Band-gap reference voltage source with high driving capability, low noise and low temperature drift coefficient

Abstract

The invention discloses a band-gap reference voltage source with high driving capability, low noise and low temperature drift coefficient, and belongs to the technical field of analog integrated circuits. The band-gap reference voltage source comprises a band-gap core circuit, a segmented curvature compensation circuit and an in-loop output driving stage, and the band-gap core circuit is used for generating CTAT voltage and PTAT voltage to form first-order band-gap reference voltage; the segmented curvature compensation circuit is used for performing temperature segmented compensation on the curvature of the first-order band-gap reference voltage to obtain a compensation voltage, and calibrating the band-gap reference voltage according to the first-order band-gap reference voltage and the compensation voltage; and the output driving stage in the loop is used for realizing direct load current driving capability. According to the band-gap reference voltage source, low imbalance and low noise can be achieved, dynamic noise reduction is not needed, reliability is high, and the band-gap reference voltage source has high driving capacity and a low-temperature drift coefficient.

Description

Technical Field

[0001] This invention belongs to the field of analog integrated circuit technology, and particularly relates to a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source. Background Technology

[0002] The bandgap reference voltage source is the core module of analog integrated circuits and needs to provide a high-precision, low-noise reference voltage for ADC (Analog-to-Digital Converter). Existing technical solutions include: (1) First-order Brokaw structure: First-order temperature drift compensation is achieved by superimposing PTAT (Proportional To Absolute Temperature) and CTAT (Complementary To Absolute Temperature) voltages, but the driving capability is limited, requiring an external buffer, increasing power consumption and area. For example, the static current of LDO (low dropout regulator) is >100μA, and the temperature drift coefficient is large. (2) Chopper stabilization technology: Reduces noise but requires a clock signal, introduces ripple, and has poor reliability in extreme environments. (3) High-order temperature compensation technology: In view of the problem that the flicker noise and offset voltage of the input pair tubes of CMOS (Complementary Metal Oxide Semiconductor) op-amp affect the accuracy, the temperature drift coefficient (TC) is difficult to meet the requirements of high-precision ADC (<10 ppm / °C). There are existing high-order compensation schemes, but they have high requirements for process characteristics and stability, or large residual error of second curvature (2–4mV), and the compensation circuit is too complicated. Summary of the Invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source to address the shortcomings of the prior art.

[0004] To address the aforementioned technical problems, this invention discloses a high-driving-capability, low-noise, low-temperature-drift bandgap reference voltage source, comprising a bandgap core circuit, a segmented curvature compensation circuit, and an output drive stage within the loop.

[0005] The bandgap core circuit is used to generate CTAT voltage and PTAT voltage to form a first-order bandgap reference voltage.

[0006] The segmented curvature compensation circuit is used to perform temperature segmented compensation on the curvature of the first-order bandgap reference voltage to obtain a compensation voltage, and to calibrate the bandgap reference voltage based on the first-order bandgap reference voltage and the compensation voltage.

[0007] The output drive stage within the loop is used to achieve direct load current drive capability.

[0008] Furthermore, the bandgap core circuit includes a Brokaw structure, a first MOS transistor M1, and a Miller compensation capacitor C. C Compensation resistor R comp The Brokaw structure includes a pair of bipolar transistors, a first load resistor connected to the collectors of the pair of bipolar transistors, a resistor network connected to the emitters of the pair of bipolar transistors, and a low-offset voltage operational amplifier. The bases of the pair of bipolar transistors are connected together. The input of the low-offset voltage operational amplifier is connected to the collectors of the pair of bipolar transistors, and the output is connected to the gate of a first MOS transistor M1. The source of the first MOS transistor M1 is connected to the power supply voltage VDD, and the drain is connected to the compensation resistor R. comp The connection point outputs a bandgap reference voltage, and a Miller compensation capacitor C is connected between the gate and drain. C The first MOS transistor M1 is also connected to the output driver stage within the loop; compensation resistor R comp The base of the pair of bipolar transistors, the segmented curvature compensation circuit, and the resistor divider R4 are connected respectively.

[0009] Furthermore, the output drive stage within the loop includes a cascaded low-gain common-source stage and one or more third MOS transistors M3. The cascaded low-gain common-source stage includes a second MOS transistor M2, a fourth MOS transistor M4, a fifth load resistor R5, and a sixth load resistor R6. The gate of the second MOS transistor M2 is connected to the output terminal of the low-offset voltage operational amplifier, its source is connected to the power supply voltage VDD, and its drain is connected to the fifth load resistor R5 and the gate of the fourth MOS transistor M4, respectively. The fifth load resistor R5 is grounded. The drain of the fourth MOS transistor M4 is connected to the sixth load resistor R6 and the gate of the third MOS transistor M3, respectively. The source of the fourth MOS transistor M4 is grounded, and the sixth load resistor R6 is connected to the power supply voltage VDD. The source of the third MOS transistor M3 is connected to the power supply voltage VDD, and its drain is connected to the drain of the first MOS transistor M1.

[0010] Furthermore, the number of the third MOS transistors M3 is set according to the load current driving capability.

[0011] Furthermore, a load capacitor C is connected at the connection point between the drain of the third MOS transistor M3 and the drain of the first MOS transistor M1 (the output bandgap reference voltage node). L Depending on the actual application, you can choose to connect or not connect a load capacitor.

[0012] Furthermore, the low offset voltage operational amplifier includes an input pair of transistors and a cascode structure. The input pair uses NPN (Negative-Positive-Negative) bipolar transistors. The cascode structure includes a current mirror load transistor, a source negative feedback resistor, and a cascode transistor connected to the current mirror load transistor. The source of the current mirror load transistor is connected to the source negative feedback resistor, and the collector of the input pair is connected to the drain of the current mirror load transistor. The NPN bipolar transistor input pair and source negative feedback resistor enable low noise (0.93 μVrms) and low offset (<500 μV).

[0013] Furthermore, the first-order bandgap reference voltage is divided into N temperature-segmented reference voltages by the resistor divider R4 in the output stage. Each temperature segment's reference voltage and PTAT voltage's temperature domain intersection point corresponds to a compensation temperature range segment point temperature T. i Forming a temperature range T L and T H These represent the lowest and highest temperature thresholds at the segment points of the compensation temperature range, respectively. The segmented curvature compensation circuit obtains a compensation current for each temperature segment of the temperature domain, and the compensation currents in different temperature domains are added together and then injected into the compensation resistor R. comp A compensation voltage is superimposed on a first-order bandgap reference voltage to compensate for the curvature voltage, with the curvature voltage defined by a reference temperature T. r As a boundary, when the temperature is less than the reference temperature T r The time increases as the temperature decreases; when the temperature is above the reference temperature T... r The time increases with increasing temperature, exhibiting the characteristics of a quadratic parabola over the temperature range.

[0014] Furthermore, the segmented curvature compensation circuit includes a high-temperature compensation current unit and a low-temperature compensation current unit. The high-temperature compensation current unit is used to compensate for current at the segmented point temperature T within the compensation temperature range. i Greater than the reference temperature T r At that time, the compensation current I is obtained. compTi The low-temperature compensation current unit is used to compensate for current at the segment point temperature T of the compensation temperature range. i Less than reference temperature T r At that time, the compensation current I is obtained. compTi .

[0015] Furthermore, the low-temperature compensation current unit includes a voltage comparison subunit and a current subtraction subunit. The voltage comparison subunit is used to input the temperature segmented reference voltage V respectively. TiThe voltage is compared with the PTAT voltage, and the comparison current I is output. N with I P The current subtraction subunit is used to input the comparison current I respectively. N with I P Subtracting the two yields the compensation current I in different temperature ranges. compTi Compensation current I in different temperature ranges compTi After addition, and the compensation resistor R comp The compensation voltage is obtained by multiplying the two voltages; the first-order bandgap reference voltage is added to the compensation voltage to obtain the compensated bandgap reference voltage.

[0016] Furthermore, the high-temperature compensation current unit structure is the same as the low-temperature compensation current unit structure. The input of the voltage comparison subunit in the high-temperature compensation current unit is relative to the input of the voltage comparison subunit in the low-temperature compensation current unit, where the temperature-segmented reference voltage V is... Ti Swap positions with PTAT voltage.

[0017] Beneficial effects:

[0018] 1. Static low noise: Static operating mode, no clock dependence, low offset (<500μV) and low noise (0.93μVrms) are achieved through BJT-MOS hybrid op-amp, no dynamic noise reduction is required, and high reliability is achieved.

[0019] 2. High drive capability: Integrated output stage in the loop directly provides 20mA current without the need for a buffer, optimizing power consumption and area, and saving buffer power consumption (quiescent current 95μA).

[0020] 3. Low temperature drift coefficient and high process consistency: segmented curvature compensation technology, error after single-point calibration ±0.2% (3σ), temperature drift 6.5 ppm / °C (-40°C–125°C).

[0021] 4. Process compatibility: 130nm CMOS process, area 0.32mm². Attached Figure Description

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0023] Figure 1 This is a schematic diagram of a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source provided in an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of a low-offset operational amplifier in a high-drive-capability, low-noise, low-temperature-drift bandgap reference voltage source provided in an embodiment of this application.

[0025] Figure 3 This is a schematic diagram of Monte Carlo simulation results for a low-offset operational amplifier in a high-drive-capability, low-noise, low-temperature-drift bandgap reference voltage source provided in this application embodiment.

[0026] Figure 4 This is a schematic diagram of a segmented curvature compensation circuit in a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source provided in an embodiment of this application.

[0027] Figure 5 This is a schematic diagram showing the temperature variations of PTAT voltage, compensation current, and first-order bandgap reference voltage in a high-driving-capacity, low-noise, low-temperature drift coefficient bandgap reference voltage source provided in this application embodiment. Detailed Implementation

[0028] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0029] This application provides a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source that can be applied to ADCs to provide high-precision, low-noise reference voltages for ADCs.

[0030] like Figure 1 As shown in the figure, this application discloses a high-driving-capability, low-noise, low-temperature-drift bandgap reference voltage source, including a bandgap core circuit, a segmented curvature compensation circuit, and an output drive stage within the loop.

[0031] The bandgap core circuit is used to generate CTAT voltage and PTAT voltage to form a first-order bandgap reference voltage.

[0032] The segmented curvature compensation circuit is used to perform temperature segmented compensation on the curvature of the first-order bandgap reference voltage to obtain a compensation voltage, and to calibrate the bandgap reference voltage based on the first-order bandgap reference voltage and the compensation voltage.

[0033] The output drive stage within the loop is used to achieve direct load current drive capability.

[0034] In this embodiment, the bandgap core circuit includes a Brokaw structure, a first MOS transistor M1, and a Miller compensation capacitor C. C Compensation resistor R compThe Brokaw structure includes a pair of bipolar transistors, a first load resistor connected to the collectors of the pair of bipolar transistors, a resistor network connected to the emitters of the pair of bipolar transistors, and a low-offset voltage operational amplifier. The bases of the pair of bipolar transistors are connected together. The input of the low-offset voltage operational amplifier is connected to the collectors of the pair of bipolar transistors, and the output is connected to the gate of a first MOS transistor M1. The source of the first MOS transistor M1 is connected to the power supply voltage VDD, and the drain is connected to the compensation resistor R. comp The connection point outputs a bandgap reference voltage, and a Miller compensation capacitor C is connected between the gate and drain. C The first MOS transistor M1 is also connected to the output driver stage within the loop; compensation resistor R comp The base of the pair of bipolar transistors, the segmented curvature compensation circuit, and the resistor divider R4 are connected respectively.

[0035] The pair of bipolar transistors includes a first bipolar transistor Q1 and a second bipolar transistor Q2. The collectors of the first bipolar transistor Q1 and the second bipolar transistor Q2 are respectively connected to a first load resistor R3. The collector of the first bipolar transistor Q1 is connected to the positive terminal of the input of the low-offset voltage operational amplifier A1, and the collector of the second bipolar transistor Q2 is connected to the negative terminal of the input of the low-offset voltage operational amplifier A1. The resistor network includes a first resistor R1 and a second resistor R2. The emitter of the first bipolar transistor Q1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to the emitter of the second bipolar transistor Q2. The connection point is connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded. The bases of the first bipolar transistor Q1 and the bases of the second bipolar transistor Q2 are connected to generate a first-order bandgap reference voltage V. REF0 In the specific implementation, the ratio of the number of Q1 to Q2 is M, which is set according to the ratio of the first resistor R1 and the second resistor R2, requiring the PTAT voltage... With CTAT voltage V BE The first-order curvature cancels each other out.

[0036] The bandgap core circuit of the Brokaw structure uses the CTAT voltage V generated by a bipolar junction transistor (BJT) operating at the same collector current. BE With PTAT voltage The two voltages are added together to form a first-order bandgap reference voltage V. REF0 V REF0 The curvature is compensated for temperature using a segmented curvature compensation circuit to form the output bandgap reference voltage V. REF .

[0037] Under the Brokaw structure, the first-order bandgap reference voltage V REF0 The high-impedance node gives its output stage (the branch containing the first MOS transistor M1) a natural level-shifting capability; simultaneously, the output node (V) of the Brokaw structure... REF The node has a certain current-driving capability. The Brokaw loop also has the capability to handle the op-amp offset voltage V reflected in the output. OS The suppression capability is affected by the offset voltage V introduced by the op-amp. OS The effect is limited to the collectors of the first bipolar transistor Q1 and the second bipolar transistor Q2; the change in collector voltage has only an Earliest effect on the collector current. This is reflected in the first-order bandgap reference voltage V. REF0 of The loop reflects the output offset voltage V. REF,os It has approximately 5 times the inhibitory effect.

[0038] In this embodiment, without introducing an offset voltage V OS To achieve strong drive capability in this situation, an in-loop output driver stage is considered. The traditional Brokaw structure has a certain drive capability. However, in this case, all load current needs to be supplied by the source-drain current of the first MOS transistor M1. Provided. When driving a large load current (mA level current), the first MOS transistor M1 may enter the linear region, at which point the loop gain decreases, and the bandgap reference voltage V... REF It will also reduce At the output bandgap reference voltage V REF This leads to large errors. Even if the first MOS transistor M1 is not in the linear region, the gate-source voltage of the first MOS transistor M1 will vary due to the need to provide different load currents. This will change because of the limited gain of the low offset voltage operational amplifier A1. Figure 1 In the circuit shown, the voltage difference between points A and B will change slightly, thus affecting the bandgap reference voltage V. REF The value.

[0039] Ensure relatively constant loop gain and bandgap reference voltage V REF The core of this value lies in ensuring that the operating environment of the first MOS transistor M1 remains stable under both high load current and no load current conditions, that is, the current flowing through M1... The drain-source voltage of the first MOS transistor M1 remains relatively constant. This ensures relative constancy. Simultaneously, the transconductance with the first MOS transistor M1... The relevant loop gain and PSR (Power Supply Rejection) can also remain relatively constant.

[0040] To address this issue, this embodiment proposes an in-loop output driver stage that achieves high load current driving capability without introducing additional offset voltage. The in-loop output driver stage includes a cascaded low-gain common-source stage and one or more third MOS transistors M3. The cascaded low-gain common-source stage includes a second MOS transistor M2, a fourth MOS transistor M4, a fifth load resistor R5, and a sixth load resistor R6. The gate of the second MOS transistor M2 is connected to the output of a low-offset voltage operational amplifier A1, its source is connected to the power supply voltage VDD, and its drain is connected to both the fifth load resistor R5 and the gate of the fourth MOS transistor M4. The fifth load resistor R5 is grounded. The drain of the fourth MOS transistor M4 is connected to both the sixth load resistor R6 and the gate of the third MOS transistor M3. The source of the fourth MOS transistor M4 is grounded, and the sixth load resistor R6 is connected to the power supply voltage VDD. The source of the third MOS transistor M3 is connected to the power supply voltage VDD, and its drain is connected to the drain of a first MOS transistor M1.

[0041] It consists of a cascaded low-gain common-source stage (second MOS transistor M2 - fifth load resistor R5, fourth MOS transistor M4 - sixth load resistor R6) and a third MOS transistor M3 (PMOS load transistor) that directly outputs the drive current. In this output drive stage structure, the high current portion is directly provided by the third MOS transistor M3, while the drain-source current of the first MOS transistor M1 in the loop is... It remains essentially constant. The voltage gain of the cascaded low-gain common-source stage is... ,in and These represent the transconductance of the second MOS transistor M2 and the transconductance of the fourth MOS transistor M4, respectively. Due to the gain... Under the condition of driving the same load current, the drain-source voltage of the first MOS transistor M1 is... The change compared to the drain-source voltage of the third MOS transistor M3 Reduced The drain-source voltage of the first MOS transistor M1 is times that of the first MOS transistor M1. The stability of the first MOS transistor M1 can guarantee its transconductance. and This ensures the stability of the loop gain, the PSR, and the output bandgap reference voltage V. REF Stability.

[0042] The number K of the third MOS transistors M3 is set according to the load current driving capability. The driving capability of the output node is positively correlated with the number K of the third MOS transistors M3. Under the same process conditions, the larger the number K of the third MOS transistors M3, the stronger the driving capability of the output node within a certain range.

[0043] In the application scenario of the chip, an external 1kF load capacitor C was designed. L With no external load capacitor C L This is one of the options. Depending on the application scenario, when high output noise requirements are needed, an external load capacitor C can be connected at the connection point between the drain of the third MOS transistor M3 and the drain of the first MOS transistor M1. L When output noise requirements are not high, an external load capacitor C is not necessary. L Without connecting the load capacitor C L At that time, the gate and drain of the first MOS transistor M1 in the circuit were directly connected to the Miller compensation capacitor C. C Without an external 1µF load capacitor, the dominant pole is designed at the internal node C. With an external 1µF load capacitor, the dominant pole is designed at the output bandgap reference voltage V. REF Node. In the worst case, simulation results show that its phase margin is no less than 49 degrees.

[0044] The loop has a certain tolerance for op-amp offset voltage, but the op-amp's own error voltage also needs to be less than 1mV to ensure it doesn't become a major source of error. To address this issue, such as... Figure 2 As shown, the low offset voltage operational amplifier A1 in this embodiment uses a hybrid cascode operational amplifier. The low offset voltage operational amplifier includes an input pair and a cascode structure. The input pair uses NPN bipolar transistors. The cascode structure includes a current mirror load transistor, a source negative feedback resistor, and a cascode transistor connected to the current mirror load transistor. The source of the current mirror load transistor is connected to the source negative feedback resistor, and the collector of the input pair is connected to the drain of the current mirror load transistor.

[0045] Specifically, the input transistor pair includes a third bipolar transistor Q3 and a fourth bipolar transistor Q4; the current mirror load transistor includes a first PMOS transistor M5, a second PMOS transistor M6, a first NMOS transistor M7, and a second NMOS transistor M8; and the common-source cascode transistor includes a third PMOS transistor M... 51 The fourth PMOS transistor M 61 The third NMOS transistor M 71 and the fourth NMOS transistor M 81 The source negative feedback resistor includes a first negative feedback resistor R.7a Second negative feedback resistor R 7b The third negative feedback resistor R 8a and the fourth negative feedback resistor R 8b ,

[0046] The base (INP) of the third bipolar transistor Q3 is connected to the collector of the first bipolar transistor Q1, the emitter is grounded, and the collector is connected to the drain of the first PMOS transistor M5; the base (INN) of the fourth bipolar transistor Q4 is connected to the collector of the second bipolar transistor Q2, the emitter is grounded, and the collector is connected to the drain of the second PMOS transistor M6.

[0047] First PMOS transistor M5 and third PMOS transistor M 51 Cascaded, second PMOS transistor M6 and fourth PMOS transistor M 61 Cascaded; the gate of the first PMOS transistor M5 and the gate of the second PMOS transistor M6 are connected, and their sources are respectively connected to the first negative feedback resistor R. 7a One end and the second negative feedback resistor R 7b One end; the first negative feedback resistor R 7a The other end and the second negative feedback resistor R 7b The other end is connected to the power supply voltage; the third PMOS transistor M 51 The gate and the fourth PMOS transistor M 61 The gates of the two transistors are connected, and their drains are respectively connected to the third NMOS transistor M. 71 The drain and the fourth NMOS transistor M 81 The drain electrode.

[0048] The first NMOS transistor M7 and the third NMOS transistor M 71 Cascaded, the second NMOS transistor M8 and the fourth NMOS transistor M 81 Cascading; the gate of the first NMOS transistor M7 is connected to the gate of the second NMOS transistor M8, and the connection point is connected to the third PMOS transistor M... 51 Drain and third NMOS transistor M 71 The drain connection is made; the source of the first NMOS transistor M7 and the source of the second NMOS transistor M8 are respectively connected to the third negative feedback resistor R. 8a One end and the fourth negative feedback resistor R 8b One end, the third negative feedback resistor R 8a The other end and the fourth negative feedback resistor R 8b The other end is grounded. The third NMOS transistor M... 71 The gate and the fourth NMOS transistor M 81 The gate connection of the fourth PMOS transistor M61 The drain and the fourth NMOS transistor M 81 The drain connection is the output OUT of the low offset voltage operational amplifier A1.

[0049] Due to the excellent matching characteristics and low flicker noise of the bipolar transistor, the offset voltage of the low offset voltage operational amplifier A1 is... And low-frequency flicker noise is significantly reduced.

[0050] However, due to the limited current gain of BJTs (the ratio of collector current to emitter current), The base leakage current of NPNs is not negligible. However, because the two branches of Brokaw's bandgap core are strictly symmetrical, the base current flows symmetrically through the two branches of the first load resistor R3. This only causes a symmetrical current shift in the collector currents of the two main bipolar transistors Q1 and Q2 in the bandgap core (at this time, the currents in the two branches are still strictly equal), and does not affect the output bandgap reference voltage V. REF A significant change in value.

[0051] The low offset operational amplifier uses a BJT-MOS hybrid structure, replacing the differential input pair transistors with BJT transistors to achieve low offset voltage.

[0052] To further reduce the offset and flicker noise introduced by the current mirror load transistors M5-M8 in the operational amplifier, source negative feedback resistors R7-R8 were added to the source of the current mirror load transistors. After adding the source negative feedback resistors, the low-frequency noise of the circuit was significantly reduced. The Cadence simulation results show that the noise contribution (@1Hz) of the current mirror transistors M5-M8 was reduced from 41% to 23%.

[0053] Figure 3 The results of Monte Carlo simulations of the low-offset operational amplifier are shown in Figure 3. Within this range, the offset voltage contributed by the low-offset operational amplifier is no greater than [value missing]. 500kV, converted to output, Not greater than 100kV, It represents the standard deviation of the sample.

[0054] First-order V REF The temperature coefficient can be offset by the PTAT voltage, but the remaining second-order or higher curvature remains. In the 130nm process, the magnitude of the residual second-order curvature is approximately 2mV~4mV. Due to the presence of this residual curvature, the design requirement of less than 10ppm / °C is not met. To address this issue, such as... Figure 4As shown, this embodiment proposes a high-order segmented curvature compensation circuit that can achieve a low temperature drift of 6.5 ppm / °C on average.

[0055] The first-order bandgap reference voltage is divided into N temperature-segmented reference voltages by the resistor divider R4 at the output stage. The reference voltage and PTAT voltage V for each temperature segment PTAT The intersection of the temperature domains corresponds to a segment point temperature T of a compensated temperature range. i Forming a temperature range T L and T H These represent the lowest and highest temperature thresholds at the segment points of the compensation temperature range, respectively. The segmented curvature compensation circuit obtains a compensation current for each temperature segment of the temperature domain, and the compensation currents in different temperature domains are added together and then injected into the compensation resistor R. comp A compensation voltage is superimposed on a first-order bandgap reference voltage to compensate for the curvature voltage, with the curvature voltage defined by a reference temperature T. r As a boundary, when the temperature is less than the reference temperature T r The time increases as the temperature decreases; when the temperature is above the reference temperature T... r The time increases with increasing temperature, exhibiting the characteristics of a quadratic parabola over the temperature range.

[0056] The segmented curvature compensation circuit includes a high-temperature compensation current unit and a low-temperature compensation current unit. The high-temperature compensation current unit is used to compensate for current at the segmented point temperature T within the compensation temperature range. i Greater than the reference temperature T r At that time, the compensation current I is obtained. compTi The low-temperature compensation current unit is used to compensate for current at the segment point temperature T of the compensation temperature range. i Less than reference temperature T r At that time, the compensation current I is obtained. compTi .

[0057] The low-temperature compensation current unit includes a voltage comparison subunit and a current subtraction subunit. The voltage comparison subunit is used to input the temperature segmented reference voltage V respectively. Ti The voltage is compared with the PTAT voltage, and the comparison current I is output. N with I P The current subtraction subunit is used to input the comparison current I respectively. N with I P Subtracting the two yields the compensation current I in different temperature ranges. compTi Compensation current I in different temperature ranges compTi After addition, and the compensation resistor R compThe compensation voltage is obtained by multiplying the two voltages; the first-order bandgap reference voltage is added to the compensation voltage to obtain the compensated bandgap reference voltage.

[0058] Specifically, the voltage comparator subunit includes a fifth PMOS transistor M9 and a sixth PMOS transistor M... 10 The source of the fifth PMOS transistor M9 and the sixth PMOS transistor M 10 The sources of all transistors are connected to the compensation current source I1, and the gate input temperature segmented reference voltage V of the fifth PMOS transistor M9 is... Ti The sixth PMOS transistor M 10 The gate input PTAT voltage;

[0059] The current subtraction subunit includes a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor, and an eighth NMOS transistor, with the sources of all four NMOS transistors grounded. The gate of the fifth NMOS transistor is connected to the gate of the sixth NMOS transistor, the drain of the fifth NMOS transistor is connected to the drain of the fifth PMOS transistor, and the drain and gate of the fifth NMOS transistor are connected. The gate of the seventh NMOS transistor is connected to the gate of the eighth NMOS transistor, and the gate and drain of the seventh NMOS transistor are connected. The drain of the sixth NMOS transistor is connected to the drain of the seventh NMOS transistor, and the connection point is connected to the sixth PMOS transistor M. 10 The drain connection of the eighth NMOS transistor is the first-order bandgap reference voltage V. REF0 .

[0060] The high-temperature compensation current unit structure is the same as the low-temperature compensation current unit structure. The input of the voltage comparison subunit in the high-temperature compensation current unit is relative to the input of the voltage comparison subunit in the low-temperature compensation current unit. The temperature segmented reference voltage V Ti Swap positions with PTAT voltage.

[0061] In the specific implementation process, assuming N=4, the resistor divider R4 includes a first voltage divider resistor R 4a Second voltage divider resistor R 4b Third voltage divider resistor R 4c Fourth voltage divider resistor R 4d and the fifth voltage divider resistor R 4e Uncompensated bandgap reference output V REF0 At the output stage, the voltage is divided to V by the resistor divider R4. T1 V T2 V T3 V T4 The voltage V Ti(i=1,2,3,4) With PTAT voltage In comparison, the temperature range is divided into five intervals. In each temperature range, the compensation current I comp Injection compensation resistor R comp Forming a compensation voltage superimposed on V REF0 The curvature voltage is compensated.

[0062] like Figure 5 As shown, the curvature voltage is relative to the reference temperature T. r As a boundary, when the temperature is less than the reference temperature T r The time increases as the temperature decreases; when the temperature is above the reference temperature T... r The voltage increases with increasing temperature, exhibiting a quadratic parabolic characteristic over the temperature domain. To compensate for the curvature voltage, a compensation current I is required. compTi The compensation at low temperatures (< T2) increases as the temperature decreases; while the compensation at high temperatures (> T3) increases as the temperature increases. This is achieved through a high and low temperature compensation current unit.

[0063] During low-temperature compensation, the voltage V T1 With V T2 respectively with V PTAT For comparison, since V at this time T1 With V T2 Less than V PTAT , so I N Less than I P I P with I N It is fed into the current subtraction subunit, and because at lower temperatures, V PTAT With V T The greater the voltage difference between them, the more I compT1 I compT2 It increases slowly as the temperature decreases.

[0064] During high-temperature compensation, the voltage V T3 With V T4 respectively with V PTAT For comparison, since V at this time T3 With V T4 Greater than V PTAT Furthermore, when the voltage comparator is fed into the voltage comparator subunit, the positive and negative positions of the two are swapped relative to the low-temperature compensation, therefore I N Less than I P I compT3 I compT4 It is produced in the same way as at low temperatures, and because V increases at higher temperatures... PTAT With V T The greater the voltage difference between them, the more I compT3 I compT4The voltage increases with increasing temperature. The temperature discontinuity is defined by the resistor voltage division ratio, ensuring process stability. Since the PTAT voltage changes continuously with temperature, there are no sudden voltage jumps at the discontinuity. The compensation current source I1 is generated by an on-chip constant transconductance (Const-Gm) circuit and drops across the compensation resistor R. comp A compensation voltage V is formed on top comp The voltage is converted into current through resistors R and R in the on-chip constant transconductance circuit. comp Using the same type of resistors (polysilicon resistors), and in fact, all on-chip resistors are polysilicon resistors, can offset process variations in the resistors. This further reduces process variations and maintains the output V. REF Good process stability.

[0065] This invention provides a high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A high-driving-capability, low-noise, low-temperature-drift bandgap reference voltage source, characterized in that, Includes a bandgap core circuit, a segmented curvature compensation circuit, and an output drive stage within the loop. The bandgap core circuit is used to generate CTAT voltage and PTAT voltage to form a first-order bandgap reference voltage. The segmented curvature compensation circuit is used to perform temperature segmented compensation on the curvature of the first-order bandgap reference voltage to obtain a compensation voltage, and to calibrate the bandgap reference voltage based on the first-order bandgap reference voltage and the compensation voltage. The output drive stage within the loop is used to achieve direct load current drive capability.

2. The high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 1, characterized in that, The bandgap core circuit includes a Brokaw structure, a first MOS transistor M1, and a Miller compensation capacitor C. C Compensation resistor R comp The Brokaw structure includes a pair of bipolar transistors, a first load resistor connected to the collectors of the pair of bipolar transistors, a resistor network connected to the emitters of the pair of bipolar transistors, and a low-offset voltage operational amplifier. The bases of the pair of bipolar transistors are connected together. The input of the low-offset voltage operational amplifier is connected to the collectors of the pair of bipolar transistors, and the output is connected to the gate of a first MOS transistor M1. The source of the first MOS transistor M1 is connected to the power supply voltage VDD, and the drain is connected to the compensation resistor R. comp The connection point outputs a bandgap reference voltage, and a Miller compensation capacitor C is connected between the gate and drain. C The first MOS transistor M1 is also connected to the output driver stage within the loop; compensation resistor R comp The base of the pair of bipolar transistors, the segmented curvature compensation circuit, and the resistor divider R4 are connected respectively.

3. The high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 2, characterized in that, The output drive stage within the loop includes a cascaded low-gain common-source stage and one or more third MOS transistors M3. The cascaded low-gain common-source stage includes a second MOS transistor M2, a fourth MOS transistor M4, a fifth load resistor R5, and a sixth load resistor R6. The gate of the second MOS transistor M2 is connected to the output terminal of the low-offset voltage operational amplifier, its source is connected to the power supply voltage VDD, and its drain is connected to the fifth load resistor R5 and the gate of the fourth MOS transistor M4, respectively. The fifth load resistor R5 is grounded. The drain of the fourth MOS transistor M4 is connected to the sixth load resistor R6 and the gate of the third MOS transistor M3, respectively. The source of the fourth MOS transistor M4 is grounded, and the sixth load resistor R6 is connected to the power supply voltage VDD. The source of the third MOS transistor M3 is connected to the power supply voltage VDD, and its drain is connected to the drain of the first MOS transistor M1.

4. The high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 3, characterized in that, The number of the third MOS transistors M3 is set according to the load current driving capability.

5. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 4, characterized in that, A load capacitor C is also connected at the connection point between the drain of the third MOS transistor M3 and the drain of the first MOS transistor M1. L .

6. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 3, characterized in that, The low offset voltage operational amplifier includes an input pair of transistors and a common-source cascode structure. The input pair of transistors uses NPN bipolar transistors. The common-source cascode structure includes a current mirror load transistor, a source negative feedback resistor, and a common-source cascode transistor connected to the current mirror load transistor. The source of the current mirror load transistor is connected to the source negative feedback resistor, and the collector of the input pair of transistors is connected to the drain of the current mirror load transistor.

7. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 6, characterized in that, The first-order bandgap reference voltage is divided into N temperature-segmented reference voltages by the resistor divider R4 at the output stage. Each temperature segment's reference voltage and PTAT voltage's temperature domain intersection point corresponds to a compensation temperature range segment point temperature T. i Forming a temperature range T L and T H These represent the lowest and highest temperature thresholds at the segment points of the compensation temperature range, respectively. The segmented curvature compensation circuit obtains a compensation current for each temperature segment of the temperature domain, and the compensation currents in different temperature domains are added together and then injected into the compensation resistor R. comp A compensation voltage is superimposed on a first-order bandgap reference voltage to compensate for the curvature voltage, with the curvature voltage defined by a reference temperature T. r As a boundary, when the temperature is less than the reference temperature T r The time increases as the temperature decreases; when the temperature is above the reference temperature T... r The time increases with increasing temperature, exhibiting the characteristics of a quadratic parabola over the temperature range.

8. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 7, characterized in that, The segmented curvature compensation circuit includes a high-temperature compensation current unit and a low-temperature compensation current unit. The high-temperature compensation current unit is used to compensate for current at the segmented point temperature T within the compensation temperature range. i Greater than the reference temperature T r At that time, the compensation current I is obtained. compTi The low-temperature compensation current unit is used to compensate for current at the segment point temperature T of the compensation temperature range. i Less than reference temperature T r At that time, the compensation current I is obtained. compTi .

9. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 8, characterized in that, The low-temperature compensation current unit includes a voltage comparison subunit and a current subtraction subunit. The voltage comparison subunit is used to input the temperature segmented reference voltage V respectively. Ti The voltage is compared with the PTAT voltage, and the comparison current I is output. N with I P The current subtraction subunit is used to input the comparison current I respectively. N with I P Subtracting the two yields the compensation current I in different temperature ranges. compTi Compensation current I in different temperature ranges compTi After addition, and the compensation resistor R comp The compensation voltage is obtained by multiplying the two voltages; the first-order bandgap reference voltage is added to the compensation voltage to obtain the compensated bandgap reference voltage.

10. A high-driving-capability, low-noise, low-temperature drift coefficient bandgap reference voltage source according to claim 9, characterized in that, The high-temperature compensation current unit structure is the same as the low-temperature compensation current unit structure. The input of the voltage comparison subunit in the high-temperature compensation current unit is relative to the input of the voltage comparison subunit in the low-temperature compensation current unit. The temperature segmented reference voltage V Ti Swap positions with PTAT voltage.

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