Band-gap reference circuit with temperature compensation
By using an operational amplifier circuit and a compensation loop composed of transistors for low-temperature and high-temperature compensation circuits, the temperature compensation method is simplified, solving the problem of reference voltage variation in bandgap reference circuits at high and low temperatures, thus achieving improved accuracy and reduced cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAMEN KIWI MICROELECTRONICS TECH CO LTD
- Filing Date
- 2025-05-15
- Publication Date
- 2026-05-12
AI Technical Summary
Existing bandgap reference circuits suffer from significant variations in reference voltage VREF at high and low temperatures, affecting quantization accuracy and circuit dynamics. Furthermore, the complexity of existing temperature compensation circuits increases chip costs.
Low-temperature compensation circuits and high-temperature compensation circuits are used to generate compensation current at low and high temperatures, respectively. The temperature compensation method is simplified by using a compensation loop composed of an operational amplifier circuit and transistors. NMOS and PMOS transistors are used for current compensation.
It effectively suppresses temperature drift, improves the accuracy of the reference voltage, optimizes the dynamic characteristics and linearity of the quantization circuit, and reduces chip cost.
Smart Images
Figure CN224232131U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronics, specifically but not limited to a bandgap reference circuit with temperature compensation. Background Technology
[0002] Bandgap reference circuits provide a reference voltage, and the accuracy of the reference voltage is the most important indicator of a bandgap reference circuit. Figure 1 This paper illustrates a conventional bandgap reference circuit. This bandgap reference circuit lacks temperature compensation, resulting in a large variation in the reference voltage VREF at high and low temperatures during high-precision applications. This affects the quantization accuracy of subsequent quantization circuits. Particularly at high and low temperatures, the voltage deviation of the reference voltage VREF is significant, which degrades the quantization accuracy of subsequent circuits and impacts the dynamic characteristics and linearity of the final result.
[0003] Some existing bandgap reference circuits have temperature compensation circuits, but these circuits are generally quite complex, increasing chip costs. Therefore, there is a need for a bandgap reference circuit with temperature compensation that is simple in design, reducing chip costs while compensating for changes in the reference voltage VREF caused by temperature variations. Utility Model Content
[0004] Addressing at least one or more problems in the background art, this invention proposes a temperature-compensated bandgap reference circuit. The bandgap reference circuit includes: a bandgap reference source circuit, including a first transistor, wherein the output of the bandgap reference source circuit provides a reference voltage; a low-temperature compensation circuit, including a first operational amplifier circuit, wherein a first input of the first operational amplifier circuit receives a first reference voltage, and a second input of the first operational amplifier circuit is coupled to the first transistor; and a high-temperature compensation circuit, including a second operational amplifier circuit, wherein a first input of the second operational amplifier circuit receives a second reference voltage, and a second input of the second operational amplifier circuit is coupled to the first transistor; when the temperature is below a low-temperature threshold, the first operational amplifier circuit generates a first compensation current to compensate the reference voltage of the bandgap reference source circuit; when the temperature is above a high-temperature threshold, the second operational amplifier circuit generates a second compensation current to compensate the reference voltage of the bandgap reference source circuit.
[0005] Optionally, the bandgap reference source circuit includes a resistor through which a first compensation current or a second compensation current flows to increase the reference voltage.
[0006] Optionally, the first operational amplifier circuit includes: a first compensation transistor, wherein the control terminal of the first compensation transistor receives a first reference voltage, a first terminal of the first compensation transistor is coupled to a power supply terminal, and a second terminal of the first compensation transistor is coupled to a reference ground; and a second compensation transistor, wherein the control terminal of the second compensation transistor is coupled to a first terminal of the first transistor, a first terminal of the second compensation transistor is coupled to a resistor, and a second terminal of the second compensation transistor is coupled to a reference ground, wherein the control terminal and the second terminal of the first transistor are coupled to a reference ground.
[0007] Optionally, the first compensation transistor and the second compensation transistor include N-type metal-oxide-semiconductor field-effect transistors (NMOS).
[0008] Optionally, the second operational amplifier circuit includes a third compensation transistor and a fourth compensation transistor with two pairs of transistors.
[0009] Optionally, the high-temperature compensation circuit further includes a current mirror, the input of which is coupled to the output of the second operational amplifier circuit, and the output of which is coupled to a resistor.
[0010] Optionally, the third and fourth compensation transistors include P-type metal-oxide-semiconductor field-effect transistors (PMOS).
[0011] The bandgap reference circuit proposed in this invention can suppress temperature-induced drift of the reference voltage. At the same time, the compensation method has a simple structure, can improve quantization accuracy, and optimize the dynamic characteristics and linearity of the quantization circuit results. Attached Figure Description
[0012] The accompanying drawings are provided to further illustrate the present invention and, together with the description, serve to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:
[0013] Figure 1 An existing bandgap reference circuit is shown;
[0014] Figure 2 A block diagram of a temperature-compensated bandgap reference circuit according to an embodiment of the present invention is shown.
[0015] Figure 3 A temperature-compensated bandgap reference circuit according to a specific embodiment of the present invention is shown. Detailed Implementation
[0016] To further understand this utility model, preferred embodiments of this utility model are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of this utility model, and not for limiting the scope of the claims of this utility model.
[0017] The description in this section pertains to only a few typical embodiments, and this utility model is not limited to the scope of the embodiments described. Combinations of different embodiments, substitution of some technical features in different embodiments, and substitution of the same or similar prior art with some technical features in the embodiments are also within the scope of the description and protection of this utility model.
[0018] The terms "coupled" or "connected" in this specification include both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as a connection through an electrically conductive medium like a conductor, which may contain parasitic inductance or capacitance. It can also be a connection through an intermediate circuit or component described in the embodiments of this specification. Indirect connections may also include connections through other active or passive devices that can achieve the same or similar functions, such as connections through circuits or components like switches, signal amplification circuits, or follower circuits.
[0019] Figure 2 A block diagram of a temperature-compensated bandgap reference circuit according to an embodiment of the present invention is shown. The temperature-compensated bandgap reference circuit includes a low-temperature compensation circuit 21, a high-temperature compensation circuit 22, and a bandgap reference source circuit 23. The bandgap reference source circuit 23 may include… Figure 1 The circuit shown can also have other forms and can be any existing bandgap reference source circuit. The bandgap reference source circuit 23 includes a first transistor Q, the terminal voltage of which is affected by temperature. The output of the bandgap reference source circuit 23 provides a reference voltage VREF. In one embodiment, transistor Q is... Figure 1 Transistor Q1 in the bandgap reference circuit. In another embodiment, the first transistor Q is... Figure 3 The first transistor Q is a bipolar junction transistor (BJT). In the illustrated embodiment, the first transistor Q comprises a transistor with its first terminal being its emitter E, its second terminal being its collector C, coupled to reference ground GND, and its control terminal being its base B, also coupled to reference ground GND. In other embodiments, the transistor Q can be other types of devices whose terminal voltage is affected by temperature.
[0020] The terminal voltage of the first transistor Q in the bandgap reference source circuit 23 is input to the low-temperature compensation circuit 21 and the high-temperature compensation circuit 22 to generate a low-temperature compensation signal at low temperatures and a high-temperature compensation signal at high temperatures. The low-temperature compensation circuit 21 includes a first operational amplifier circuit, wherein the first input terminal of the first operational amplifier circuit receives a first reference voltage VR1, and the second input terminal of the first operational amplifier circuit is coupled to the first transistor Q to receive the terminal voltage of the first transistor Q. When the temperature is too low, the terminal voltage controls the low-temperature compensation circuit 21 to output a first compensation current Icp1. The high-temperature compensation circuit 22 includes a second operational amplifier circuit, wherein the first input terminal of the second operational amplifier circuit receives a second reference voltage VR2, and the second input terminal of the second operational amplifier circuit is coupled to the first transistor Q to receive the terminal voltage. When the temperature is too high, the high-temperature compensation circuit 22 outputs a second compensation current Icp2. The output terminals of the low-temperature compensation circuit 21 and the high-temperature compensation circuit 22 are coupled to the compensation input terminal CMP of the bandgap reference source circuit 33. Preferably, when the temperature is below the low temperature threshold, the first operational amplifier circuit generates a first compensation current Icp1 to compensate the reference voltage VREF of the bandgap reference source circuit; when the temperature is above the high temperature threshold, the second operational amplifier circuit generates a second compensation current Icp2 to compensate the reference voltage VREF of the bandgap reference source circuit.
[0021] Figure 3 A temperature-compensated bandgap reference circuit according to a specific embodiment of the present invention is shown. The bandgap reference source circuit includes a low-temperature compensation circuit 31, a high-temperature compensation circuit 32, and a bandgap reference source circuit 33. The bandgap reference source circuit 33 includes a first transistor Q, which is coupled between the output terminal VREF of the bandgap reference source circuit and the reference ground GND. This coupling can be any other suitable circuit structure in any bandgap reference source circuit. Figure 3The blank boxes indicate this. Similarly, the output of the bandgap reference source circuit 33 can be coupled to the power supply terminal VCC via any suitable circuit. Specifically, the first terminal of the first transistor Q is coupled to the output terminal VREF of the bandgap reference source circuit via other circuitry, and the second terminal and control terminal of the first transistor Q are coupled to the reference ground GND. The reference voltage VREF output by the bandgap reference source circuit 33 and the terminal voltage VEB of the first terminal of the first transistor Q will drift with temperature. The bandgap reference source circuit 33 further includes a resistor R1. The first compensation current Icp1 generated by the low-temperature compensation circuit 31 and the second compensation current Icp2 generated by the high-temperature compensation circuit 32 flow through the resistor R1 to compensate the reference voltage VREF. Preferably, the resistor R1 is coupled between the output terminal VREF and the compensation input terminal CMP of the bandgap reference source circuit 33 to raise the reference voltage VREF when the first compensation current Icp1 or the second compensation current Icp2 flows. The bandgap reference source circuit 33 also further includes other circuit components, which will not be described in detail here. The first operational amplifier circuit in the low-temperature compensation circuit 31 includes N-type metal-oxide-semiconductor field-effect transistors (NMOS) 311 and 312 as input pairs. The second operational amplifier circuit in the high-temperature compensation circuit 32 includes P-type metal-oxide-semiconductor field-effect transistors (PMOS) 321 and 322 as input pairs. Specifically, the first operational amplifier circuit 31 includes a first compensation transistor 311 and a second compensation transistor 312. The control terminal of the first compensation transistor 311 receives a first reference voltage VR1, the first terminal of the first compensation transistor 311 is coupled to the power supply terminal VCC, and the second terminal of the first compensation transistor 311 is coupled to the reference ground GND. The control terminal of the second compensation transistor 312 is coupled to the first terminal of the first transistor Q, the first terminal of the second compensation transistor 312 is coupled to a resistor R1, and the second terminal of the second compensation transistor 312 is coupled to the reference ground GND. The terminal voltage VEB of the first terminal of transistor Q is inversely proportional to the temperature; when the temperature is low, the terminal voltage VEB of transistor Q is high. At this time, the reference voltage VREF is low. When the temperature is below the low temperature threshold, the terminal voltage VEB of transistor Q rises to a level greater than the first reference voltage VR1 in the low temperature compensation circuit 31. Since VEB > VR1, the second compensation transistor NMOS 312 is turned on, and a first compensation current Icp1 is formed in the second compensation transistor 312. That is, the first operational amplifier circuit 31 generates the first compensation current Icp1, which is drawn from the resistor R1 and used to boost the reference voltage VREF, thereby compensating for the reference voltage VREF of the bandgap reference source circuit.
[0022] The second operational amplifier circuit in the high-temperature compensation circuit 32 includes two third compensation transistors 321 and fourth compensation transistors 322 that form a pair of transistors. In the illustrated embodiment, the first compensation transistor and the second compensation transistor include NMOS transistors, and the third compensation transistor and the fourth compensation transistor include PMOS transistors. In other embodiments, the first compensation transistor, the second compensation transistor, the third compensation transistor, and the fourth compensation transistor may be other types of transistors, such as JFETs or IGBTs, etc. Specifically, the control terminal of the third compensation transistor 321 receives the second reference voltage VR2, the first terminal of the third compensation transistor 321 is coupled to the power supply terminal VCC, and the second terminal of the third compensation transistor 321 is coupled to the reference ground GND. The control terminal of the fourth compensation transistor 322 is coupled to the first terminal of the first transistor Q for receiving the terminal voltage VEB, the first terminal of the fourth compensation transistor 322 is coupled to the power supply terminal VCC, and the second terminal of the fourth compensation transistor 322 is coupled to the reference ground GND. In Figure 3 In the illustrated embodiment, the high-temperature compensation circuit 32 further includes a current mirror 323. The input terminal of the current mirror is coupled to the output terminal of the second operational amplifier circuit, that is, the input arm of the current mirror is connected in series with the fourth compensation transistor 322. The output terminal of the current mirror 323 is coupled to the resistor R1, so that the provided second compensation current Icp2 is proportional to the current flowing through the fourth compensation transistor 322 when the fourth compensation transistor 322 is turned on. In another embodiment, the current mirror may not be included, and the first terminal of the fourth compensation transistor 322 is directly coupled to the resistor R1. When the temperature is relatively high, the terminal voltage VEB of the transistor Q is relatively low. At this time, the reference voltage VREF is also lower than the standard value. When the temperature is higher than the high-temperature threshold, the terminal voltage VEB of the transistor Q decreases to be less than the second reference voltage VR2 in the high-temperature compensation circuit 32, VEB < VR2. At this time, the fourth compensation transistor PMOS 322 is turned on, a current flows through the fourth compensation transistor PMOS 322, and the second operational amplifier circuit 32 generates a second compensation current Icp2, which is extracted from the resistor R1 and used to increase the reference voltage VREF, thereby compensating for the decrease in VREF caused by the increase in temperature, and the high-temperature compensation is completed.
[0023] The compensation loop composed of the low-temperature compensation circuit 31 and the high-temperature compensation circuit 32 described above can improve the influence of temperature on the reference voltage VREF, compensate for the second-order term in the reference voltage VREF, and suppress the drift of the reference voltage VREF caused by temperature. At the same time, this compensation method has a simple structure, significantly improves the temperature characteristics of the reference voltage VREF output by the bandgap reference circuit, can significantly improve the quantization accuracy in high-precision applications, and optimizes the dynamic characteristics and linearity of the quantization circuit results.
[0024] The description and application of this utility model herein are illustrative and not intended to limit the scope of the utility model to the above embodiments. The effects or advantages described in the specification may not be apparent in actual experimental examples due to uncertainties in specific conditions or parameters or other factors, and such descriptions are not intended to limit the scope of the utility model. Variations and modifications to the embodiments disclosed herein are possible, and various substitutions and equivalent components of the embodiments are well known to those skilled in the art. It should be clear to those skilled in the art that this utility model can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the utility model. Other variations and modifications can be made to the embodiments disclosed herein without departing from the scope and spirit of the utility model.
Claims
1. A bandgap reference circuit with temperature compensation, characterized in that, include: A bandgap reference source circuit includes a first transistor, wherein the output of the bandgap reference source circuit provides a reference voltage; The low-temperature compensation circuit includes a first operational amplifier circuit, wherein a first input terminal of the first operational amplifier circuit receives a first reference voltage, and a second input terminal of the first operational amplifier circuit is coupled to a first transistor. as well as The high temperature compensation circuit includes a second operational amplifier circuit, wherein the first input terminal of the second operational amplifier circuit receives a second reference voltage, and the second input terminal of the second operational amplifier circuit is coupled to a first transistor. When the temperature is below the low temperature threshold, the first operational amplifier circuit generates a first compensation current to compensate the reference voltage of the bandgap reference source circuit. When the temperature is above the high temperature threshold, the second operational amplifier circuit generates a second compensation current to compensate the reference voltage of the bandgap reference source circuit.
2. The bandgap reference circuit as described in claim 1, characterized in that, The bandgap reference source circuit includes a resistor. When the temperature is below the low temperature threshold, a first compensation current flows through the resistor, increasing the reference voltage. When the temperature is above the high temperature threshold, a second compensation current flows through the resistor, increasing the reference voltage.
3. The bandgap reference circuit as described in claim 2, characterized in that, The first operational amplifier circuit includes: A first compensation transistor, wherein a control terminal of the first compensation transistor receives a first reference voltage, a first terminal of the first compensation transistor is coupled to a power supply terminal, and a second terminal of the first compensation transistor is coupled to a reference ground; and The second compensation transistor has a control terminal coupled to the first terminal of the first transistor, the first terminal of the second compensation transistor is coupled to a resistor, and the second terminal of the second compensation transistor is coupled to a reference ground, wherein the control terminal and the second terminal of the first transistor are coupled to the reference ground.
4. The bandgap reference circuit as described in claim 3, characterized in that, The first compensation transistor and the second compensation transistor include N-type metal-oxide-semiconductor field-effect transistors (NMOS).
5. The bandgap reference circuit as described in claim 2, characterized in that, The second operational amplifier circuit includes a third compensation transistor and a fourth compensation transistor, which are two pairs of transistors.
6. The bandgap reference circuit as described in claim 5, characterized in that, The high-temperature compensation circuit further includes a current mirror, the input of which is coupled to the output of the second operational amplifier circuit, and the output of which is coupled to a resistor.
7. The bandgap reference circuit as described in claim 5, characterized in that, The third and fourth compensation transistors include P-type metal-oxide-semiconductor field-effect transistors (PMOS).