Temperature-insensitive band-gap reference voltage source, low-dropout linear regulator, power management circuit, high-side switch and signal conversion chip

Abstract

The embodiment of the utility model provides a temperature-insensitive band-gap reference voltage source, a low-dropout linear regulator, a power management circuit, a high-side switch and a signal conversion chip. The temperature-insensitive band-gap reference voltage source comprises a band-gap reference circuit and a negative feedback circuit, and the negative feedback circuit comprises a calibration voltage generation module used for generating calibration voltage the same as band-gap reference voltage; the negative end of the operational amplifier is connected with the output node of the band-gap reference circuit, the positive end of the operational amplifier is connected with the output node of the calibration voltage generation module, and the output end of the operational amplifier is connected with the output node of the band-gap reference circuit through a first resistor; the first resistor is also located between transistors on both sides of the output node in the bandgap reference circuit. The operational amplifier and the calibration voltage are adopted, whether the band-gap reference voltage is the same as the calibration voltage or not is monitored in real time, feedback is conducted on the band-gap reference circuit based on the monitoring result, and therefore it is guaranteed that the band-gap reference voltage is accurate.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a temperature-insensitive bandgap reference voltage source, a low voltage drop linear regulator, a power management circuit, a high-side switch and a signal conversion chip. Background Art

[0002] The bandgap reference voltage source originates from the need for a stable and accurate voltage reference, especially in integrated circuit (IC) design. Its main purpose is to provide a stable voltage source that is independent of temperature and supply voltage changes. This voltage source is very important in both analog and digital circuits because many circuit functions rely on a precise reference voltage. The bandgap reference voltage source circuit usually combines two voltages with opposite temperature coefficients: 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; 2. Negative temperature coefficient voltage: This part of the voltage is usually provided by the forward voltage drop (VBE) of a diode. As the temperature increases, this part of the voltage will decrease. By combining these two parts of the voltage in an appropriate proportion, a total voltage can be obtained, whose temperature coefficient is close to zero, so that it remains stable within a certain temperature range. However, if the bandgap circuit does not make any compensation, the bandgap reference voltage will still change greatly with temperature. After the large change, it will affect the subsequent circuit, which may cause the circuit to not work or the circuit output result to be incorrect. Therefore, a simple and effective bandgap reference voltage source is needed. Utility Model Content

[0003] In view of the deficiencies in the prior art, the present application provides a temperature-insensitive bandgap reference voltage source, a low voltage dropout linear regulator, a power management circuit, a high-side switch and a signal conversion chip, which solve the problems of cumbersome design process and complex structure of the bandgap reference voltage source in the prior art.

[0004] In the first aspect, according to an embodiment of the present application, a temperature-insensitive bandgap reference voltage source is provided, comprising a bandgap reference circuit and a negative feedback circuit, wherein the negative feedback circuit comprises: a calibration voltage generation module for generating a calibration voltage identical to the bandgap reference voltage; an operational amplifier, wherein the negative terminal of the operational amplifier is connected to the output node of the bandgap reference circuit, the positive terminal of the operational amplifier is connected to the output node of the calibration voltage generation module, and the output terminal of the operational amplifier is connected to the output node of the bandgap reference circuit via a first resistor, wherein the first resistor is also located between the transistors on both sides of the output node in the bandgap reference circuit.

[0005] According to an embodiment of the present application, the calibration voltage generating module is a voltage divider subcircuit.

[0006] According to an embodiment of the present application, the voltage divider sub-circuit includes: a second resistor, one end of which is connected to the power supply voltage and the other end of which is connected to a third resistor; a third resistor, one end of which is not connected to the second resistor is grounded, wherein the output node of the calibration voltage generating module is located between the second resistor and the third resistor.

[0007] According to an embodiment of the present application, the bandgap reference circuit includes: a first PMOS field effect transistor, whose source is connected to the power supply voltage, whose drain is connected to the collector of the first equivalent NPN transistor, and whose gate is connected to the gate of the second PMOS field effect transistor, wherein the gate of the first PMOS field effect transistor is connected to the drain; a second PMOS field effect transistor, whose source is connected to the power supply voltage, and whose drain is connected to the collector of the second NPN transistor; a first equivalent NPN transistor, formed by connecting a plurality of identical NPN transistors in parallel, whose emitter is grounded via a fourth resistor and a fifth resistor, and whose base is connected to the first resistor; a second NPN transistor, whose emitter is grounded via the fifth resistor, and whose base is also connected to the first resistor.

[0008] According to an embodiment of the present application, the number of NPN transistors in the first equivalent NPN transistor is 8.

[0009] In a second aspect, according to another embodiment of the present application, a low voltage dropout linear regulator is provided, comprising a temperature-insensitive bandgap reference voltage source as described in the first aspect.

[0010] In a third aspect, according to another embodiment of the present application, a power management circuit is provided, comprising a low voltage dropout linear regulator as described in the second aspect.

[0011] In a fourth aspect, according to another embodiment of the present application, a high-side switch is provided, comprising a temperature-insensitive bandgap reference voltage source as described in the first aspect.

[0012] In a fifth aspect, according to another embodiment of the present application, a signal conversion chip is provided, including an analog-to-digital converter or a digital-to-analog converter, including a temperature-insensitive bandgap reference voltage source as described in the first aspect.

[0013] The technical principle of the present application is: by adopting an operational amplifier and a calibration voltage, whether the bandgap reference voltage is the same as the calibration voltage is monitored in real time, and feedback is given to the bandgap reference circuit based on the monitoring result to ensure the accuracy of the bandgap reference voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a conventional bandgap reference voltage source according to an embodiment of the present application.

[0015] Figure 2 Schematic diagram of a bandgap reference voltage source according to an embodiment of the present application.

[0016] Figure 3 The graph is a graph showing how the output voltage of the bandgap reference voltage source according to an embodiment of the present application changes with temperature. DETAILED DESCRIPTION

[0017] The technical solution in this application is further described below in conjunction with the accompanying drawings and embodiments.

[0018] In order to better understand the present application, the bandgap reference voltage source in the prior art is first reviewed. Figure 1 A (brokaw) bandgap reference voltage source is shown. The bandgap reference core circuit is composed of bipolar transistors (hereinafter referred to as transistors) Q1~Q4 and resistors R1~R6. Among them, transistors Q1 and Q2 are active loads, the voltages at the C and D nodes are equal, and the collector currents flowing through transistors Q1 and Q2 are equal. The voltage difference between the BE (base and emitter) of Q3 and Q4 is:

[0019]

[0020] vref=2VT ln N*Rq / R1+VBE 4 ,

[0021] Rq=R2+(R3 / / R4 / / R5 / / R6),

[0022] Where N is the ratio of the number of transistors Q3 and Q4, VT is the thermal voltage drop, I C is the collector current, I S The E-pole current of transistor Q3 is VT ln N / R1, and the current flowing through resistor R3 is 2VT ln N / R1. Then the voltage at node A is 2VT ln N*Rq / R1+VBE. 4 , which is the bandgap reference voltage vref.

[0023] Combined with the positive temperature coefficient voltage and negative temperature coefficient voltage content in the background technology, it can be seen from the above that the components in the bandgap reference voltage source in the prior art are easily affected by temperature. In order to obtain a constant voltage value bandgap reference voltage source within the operating temperature range, it is necessary to fully understand the working state of each component within the operating temperature range, and on this basis, combine other temperature compensation circuits for design. Therefore, the design process is complicated and the designed structure is often complicated.

[0024] In view of the above problems, the embodiment of the present application proposes a temperature-insensitive bandgap reference voltage source 100, including a bandgap reference circuit 110 and a negative feedback circuit 120, wherein the negative feedback circuit 120 includes: a calibration voltage generation module 121 for generating a calibration voltage identical to the bandgap reference voltage; an operational amplifier 122, whose negative end is connected to the output node of the bandgap reference circuit 110, whose positive end is connected to the output node of the calibration voltage generation module 121, and whose output end is connected to the output node of the bandgap reference circuit 110 via a first resistor R1, wherein the first resistor R1 is also located between the transistors on both sides of the output node in the bandgap reference circuit 110. By adopting an operational amplifier and a calibration voltage, whether the bandgap reference voltage is identical to the calibration voltage is monitored in real time, and the bandgap reference circuit is fed back based on the monitoring result to ensure that the bandgap reference voltage is accurate. Compared with considering the complex temperature characteristics of each component, it is only necessary to consider whether the output voltage is identical to the calibration voltage, so as to perform corresponding voltage compensation.

[0025] According to an embodiment of the present application, the calibration voltage generation module 121 is a voltage divider subcircuit. In addition, the calibration voltage generation module can be any circuit that can generate a specific voltage value, but preferably is insensitive to temperature.

[0026] In detail, according to an embodiment of the present application, the voltage divider subcircuit includes: a second resistor R2, one end of which is connected to the power supply voltage, and the other end of which is connected to the third resistor R3; the third resistor R3, one end of which is not connected to the second resistor R2 is grounded, wherein the output node of the calibration voltage generation module is located between the second resistor R2 and the third resistor R3. Similarly, other circuit elements, such as diodes, can be selected, but the selection criterion is preferably insensitive to temperature.

[0027] According to an embodiment of the present application, the bandgap reference circuit includes: a first PMOS field effect transistor MP1, whose source is connected to the power supply voltage, whose drain is connected to the collector of the first equivalent NPN transistor, and whose gate is connected to the gate of the second PMOS field effect transistor MP2, wherein the gate and drain of the first PMOS field effect transistor MP1 are connected; a second PMOS field effect transistor MP2, whose source is connected to the power supply voltage, and whose drain is connected to the collector of the second NPN transistor MN2; a first equivalent NPN transistor, whose emitter is grounded via a fourth resistor R4 and a fifth resistor R5, and whose base is connected to the first resistor R1; a second NPN transistor MN2, whose emitter is grounded via the fifth resistor R5, and whose base is also connected to the first resistor R1.

[0028] According to an embodiment of the present application, the number of NPN transistors in the first equivalent NPN transistor is 8.

[0029] Figure 3 The voltage characteristic of the voltage source according to the embodiment of the present application that varies with temperature is shown. Its horizontal axis represents temperature, in degrees Celsius, spanning -40 degrees to 100 degrees. The vertical axis is voltage, in mV. It can be seen that within the entire temperature range, the voltage changes from 960.1mV to 960.68mV, and the temperature drift coefficient can be obtained as 3.477ppm (i.e., the voltage change caused by unit temperature). It can be seen that the voltage source according to the embodiment of the present application is not sensitive to temperature and maintains a relatively constant voltage value within the entire temperature range.

[0030] According to another embodiment of the present application, a low voltage dropout linear regulator is provided, comprising a temperature-insensitive bandgap reference voltage source as described above.

[0031] According to another embodiment of the present application, a power management circuit is provided, comprising a low voltage dropout linear regulator as described above.

[0032] According to another embodiment of the present application, a high-side switch is provided, comprising a temperature-insensitive bandgap reference voltage source as described above.

[0033] According to another embodiment of the present application, a signal conversion chip is provided, including an analog-to-digital converter or a digital-to-analog converter, including a temperature-insensitive bandgap reference voltage source as described above.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present application, which should be included in the scope of the claims of the present application.

Claims

1. A temperature-insensitive bandgap reference voltage source, comprising a bandgap reference circuit and a negative feedback circuit, characterized in that: The negative feedback circuit comprises: A calibration voltage generating module, used for generating a calibration voltage which is the same as the bandgap reference voltage; an operational amplifier, a negative terminal of which is connected to the output node of the bandgap reference circuit, a positive terminal of which is connected to the output node of the calibration voltage generating module, and an output terminal of which is connected to the output node of the bandgap reference circuit via a first resistor, wherein the first resistor is also located between transistors on both sides of the output node in the bandgap reference circuit.

2. A temperature-insensitive bandgap reference voltage source as claimed in claim 1, characterized in that: The calibration voltage generation module is a voltage divider subcircuit.

3. A temperature-insensitive bandgap reference voltage source as claimed in claim 2, characterized in that: The voltage divider subcircuit comprises: a second resistor having one end connected to the power supply voltage and the other end connected to the third resistor; A third resistor has one end not connected to the second resistor connected to ground, wherein the output node of the calibration voltage generating module is located between the second resistor and the third resistor.

4. A temperature-insensitive bandgap reference voltage source according to any one of claims 1 to 3, characterized in that: The bandgap reference circuit comprises: A first PMOS field effect transistor, whose source is connected to the power supply voltage, whose drain is connected to the collector of the first equivalent NPN transistor, and whose gate is connected to the gate of the second PMOS field effect transistor, wherein the gate and drain of the first PMOS field effect transistor are connected; A second PMOS field effect transistor, whose source is connected to the power supply voltage and whose drain is connected to the collector of the second NPN transistor; A first equivalent NPN transistor, formed by connecting a plurality of identical NPN transistors in parallel, an emitter of which is grounded via a fourth resistor and a fifth resistor, and a base of which is connected to the first resistor; The emitter of the second NPN transistor is grounded via the fifth resistor, and the base of the second NPN transistor is also connected to the first resistor.

5. A temperature-insensitive bandgap reference voltage source as claimed in claim 4, characterized in that: The number of NPN transistors in the first equivalent NPN transistor is 8.

6. A low voltage dropout linear regulator, characterized in that: The invention comprises a temperature-insensitive bandgap reference voltage source as claimed in any one of claims 1 to 5.

7. A power management circuit, characterized in that: It comprises a low voltage dropout linear regulator as claimed in claim 6.

8. A high side switch, characterized in that: The invention comprises a temperature-insensitive bandgap reference voltage source as claimed in any one of claims 1 to 5.

9. A signal conversion chip, comprising an analog-to-digital converter or a digital-to-analog converter, characterized in that: The invention comprises a temperature-insensitive bandgap reference voltage source as claimed in any one of claims 1 to 5.

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