Band-gap reference voltage source and chip

Abstract

The invention provides a band-gap reference voltage source and a chip, and belongs to the technical field of electronic circuits. The band-gap reference voltage source comprises an operational amplifier; the band-gap reference core circuit is electrically connected with the first input end and the second input end of the operational amplifier and used for providing input voltage for the first input end and the second input end of the operational amplifier; and the current negative feedback loop is electrically connected with the output end of the operational amplifier and is used for stabilizing the band-gap reference voltage output by the output end of the operational amplifier through current negative feedback. The band-gap reference voltage source is used for overcoming the defects that a traditional band-gap reference voltage source needs an additional circuit module to provide bias current for a whole circuit, power consumption is greatly increased, meanwhile, the generated bias current is greatly influenced by temperature, and therefore the temperature coefficient of reference voltage is influenced.

Description

Technical Field

[0001] The invention relates to the technical field of electronic circuits, and in particular to a bandgap reference voltage source and a chip. Background Art

[0002] As one of the core modules in electronic systems, bandgap reference voltage source is the basis of various integrated circuits such as voltage regulators, signal converters and oscillators, and is widely used in medical electronics, power management, wireless environmental sensors, communication circuits and other fields. Its advantages mainly include: fully compatible with standard CMOS process, easy to integrate with other devices and circuits on the same chip; the operating voltage can be very low, suitable for low-voltage operating environment and application requirements of portable devices; small temperature drift, can maintain high output voltage stability in a wide temperature range; flexible structure, can meet the requirements of different systems for reference voltage and current accuracy through design optimization. With the improvement of process, the chip area continues to shrink, especially in nano-level applications, the requirements for structural optimization and noise resistance of reference voltage are also increasing sharply.

[0003] Traditional bandgap reference voltage sources require additional circuit modules to provide bias current for the entire circuit, which greatly increases power consumption. At the same time, the generated bias current is greatly affected by temperature, thereby affecting the temperature coefficient of the reference voltage. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a bandgap reference voltage source and a chip to solve the defects that the traditional bandgap reference voltage source requires an additional circuit module to provide bias current for the entire circuit, which greatly increases power consumption, and the bias current generated is greatly affected by temperature, thereby affecting the temperature coefficient of the reference voltage.

[0005] In order to achieve the above object, an embodiment of the present invention provides a bandgap reference voltage source, comprising:

[0006] Operational amplifier;

[0007] a bandgap reference core circuit, electrically connected to the first input terminal and the second input terminal of the operational amplifier, and configured to provide input voltages to the first input terminal and the second input terminal of the operational amplifier;

[0008] A current negative feedback loop is electrically connected to the output end of the operational amplifier and is used to stabilize the bandgap reference voltage output by the output end of the operational amplifier through current negative feedback.

[0009] Optionally, the current negative feedback loop includes: a current mirror circuit, a first three-terminal switch device, a second three-terminal switch device and a first resistor;

[0010] The current mirror circuit is used to provide two current paths of equal magnitude, a first current and a second current; a first end of a first three-terminal switch device is electrically connected to a first output end of the current mirror circuit generating the first current, a control end of the first three-terminal switch device is electrically connected to a first set voltage source, a first end of a second three-terminal switch device is electrically connected to a second output end of the current mirror circuit generating the second current, a control end of the second three-terminal switch device is electrically connected to an output end of the operational amplifier, a second end of the first three-terminal switch device is electrically connected to a second end of the second three-terminal switch device, a first end of the first resistor is electrically connected to a second end of the second three-terminal switch device, and a second end of the first resistor is grounded.

[0011] Optionally, the current mirror circuit includes a third three-terminal switch device and a fourth three-terminal switch device; the control end of the third three-terminal switch device is electrically connected to the control end of the fourth three-terminal switch device, the first end of the third three-terminal switch device and the first end of the fourth three-terminal switch device are respectively electrically connected to a second set voltage source, the second end of the third three-terminal switch device serves as the first output end of the current mirror circuit, the second end of the fourth three-terminal switch device serves as the second output end of the current mirror circuit, and the control end of the third three-terminal switch device is electrically connected to the second end of the third three-terminal switch device.

[0012] Optionally, the bandgap reference voltage source also includes a compensation network, which includes a second resistor and a first capacitor, the first end of the second resistor is electrically connected to the control end of the second three-terminal switch device, the first end of the second resistor is current-connected to the first end of the first capacitor, and the second end of the first capacitor is grounded.

[0013] Optionally, the operational amplifier includes a fifth three-terminal switch device, a sixth three-terminal switch device, a seventh three-terminal switch device, an eighth three-terminal switch device and a ninth three-terminal switch device; the control end of the fifth three-terminal switch device is electrically connected to the control end of the sixth three-terminal switch device, the first end of the fifth three-terminal switch device and the first end of the sixth three-terminal switch device are respectively electrically connected to the first end of the second three-terminal switch device, the second end of the fifth three-terminal switch device is electrically connected to the first end of the seventh three-terminal switch device, the control end of the seventh three-terminal switch device serves as the first input end of the operational amplifier, the second end of the sixth three-terminal switch device is electrically connected to the first end of the eighth three-terminal switch device, the control end of the eighth three-terminal switch device serves as the second input end of the operational amplifier, the first end of the ninth three-terminal switch device is respectively electrically connected to the second ends of the seventh three-terminal switch device and the eighth three-terminal switch device, the control end of the ninth three-terminal switch device is electrically connected to a set current source, and the second end of the ninth three-terminal switch device is grounded.

[0014] Optionally, the bandgap reference voltage source also includes a third resistor and a thirteenth-terminal switching device, the first end of the third resistor is electrically connected to a set current source as the first set voltage source, the second end of the third resistor is electrically connected to the first end of the thirteenth-terminal switching device, the second end of the thirteenth-terminal switching device is grounded, the control end of the thirteenth-terminal switching device is electrically connected to the first end of the thirteenth-terminal switching device, and is electrically connected to the control end of the ninth three-terminal switching device to form a current mirror.

[0015] Optionally, the bandgap reference core circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, an eleventh three-terminal switch device and a twelfth three-terminal switch device; the first end of the fourth resistor and the first end of the fifth resistor are respectively electrically connected to the second output end of the current mirror circuit, the second end of the fourth resistor is electrically connected to the first end of the eleventh thirteen-terminal switch device, the second end of the eleventh thirteen-terminal switch device is electrically connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the second end of the fifth resistor is electrically connected to the first end of the twelfth three-terminal switch device, the second end of the twelfth three-terminal switch device is grounded, the control end of the twelfth three-terminal switch device is electrically connected to the control end of the twelfth three-terminal switch device and together with the second input end of the operational amplifier, and the first end of the twelfth three-terminal switch device is electrically connected to the first input end of the operational amplifier.

[0016] Optionally, the bandgap reference core circuit utilizes a combination of a positive temperature coefficient voltage and a negative temperature coefficient voltage to obtain a zero temperature coefficient voltage, wherein the negative temperature coefficient voltage is provided by the base-emitter voltage difference of the eleventh three-terminal switch device, and the positive temperature coefficient voltage is provided by the difference between the base-emitter voltage difference of the eleventh three-terminal switch device and the base-emitter voltage difference of the twelfth three-terminal switch device.

[0017] Optionally, the bandgap reference voltage is expressed by the following formula:

[0018]

[0019] Among them, V ref is the bandgap reference voltage, Vbe Q1 is the base-emitter voltage difference of the eleventh three-terminal switch device, V T is the thermal voltage, N is the ratio of the emitter junction area of ​​the eleventh three-terminal switch device to the emitter junction area of ​​the twelfth three-terminal switch device, R 1 is the sixth resistor, R 2 is the fourth resistor.

[0020] On the other hand, an embodiment of the present invention further provides a chip, comprising the above-mentioned bandgap reference voltage source.

[0021] Through the above technical solution, the current negative feedback loop of the embodiment of the present invention stabilizes the bandgap reference voltage output by the output end of the operational amplifier through current negative feedback. The embodiment of the present invention replaces the conventional method of improving the power supply rejection ratio through the current negative feedback loop, and is suitable for low power consumption application scenarios while achieving high power supply rejection ratio characteristics, and has excellent stability and temperature characteristics.

[0022] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0024] Figure 1 It is a structural schematic diagram of a bandgap reference voltage source provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of a typical bandgap reference circuit provided by the prior art. DETAILED DESCRIPTION

[0026] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0027] Please refer to Figure 1 An embodiment of the present invention provides a bandgap reference voltage source, comprising: an operational amplifier 1, a bandgap reference core circuit 2 and a current negative feedback loop 3.

[0028] The current negative feedback loop 3 is electrically connected to the output terminal of the operational amplifier 1 and is used to stabilize the bandgap reference voltage outputted from the output terminal of the operational amplifier 1 through current negative feedback. In one embodiment, the current negative feedback loop 3 includes: a current mirror circuit, a first three-terminal switch device M N1 , the second three-terminal switch device M P5 and the first resistor R 4 .

[0029] The current mirror circuit is used to provide two current paths with the same magnitude of the first current and the second current; the first three-terminal switch device M N1 The first end of the first three-terminal switch device M is electrically connected to the first output end of the current mirror circuit generating the first current, and the first three-terminal switch device M N1 The control end of the second three-terminal switch device M is electrically connected to the first set voltage source. P5The first end of the second three-terminal switch device M is electrically connected to the second output end of the current mirror circuit generating the second current, and the second three-terminal switch device M P5 The control end of the first three-terminal switch device M is electrically connected to the output end of the operational amplifier 1. N1 The second terminal of the second three-terminal switch device M P5 The second end of the first resistor R 4 The first terminal and the second three-terminal switch device M P5 The second end of the first resistor R 4 The second end of is grounded. Wherein, the current mirror circuit includes a third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 The third three-terminal switch device M P1 The control terminal of the fourth three-terminal switch device M P2 The control end is electrically connected to the third three-terminal switch device M P1 The first terminal and the fourth three-terminal switch device M P2 The first ends of the third three-terminal switch device M are respectively electrically connected to the second setting voltage source VINT, and the P1 The second end of the fourth three-terminal switch device M is used as the first output end of the current mirror circuit. P2 The second end of the third three-terminal switch device M is used as the second output end of the current mirror circuit. P1 The control terminal and the third three-terminal switch device M P1 The second end is electrically connected to

[0030] In the embodiment of the present invention, the first three-terminal switch device M N1 , the second three-terminal switch device M P5 , the third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 It can be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) or a triode. In one embodiment, please refer to Figure 1 , the first three-terminal switch device M N1 is an NMOS tube (N-channel MOS tube), the second three-terminal switch device M P5 is a PMOS tube (P-channel MOS tube), the third three-terminal switch device M P1 is a PMOS tube, the fourth three-terminal switch device M P2 The current negative feedback loop 3 is mainly through the first three-terminal switch device M N1 The branch where it is located adjusts the current size. The third three-terminal switch device M P1and the fourth three-terminal switch device M P2 The source is connected to the internal power supply VDD, the gate is connected, and the third three-terminal switch device M P1 The gate and drain of the third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 The fourth three-terminal switch device M P2 The drain of the tube and the second three-terminal switch device M P5 The source of the second three-terminal switch device M P5 The drain and resistor R 4 The upper end is connected to the resistor R 4 The lower end is grounded, the resistor R 4 The upper end is also connected to the first three-terminal switch device M N1 The source of the first three-terminal switch device M N1 The drain of the third three-terminal switch device M P1 is connected to the drain of the device to form the current negative feedback loop 3.

[0031] In other aspects of the embodiments of the present invention, the bandgap reference voltage source further includes a compensation network, wherein the compensation network includes a second resistor R 5 and the first capacitor C 2 , the second resistor R 5 The first terminal and the second three-terminal switch device M P5 The control end is electrically connected to the second resistor R 5 The second end of the first capacitor C 2 The first end current is connected to the first capacitor C 2 The second end of the resistor R is grounded. 5 and the first capacitor C 2 The formed compensation network is then input to the gate of the second three-terminal switch device MP5. In the embodiment of the present invention, the compensation network is provided to make the operational amplifier more stable.

[0032] The operational amplifier 1 includes a fifth three-terminal switch device M P3 , the sixth three-terminal switch device M P4 , the seventh three-terminal switch device M N2 , the eighth three-terminal switch device M N3 and the ninth three-terminal switch device M N5 The fifth three-terminal switch device M P3 The control terminal of the sixth three-terminal switch device M P4 The control end is electrically connected to the fifth three-terminal switch device M P3 The first terminal and the sixth three-terminal switch device M P4 The first end of each of the second three-terminal switch devices M P5The first end of the fifth three-terminal switch device M is electrically connected to P3 The second end of the seventh three-terminal switch device M N2 The first end of the seventh three-terminal switch device M is electrically connected to N2 The control end of the sixth three-terminal switch device M is used as the first input end of the operational amplifier 1. P4 The second end of the eighth three-terminal switch device M N3 The first end of the eighth three-terminal switch device M is electrically connected to N3 The control end of the ninth three-terminal switch device M is used as the second input end of the operational amplifier 1. N5 The first end of each of the seventh three-terminal switch devices M N2 and the eighth three-terminal switch device M N3 The second end of the ninth three-terminal switch device M is electrically connected to N5 The control end of the ninth three-terminal switch device M is electrically connected to the set current source. N5 The second end is grounded.

[0033] In the embodiment of the present invention, the fifth three-terminal switch device M P3 , the sixth three-terminal switch device M P4 , the seventh three-terminal switch device M N2 , the eighth three-terminal switch device M N3 and the ninth three-terminal switch device M N5 It can be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) or a triode. In one embodiment, please refer to Figure 1 , the fifth three-terminal switch device M P3 and the sixth three-terminal switching device M P4 is a PMOS tube (P-channel MOS tube), the seventh three-terminal switch device M N2 , the eighth three-terminal switch device M N3 and the ninth three-terminal switch device M N5 It is an NMOS tube (N-channel MOS tube).

[0034] Fifth three-terminal switch device M P3 , the sixth three-terminal switch device M P4 , the seventh three-terminal switch device M N2 , the eighth three-terminal switch device M N3 , the ninth three-terminal switch device M N5 The 5-tube differential structure is the first stage of the operational amplifier. The second stage of the operational amplifier consists of the second three-terminal switch device M P5 The fifth three-terminal switch device M P3The gate and drain of the tube are connected to the sixth three-terminal switch device M P4 The seventh three-terminal switch device M N2 , the eighth three-terminal switch device M N3 The drain of the fifth three-terminal switch device M P3 , the sixth three-terminal switch device M P4 The drain of the seventh three-terminal switch device M N2 The gate input is the positive input terminal of the operational amplifier, and the eighth three-terminal switch device M N3 The gate input is the inverting input terminal of the operational amplifier. N2 The source and the eighth three-terminal switching device M N3 The source of the seventh three-terminal switch device M N2 The source and the eighth three-terminal switching device M N3 The source of the ninth three-terminal switch device M N5 The drain of the ninth three-terminal switch device M N5 It is a tail current source of a 5-transistor differential structure. The second three-terminal switch device M P5 At the same time, as a part of the current negative feedback loop 3 and the second stage of the operational amplifier 1, as the second stage of the operational amplifier 1, the second three-terminal switch device MP5 tube plays the role of a voltage buffer and improves the driving load capability of the operational amplifier.

[0035] In other aspects of the embodiments of the present invention, the bandgap reference voltage source further includes a third resistor R 6 and the thirteenth terminal switch device M N4 , the third resistor R 6 The first end of the third resistor R is electrically connected to the setting current source PIBI as the first setting voltage source. 6 The second end and the thirteenth end of the switch device M N4 The first end of the switch device M is electrically connected to the N4 The second end of the switch device M is grounded, and the thirteenth end of the switch device M N4 The control terminal and the thirteenth terminal switch device M N4 The first end is electrically connected to the ninth three-terminal switch device M N5 The control end of the thirteenth terminal switch device M is electrically connected to form a current mirror. N4 The control end of the ninth three-terminal switch device M forms the set current source. N5 It can be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) or a triode.

[0036] In one embodiment, please refer to Figure 1 , the ninth three-terminal switch device M N5 NMOS tube (N-channel MOS tube). The ninth three-terminal switch device M N5 The gate and the thirteenth terminal switching device M N4 The gate of the thirteenth terminal switch device M N4 The drain and gate are connected, and the source is grounded. The thirteenth terminal switch device M N4 and the ninth three-terminal switch device M N5 The thirteenth terminal switch device M N4 The drain and the third resistor R 6 The lower end is connected to the third resistor R 6 The upper end and the first three-terminal switch device M N1 The gate of the current source PIBI pin is set as the quiescent current input and the third resistor R 6 In one embodiment, the static input current of the current source PIBI is set to 50nA, flowing through the third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 The total current of the bandgap reference voltage source of the embodiment of the present invention is about 5*10 -6 W, suitable for low power working conditions.

[0037] Typical bandgap reference circuits in the prior art are as follows: Figure 2 As shown in the figure, the bandgap reference circuit introduces an operational amplifier clamp so that the resistor R 1 The voltage drop across the two ends is Q 1 , Q 2 The base-emitter voltage difference ΔVbe, the power supply rejection ratio of the typical bandgap reference circuit is low, and it is difficult to show good stability when facing a large disturbance of the input voltage VDD. The power supply rejection ratio (PSRR) is an indicator to measure the ability of the reference source circuit to suppress power supply fluctuations under small signal conditions. It is an AC parameter with a unit of decibel (dB) and the expression formula is:

[0038]

[0039] Wherein, ΔVDD represents the input power supply change (in volts), VDD represents the input power supply, ΔVFB represents the converter output change (in volts), and VFB represents the converter output.

[0040] The power supply rejection ratio is an important parameter to measure the noise immunity of the reference voltage source. The power supply rejection ratio of the bandgap reference voltage source directly affects its anti-interference ability and the stability of the output voltage.

[0041] The current negative feedback loop 3 of the embodiment of the present invention is mainly through the first three-terminal switch device M N1 For example, when the input voltage value of the second set voltage source VINT increases, the current flowing through the second three-terminal switch device M P5 The current becomes larger and flows through the first resistor R 4 The current becomes larger, the first resistor R 4 The voltage at the upper end becomes larger, that is, the first three-terminal switch device M N1 The source voltage increases because the first three-terminal switch device M N1 The gate input is a fixed value, and the third resistor R 6 To ensure that the first three-terminal switch device M N1 Therefore, the first three-terminal switch device M N1 The gate-source voltage difference (Vgs) of the first three-terminal switch device M becomes smaller, resulting in N1 The current of the tube becomes smaller, that is, it flows through the third three-terminal switch device M P1 The current decreases, and the third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 A current mirror is formed, and the mirror relationship of the current mirror causes the fourth three-terminal switch device M P2 The tube current becomes smaller, thereby making the current flowing through the second three-terminal switch device M P5 The current becomes smaller, completing the control of the current negative feedback loop 3.

[0042] and Figure 2 Compared with the typical bandgap reference circuit structure shown in the figure, the embodiment of the present invention can improve the power supply rejection ratio by 30 dB through the current negative feedback loop 3, effectively enhance the anti-interference ability of the circuit, and improve the stability to a certain extent.

[0043] The bandgap reference core circuit 2 is electrically connected to the first input terminal and the second input terminal of the operational amplifier 1, and is used to provide input voltages to the first input terminal and the second input terminal of the operational amplifier 1. In one embodiment, the bandgap reference core circuit 2 includes: a fourth resistor R 2 , the fifth resistor R 3 , the sixth resistor R 1 、11. Three-terminal switch device Q 1 and the twelfth three-terminal switch device Q 2 The fourth resistor R 2 The first end and the fifth resistor R 3 The first ends of the fourth resistor R 2 The second terminal of the eleventh terminal of the switching device Q 1The first end of the eleventh three-terminal switching device Q 1 The second end of the sixth resistor R 1 The first end of the sixth resistor R 1 The second end of the fifth resistor R 3 The second terminal of the twelfth three-terminal switching device Q 2 The first end of the twelfth three-terminal switching device Q 2 The second terminal of the twelfth three-terminal switch device Q 2 The control terminal and the twelfth three-terminal switch device Q 2 The control end of the twelfth three-terminal switch device Q is electrically connected to the second input end of the operational amplifier 1, and the twelfth three-terminal switch device Q 2 The first end of is electrically connected to the first input end of the operational amplifier 1.

[0044] In the embodiment of the present invention, the eleventh three-terminal switch device Q 1 and the twelfth three-terminal switch device Q 2 It can be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) or a triode. In one embodiment, please refer to Figure 1 , the eleventh three-terminal switch device Q 1 and the twelfth three-terminal switch device Q 2 The fourth three-terminal switch device M P2 The drain and the fourth resistor R 2 , the fifth resistor R 3 The upper end is connected to the fourth resistor R 2 , the fifth resistor R 3 The lower end is respectively connected to the eleventh and third terminal switching devices Q 1 , 12th three-terminal switch device Q 2 Collector connected, eleventh three-terminal switching device Q 1 The emitter and the sixth resistor R 1 The upper end is connected, and the eleventh three-terminal switching device Q 1 The base is connected to the collector and connected to the eighth three-terminal switch device M N3 The gate of the sixth resistor R 1 The other end is grounded. 2 The emitter is grounded, and its base is connected to the eleventh three-terminal switching device Q 1 The collector is connected. The fifth resistor R 3 The lower end of the seventh three-terminal switch device M N2The gate of the transistor is connected as the positive input of the operational amplifier 1, which constitutes the bandgap reference core circuit 2. In addition, the capacitor C 1 The lower end is grounded, and the fifth three-terminal switch device M P3 , the sixth three-terminal switch device M P4 , the second three-terminal switch device M P5 The source and the fourth resistor R 2 , the fifth resistor R 3 And the capacitor C 1 The upper ends are connected and output to the VFB pin as a bandgap reference voltage.

[0045] The generation of the bandgap reference voltage in the embodiment of the present invention is mainly generated by the bandgap reference core circuit 2. With good temperature characteristics, although MOS devices have been used in some bandgap reference circuits, the bipolar circuit with transistors (BJT) as the main body in the embodiment of the present invention is still the core of the bandgap reference circuit. Specifically, the embodiment of the present invention obtains a zero temperature coefficient voltage by combining a positive temperature coefficient voltage and a negative temperature coefficient voltage. The transistor emitter junction voltage Vbe provides a negative temperature coefficient voltage, and the emitter junction voltage difference ΔVbe provides a positive temperature coefficient voltage. That is, the bandgap reference core circuit 2 uses a combination of a positive temperature coefficient voltage and a negative temperature coefficient voltage to obtain a zero temperature coefficient voltage, and the negative temperature coefficient voltage is generated by the eleventh three-terminal switch device Q 1 The positive temperature coefficient voltage is provided by the base-emitter voltage difference of the eleventh three-terminal switching device Q 1 The base-emitter voltage difference of the twelfth three-terminal switch device Q 2 The difference of the base-emitter voltage difference provides.

[0046] The bandgap reference core circuit 2 uses a combination of a positive temperature coefficient voltage and a negative temperature coefficient voltage to obtain a zero temperature coefficient voltage. 2 and the fifth resistor R 3 The lower end of each of the eleventh and third terminal switching devices Q 1 and the twelfth three-terminal switch device Q 2 The collector of the fourth resistor R 2 and the fifth resistor R 3 The upper end of is connected to the output of operational amplifier 1 to ensure that the positive input and negative input voltages of the operational amplifier are equal. 1 The base and collector are connected and connected to the eighth three-terminal switch device M N3 The gate is connected as the negative input terminal of the operational amplifier 1, and the eleventh three-terminal switch device Q 1 The emitter and the sixth resistor R 1 The top ends are connected. The twelfth three-terminal switch device Q 2 The base and the eleventh terminal switching device Q 1The collector is connected, and at the same time the twelfth three-terminal switch device Q 2 The collector and the seventh three-terminal switch device M N2 The gate is connected to the positive input terminal of operational amplifier 1. The base-emitter voltage difference (Vbe) of the transistor has a negative temperature coefficient. When Vbe≈750mV and T=300K, The positive temperature coefficient voltage is provided by the emitter junction voltage difference ΔVbe, so that the eleventh terminal switch device Q 1 The base-emitter voltage difference is Vbe1, and the twelfth three-terminal switch device Q 2 The base-emitter voltage difference is Vbe2. In the bandgap reference core circuit 2, the fourth resistor R 2 and the fifth resistor R 3 When the circuit is in a balanced state, the voltages at the positive and negative input terminals of the operational amplifier 1 remain equal, and the sixth resistor R 1 The voltage across the two ends is ΔVbe.

[0047] ΔVbe=Vbe1-Vbe2=V T ln N

[0048] The output bandgap reference voltage is:

[0049] Vref=α 1 Vbe+α 2 V T ln N

[0050] Where N is the eleventh three-terminal switch device Q 1 and the twelfth three-terminal switch device Q 2 The ratio of the emitter junction area, N = 15, V T is the thermal voltage, generally V T ≈26mV, α 1 =1,α 2 ln N ≈17.2, Vref is the output bandgap reference voltage, Vref≈Vbe+17.2V T ≈1.25V. Flows through the sixth resistor R 1 The current is:

[0051]

[0052] The output bandgap reference voltage Vref can be expressed as:

[0053]

[0054] make Pick A zero temperature coefficient voltage can be obtained.

[0055] Please refer to Figure 1 As shown, VINT provides a low voltage power supply for the internal bandgap reference circuit, which is about 5V. When the circuit is working normally, the current flowing through the third three-terminal switch device M P1 The current passes through the third three-terminal switch device M P1 , the fourth three-terminal switch device M P2 The current mirror formed is mirrored to the fourth three-terminal switch device M P2 , through the fourth three-terminal switch device M P2 The current flows through the fourth resistor R 2 and the fifth resistor R 3 The bandgap reference core circuit 2 starts to work. 2 and the fifth resistor R 3 The same resistance value ensures that the voltage at the two input terminals of the operational amplifier 1 is the same, and the current flows through the fourth resistor R 2 and the fifth resistor R 3 The current in the branch is also the same. 1 It is composed of 15 parallel transistors, the twelfth three-terminal switch device Q 2 The number of transistors is 1. And the twelfth three-terminal switch device Q 2 The collector is connected to the positive input terminal of operational amplifier 1, and the eleventh three-terminal switching device Q 1 The collector is connected to the negative input terminal of the operational amplifier 1. The sixth resistor R 1 A positive temperature coefficient voltage ΔVbe (V T ln N ),Vbe Q1 The current input from the PIBI pin passes through the ninth three-terminal switch device M N5 and the thirteenth terminal switch device M N4 The current mirror formed is mirrored to the ninth three-terminal switch device M N5 The compensation network is set to make the operational amplifier more stable. The output of the first stage of the operational amplifier is connected to the second resistor R 5 and the first capacitor C 2 The compensation network is then input to the second three-terminal switch device M P5 The gate of the operational amplifier is the second stage. The second stage of the operational amplifier is connected to the gate of the operational amplifier via the second three-terminal switch device M P5 The source of the output is connected to the Vref pin. As shown in the above derivation, the output bandgap reference voltage is is the zero temperature coefficient voltage. ref is the bandgap reference voltage, Vbe Q1 The eleventh three-terminal switch device Q 1The base-emitter voltage difference, V T is the thermal voltage, N is the eleventh three-terminal switch device Q 1 and the twelfth three-terminal switching device Q 2 The ratio of the emitter junction area, R 1 The sixth resistor R 1 , R 2 The fourth resistor R 2 .

[0056] When the VINT input voltage changes, the current negative feedback loop 3 starts to work. For example, when the VINT input voltage decreases, the current flowing through the second three-terminal switch device M P5 The current becomes smaller and flows through the first resistor R 4 The current becomes smaller, the first resistor R 4 The upper voltage becomes smaller, that is, the first three-terminal switch device M N1 The source voltage of the first three-terminal switch device M N1 The gate input is a fixed value, the first three-terminal switch device R 6 To ensure that the first three-terminal switch device M N1 Therefore, the first three-terminal switch device M N1 The gate-source voltage difference (Vgs) increases, causing the current flowing through the first three-terminal switch device M N1 The current becomes larger, that is, it flows through the third three-terminal switch device M P1 The current increases, and the third three-terminal switch device M P1 and the fourth three-terminal switch device M P2 A current mirror is formed, and the mirror relationship of the current mirror causes the fourth three-terminal switch device M P2 The current becomes larger, so that the current flowing through the second three-terminal switch device M P5 The current becomes larger, completing the control of the current negative feedback loop 3.

[0057] The disadvantage of the traditional bandgap reference voltage source is that it is easily affected by the external environment and the output voltage is unstable. The method of improving the power supply rejection ratio is at the expense of chip area and power consumption, such as using a low-dropout voltage regulator to power the reference circuit, adding an amplifier, using a long-channel transistor and a common source and common gate structure, adding a gain stage, etc. However, such methods will increase the area and power consumption of the circuit to a certain extent. The bandgap reference voltage source provided by the embodiment of the present invention uses a current negative feedback loop 3 to replace the traditional method of improving the power supply rejection ratio, without the cost of high current consumption, and still has a high power supply rejection ratio characteristic in a low-power application scenario, and has a high ability to suppress power supply voltage changes in a wide frequency range, optimizes the circuit structure of the traditional bandgap reference, and maintains good temperature drift characteristics.

[0058] On the other hand, an embodiment of the present invention further provides a chip, comprising the above-mentioned bandgap reference voltage source.

[0059] The specific structure of the bandgap reference voltage source refers to the above embodiments. Since this chip adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bandgap reference voltage source, characterized in that: include: Operational amplifier; a bandgap reference core circuit, electrically connected to the first input terminal and the second input terminal of the operational amplifier, and configured to provide an input voltage to the first input terminal and the second input terminal of the operational amplifier; A current negative feedback loop is electrically connected to the output end of the operational amplifier and is used to stabilize the bandgap reference voltage output by the output end of the operational amplifier through current negative feedback.

2. The bandgap reference voltage source according to claim 1, characterized in that: The current negative feedback loop includes: a current mirror circuit, a first three-terminal switch device, a second three-terminal switch device and a first resistor; The current mirror circuit is used to provide two current paths of equal magnitude, a first current and a second current; a first end of a first three-terminal switch device is electrically connected to a first output end of the current mirror circuit generating the first current, a control end of the first three-terminal switch device is electrically connected to a first set voltage source, a first end of a second three-terminal switch device is electrically connected to a second output end of the current mirror circuit generating the second current, a control end of the second three-terminal switch device is electrically connected to an output end of the operational amplifier, a second end of the first three-terminal switch device is electrically connected to a second end of the second three-terminal switch device, a first end of the first resistor is electrically connected to a second end of the second three-terminal switch device, and a second end of the first resistor is grounded.

3. The bandgap reference voltage source according to claim 2, characterized in that: The current mirror circuit includes a third three-terminal switch device and a fourth three-terminal switch device; the control end of the third three-terminal switch device is electrically connected to the control end of the fourth three-terminal switch device, the first end of the third three-terminal switch device and the first end of the fourth three-terminal switch device are respectively electrically connected to a second set voltage source, the second end of the third three-terminal switch device serves as the first output end of the current mirror circuit, the second end of the fourth three-terminal switch device serves as the second output end of the current mirror circuit, and the control end of the third three-terminal switch device is electrically connected to the second end of the third three-terminal switch device.

4. The bandgap reference voltage source according to claim 2, characterized in that: The bandgap reference voltage source also includes a compensation network, which includes a second resistor and a first capacitor, wherein the first end of the second resistor is electrically connected to the control end of the second three-terminal switch device, the first end of the second resistor is current-connected to the first end of the first capacitor, and the second end of the first capacitor is grounded.

5. The bandgap reference voltage source according to claim 2, characterized in that: The operational amplifier includes a fifth three-terminal switch device, a sixth three-terminal switch device, a seventh three-terminal switch device, an eighth three-terminal switch device and a ninth three-terminal switch device; the control end of the fifth three-terminal switch device is electrically connected to the control end of the sixth three-terminal switch device, the first end of the fifth three-terminal switch device and the first end of the sixth three-terminal switch device are respectively electrically connected to the first end of the second three-terminal switch device, the second end of the fifth three-terminal switch device is electrically connected to the first end of the seventh three-terminal switch device, the control end of the seventh three-terminal switch device serves as the first input end of the operational amplifier, the second end of the sixth three-terminal switch device is electrically connected to the first end of the eighth three-terminal switch device, the control end of the eighth three-terminal switch device serves as the second input end of the operational amplifier, the first end of the ninth three-terminal switch device is respectively electrically connected to the second ends of the seventh three-terminal switch device and the eighth three-terminal switch device, the control end of the ninth three-terminal switch device is electrically connected to a set current source, and the second end of the ninth three-terminal switch device is grounded.

6. The bandgap reference voltage source according to claim 5, characterized in that: The bandgap reference voltage source also includes a third resistor and a thirteenth-terminal switching device, the first end of the third resistor is electrically connected to the set current source, serving as the first set voltage source, the second end of the third resistor is electrically connected to the first end of the thirteenth-terminal switching device, the second end of the thirteenth-terminal switching device is grounded, the control end of the thirteenth-terminal switching device is electrically connected to the first end of the thirteenth-terminal switching device, and is electrically connected to the control end of the ninth three-terminal switching device to form a current mirror.

7. The bandgap reference voltage source according to claim 2, characterized in that: The bandgap reference core circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, an eleventh three-terminal switch device and a twelfth three-terminal switch device; the first end of the fourth resistor and the first end of the fifth resistor are respectively electrically connected to the second output end of the current mirror circuit, the second end of the fourth resistor is electrically connected to the first end of the eleventh thirteen-terminal switch device, the second end of the eleventh thirteen-terminal switch device is electrically connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the second end of the fifth resistor is electrically connected to the first end of the twelfth three-terminal switch device, the second end of the twelfth three-terminal switch device is grounded, the control end of the twelfth three-terminal switch device is electrically connected to the control end of the twelfth three-terminal switch device and is electrically connected together to the second input end of the operational amplifier, and the first end of the twelfth three-terminal switch device is electrically connected to the first input end of the operational amplifier.

8. The bandgap reference voltage source according to claim 7, characterized in that: The bandgap reference core circuit utilizes a combination of a positive temperature coefficient voltage and a negative temperature coefficient voltage to obtain a zero temperature coefficient voltage, wherein the negative temperature coefficient voltage is provided by the base-emitter voltage difference of the eleventh three-terminal switch device, and the positive temperature coefficient voltage is provided by the difference between the base-emitter voltage difference of the eleventh three-terminal switch device and the base-emitter voltage difference of the twelfth three-terminal switch device.

9. The bandgap reference voltage source according to claim 7, characterized in that: The bandgap reference voltage is expressed by the following formula: Among them, V ref is the bandgap reference voltage, Vbe Q1 is the base-emitter voltage difference of the eleventh three-terminal switch device, V T is the thermal voltage, N is the ratio of the emitter junction areas of the eleventh three-terminal switch device and the twelfth three-terminal switch device, R1 is the sixth resistor, and R2 is the fourth resistor.

10. A chip, characterized in that: The invention comprises the bandgap reference voltage source according to any one of claims 1 to 9.

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