Bandgap reference voltage source and chip

Abstract

The application 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; a band gap reference core circuit, which is electrically connected with a first input end and a second input end of the operational amplifier, and is used for providing input voltages for the first input end and the second input end of the operational amplifier; and a current negative feedback loop, which is electrically connected with an output end of the operational amplifier, and is used for stabilizing a band gap reference voltage output by the output end of the operational amplifier through current negative feedback.The application is used to solve the defects of the conventional band gap reference voltage source, i.e., the conventional band gap reference voltage source needs additional circuit modules to provide bias currents for the whole circuit, which greatly increases power consumption, and the generated bias current is greatly affected by temperature, thereby affecting the temperature coefficient of the reference voltage.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and more specifically to a bandgap reference voltage source and a chip. Background Technology

[0002] As a core module in electronic systems, bandgap voltage references form the basis of various integrated circuits such as voltage regulators, signal converters, and oscillators, and are widely used in medical electronics, power management, wireless environmental sensors, and communication circuits. Their advantages include: full compatibility with standard CMOS processes, facilitating integration with other devices and circuits on the same chip; low operating voltage, suitable for low-voltage operating environments and portable device applications; low temperature drift, maintaining high output voltage stability over a wide temperature range; and flexible structure, allowing for design optimization to meet the reference voltage and current accuracy requirements of different systems. With advancements in manufacturing processes and continuous reduction in chip area, especially in nanoscale applications, the requirements for reference voltage structure optimization and noise immunity are rapidly increasing.

[0003] Traditional bandgap voltage reference 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, thus affecting the temperature coefficient of the reference voltage. Summary of the Invention

[0004] The purpose of this invention is to provide a bandgap reference voltage source and a chip to solve the problems of traditional bandgap reference voltage sources that 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, thus affecting the temperature coefficient of the reference voltage.

[0005] To achieve the above objectives, embodiments of the present invention provide a bandgap reference voltage source, comprising:

[0006] Operational amplifier;

[0007] The bandgap reference core circuit is electrically connected to the first and second input terminals of the operational amplifier and is used to provide input voltage to the first and second input terminals of the operational amplifier.

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

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

[0010] A current mirror circuit is used to provide two currents of the same magnitude: a first current and a second current. The first terminal of a first three-terminal switch is electrically connected to the first output terminal of the current mirror circuit that generates the first current. The control terminal of the first three-terminal switch is electrically connected to a first set voltage source. The first terminal of a second three-terminal switch is electrically connected to the second output terminal of the current mirror circuit that generates the second current. The control terminal of the second three-terminal switch is electrically connected to the output terminal of the operational amplifier. The second terminal of the first three-terminal switch is electrically connected to the second terminal of the second three-terminal switch. The first terminal of the first resistor is electrically connected to the second terminal of the second three-terminal switch. The second terminal of the first resistor is grounded.

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

[0012] Optionally, the bandgap reference voltage source further 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 terminal of the second three-terminal switching device, and the first end of the second resistor is currently connected to the first end of the first capacitor. The second end of the first capacitor is grounded.

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

[0014] Optionally, the bandgap reference voltage source further 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 terminal of the thirteenth-terminal switching device is electrically connected to the first end of the thirteenth-terminal switching device and to the control terminal of the ninth-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-terminal thirteenth-terminal switching device, and a twelfth-terminal thirteenth-terminal switching device; the first ends of the fourth resistor and the fifth resistor are respectively electrically connected to the second output terminal of the current mirror circuit; the second end of the fourth resistor is electrically connected to the first end of the eleventh-terminal thirteenth-terminal switching device; the second end of the eleventh-terminal thirteenth-terminal switching 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-terminal thirteenth-terminal switching device; the second end of the twelfth-terminal thirteenth-terminal switching device is grounded; the control terminal of the twelfth-terminal thirteenth-terminal switching device is electrically connected to the control terminal of the twelfth-terminal thirteenth-terminal switching device and together they are electrically connected to the second input terminal of the operational amplifier; the first end of the twelfth-terminal thirteenth-terminal switching device is electrically connected to the first input terminal of the operational amplifier.

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

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

[0018]

[0019] Among them, V ref Vbe is the bandgap reference voltage. Q1 V is the base-emitter voltage difference of the eleventh-terminal switching device. T R1 is the thermal voltage, N is the ratio of the emitter junction area of ​​the eleventh-terminal thirteenth-terminal switch device and the twelfth-terminal thirteenth-terminal switch device, R1 is the sixth resistor, and R2 is the fourth resistor.

[0020] On the other hand, embodiments of the present invention also provide a chip including the above-described bandgap reference voltage source.

[0021] Through the above technical solution, the current negative feedback loop of this invention stabilizes the bandgap reference voltage output from the output terminal of the operational amplifier. This invention replaces conventional methods for improving power supply rejection ratio (PSRR) with a current negative feedback loop, achieving high PSRR characteristics while being suitable for low-power applications, and exhibiting excellent stability and temperature characteristics.

[0022] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

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

[0025] Figure 2 This is a schematic diagram of a typical bandgap reference circuit provided by existing technology. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0027] Please refer to Figure 1 This 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] A 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 output 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 and a first three-terminal switching device M. N1 Second and third terminal switching device M P5 And the first resistor R4.

[0029] The current mirror circuit is used to provide two currents of equal magnitude, a first current and a second current; the first three-terminal switching device M N1 The first terminal is electrically connected to the first output terminal of the current mirror circuit that generates the first current, and the first three-terminal switching device M N1 The control terminal is electrically connected to the first set voltage source, and the second three-terminal switching device M P5The first terminal is electrically connected to the second output terminal of the current mirror circuit that generates the second current, and the second three-terminal switching device M P5 The control terminal is electrically connected to the output terminal of the operational amplifier 1, and the first three-terminal switching device M N1 The second terminal and the second and third terminal switching device M P5 The second terminal is electrically connected, and the first terminal of the first resistor R4 is connected to the second three-terminal switching device M. P5 The second terminal of the first resistor R4 is electrically connected, and the second terminal of the first resistor R4 is grounded. The current mirror circuit includes a third three-terminal switching device M. P1 and the fourth three-terminal switching device M P2 The third three-terminal switching device M P1 The control terminal and the fourth three-terminal switching device M P2 The control terminal is electrically connected, and the third three-terminal switching device M is... P1 The first terminal and the fourth three-terminal switching device M P2 The first terminal is electrically connected to the second set voltage source VINT, and the third three-terminal switching device M P1 The second terminal serves as the first output terminal of the current mirror circuit, and the fourth three-terminal switching device M... P2 The second terminal serves as the second output terminal of the current mirror circuit, and the third three-terminal switching device M... P1 The control terminal and the third three-terminal switching device M P1 The second end is electrically connected.

[0030] In this embodiment of the invention, the first three-terminal switching device M N1 Second and third terminal switching device M P5 The third three-terminal switching device M P1 and the fourth three-terminal switching device M P2 It can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or a bipolar junction transistor. In one embodiment, please refer to... Figure 1 The first three-terminal switching device M N1 For NMOS transistors (N-channel MOS transistors), the second three-terminal switching device M P5 For PMOS transistors (P-channel MOS transistors), the third three-terminal switching device M P1 For PMOS transistors, the fourth three-terminal switching device M P2 It is a PMOS transistor. The current negative feedback loop 3 mainly passes through the first three-terminal switching device M. N1 The magnitude of the current in the branch is adjusted. The third three-terminal switching device M... P1 With the fourth three-terminal switching device M P2The source is connected to the internal power supply VDD, and the gate is connected to the third three-terminal switching device M. P1 The gate and drain are connected, and the third three-terminal switching device M P1 With the fourth three-terminal switching device M P2 This forms a current mirror. The fourth three-terminal switching device M... P2 The drain of the tube and the second and third terminal switching device M P5 The source is connected, and the second and third terminal switching device M P5 The drain of the resistor is connected to the upper end of the resistor R4, the lower end of the resistor R4 is grounded, and the upper end of the resistor R4 is also connected to the first three-terminal switching device M. N1 The source is connected, and the first three-terminal switching device M N1 The drain and the third three-terminal switching device M P1 The drains are connected 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, the compensation network including a second resistor R5 and a first capacitor C2, wherein a first terminal of the second resistor R5 is connected to the second three-terminal switching device M. P5 The control terminal is electrically connected, the second terminal of the second resistor R5 is current-connected to the first terminal of the first capacitor C2, and the second terminal of the first capacitor C2 is grounded. In this embodiment of the invention, the compensation network formed by the second resistor R5 and the first capacitor C2 is input to the gate of the second three-terminal switching device MP5. In this embodiment of the invention, the compensation network is set up to make the operational amplifier more stable.

[0032] Operational amplifier 1 includes a fifth three-terminal switching device M P3 The sixth three-terminal switching device M P4 7. Three-terminal switching device M N2 Eighth three-terminal switching device M N3 and the ninth three-terminal switching device M N5 The fifth three-terminal switching device M P3 The control terminal and the sixth three-terminal switching device M P4 The control terminal is electrically connected, and the fifth three-terminal switching device M P3 The first terminal and the sixth three-terminal switching device M P4 The first terminal is connected to the second and third terminal switching device M respectively. P5 The first terminal is electrically connected, and the fifth three-terminal switching device M P3 The second terminal and the seventh three-terminal switching device M N2 The first terminal is electrically connected, and the seventh three-terminal switching device M N2 The control terminal serves as the first input terminal of the operational amplifier 1, and the sixth three-terminal switching device M... P4 The second terminal and the eighth three-terminal switching device M N3The first terminal is electrically connected, and the eighth three-terminal switching device M N3 The control terminal serves as the second input terminal of the operational amplifier 1, and the ninth three-terminal switching device M... N5 The first terminal is respectively connected to the seventh three-terminal switching device M N2 and the eighth three-terminal switching device M N3 The second terminal is electrically connected, and the ninth and third terminal switching device M N5 The control terminal is electrically connected to the set current source, and the ninth-third terminal switching device M... N5 The second terminal is grounded.

[0033] In this embodiment of the invention, the fifth three-terminal switching device M P3 The sixth three-terminal switching device M P4 7. Three-terminal switching device M N2 Eighth three-terminal switching device M N3 and the ninth three-terminal switching device M N5 It can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or a bipolar junction transistor. In one embodiment, please refer to... Figure 1 The fifth three-terminal switching device M P3 and the sixth three-terminal switching device M P4 For PMOS transistors (P-channel MOSFETs), the seventh three-terminal switching device M N2 Eighth three-terminal switching device M N3 and the ninth three-terminal switching device M N5 It is an NMOS transistor (N-channel MOS transistor).

[0034] Fifth three-terminal switching device M P3 The sixth three-terminal switching device M P4 7. Three-terminal switching device M N2 Eighth three-terminal switching device M N3 , Ninth three-terminal switching device M N5 This forms a 5-transistor differential structure, which is the first stage of the operational amplifier. The second stage of the operational amplifier consists of a second three-terminal switching device M. P5 This constitutes a source follower. The fifth three-terminal switching device M... P3 The gate and drain of the transistor are connected, and it is connected to the sixth three-terminal switching device M. P4 The tube forms a current mirror. The seventh three-terminal switching device M... N2 Eighth three-terminal switching device M N3 The drains of the devices are respectively connected to the fifth three-terminal switching device M. P3 The sixth three-terminal switching device M P4 The drains are connected, and the seventh three-terminal switching device M N2The gate input is the positive input terminal of the operational amplifier, and the eighth three-terminal switching device M... N3 The gate input is the inverting input of the operational amplifier. The seventh three-terminal switching device M... N2 The source and the eighth three-terminal switching device M N3 The source is connected, and the seventh three-terminal switching device M N2 The source and the eighth three-terminal switching device M N3 The source terminals are respectively connected to the ninth and third terminal switching device M. N5 The drain is connected, and the ninth three-terminal switching device M N5 This is a tail current source with a 5-transistor differential structure. The second and third-terminal switching device M... P5 Simultaneously, as part of the current negative feedback loop 3 and the second stage of operational amplifier 1, the second three-terminal switching device MP5 acts as 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 R6 and a thirteenth-terminal switching device M. N4 The first terminal of the third resistor R6 is electrically connected to the set current source PIBI, serving as the first set voltage source. The second terminal of the third resistor R6 is connected to the thirteenth terminal switching device M. N4 The first terminal is electrically connected, and the thirteenth terminal switching device M N4 The second terminal is grounded, and the thirteenth terminal switching device M N4 The control terminal and the thirteenth terminal switching device M N4 The first terminal is electrically connected, and is connected to the ninth third-terminal switching device M. N5 The control terminal is electrically connected to form a current mirror, and the thirteenth terminal switching device M N4 The control terminal forms the set current source. The ninth and third terminal switching device M... N5 It can be a MOS transistor (Metal-Oxide-Semiconductor Field-Effect Transistor) or a triode.

[0036] In one embodiment, please refer to Figure 1 The ninth three-terminal switching device M N5 It is an NMOS transistor (N-channel MOS transistor). The ninth three-terminal switching device M... N5 Gate and thirteenth terminal switching device M N4 The gate is connected, and the thirteenth terminal switching device M N4 The drain and gate are connected, and the source is grounded. The thirteenth terminal switching device M... N4 and the ninth three-terminal switching device M N5The tube forms a current mirror. The thirteenth-terminal switching device M... N4 The drain of the device is connected to the lower end of the third resistor R6, and the upper end of the third resistor R6 is connected to the first three-terminal switching device M. N1 The gate of the current source PIBI is connected. The current source PIBI pin is set as the quiescent current input and connected to the upper end of the third resistor R6. In one embodiment, the quiescent input current of the current source PIBI is set to 50nA, flowing through the third three-terminal switching device M. P1 and the fourth three-terminal switching device M P2 The total current is 1μA. With an input voltage VINT of 5V, the total power consumption of the bandgap reference voltage source in this embodiment is approximately 5*10⁻⁶. -6 W is suitable for low-power operating conditions.

[0037] Typical bandgap reference circuits in the prior art include Figure 2 As shown, this bandgap reference circuit, by introducing operational amplifier clamping, makes the voltage drop across resistor R1 equal to the base-emitter voltage difference ΔVbe of Q1 and Q2. Typical bandgap reference circuits have low power supply rejection ratios (PSRR), making them difficult to maintain good stability when faced with large input voltage VDD disturbances. The Power Supply Rejection Ratio (PSRR) is an AC parameter that measures the ability of a reference source circuit to suppress power supply fluctuations under small-signal conditions. It is expressed by the formula:

[0038]

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

[0040] Power supply rejection ratio (PSRR) is an important parameter for measuring the immunity of a reference voltage source. The PRR of a bandgap reference voltage source directly affects its anti-interference capability and the stability of its output voltage.

[0041] The current negative feedback loop 3 in this embodiment of the invention mainly uses the first three-terminal switching device M N1 The magnitude of the current in the branch is adjusted. For example, when the input voltage value of the second set voltage source VINT increases, the current flows through the second three-terminal switching device M. P5 As the current increases, the current flowing through the first resistor R4 increases, and the voltage across the first resistor R4 increases, meaning the voltage across the first three-terminal switching device M... N1 The source voltage increases because of the first three-terminal switching device M. N1 The gate input is a fixed value, and the third resistor R6 is to ensure the first three-terminal switching device M N1 It is set to be constantly on. Therefore, the first three-terminal switching device MN1 The gate-source voltage difference (Vgs) decreases, causing current to flow through the first three-terminal switching device M. N1 The current in the tube decreases, meaning it flows through the third three-terminal switching device M. P1 The current decreases, and the third three-terminal switching device M... P1 With the fourth three-terminal switching device M P2 This forms a current mirror, and through the mirror relationship of the current mirror, it causes the fourth three-terminal switching device M to... P2 The tube current decreases, thus reducing the current flowing through the second and third terminal switching device M. P5 The current decreases, thus completing the control of the current negative feedback loop 3.

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

[0043] The bandgap reference core circuit 2 is electrically connected to the first and second input terminals of the operational amplifier 1, and is used to provide input voltage to the first and second input terminals of the operational amplifier 1. In one embodiment, the bandgap reference core circuit 2 includes: a fourth resistor R2, a fifth resistor R3, a sixth resistor R1, an eleventh-terminal switching device Q1, and a twelfth-terminal switching device Q2; the first ends of the fourth resistor R2 and the fifth resistor R3 are respectively electrically connected to the second output terminal of the current mirror circuit; the second end of the fourth resistor R2 is electrically connected to the first end of the eleventh-terminal switching device Q1; the second end of the eleventh-terminal switching device Q1 is electrically connected to the first end of the sixth resistor R1; the second end of the sixth resistor R1 is grounded; the second end of the fifth resistor R3 is electrically connected to the first end of the twelfth-terminal switching device Q2; the second end of the twelfth-terminal switching device Q2 is grounded; the control terminal of the twelfth-terminal switching device Q2 is electrically connected to the control terminal of the twelfth-terminal switching device Q2 and together they are electrically connected to the second input terminal of the operational amplifier 1; the first end of the twelfth-terminal switching device Q2 is electrically connected to the first input terminal of the operational amplifier 1.

[0044] In this embodiment of the invention, the eleventh-terminal switch Q1 and the twelfth-terminal switch Q2 can be MOS transistors (Metal-Oxide-Semiconductor Field-Effect Transistors) or bipolar transistors. In one embodiment, please refer to... Figure 1 The eleventh-terminal switch Q1 and the twelfth-terminal switch Q2 are NPN transistors. The fourth-terminal switch M... P2The drain is connected to the upper ends of the fourth resistor R2 and the fifth resistor R3. The lower ends of the fourth resistor R2 and the fifth resistor R3 are connected to the collectors of the eleventh-terminal switch Q1 and the twelfth-terminal switch Q2, respectively. The emitter of the eleventh-terminal switch Q1 is connected to the upper end of the sixth resistor R1, and the base and collector of the eleventh-terminal switch Q1 are connected to the eighth-terminal switch M. N3 The gate of the first resistor is used as the negative input of operational amplifier 1. The other end of the sixth resistor R1 is grounded. The emitter of the twelfth-th terminal switching device Q2 is grounded, and its base is connected to the collector of the eleventh-thirteenth terminal switching device Q1. The lower end of the fifth resistor R3 is connected to the seventh three-terminal switching device M. N2 The gate of the transistor is connected to the positive input of operational amplifier 1, forming the core circuit 2 of the bandgap reference. Additionally, the lower end of capacitor C1 is grounded, and the fifth three-terminal switching device M... P3 The sixth three-terminal switching device M P4 Second and third terminal switching device M P5 The source of the capacitor is connected to the fourth resistor R2, the fifth resistor R3, and the upper end of the capacitor C1, and is output to the VFB pin as a bandgap reference voltage.

[0045] In this embodiment of the invention, the bandgap reference voltage is primarily generated by the bandgap reference core circuit 2. Despite the use of MOS devices in some bandgap reference circuits due to their excellent temperature characteristics, this embodiment of the invention uses a bipolar circuit based on a transistor (BJT) as the core of the bandgap reference circuit. Specifically, this embodiment of the invention obtains a zero temperature coefficient voltage through a combination of positive and negative temperature coefficient voltages. The transistor emitter-junction voltage Vbe provides the negative temperature coefficient voltage, and the emitter-junction voltage difference ΔVbe provides the positive temperature coefficient voltage. That is, the bandgap reference core circuit 2 obtains a zero temperature coefficient voltage by combining positive and negative temperature coefficient voltages. The negative temperature coefficient voltage is provided by the base-emitter voltage difference of the eleventh-terminal switching device Q1, and the positive temperature coefficient voltage is provided by the difference between the base-emitter voltage difference of the eleventh-terminal switching device Q1 and the base-emitter voltage difference of the twelfth-terminal switching device Q2.

[0046] The core circuit 2 of the bandgap reference utilizes a combination of positive and negative temperature coefficient voltages to obtain a zero temperature coefficient voltage. The lower ends of the fourth resistor R2 and the fifth resistor R3 are connected to the collectors of the eleventh-terminal thirteen-terminal switching device Q1 and the twelfth-terminal thirteen-terminal switching device Q2, respectively. The upper ends of the fourth resistor R2 and the fifth resistor R3 are connected to the output of operational amplifier 1 to ensure that the positive and negative input voltages of the operational amplifier are equal. The base and collector of the eleventh-terminal thirteen-terminal switching device Q1 are connected to the eighth-terminal thirteen-terminal switching device M. N3The gates of the eleventh-thirteenth-terminal switching device Q1 are connected, serving as the negative input terminal of operational amplifier 1. The emitter of the eleventh-thirteenth-terminal switching device Q1 is connected to the upper end of the sixth resistor R1. The base of the twelfth-thirteenth-terminal switching device Q2 is connected to the collector of the eleventh-thirteenth-terminal switching device Q1, and the collector of the twelfth-thirteenth-terminal switching device Q2 is connected to the seventh-thirteenth-terminal switching device M. N2 The gate is connected, serving as 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. Let the base-emitter voltage difference of the eleventh-terminal switching device Q1 be Vbe1, and the base-emitter voltage difference of the twelfth-terminal switching device Q2 be Vbe2. In the bandgap reference core circuit 2, the resistances of the fourth resistor R2 and the fifth resistor R3 are equal. When the circuit is in equilibrium, the voltages at the positive and negative input terminals of operational amplifier 1 remain equal. Therefore, the voltage across the sixth resistor R1 is ΔVbe. Thus:

[0047] ΔVbe=Vbe1-Vbe2=V T ln N

[0048] The output bandgap reference voltage is:

[0049] Vref=α1Vbe+α2V T ln N

[0050] Where N is the ratio of the emitter junction areas of the eleventh-thirteenth terminal switching device Q1 and the twelfth-thirteenth terminal switching device Q2, N = 15, V T For thermal voltage, generally V T ≈26mV, α1=1, α2ln N ≈17.2, where Vref is the output bandgap reference voltage, Vref≈Vbe+17.2V. T ≈1.25V. The current flowing through the sixth resistor R1 is:

[0051]

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

[0053]

[0054] make Pick This will give you a voltage with zero temperature coefficient.

[0055] Please refer to Figure 1As shown, VINT provides a low-voltage power supply of approximately 5V to the internal bandgap reference circuit. When the circuit is operating normally, current flows through the third three-terminal switching device M. P1 The current passes through the third three-terminal switching device M P1 The fourth three-terminal switching device M P2 The current mirror formed is reflected to the fourth three-terminal switching device M. P2 After passing through the fourth three-terminal switching device M P2 The current flows through the branch containing the fourth resistor R2 and the fifth resistor R3, and the bandgap reference core circuit 2 begins to operate. The fourth resistor R2 and the fifth resistor R3 have the same resistance value to ensure that the voltages at the two input terminals of operational amplifier 1 are the same, and the current flowing through the branches containing the fourth resistor R2 and the fifth resistor R3 is also the same. The eleventh three-terminal switching device Q1 consists of 15 transistors connected in parallel, and the twelfth three-terminal switching device Q2 has one transistor. The collector of the twelfth three-terminal switching device Q2 is connected to the positive input terminal of operational amplifier 1, and the collector of the eleventh three-terminal switching device Q1 is connected to the negative input terminal of operational amplifier 1. A positive temperature coefficient voltage ΔVbe (i.e., V) is generated across the sixth resistor R1. T ln N ),Vbe Q1 This is a negative temperature coefficient voltage. The current input from the PIBI pin passes through the 93rd terminal switching device M. N5 and the thirteenth terminal switching device M N4 The current mirror formed is reflected to the ninth and third terminal switching device M. N5 At this point, it serves as the tail current source of the first-stage operational amplifier. A compensation network is included to make the operational amplifier more stable. The output of the first-stage operational amplifier passes through the compensation network consisting of the second resistor R5 and the first capacitor C2 before being input to the second three-terminal switching device M. P5 The gate of the operational amplifier is the second stage. The second stage of the operational amplifier is connected via the second three-terminal switching device M. P5 The source output is connected to the Vref pin. As shown in the derivation above, the output bandgap reference voltage is... This is the voltage with zero temperature coefficient. Where V... ref Vbe is the bandgap reference voltage. Q1 V is the base-emitter voltage difference of the eleventh-terminal switching device Q1. T Where N is the thermal voltage, N is the ratio of the emitter junction area of ​​the eleventh-terminal switch Q1 and the twelfth-terminal switch Q2, R1 is the sixth resistor R1, and R2 is the fourth resistor R2.

[0056] When the VINT input voltage changes, the current negative feedback loop 3 starts to operate. For example, when the VINT input voltage decreases, current flows through the second three-terminal switching device M. P5The current decreases, the current flowing through the first resistor R4 decreases, and the voltage across the first resistor R4 decreases, meaning the voltage across the first three-terminal switching device M... N1 The source voltage decreases because the first three-terminal switching device M N1 The gate input is a fixed value, and the first three-terminal switching device R6 is used to ensure the first three-terminal switching device M N1 It is set to be constantly on. Therefore, the first three-terminal switching device M N1 The gate-source voltage difference (Vgs) increases, causing current to flow through the first three-terminal switching device M. N1 The current increases, that is, it flows through the third three-terminal switching device M. P1 As the current increases, the third three-terminal switching device M... P1 With the fourth three-terminal switching device M P2 This forms a current mirror, and through the mirror relationship of the current mirror, it causes the fourth three-terminal switching device M to... P2 The current increases, thus increasing the current flowing through the second and third terminal switching device M. P5 The current increases, completing the control of the current negative feedback loop 3.

[0057] The drawback of traditional bandgap voltage references is their susceptibility to external environmental influences, resulting in unstable output voltage. Methods to improve the power supply rejection ratio (PSRR) come at the cost of increased chip area and power consumption, such as using low-dropout regulators to power the reference circuit, adding amplifiers, utilizing long-channel transistors and cascode structures, and adding gain stages. However, these methods all increase circuit area and power consumption to some extent. The bandgap voltage reference provided in this invention utilizes a current negative feedback loop 3 instead of traditional methods to improve the PSRR, without sacrificing high current consumption. It maintains a high PSRR even in low-power applications, exhibits strong suppression of power supply voltage variations over a wide frequency range, optimizes the circuit structure of traditional bandgap references, and maintains good temperature drift characteristics.

[0058] On the other hand, embodiments of the present invention also provide a chip including the above-described bandgap reference voltage source.

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

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate 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; The bandgap reference core circuit is electrically connected to the first and second input terminals of the operational amplifier and is used to provide input voltage to the first and second input terminals of the operational amplifier. A current negative feedback loop is electrically connected to the output terminal of the operational amplifier and is used to stabilize the bandgap reference voltage output from the output terminal of the operational amplifier through current negative feedback. The current negative feedback loop includes: a current mirror circuit, a first three-terminal switching device, a second three-terminal switching device, and a first resistor; A current mirror circuit is used to provide two currents of the same magnitude: a first current and a second current. The first terminal of a first three-terminal switching device is electrically connected to the first output terminal of the current mirror circuit that generates the first current. The control terminal of the first three-terminal switching device is electrically connected to a first set voltage source. The first terminal of a second three-terminal switching device is electrically connected to the second output terminal of the current mirror circuit that generates the second current. The control terminal of the second three-terminal switching device is electrically connected to the output terminal of the operational amplifier. The second terminal of the first three-terminal switching device is electrically connected to the second terminal of the second three-terminal switching device. The first terminal of the first resistor is electrically connected to the second terminal of the second three-terminal switching device. The second terminal of the first resistor is grounded. The current mirror circuit includes a third three-terminal switching device and a fourth three-terminal switching device; the control terminal of the third three-terminal switching device is electrically connected to the control terminal of the fourth three-terminal switching device, the first terminal of the third three-terminal switching device and the first terminal of the fourth three-terminal switching device are respectively electrically connected to a second set voltage source, the second terminal of the third three-terminal switching device serves as the first output terminal of the current mirror circuit, the second terminal of the fourth three-terminal switching device serves as the second output terminal of the current mirror circuit, and the control terminal of the third three-terminal switching device is electrically connected to the second terminal of the third three-terminal switching device.

2. The bandgap reference voltage source according to claim 1, characterized in that, The bandgap reference voltage source further 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 terminal of the second three-terminal switching device, and the first end of the second resistor is connected to the first end of the first capacitor. The second end of the first capacitor is grounded.

3. The bandgap reference voltage source according to claim 1, characterized in that, The operational amplifier includes a fifth three-terminal switching device, a sixth three-terminal switching device, a seventh three-terminal switching device, an eighth three-terminal switching device, and a ninth three-terminal switching device. The control terminal of the fifth three-terminal switching device is electrically connected to the control terminal of the sixth three-terminal switching device. The first terminals of the fifth and sixth three-terminal switching devices are respectively electrically connected to the first terminals of the second three-terminal switching device. The second terminal of the fifth three-terminal switching device is electrically connected to the first terminal of the seventh three-terminal switching device. The control terminal of the seventh three-terminal switching device serves as the first input terminal of the operational amplifier. The second terminal of the sixth three-terminal switching device is electrically connected to the first terminal of the eighth three-terminal switching device. The control terminal of the eighth three-terminal switching device serves as the second input terminal of the operational amplifier. The first terminal of the ninth three-terminal switching device is electrically connected to the second terminals of the seventh and eighth three-terminal switching devices. The control terminal of the ninth three-terminal switching device is electrically connected to a set current source. The second terminal of the ninth three-terminal switching device is grounded.

4. The bandgap reference voltage source according to claim 3, characterized in that, The bandgap reference voltage source further 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 terminal of the thirteenth-terminal switching device is electrically connected to the first end of the thirteenth-terminal switching device and to the control terminal of the ninth-terminal switching device to form a current mirror.

5. The bandgap reference voltage source according to claim 1, characterized in that, The bandgap reference core circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, an eleventh-terminal thirteenth-terminal switching device, and a twelfth-terminal thirteenth-terminal switching device; the first ends of the fourth resistor and the fifth resistor are electrically connected to the second output terminal of the current mirror circuit, the second end of the fourth resistor is electrically connected to the first end of the eleventh-terminal thirteenth-terminal switching device, the second end of the eleventh-terminal thirteenth-terminal switching 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-terminal thirteenth-terminal switching device, the second end of the twelfth-terminal thirteenth-terminal switching device is grounded, the control terminal of the twelfth-terminal thirteenth-terminal switching device is electrically connected to the control terminal of the twelfth-terminal thirteenth-terminal switching device and together they are electrically connected to the second input terminal of the operational amplifier, and the first end of the twelfth-terminal thirteenth-terminal switching device is electrically connected to the first input terminal of the operational amplifier.

6. The bandgap reference voltage source according to claim 5, characterized in that, The bandgap reference core circuit uses a combination of positive and negative temperature coefficient voltages to obtain a zero temperature coefficient voltage. The negative temperature coefficient voltage is provided by the base-emitter voltage difference of the eleventh-terminal switching device, and the positive temperature coefficient voltage is provided by the difference between the base-emitter voltage difference of the eleventh-terminal switching device and the base-emitter voltage difference of the twelfth-terminal switching device.

7. The bandgap reference voltage source according to claim 5, characterized in that, The bandgap reference voltage is expressed by the following formula: ； Among them, V ref Vbe is the bandgap reference voltage. Q1 V is the base-emitter voltage difference of the eleventh-terminal switching device. T R1 is the thermal voltage, N is the ratio of the emitter junction area of ​​the eleventh-terminal thirteenth-terminal switching device and the twelfth-terminal thirteenth-terminal switching device, R1 is the sixth resistor, and R2 is the fourth resistor.

8. A chip, characterized in that, Includes the bandgap reference voltage source according to any one of claims 1 to 7.

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