of the transistor Q1 is used as a second connection end of the compensation circuit and is short-circuited with the base of the transistor Q1; the collector of the transistor Q2 is used as the output of the power supply circuit.

8. A bandgap reference circuit structure, characterized by The circuit structure includes: Bandgap reference circuit for generating a zero-temperature- coefficient reference voltage V REF ; a temperature compensation circuit for generating a compensation voltage opposite to a reference voltage V REF compensation is performed; The temperature compensation circuit is the temperature compensation circuit of any one of claims 1-7.

9. The bandgap reference circuit structure of claim 8, wherein, The bandgap reference circuit includes a transistor Q6, a transistor Q7, a transistor Q8, a transistor Q9, a resistor R7 and a resistor R8; the base and the emitter of the transistor Q6 are connected to the base and the emitter of the transistor Q7 respectively, the base of the transistor Q6 is also short-circuited with the collector, and the collector of the transistor Q6 is connected to the collector of the transistor Q8; the base of the transistor Q8 is connected to the base of the transistor Q9, and the emitter is connected to the circuit ground of the bandgap reference circuit structure through the resistor R7 and the resistor R8; the collector of the transistor Q7 is connected to the collector of the transistor Q9, and the emitter of the transistor Q9 is connected to the circuit ground through the resistor R8.

10. An integrated circuit, characterized by The circuit includes the second-order temperature compensation circuit of any one of claims 1-7.

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