A low temperature drift high precision segmented compensated bandgap reference circuit for information storage

Abstract

The application discloses a low-temperature-drift high-precision segmented compensation bandgap reference circuit for information storage, which comprises the following steps: according to a power supply voltage, a starting circuit is used to drive a bandgap reference core circuit to get rid of a degenerate state and is turned off after the bandgap reference core circuit is established to reduce power consumption; according to the bandgap reference core circuit, a first-order bandgap reference core module is used to generate a first-order bandgap reference voltage; and according to the first-order bandgap reference voltage, a segmented compensation circuit is used to carry out temperature coefficient compensation in a low-temperature section and a high-temperature section respectively, and a low-temperature-drift high-precision reference voltage is output. The application can fundamentally solve a series of negative effects caused by insufficient performance of a DCDC converter on output precision, temperature stability and light load efficiency of the DCDC converter, and finally realizes a high-performance and high-reliability power management system.

Description

Technical Field

[0001] This invention belongs to the field of reference circuit technology, and particularly relates to a low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage. Background Technology

[0002] The basic principle of traditional bandgap reference circuits is to use the negative temperature coefficient of the base-emitter voltage (VBE) of a bipolar transistor, and the positive temperature coefficient of the thermal voltage difference (ΔVBE) generated by two bipolar transistors operating at different current densities, to perform a weighted superposition. The thermal voltage V... T =kT / q, which is proportional to the absolute temperature. By carefully designing the circuit parameters, the sum of these two voltages with opposite temperature coefficients can achieve first-order temperature compensation at a specific temperature point (usually 27°C), thereby outputting a stable reference voltage of approximately 1.25V.

[0003] However, this classic first-order temperature compensation method has inherent limitations: 1. High-order nonlinear temperature drift: The VBE voltage of a bipolar transistor changes with temperature in an inherently highly nonlinear manner. Its temperature characteristics can be described as follows: ; This includes a nonlinear term related to the logarithm of temperature. Traditional first-order compensation can only compensate for the linear portion, but cannot eliminate this nonlinear term (often referred to as "curvature" error). Therefore, over a wide temperature range (e.g., -40°C to 125°C), the output voltage exhibits a pronounced "bow-shaped" curve, resulting in a significant decrease in the accuracy of the reference voltage across the entire temperature range.

[0004] 2. The trade-off between compensation accuracy and flexibility: To correct the aforementioned nonlinear errors, those skilled in the art have proposed several high-order temperature compensation or curvature correction techniques. For example, by introducing resistors, transistors, or operational amplifier networks into conventional structures, compensation currents related to higher-order temperature terms are injected into the core circuit. However, these methods typically suffer from difficulties in global optimization and design complexity.

[0005] 3. Performance trade-offs: While pursuing a low temperature coefficient, other performance indicators of the circuit, such as power supply rejection ratio, startup characteristics, noise and power consumption, may also be affected by the introduction of compensation circuits. Designers often need to make difficult trade-offs between these performance characteristics.

[0006] In summary, despite years of development, existing bandgap reference technologies suffer from a core problem: they cannot effectively compensate for the higher-order nonlinear temperature drift of the VBE in a simple, reliable, and easily implementable manner over an ultra-wide temperature range and with varying process angles. This has become a long-standing and urgent technical challenge in the design of high-precision reference voltage sources. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage. This invention can fundamentally solve a series of negative impacts on the output accuracy, temperature stability, and light-load efficiency of DC-DC converters caused by their insufficient performance, ultimately achieving a high-performance, highly reliable power management system.

[0008] To achieve the above objectives, the present invention provides a low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage, comprising: Based on the power supply voltage, the bandgap reference core circuit is driven out of the degenerate state by the startup circuit and shut down after the bandgap reference core circuit is established to reduce power consumption. According to the bandgap reference core circuit, a first-order bandgap reference voltage is generated through a first-order bandgap reference core module. Based on the first-order bandgap reference voltage, temperature coefficient compensation is performed in the low-temperature and high-temperature ranges through a segmented compensation circuit to output a high-precision reference voltage with low temperature drift.

[0009] Optionally, depending on the power supply voltage, the bandgap reference core circuit is driven out of the degenerate state by a startup circuit and shut down after the bandgap reference core circuit has been established to reduce power consumption, including: Based on the power supply voltage, a gate control voltage that rises with the power supply voltage is generated through a startup branch composed of a resistor and a transistor. According to the gate control voltage, the gate voltage of the current mirror in the bandgap reference core circuit is pulled down by the first transistor and the second transistor to start the current mirror to work normally. Based on the feedback voltage after the bandgap reference core circuit enters steady state, the gate-source voltage of the first and second transistors is pulled below the threshold voltage by the third transistor to shut down the startup circuit.

[0010] Optionally, according to the bandgap reference core circuit, generating a first-order bandgap reference voltage through a first-order bandgap reference core module includes: Based on the first and second node voltages clamped by the operational amplifier, a positive temperature coefficient current proportional to the absolute temperature is generated through a positive temperature coefficient current generation circuit. Based on the voltage of the first node, a negative temperature coefficient current that is inversely proportional to the absolute temperature is generated through a negative temperature coefficient current generating circuit. Based on the positive temperature coefficient current and the negative temperature coefficient current, the positive temperature coefficient current and the negative temperature coefficient current are injected into the same resistor through a current mirror to obtain the first-order bandgap reference voltage.

[0011] Optionally, generating a negative temperature coefficient current that is inversely proportional to the absolute temperature through a negative temperature coefficient current generating circuit includes: Based on the condition that the first node voltage and the second node voltage of the operational amplifier clamp are equal, a base-emitter voltage difference is generated by the first bipolar transistor and the second bipolar transistor operating at different current densities. The positive temperature coefficient current is obtained based on the base-emitter voltage difference falling across the first resistor.

[0012] Optionally, based on the first-order bandgap reference voltage, temperature coefficient compensation is performed separately in the low-temperature and high-temperature ranges using a segmented compensation circuit, including: Based on the temperature characteristic curve of the first-order bandgap reference voltage, the temperature range is divided into three sub-ranges: low temperature range, intermediate range, and high temperature range. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low temperature range, a positive temperature coefficient compensation current is generated in the low temperature range to counteract the negative temperature coefficient voltage trend. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature section, a negative temperature coefficient compensation current is generated in the high-temperature section to counteract the positive temperature coefficient voltage trend. Based on the relatively gentle temperature characteristics of the middle section, no compensation is performed in the middle section.

[0013] Optionally, based on the magnitude relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low-temperature range, generating a positive temperature coefficient compensation current in the low-temperature range to offset the negative temperature coefficient voltage trend includes: The positive temperature coefficient current is copied to the first compensation branch according to the first current mirror ratio to obtain the first proportional positive temperature coefficient current. The negative temperature coefficient current is copied to the second compensation branch according to the second current mirror ratio to obtain the first proportional negative temperature coefficient current. Based on the comparison result of the first proportional positive temperature coefficient current and the first proportional negative temperature coefficient current at the low temperature compensation point, the first difference current is generated by the current calculation circuit. The first differential current is extracted to the compensation node according to the ratio of the third current mirror, and positive temperature coefficient compensation is achieved in the low temperature range.

[0014] Optionally, based on the magnitude relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature range, generating a negative temperature coefficient compensation current in the high-temperature range to offset the positive temperature coefficient voltage trend includes: The negative temperature coefficient current is copied to the third compensation branch according to the fourth current mirror ratio to obtain the second proportional negative temperature coefficient current. The positive temperature coefficient current is copied to the fourth compensation branch according to the fifth current mirror ratio to obtain the second proportional positive temperature coefficient current. Based on the comparison result of the second proportional negative temperature coefficient current and the second proportional positive temperature coefficient current at the high temperature compensation point, a second differential current is generated by the current calculation circuit. The second differential current is extracted to the compensation node according to the sixth current mirror ratio, thereby achieving negative temperature coefficient compensation in the high-temperature range.

[0015] Optionally, the segmented compensation circuit determines the segmented compensation temperature point by setting different replication ratio coefficients of the current mirror, controls the magnitude of the compensation current by adjusting the compensation current ratio coefficient, and can be expanded to multiple segmented points for compensation according to accuracy requirements.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: This invention introduces base resistor compensation and dynamically improves the accuracy of ΔVbe through MOSFET switching; the high-order compensation current technology significantly improves the temperature coefficient of the reference voltage by generating PTAT², providing a stable reference voltage for high-performance IC design. This invention can simultaneously improve both temperature drift and reference voltage accuracy. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is an overall circuit diagram of the segmented compensated bandgap reference according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the low-temperature compensation point in an embodiment of the present invention; Figure 3 This is a schematic diagram of the high-temperature section compensation point according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the temperature drift coefficient simulation curve according to an embodiment of the present invention; Figure 5 This is a simulation diagram of the reference voltage establishment time according to an embodiment of the present invention. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0020] The primary objective of this invention is to address the issue of reduced reference voltage accuracy caused by nonlinear temperature drift in traditional bandgap references over a wide temperature range. By employing a segmented temperature compensation technique, the entire operating temperature range is divided into multiple sub-ranges, and an optimal, adaptive compensation coefficient is used within each sub-range. This achieves high-precision, segment-by-segment fitting and cancellation of the VBE nonlinear curvature, thereby obtaining an extremely low temperature coefficient across the entire operating temperature range (e.g., -55°C to 125°C).

[0021] The second objective of this invention is to enhance the system stability and efficiency of DC-DC converters under light or variable load conditions. Modern DC-DC converters commonly employ advanced control modes such as automatic switching between pulse width modulation (PWM) and pulse frequency modulation (PWM) to improve efficiency under light load conditions. The thresholds for these mode switching modes are typically directly related to a reference voltage or an internal reference signal derived from it. If the reference voltage experiences significant temperature drift, the mode switching point may shift with temperature, causing the operating mode to oscillate frequently near the critical point, resulting in increased output voltage ripple and system instability. The high-precision, low-noise reference voltage provided by this invention provides a stable and reliable decision threshold for these internal comparators, ensuring smooth and accurate switching of operating modes, thereby improving overall system stability and efficiency under light load conditions.

[0022] In summary, the core objective of this invention is to create a high-precision, low-temperature-coefficient, and high-stability segmented bandgap reference circuit to fundamentally solve a series of negative impacts on the output accuracy, temperature stability, and light-load efficiency of DC-DC converters caused by their insufficient performance, and ultimately achieve a high-performance and highly reliable power management system.

[0023] This embodiment proposes a low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage, such as... Figure 1 As shown, it specifically includes: Based on the power supply voltage, the bandgap reference core circuit is driven out of the degenerate state by the startup circuit and shut down after the bandgap reference core circuit is established to reduce power consumption. According to the bandgap reference core circuit, a first-order bandgap reference voltage is generated through a first-order bandgap reference core module. Based on the first-order bandgap reference voltage, temperature coefficient compensation is performed in the low-temperature and high-temperature ranges through a segmented compensation circuit to output a high-precision reference voltage with low temperature drift.

[0024] Specifically, the startup circuit is connected to the gates of the bandgap reference cores M2 and M9 through the drains of M22 and M23, and the compensation circuit is connected to the gates of the bandgap reference core circuits M2 and M9 through the gates of M6 and M12. The three module circuits share the power supply voltage and ground.

[0025] The startup circuit drives the bandgap reference circuit out of the degenerate state and shuts down the startup circuit after the bandgap reference core circuit is established to reduce power consumption. The bandgap reference core circuit is used to generate the first-order bandgap reference voltage to provide a reference for subsequent compensation. The segmented compensation circuit compensates the first-order bandgap reference in the low-temperature and high-temperature ranges to optimize the temperature of the reference voltage.

[0026] Furthermore, based on the power supply voltage, the bandgap reference core circuit is driven out of the degenerate state by the startup circuit and shut down after the bandgap reference core circuit is established to reduce power consumption, including: Based on the power supply voltage, a gate control voltage that rises with the power supply voltage is generated through a startup branch composed of a resistor and a transistor. According to the gate control voltage, the gate voltage of the current mirror in the bandgap reference core circuit is pulled down by the first transistor and the second transistor to start the current mirror to work normally. Based on the feedback voltage after the bandgap reference core circuit enters steady state, the gate-source voltage of the first and second transistors is pulled below the threshold voltage by the third transistor to shut down the startup circuit.

[0027] Specifically, since the bandgap reference has two or more stable operating points, the circuit is in a steady state at the stable operating points. Therefore, in order to make the circuit work in a normal state, a startup circuit needs to be designed to get it out of the degenerate state. When the circuit is working normally, the startup circuit is turned off to reduce current loss.

[0028] like Figure 1 As shown, the startup circuit consists of M1, M8, M18, M19, M20, M21, M22, M23, and R1. Upon power-up, the gate voltages of M1 and M8 are initially high, and the circuit is in a zero-steady-state. As the power supply voltage VDD gradually increases, the gate voltages of M22 and M23 gradually rise, while the gate voltages of M1-M7 and M8-M13 are pulled low. The current mirror begins normal operation, and the bandgap reference circuit completes normal power-on startup. When the circuit is in a steady-state, the gate voltage of M21 increases, and the gate-source voltages of M22 and M23 are pulled below the threshold voltage, shutting off the startup circuit.

[0029] The source of M1 is connected to the power supply voltage VDD, and the drain of M1 is connected to the source of M8; the gate of M1 is connected to the drain of M22; the drain of M8 is connected to the drain of M18, and the gate of M8 is connected to the drain of M23; the gate and drain of M18 are connected to the drain of M8; the gate of M19 is connected to the drain of M19 and the source of M18, and the source of M19 is connected to the drain of M20; the gates of M20 and M21 are connected to the source of M19; the sources of M20, M21, M22, and M23 are connected to ground; the upper end of resistor R1 is connected to the power supply voltage VDD, and the lower end of R1 is connected to the drain of M21, the gate of M22, and the gate of M23.

[0030] Furthermore, according to the aforementioned bandgap reference core circuit, generating a first-order bandgap reference voltage through a first-order bandgap reference core module includes: Based on the first and second node voltages clamped by the operational amplifier, a positive temperature coefficient current proportional to the absolute temperature is generated through a positive temperature coefficient current generation circuit. Based on the voltage of the first node, a negative temperature coefficient current that is inversely proportional to the absolute temperature is generated through a negative temperature coefficient current generating circuit. Based on the positive temperature coefficient current and the negative temperature coefficient current, the positive temperature coefficient current and the negative temperature coefficient current are injected into the same resistor through a current mirror to obtain the first-order bandgap reference voltage.

[0031] Furthermore, generating a negative temperature coefficient current that is inversely proportional to the absolute temperature through a negative temperature coefficient current generating circuit includes: Based on the condition that the first node voltage and the second node voltage of the operational amplifier clamp are equal, a base-emitter voltage difference is generated by the first bipolar transistor and the second bipolar transistor operating at different current densities. The positive temperature coefficient current is obtained based on the base-emitter voltage difference falling across the first resistor.

[0032] Specifically, the core circuit of the first-order bandgap reference adopts a traditional current-mode bandgap reference. Its operation is as follows: an operational amplifier is used to force the voltages at nodes A and B to be equal. Here, a two-stage operational amplifier is used. The two-stage operational amplifier can ensure a large swing while maintaining high gain, and the structure is simple. A reference circuit schematic is shown in the figure below: Figure 1The operational amplifier in the circuit consists of PMOS transistors MP1, MP2, MP3, NMOS transistors MN1, MN2, MN3, MN4, MN5, capacitor CL, and Miller capacitor CC. The sources of MP1, MP2, and MP3, the gate of MN3, and the drain of MN3 are connected to the power supply voltage VDD; the gates of MP1, MP2, and MP3, the drain of MP1, and the drain of MN1 are connected together; the drain of MN2 is connected to the drain of MP2, and the sources of MN1 and MN2 are connected to the drain of MN4; the drain of MP3 is connected to the drain of MN5, and the upper end of capacitor CL is connected to the lower plate of capacitor CL; one end of Miller capacitor CC is connected to the gate of MP3, and the other end is connected to the drain of MN5; the gates of MN3, MN4, and MN5 are connected together, and the drains of MN3, MN4, and MN5 are connected to ground.

[0033] More specifically, the core circuit of the bandgap reference mainly includes a positive temperature coefficient current generation circuit composed of Q1, Q2, M2, M3 and operational amplifier OP2; a negative temperature coefficient current ICTAT generation circuit composed of M9, M10, R2, M24 and operational amplifier OP1; and a first-order bandgap reference generation circuit composed of PMOS transistors M4, M5, M11, NMOS transistor M25, and resistor R4.

[0034] The sources of M2, M3, M4, M5, M9, M10, and M11 are connected to the power supply voltage VDD. The gates of M2, M3, M4, and M5 are connected to the output of op-amp OP2 and to the gate of M1 in the startup circuit. The gates of M9, M10, and M11 are connected to the output of op-amp OP1 and to the gate of M8 in the startup circuit. The drain of M9 is connected to the non-inverting input of op-amp OP1, and the upper end of resistor R2 is connected to it. The drain of M10 is connected to the drain of M24. The source of M24 is connected to M24. The drain of M2 is connected to the non-inverting input of op-amp OP2, the inverting input of op-amp OP2, and the emitter of Q1; the drain of M3 is connected to the non-inverting input of op-amp OP2 and the upper end of resistor R3; the lower end of resistor R3 is connected to the emitter of Q2; the drain of M4 is connected to the source of M25 and the drain of M25; the drains of M11 and M5 are connected to the upper end of R4; the lower end of resistor R2, the source of M24, the collector of Q1, the collector of Q2, the drain of M25, and the lower end of R4 are connected to ground.

[0035] By injecting positive temperature coefficient current and negative temperature coefficient current into resistor R4 through a current mirror, the voltage across R4 at this time is the zero temperature coefficient voltage, and its expression is: ; ; ; In this module, the negative feedback coefficient is greater than the positive feedback coefficient, ensuring loop stability. Using the operational amplifier (AMP) clamp, and ignoring the AMP offset, the A / B voltage nodes are clamped equally. The ratio of I1 to I2 is determined by setting different resistor and current mirror ratios. If I1:I2 = 1:N; Q1:Q2 = M:1; when the two transistors operate at different current densities, then V... BE The difference is proportional to the absolute temperature, resulting in a positive temperature coefficient voltage Vptat, at which point ΔV BE The current falls across resistor R2, and neglecting the temperature coefficient of resistance, it generates a PTAT current: ; ; Where I1 and I2 are the currents of Q1 and Q2, respectively; I S1 I S2 Here are the saturation currents of Q1 and Q2; ΔV BE The collector voltage difference between Q1 and Q2 is given.

[0036] Furthermore, based on the first-order bandgap reference voltage, temperature coefficient compensation is performed separately in the low-temperature and high-temperature ranges using a segmented compensation circuit, including: Based on the temperature characteristic curve of the first-order bandgap reference voltage, the temperature range is divided into three sub-ranges: low temperature range, intermediate range, and high temperature range. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low temperature range, a positive temperature coefficient compensation current is generated in the low temperature range to counteract the negative temperature coefficient voltage trend. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature section, a negative temperature coefficient compensation current is generated in the high-temperature section to counteract the positive temperature coefficient voltage trend. Based on the relatively gentle temperature characteristics of the middle section, no compensation is performed in the middle section.

[0037] Furthermore, based on the magnitude relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low-temperature range, generating a positive temperature coefficient compensation current in the low-temperature range to offset the negative temperature coefficient voltage trend includes: The positive temperature coefficient current is copied to the first compensation branch according to the first current mirror ratio to obtain the first proportional positive temperature coefficient current. The negative temperature coefficient current is copied to the second compensation branch according to the second current mirror ratio to obtain the first proportional negative temperature coefficient current. Based on the comparison result of the first proportional positive temperature coefficient current and the first proportional negative temperature coefficient current at the low temperature compensation point, the first difference current is generated by the current calculation circuit. The first differential current is extracted to the compensation node according to the ratio of the third current mirror, and positive temperature coefficient compensation is achieved in the low temperature range.

[0038] Furthermore, based on the magnitude relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature range, generating a negative temperature coefficient compensation current in the high-temperature range to offset the positive temperature coefficient voltage trend includes: The negative temperature coefficient current is copied to the third compensation branch according to the fourth current mirror ratio to obtain the second proportional negative temperature coefficient current. The positive temperature coefficient current is copied to the fourth compensation branch according to the fifth current mirror ratio to obtain the second proportional positive temperature coefficient current. Based on the comparison result of the second proportional negative temperature coefficient current and the second proportional positive temperature coefficient current at the high temperature compensation point, a second differential current is generated by the current calculation circuit. The second differential current is extracted to the compensation node according to the sixth current mirror ratio, thereby achieving negative temperature coefficient compensation in the high-temperature range.

[0039] Specifically, this invention uses a segmented temperature compensation method based on the Eastern 180BCD process, considering only the first-order temperature term, to obtain V. REF It is a parabola opening upwards. The approach of this invention is to divide the uncompensated first-order reference voltage curve into three segments. In the first segment, the voltage exhibits a negative temperature coefficient as the temperature decreases. This is because at V... REF0 In the expression, the positive temperature coefficient is smaller than the negative temperature coefficient, which can compensate for the positive temperature coefficient current I in the circuit. PTAT The first segment of the curve is lowered to improve temperature stability in the low-temperature range; in the second temperature range, the reference voltage V... REF0 The temperature characteristic curve is relatively flat and does not require compensation. Within the third temperature range, the voltage increases with temperature, therefore the positive temperature coefficient term dominates in this range. Negative temperature coefficient current can be compensated in the circuit to lower the third temperature range curve. This method provides segmented compensation for the first-order output reference voltage curve, making the temperature drift coefficients of the three temperature ranges similar and improving the overall stability of the output reference voltage.

[0040] This invention employs two segmentation points for compensation. In other applications with higher requirements, more segmentation points can be used for compensation based on this fundamental principle. The generation and selection of segmentation points will now be explained.

[0041] The segmented compensation circuit in this invention comprises two parts: a compensation current calculation circuit and a current extraction circuit. As shown in the figure, M7, M14, M15, and M28 constitute a negative temperature coefficient current compensation circuit; M13, M16, M17, and M33 constitute a positive temperature coefficient current compensation circuit; and M26, M27, M28, M29, M30, M31, and M32 constitute a current extraction circuit.

[0042] PMOS transistors M7, M14, M15 and NMOS transistor M28 constitute a negative temperature coefficient current compensation circuit; PMOS transistors M13, M16, M17 and NMOS transistor M33 constitute a positive temperature coefficient current compensation circuit; PMOS transistors M26, NMOS transistors M27, M29, M30, M31 and M32 are current extraction circuits; PMOS transistors M6 and M12 and resistors R5 and R6 are compensation voltage generation circuits. The sources of M6, M7, M12, M13, M14, M15, M16, M17, and M26 are connected to the power supply voltage VDD; the gates of M6 and M7 are connected to the gate of M1 in the startup circuit; the gates of M12 and M13 are connected to the gate of M8 in the startup circuit; the drains of M6 and M12 are connected to the upper end of R5, the lower end of R5 is connected to the upper end of R6, and the drain of M29 is connected; the gates of M26, M27, M29, and M30 are connected to the drain of M26 and the drain of M27; the drain of M7 is connected to the drain of M14, the gates of M14 and M15, and the drain of M28. Connect the following: the drain of M13 is connected to the drain of M17, the gates of M16 and M17 are connected to the drain of M33; the drains of M15 and M16 are connected to the drain of M30; the source of M30 is connected to the drain of M32, and the gates of M31 and M32 are connected; the source of M29 is connected to the drain of M31, and the drain of M29 is connected to the lower end of resistor R5 and the upper end of resistor R6; the gate of M28 is connected to the gate of M24 in the core circuit; the gate of M33 is connected to the gate of M25 in the core circuit; the lower end of R6 and the sources of M27, M28, M31, M32, and M33 are connected to ground.

[0043] The segmentation point is determined by copying the positive temperature coefficient current IPTAT generated by the bandgap reference to the M7 via a current mirror: = ; By setting the replication current ratio a1 of the current mirror and calculating the negative temperature coefficient current mirrored by the lower M28, when I d7 The current is less than I D28 At this time, a portion of the current flows from M14 into M28. M15 mirrors the current on M14, flowing to ground through M30 and M32. Simultaneously, M29 and M31 draw a portion of the negative temperature coefficient current from the point to be compensated. When I... D7The current is greater than I D28 At that time, no current flows through M14, and the low-temperature compensation circuit does not work. Similarly, the high-temperature compensation circuit operates at I... CTAT Greater than I PTAT Not working, in I CTAT Less than I PTAT Then compensation begins. In the current-temperature coordinate system, two curves, one positive and one negative, can be seen compared to two points, where a1I... PTAT With b1I CTAT The intersection point is the first segmentation point, a2I CTAT with b2I PTAT The intersection point is the second segmentation point. In the first segment, this stage tends to generate a positive temperature coefficient current to offset a negative temperature coefficient voltage; in the second segment, this stage tends to generate a negative temperature coefficient current to offset a negative temperature coefficient voltage. Within both compensation ranges, only one type of current is compensated to the reference circuit, improving the accuracy of the compensation circuit.

[0044] Furthermore, the segmented compensation circuit determines the segmented compensation temperature point by setting different replication ratio coefficients of the current mirror, controls the magnitude of the compensation current by adjusting the compensation current ratio coefficient, and can be expanded to multiple segmented points for compensation according to accuracy requirements.

[0045] Figures 2-3 To compensate for current I TC The graph of I as a function of temperature T CTAT_TC For negative temperature coefficient compensation current, I PTAT_TC This is the positive temperature coefficient compensation current. I is calculated at the segment point temperature. PTAT and I CTAT According to Kirchhoff's Current Law, the leakage currents of M15 and M16 are respectively: ; ; In the formula, , , , , , All are current mirror replication ratios.

[0046] After derivation, the segmented temperature compensation current is: T≤T 1 ; T 1 ≤T≤T 2 ; T≥T 2 ; In the formula, T1 and T2 are two segmented temperature compensation points. K1 and K2 are the compensation current proportionality coefficients, which can be determined by the current mirror M. 29 M 30 The magnitude of the compensation current is controlled by the replication ratio. The reference output circuit after compensation by M6, R5, and R6 can be analyzed to obtain the temperature-compensated reference voltage V. REF The relation is: ; <T< ; ; In the formula, V REF0 The reference voltage output before compensation is given, T1 and T2 are the segmented compensation temperature points, and K1 and K2 are the compensation current proportional coefficients. , , , , , All are current mirror replication ratios.

[0047] Figure 4 The simulation results of the temperature drift curve of the bandgap reference circuit are shown. Vref is the compensated reference voltage value. The results show that the maximum value of the bandgap reference voltage is 1.08558V and the minimum value is 1.08381V within the temperature range of -55℃ to 125℃. According to the temperature drift calculation formula: ; The compensated bandgap reference temperature drift coefficient is 9.53 ppm.

[0048] Figure 5 A simulation was established for the transient bandgap reference. After 129µs, the bandgap reference voltage curve tended to flatten out, and the output reference voltage was 1.8043V, with the voltage curve remaining stable.

[0049] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A low-temperature drift, high-precision, segmented compensated bandgap reference circuit for information storage, characterized in that, include: Based on the power supply voltage, the bandgap reference core circuit is driven out of the degenerate state by the startup circuit and shut down after the bandgap reference core circuit is established to reduce power consumption. According to the bandgap reference core circuit, a first-order bandgap reference voltage is generated through a first-order bandgap reference core module. Based on the first-order bandgap reference voltage, temperature coefficient compensation is performed in the low-temperature and high-temperature ranges through a segmented compensation circuit to output a high-precision reference voltage with low temperature drift.

2. The low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 1, characterized in that, Based on the power supply voltage, the bandgap reference core circuit is driven out of its degenerate state by the startup circuit and then shut down after the bandgap reference core circuit is established to reduce power consumption, including: Based on the power supply voltage, a gate control voltage that rises with the power supply voltage is generated through a startup branch composed of a resistor and a transistor. According to the gate control voltage, the gate voltage of the current mirror in the bandgap reference core circuit is pulled down by the first transistor and the second transistor to start the current mirror to work normally. Based on the feedback voltage after the bandgap reference core circuit enters steady state, the gate-source voltage of the first and second transistors is pulled below the threshold voltage by the third transistor to shut down the startup circuit.

3. The low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 1, characterized in that, According to the aforementioned bandgap reference core circuit, generating a first-order bandgap reference voltage through a first-order bandgap reference core module includes: Based on the first and second node voltages clamped by the operational amplifier, a positive temperature coefficient current proportional to the absolute temperature is generated through a positive temperature coefficient current generation circuit. Based on the voltage of the first node, a negative temperature coefficient current that is inversely proportional to the absolute temperature is generated through a negative temperature coefficient current generating circuit. Based on the positive temperature coefficient current and the negative temperature coefficient current, the positive temperature coefficient current and the negative temperature coefficient current are injected into the same resistor through a current mirror to obtain the first-order bandgap reference voltage.

4. The low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 3, characterized in that, Generating a negative temperature coefficient current that is inversely proportional to absolute temperature through a negative temperature coefficient current generating circuit includes: Based on the condition that the first node voltage and the second node voltage of the operational amplifier clamp are equal, a base-emitter voltage difference is generated by the first bipolar transistor and the second bipolar transistor operating at different current densities. The positive temperature coefficient current is obtained based on the base-emitter voltage difference falling across the first resistor.

5. A low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 4, characterized in that, Based on the first-order bandgap reference voltage, temperature coefficient compensation is performed separately in the low-temperature and high-temperature ranges using a segmented compensation circuit, including: Based on the temperature characteristic curve of the first-order bandgap reference voltage, the temperature range is divided into three sub-ranges: low temperature range, intermediate range, and high temperature range. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low temperature range, a positive temperature coefficient compensation current is generated in the low temperature range to counteract the negative temperature coefficient voltage trend. Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature section, a negative temperature coefficient compensation current is generated in the high-temperature section to counteract the positive temperature coefficient voltage trend. Based on the relatively gentle temperature characteristics of the middle section, no compensation is performed in the middle section.

6. A low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 5, characterized in that, Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the low-temperature range, generating a positive temperature coefficient compensation current in the low-temperature range to counteract the trend of negative temperature coefficient voltage includes: The positive temperature coefficient current is copied to the first compensation branch according to the first current mirror ratio to obtain the first proportional positive temperature coefficient current. The negative temperature coefficient current is copied to the second compensation branch according to the second current mirror ratio to obtain the first proportional negative temperature coefficient current. Based on the comparison result of the first proportional positive temperature coefficient current and the first proportional negative temperature coefficient current at the low temperature compensation point, the first difference current is generated by the current calculation circuit. The first differential current is extracted to the compensation node according to the ratio of the third current mirror, and positive temperature coefficient compensation is achieved in the low temperature range.

7. A low-temperature drift, high-precision segmented compensation bandgap reference circuit for information storage according to claim 6, characterized in that, Based on the relationship between the positive temperature coefficient current and the negative temperature coefficient current at the compensation point in the high-temperature range, the trend of generating a negative temperature coefficient compensation current to offset the positive temperature coefficient voltage in the high-temperature range includes: The negative temperature coefficient current is copied to the third compensation branch according to the fourth current mirror ratio to obtain the second proportional negative temperature coefficient current. The positive temperature coefficient current is copied to the fourth compensation branch according to the fifth current mirror ratio to obtain the second proportional positive temperature coefficient current. Based on the comparison result of the second proportional negative temperature coefficient current and the second proportional positive temperature coefficient current at the high temperature compensation point, a second differential current is generated by the current calculation circuit. The second differential current is extracted to the compensation node according to the sixth current mirror ratio, thereby achieving negative temperature coefficient compensation in the high-temperature range.

8. The bandgap reference circuit according to any one of claims 1 to 7, characterized in that, The segmented compensation circuit determines the segmented compensation temperature point by setting different replication ratio coefficients of the current mirror, controls the magnitude of the compensation current by adjusting the compensation current ratio coefficient, and can be expanded to multiple segmented points for compensation according to accuracy requirements.

Images