Band-gap reference source circuit

Abstract

The invention provides a band-gap reference source circuit which is characterized in that a bias end of a reference source output circuit receives voltage of a bias point, the voltage of the bias point controls starting of the reference source output circuit, and an output end outputs a first external control signal, a first external control signal and reference voltage; the operational amplifier circuit provides voltage of a bias point and receives a first external control signal and a second external control signal; the positive and negative temperature coefficient voltage generation circuit generates positive temperature coefficient voltage and negative temperature coefficient voltage; the drain end of the electric leakage MOS tube is connected with a first external control signal, the collector end of the electric leakage MOS tube is connected with a power supply voltage, the base end of the electric leakage MOS tube is grounded, and leakage current generated by the drain end is used for reducing the voltage of the first external control signal so as to reduce the voltage drop of the reference voltage.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor integrated circuit manufacturing, and in particular to a bandgap reference source circuit. Background Art

[0002] The bandgap reference source circuit includes a reference source output circuit, which is used to generate a reference voltage and a reference current. The reference voltage and the reference current can provide stable reference voltage and reference current for other modules, and therefore are widely used in integrated circuits.

[0003] The bandgap reference source circuit of the prior art is as follows Figure 1 , the gates of the first MOS tube M1, the second MOS tube M2 and the third MOS tube M3 are connected together to form a bias terminal, the sources of the first MOS tube M1, the second MOS tube M2 and the third MOS tube M3 are all connected to the power supply voltage VDD, the drain of the first MOS tube M1 outputs the first external control signal A, the drain of the second MOS tube M2 outputs the second external control signal B, the drain of the third MOS tube M3 outputs the reference voltage OUT, and the drain of the third MOS tube M3 is also connected to the ground GND through the third resistor R3. The bases of the first triode Q1 and the second triode Q2 are connected together and grounded GND, and the collectors of the first triode Q1 and the second triode Q2 are both grounded GND, the emitter of the first triode Q1 is connected to the drain of the first MOS tube M1, and the emitter of the second triode Q2 is connected to the drain of the second MOS tube M2 through the first resistor R1; the drain of the second MOS tube M2 is also grounded through the second resistor R2. The gates of the fourth MOS tube M4 and the fifth MOS tube M5 are short-circuited and connected to the drain of the fourth MOS tube M4; the sources of the fourth MOS tube M4 and the fifth MOS tube M5 are both connected to the power supply voltage VDD; the gates of the sixth MOS tube M6 and the seventh MOS tube M7 are respectively connected to the second external control signal B and the first external control signal A, the drain of the sixth MOS tube M6 is connected to the drain of the fourth MOS tube M4, the drain of the seventh MOS tube M7 is connected to the drain of the fifth MOS tube M5, the sources of the sixth MOS tube M6 and the seventh MOS tube M7 are short-circuited and form the tail current end of the operational amplifier circuit; the drain of the fifth MOS tube M5 outputs the voltage of the bias point PB. The drain of the eighth MOS tube M8 is connected to the tail current end of the operational amplifier circuit; the drain of the ninth MOS tube M9 is connected to the current source, and the source of the ninth MOS tube M9 is grounded GND; the gate of the eighth MOS tube M8 is short-circuited with the gate of the ninth MOS tube M9 and then connected to the drain of the ninth MOS tube M9. The Vbe difference between the first transistor Q1 and the second transistor Q2 is dVbe=(Vbe Q1 +Vbe Q2), the current flowing through the second transistor Q2 is IQ2=dVbe / R1, the current flowing through the second resistor R2 is IR2=Vbe / R2, the current with zero temperature coefficient is I3=I2=IQ2+IR2, where dVbe is the positive temperature coefficient, Vbe is the negative temperature coefficient, and the voltage with zero temperature coefficient is Vout=I3*R3. The expression of negative temperature coefficient Vbe with respect to temperature is Vbg+AT+KlnT. Where AT is the linear part, KlnT is the nonlinear part, A and K are both values ​​related to the process of the second transistor Q2, and Vbg is the BE junction voltage of the second transistor Q2 when the temperature is 0. Therefore, setting a suitable ratio of the resistance values ​​of the second resistor R2 and the first resistor R1 can partially offset the positive temperature coefficient and the negative temperature coefficient.

[0004] However, in the bandgap reference source circuit of the prior art, although the temperature coefficient of the linear part of the negative temperature coefficient is offset, the temperature coefficient of the nonlinear part still exists, resulting in a relatively large voltage drop of the reference voltage when the temperature rises. Summary of the invention

[0005] The object of the present invention is to provide a bandgap reference source circuit which can reduce the voltage drop of the reference voltage when the temperature rises.

[0006] In order to achieve the above object, the present invention provides a bandgap reference source circuit, comprising:

[0007] Reference source output circuit, positive and negative temperature coefficient voltage generation circuit, operational amplifier circuit and leakage MOS tube;

[0008] The reference source output circuit comprises a first MOS tube, a second MOS tube and a third MOS tube, the gates of the first MOS tube, the second MOS tube and the third MOS tube are connected together to form a bias end, the bias end is used to receive a voltage of a bias point, the voltage of the bias point is used to control the start of the reference source output circuit, the sources of the first MOS tube, the second MOS tube and the third MOS tube are all connected to a power supply voltage, the drain of the first MOS tube outputs a first external control signal, the drain of the second MOS tube outputs a second external control signal, the drain of the third MOS tube outputs a reference voltage, and the voltage of the first external control signal, the voltage of the second external control signal and the reference voltage are the same;

[0009] The operational amplifier circuit receives the first external control signal and the second external control signal, and the operational amplifier circuit is used to provide the voltage of the bias point to control the start-up of the reference source output circuit;

[0010] The positive and negative temperature coefficient voltage generating circuit generates a positive temperature coefficient voltage and a negative temperature coefficient voltage, and both the positive temperature coefficient voltage and the negative temperature coefficient voltage are connected to the second external control signal;

[0011] The drain terminal of the leakage MOS tube is connected to the first external control signal, the collector terminal of the leakage MOS tube is connected to the power supply voltage, the base terminal of the leakage MOS tube is grounded, and the leakage current generated by the drain terminal is used to reduce the voltage of the first external control signal to reduce the voltage drop of the reference voltage.

[0012] Optionally, in the bandgap reference source circuit, the leakage MOS tube is an NMOS tube.

[0013] Optionally, in the bandgap reference source circuit, the leakage MOS tube generates leakage current when the temperature is greater than or equal to 50°C.

[0014] Optionally, the bandgap reference source circuit further includes a current limiting resistor, one end of which is connected to the power supply voltage, and the other end of which is connected to the collector terminal of the leakage MOS tube.

[0015] Optionally, in the bandgap reference source circuit, the resistance of the current limiting resistor is 1Mohm to 900Mohm.

[0016] Optionally, in the bandgap reference source circuit, the positive and negative temperature coefficient voltage generating circuit includes: a first transistor, a second transistor, a first resistor and a second resistor; the collector of the first transistor is connected to the first external control signal, the emitters of the first transistor and the second transistor are both grounded, the base of the first transistor and the base of the second transistor are short-circuited and grounded, the collector of the second transistor is connected to the second external control signal through the first resistor, the second external control signal is also grounded through the second resistor, the connection point between the first resistor and the second external control signal generates a positive temperature coefficient voltage, and the connection point between the second resistor and the second external control signal generates a negative temperature coefficient voltage.

[0017] Optionally, the bandgap reference source circuit further includes: a third resistor, one end of the third resistor is connected to the reference voltage, and the other end is grounded.

[0018] Optionally, in the bandgap reference source circuit, the operational amplifier circuit includes:

[0019] a fourth MOS tube, a fifth MOS tube, a sixth MOS tube and a seventh MOS tube;

[0020] The gates of the fourth MOS tube and the fifth MOS tube are short-circuited and connected to the drain of the fourth MOS tube; the sources of the fourth MOS tube and the fifth MOS tube are both connected to the power supply voltage;

[0021] The gates of the sixth MOS tube and the seventh MOS tube are connected to the second external control signal and the first external control signal respectively, the drain of the sixth MOS tube is connected to the drain of the fourth MOS tube, the drain of the seventh MOS tube is connected to the drain of the fifth MOS tube, and the sources of the sixth MOS tube and the seventh MOS tube are short-circuited to form a tail current end of the operational amplifier circuit;

[0022] The drain of the fifth MOS tube outputs the voltage of the bias point.

[0023] Optionally, the bandgap reference source circuit further includes a current mirror circuit, and the current mirror circuit is connected to the tail current terminal of the operational amplifier circuit.

[0024] Optionally, in the bandgap reference source circuit, the current mirror circuit includes:

[0025] An eighth MOS tube, a ninth MOS tube and a current source;

[0026] The drain of the eighth MOS tube is connected to the tail current terminal of the operational amplifier circuit;

[0027] The drain of the ninth MOS tube is connected to the current source, and the source is grounded;

[0028] The gate of the eighth MOS tube is short-circuited with the gate of the ninth MOS tube and connected to the drain of the ninth MOS tube.

[0029] The present invention provides a bandgap reference source circuit, which compensates the voltage drop of a first external control signal at high temperature by means of a compensation voltage generated by a leakage MOS tube, thereby reducing the voltage drop of the reference voltage when the temperature rises. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a circuit diagram of a bandgap reference source circuit of the prior art;

[0031] Figure 2 is a circuit diagram of a bandgap reference source circuit according to an embodiment of the present invention;

[0032] Figure 3 is a current diagram generated by a leakage MOS tube according to an embodiment of the present invention;

[0033] Figure 4 and Figure 5 It is a comparison diagram of the reference voltage output by the embodiment of the present invention and the prior art. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0035] Hereinafter, the terms "first", "second", etc. are used to distinguish between similar elements and are not necessarily used to describe a particular order or chronological sequence. It is to be understood that these terms used in this manner are interchangeable where appropriate. Similarly, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method.

[0036] Furthermore, it should be understood that when a layer (or film), region, pattern or structure is referred to as being "on" a substrate, layer (or film), region and / or pattern, it can be directly on another layer or substrate, and / or there can be intervening layers. In addition, it should be understood that when a layer is referred to as being "under" another layer, it can be directly under another layer, and / or there can be one or more intervening layers. In addition, references to being "on" and "under" each layer can be made based on the accompanying drawings.

[0037] Please refer to Figure 2The present invention provides a bandgap reference source circuit, comprising: a reference source output circuit, a positive and negative temperature coefficient voltage generating circuit, an operational amplifier circuit and a leakage MOS tube; the reference source output circuit comprises a first MOS tube M1, a second MOS tube M2 and a third MOS tube M3; the gates of the first MOS tube M1, the second MOS tube M2 and the third MOS tube M3 are connected together to form a bias end, the bias end is used to receive the voltage of a bias point PB, the voltage of the bias point PB is used to control the start of the reference source output circuit, the sources of the first MOS tube M1, the second MOS tube M2 and the third MOS tube M3 are all connected to a power supply voltage VDD, the drain of the first MOS tube M1 is connected to the source of a high temperature leakage MOS tube M10 and outputs a first external control signal A, the drain of the second MOS tube M2 outputs a second external control signal B, the The drain of the three MOS tubes M3 outputs a reference voltage OUT, and the voltage of the first external control signal A and the voltage of the second external control signal B are the same as the reference voltage OUT; the operational amplifier circuit receives the first external control signal and the second external control signal, and the operational amplifier circuit is used to provide a voltage of a bias point to control the start-up of the reference source output circuit; the positive and negative temperature coefficient voltage generating circuit generates a positive temperature coefficient voltage and a negative temperature coefficient voltage, and both the positive temperature coefficient voltage and the negative temperature coefficient voltage are connected to the second external control signal B; the drain terminal of the leakage MOS tube M10 is connected to the first external control signal A, the collector terminal of the leakage MOS tube M10 is connected to the power supply voltage VDD, the base terminal of the leakage MOS tube M10 is grounded GND, and the leakage current generated at the drain terminal is used to reduce the voltage of the first external control signal to reduce the voltage drop of the reference voltage OUT.

[0038] The leakage MOS tube M10 of the embodiment of the present invention generates leakage current when the temperature is greater than or equal to 50° C. Figure 3 , it can be seen that at 105℃, the current generated by the leakage current terminal is 4A. Finally, the voltage drop of the reference voltage OUT is reduced as follows Figure 4 and Figure 5 , Figure 4 In the above figure and Figure 5 The lines 1 in the figure are all reference voltages of the prior art. Figure 4 The following figure and Figure 5 Line 2 in the figure is the reference voltage of the embodiment of the present invention. It can be seen that when the temperature rises to 100°C, the reference voltage of the prior art decreases by 5.326mV, and the reference voltage of the embodiment of the present invention decreases by 2.789mV. The embodiment of the present invention reduces the voltage drop of the reference voltage compared with the prior art.

[0039] The power supply voltage of the embodiment of the present invention is 1V to 5V. The first MOS tube M1, the second MOS tube M2 and the third MOS tube M3 of the embodiment of the present invention are all PMOS tubes. The first transistor Q1 and the second transistor Q2 are both PNP transistors.

[0040] Preferably, the embodiment of the present invention further comprises a current limiting resistor R4, the resistance of which is 1Mohm to 900Mohm. One end of the current limiting resistor R4 is connected to the power supply voltage VDD, and the other end is connected to the collector terminal of the leakage MOS tube M10.

[0041] The positive and negative temperature coefficient voltage generating circuit includes: a first triode Q1, a second triode Q2, a first resistor R1 and a second resistor R2, the collector of the first triode Q1 is connected to a first external control signal A, the emitters of the first triode Q1 and the second triode Q2 are both grounded GND, the base of the first triode Q1 and the base of the second triode Q2 are short-circuited and grounded, the collector of the second triode Q2 is connected to a second external control signal B through the first resistor R1, the second external control signal B is also grounded through the second resistor R2, and the current flowing through the first resistor R1 is a positive temperature coefficient I DVBE , the current flowing through the second resistor R2 has a negative temperature coefficient I VBE Therefore, the connection point between the first resistor R1 and the second external control signal B generates a positive temperature coefficient voltage, and the connection point between the second resistor R2 and the second external control signal B generates a negative temperature coefficient voltage. Therefore, adjusting the first resistor R1 and the second resistor R2 can offset the linear part of the positive temperature coefficient and the negative temperature coefficient.

[0042] Preferably, the embodiment of the present invention further includes a third resistor R3, one end of the third resistor R3 is connected to the reference voltage OUT, and the other end is connected to the ground GND.

[0043] The operational amplifier circuit includes: a fourth MOS tube M4, a fifth MOS tube M5, a sixth MOS tube M6 and a seventh MOS tube M7; the gates of the fourth MOS tube M4 and the fifth MOS tube M5 are short-circuited and connected to the drain of the fourth MOS tube M4; the sources of the fourth MOS tube M4 and the fifth MOS tube M5 are both connected to the power supply voltage VDD; the gates of the sixth MOS tube M6 and the seventh MOS tube M7 are respectively connected to the second external control signal B and the first external control signal A, the drain of the sixth MOS tube M6 is connected to the drain of the fourth MOS tube M4, the drain of the seventh MOS tube M7 is connected to the drain of the fifth MOS tube M5, the sources of the sixth MOS tube M6 and the seventh MOS tube M7 are short-circuited and form the tail current end of the operational amplifier circuit; the drain of the fifth MOS tube M5 outputs the voltage of the bias point PB. The fourth MOS tube M4 and the fifth MOS tube M5 are both PMOS tubes, and the sixth MOS tube M6 and the seventh MOS tube M7 are both NMOS tubes.

[0044] Furthermore, it also includes a current mirror circuit, which is connected to the tail current terminal of the operational amplifier circuit. The current mirror circuit includes: an eighth MOS tube M8, a ninth MOS tube M9 and a current source; the drain of the eighth MOS tube M8 is connected to the tail current terminal of the operational amplifier circuit; the drain of the ninth MOS tube M9 is connected to the current source, and the source of the ninth MOS tube M9 is grounded GND; the gate of the eighth MOS tube M8 is short-circuited with the gate of the ninth MOS tube M9 and then connected to the drain of the ninth MOS tube M9. The eighth MOS tube M8 and the ninth MOS tube M9 are both NMOS tubes.

[0045] In summary, a bandgap reference source circuit provided in an embodiment of the present invention compensates for the voltage drop of the first external control signal at high temperature by means of the compensation voltage generated by the leakage MOS tube, thereby reducing the voltage drop of the reference voltage when the temperature rises.

[0046] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A bandgap reference source circuit, characterized in that: include: Reference source output circuit, positive and negative temperature coefficient voltage generation circuit, operational amplifier circuit and leakage MOS tube; The reference source output circuit comprises a first MOS tube, a second MOS tube and a third MOS tube, the gates of the first MOS tube, the second MOS tube and the third MOS tube are connected together to form a bias end, the bias end is used to receive a voltage of a bias point, the voltage of the bias point is used to control the start of the reference source output circuit, the sources of the first MOS tube, the second MOS tube and the third MOS tube are all connected to a power supply voltage, the drain of the first MOS tube outputs a first external control signal, the drain of the second MOS tube outputs a second external control signal, the drain of the third MOS tube outputs a reference voltage, and the voltage of the first external control signal, the voltage of the second external control signal and the reference voltage are the same; The operational amplifier circuit receives the first external control signal and the second external control signal, and the operational amplifier circuit is used to provide the voltage of the bias point to control the start-up of the reference source output circuit; The positive and negative temperature coefficient voltage generating circuit generates a positive temperature coefficient voltage and a negative temperature coefficient voltage, and both the positive temperature coefficient voltage and the negative temperature coefficient voltage are connected to the second external control signal; The drain terminal of the leakage MOS tube is connected to the first external control signal, the collector terminal of the leakage MOS tube is connected to the power supply voltage, the base terminal of the leakage MOS tube is grounded, and the leakage current generated by the drain terminal is used to reduce the voltage of the first external control signal to reduce the voltage drop of the reference voltage.

2. The bandgap reference source circuit according to claim 1, characterized in that: The leakage MOS tube is an NMOS tube.

3. The bandgap reference source circuit according to claim 1, characterized in that: The leakage MOS tube generates leakage current when the temperature is greater than or equal to 50°C.

4. The bandgap reference source circuit according to claim 1, characterized in that: It also includes a current limiting resistor, one end of which is connected to the power supply voltage, and the other end of which is connected to the collector terminal of the leakage MOS tube.

5. The bandgap reference source circuit as claimed in claim 4, characterized in that: The resistance of the current limiting resistor is 1Mohm to 900Mohm.

6. The bandgap reference source circuit according to claim 1, characterized in that: The positive and negative temperature coefficient voltage generating circuit includes: a first triode, a second triode, a first resistor and a second resistor; the collector of the first triode is connected to the first external control signal, the emitters of the first triode and the second triode are both grounded, the base of the first triode and the base of the second triode are short-circuited and grounded, the collector of the second triode is connected to the second external control signal through the first resistor, the second external control signal is also grounded through the second resistor, the connection point of the first resistor and the second external control signal generates a positive temperature coefficient voltage, and the connection point of the second resistor and the second external control signal generates a negative temperature coefficient voltage.

7. The bandgap reference source circuit according to claim 1, characterized in that: Also includes: A third resistor, one end of the third resistor is connected to a reference voltage, and the other end is grounded.

8. The bandgap reference source circuit according to claim 1, characterized in that: The operational amplifier circuit comprises: a fourth MOS tube, a fifth MOS tube, a sixth MOS tube and a seventh MOS tube; The gates of the fourth MOS tube and the fifth MOS tube are short-circuited and connected to the drain of the fourth MOS tube; the sources of the fourth MOS tube and the fifth MOS tube are both connected to the power supply voltage; The gates of the sixth MOS tube and the seventh MOS tube are connected to the second external control signal and the first external control signal respectively, the drain of the sixth MOS tube is connected to the drain of the fourth MOS tube, the drain of the seventh MOS tube is connected to the drain of the fifth MOS tube, and the sources of the sixth MOS tube and the seventh MOS tube are short-circuited to form a tail current end of the operational amplifier circuit; The drain of the fifth MOS tube outputs the voltage of the bias point.

9. The bandgap reference source circuit according to claim 1, characterized in that: It also includes a current mirror circuit, which is connected to the tail current terminal of the operational amplifier circuit.

10. The bandgap reference source circuit according to claim 8, characterized in that: The current mirror circuit comprises: An eighth MOS tube, a ninth MOS tube and a current source; The drain of the eighth MOS tube is connected to the tail current terminal of the operational amplifier circuit; The drain of the ninth MOS tube is connected to the current source, and the source is grounded; The gate of the eighth MOS tube is short-circuited with the gate of the ninth MOS tube and connected to the drain of the ninth MOS tube.

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