CN113965185A - CMOS technology self-compensating temperature sensing integrated circuit - Google Patents

Abstract

The invention provides a CMOS (complementary metal oxide semiconductor) process self-compensating temperature sensing integrated circuit, which comprises a reference current source, a current load type ring oscillator and a ring oscillator driving voltage stabilizing circuit, wherein the reference current source is electrically connected with the current load type ring oscillator through a current mirror, a temperature-frequency converter (TFC) only related to an NMOS (N-channel metal oxide semiconductor) process is designed, and the influence of the NMOS process on a TFC conversion result is counteracted by adjusting the current mirror proportionality coefficient of the reference current source, so that the NMOS process self-compensation is realized. In addition, in order to improve the power supply rejection ratio of the TFC, a ring oscillator driving voltage stabilizing circuit is designed, and the influence of the system power supply voltage on the TFC conversion result is eliminated. The ultra-low power consumption temperature sensing architecture provided by the invention does not need an energy-consuming analog-digital converter (ADC), a complex time-digital signal converter (TDC) and trimming, and has the advantages of low power consumption, low complexity, small layout area and low chip cost.

Description

CMOS technology self-compensating temperature sensing integrated circuit

Technical Field

The invention relates to the field of electronic circuits, in particular to a CMOS (complementary metal oxide semiconductor) process self-compensating temperature sensing integrated circuit.

Background

The current temperature sensing technical scheme is mainly divided into three types: the temperature sensing method comprises the technical scheme of voltage domain integrated temperature sensing, the technical scheme of time domain integrated temperature sensing and the technical scheme of frequency domain integrated temperature sensing. The schematic block diagrams of the three technical solutions are respectively shown in fig. 1 to fig. 3.

As can be seen from the system schematic block diagram of fig. 1, the voltage domain integrated temperature sensing technical scheme requires an analog-to-digital converter (ADC) and a subsequent digital processing circuit, so that the system power consumption is large, the layout area is large, and the chip cost is high.

As can be seen from the schematic block diagram of the system in fig. 2, the time domain integrated temperature sensing technical solution adopts a time-to-digital signal converter (TDC), and the system power consumption is low, but the system composition complexity is high, and a more accurate reference clock needs to be provided off-chip, so the system integration level is low.

As can be seen from the schematic block diagram of the system in fig. 3, the frequency domain integrated temperature sensing technology employs a temperature-frequency converter (TFC), and the system has low power consumption, low complexity and low cost. However, the TFC is based on a ring oscillator in which inverters are cascaded, the conversion result is comprehensively affected by process corners of NMOS, PMOS, MIM capacitors, and the like, and the process corner effects of these devices can be cancelled by modifying the load capacitance of the inverters. In addition, because the in-chip trimming MIM capacitor has errors and is difficult to measure, the temperature sensing passive tag integrated circuit not only needs secondary trimming, but also has very limited measurement precision after trimming.

Disclosure of Invention

The invention provides a CMOS process self-compensating temperature sensing integrated circuit aiming at the technical problems in the prior art, which comprises a reference current source, a current load type ring oscillator and a ring oscillator driving voltage stabilizing circuit, wherein the reference current source is respectively and electrically connected with the current load type ring oscillator and the ring oscillator driving voltage stabilizing circuit through a current mirror, and the ring oscillator driving voltage stabilizing circuit is electrically connected with the current load type ring oscillator; reference current I output by reference current source_REFLinearly increases with temperature and is only influenced by the process corner of the NMOS tube, wherein I is under fast _ n process_REFSmall, i.e. in slow _ n process_REF2, partial enlargement; oscillation frequency f of current-load type ring oscillator_outLinearly increases with temperature and is only affected by the process corner of the NMOS tube, wherein f is the fast _ n process_outIs linearly greater atF under slow _ n process_outIs linear and small;

the influence of an NMOS process angle on the temperature-frequency conversion of the current load type ring oscillator is counteracted by adjusting the proportionality coefficient of the current mirror, and the power supply rejection ratio of the temperature-frequency conversion of the current load type ring oscillator is improved by stabilizing the power supply voltage of the current load type ring oscillator through the ring oscillator driving voltage stabilizing circuit.

On the basis of the technical scheme, the invention can be improved as follows.

Optionally, the reference current source includes three NMOS transistors, M1, M2 and M3 respectively, three PMOS transistors, M4, M5 and M6 respectively, a source of M1 is grounded through a resistor Rs, a drain of M1 is connected to a drain of M6, a gate of M1 is connected to a drain of M1 and a gate of M2 respectively, a source of M2 is grounded, and a drain of M2 is connected to a drain of M5 and a gate of M3 respectively; the source of M3 is grounded, the drain of M3 is connected with the grid of M4 and the drain of M4 respectively, the grid of M4 is connected with the grids of M5 and M6 respectively, the sources of M4, M5 and M6 are grounded, and the reference current source outputs a reference current I_REF。

Optionally, according to V_GS2＝V_GS1+I_REF×R_SAnd obtaining the reference current output of the reference current source:

wherein, mu_nFor the carrier mobility of NMOS, k is the ratio of width-to-length ratios of M1 and M2, Cox is the gate-oxide capacitance per unit area, and R is_SIs a precision resistor;

μ_nthe higher the temperature, the higher the carrier mobility, mu, with temperature and process variations_nThe lower, I_REFThe larger; the lower the temperature, the carrier mobility μ_nThe higher, I_REFThe smaller; the closer the NMOS is to the slow process corner, the carrier mobility μ_nThe lower, the_REFThe larger; the closer the NMOS is to the fast process corner, the carrier mobility mu_nThe higher, so I_REFThe smaller。

Optionally, the current-load ring oscillator includes three current sources E1, E2, and E3 and three NMOS transistors, M7, M8, and M9;

the output end of the current source E1 is respectively connected with the drain of M7 and the gate of M8, the output end of the current source E2 is respectively connected with the drain of M8 and the gate of M9, the output end of the current source E3 is connected with the drain of M9 and the gate of M7, and the sources of M7, M8 and M9 are all grounded; wherein the charging current of each current source is n × I_REF。

Optionally, the capacitors C1, C2, and C3 are parasitic capacitors of three cascade nodes in the current load type ring oscillator, respectively, and the oscillation phenomenon of the current load type ring oscillator may be regarded as a continuous cycle of the process of sequentially charging the three cascade nodes, reaching the threshold voltage, and turning over the output, where the turning period is 1/f_outAnd the driving current n × I_REFThreshold voltage V of NMOS flip_{th_n}There is a linear relationship:

wherein, V_th0Is the threshold voltage offset, m is the threshold voltage sensitivity coefficient, f_outAnd current nxi_REFIs proportional to the driving current n × I_REFIn the case of constant, f_outAnd V_{th_n}A linear relationship with negative correlation;

when NMOS is close to fast process corner, V_{th_n}Will also decrease, resulting in f_outThe height is higher; when the NMOS is close to slow process corner, V_{th_n}Will also rise, resulting in f_outLow; f. of_outLinearly increasing with temperature, and f under fast _ n process_outLarge, slow _ n process f_outIs small.

Optionally, the current mirror includes two NMOS transistors, M10 and M11, respectively, and two PMOS transistors, M12 and M20, respectively;

the gate of M20 is connected to the gate of M4, the source of M20 is connected to VDD, and the drain of M20 is the reference power supply output of the reference current sourceTerminal, output reference power supply I_REFThe grid and the drain of M10 are connected with a reference current I_REFM10 source is grounded, M11 gate is connected with reference current I_REFThe drain of M11 is connected to the gate and drain of M12, the source of M11 is connected to ground, and the source of M12 is connected to VDD.

Optionally, the current source E1 is a PMOS transistor M13, the current source E2 is a PMOS transistor M14, and the current source E3 is a PMOS transistor M15;

the sources of M13, M14 and M15 are connected with VDD, the drain of M13 is connected with the drain of M7, the drain of M14 is connected with the drain of M8, the drain of M15 is connected with the drain of M9, and the gates of M13, M14 and M15 are connected with the gate of M12 in the current mirror.

Optionally, the ring oscillator driving voltage stabilizing circuit includes a current source E4, two NMOS transistors, M16 and M17, respectively, and a BUF buffer;

the driving current of the current source E4 is a reference current I_REFThe output end of the current source E4 is respectively connected with the drain electrode and the grid electrode of the M17 and the first end of the BUF buffer; the source of M17 is connected with the drain of M16 and the gate of M16 respectively; the source of M16 is grounded; the second end of the BUF buffer is connected with VDD, the third end is grounded, and the fourth end is connected with V of the current load type ring oscillator_DRIVEEnd of said V_DRIVEThe end is a power supply end of the current load type ring oscillator.

The invention provides a CMOS (complementary metal oxide semiconductor) process self-compensating temperature sensing integrated circuit which comprises a reference current source, a current load type ring oscillator and a current mirror, wherein the reference current source is electrically connected with the current load type ring oscillator through the current mirror, a temperature-frequency converter (TFC) only related to an NMOS (N-channel metal oxide semiconductor) process is designed, and the influence of the NMOS process on the TFC conversion result is counteracted by adjusting the current mirror proportionality coefficient of the reference current source, so that the NMOS process self-compensation is realized. In addition, in order to improve the power supply rejection ratio of the TFC, a ring oscillator driving voltage stabilizing circuit is designed, and the influence of the system power supply voltage on the TFC conversion result is eliminated. The ultra-low power consumption temperature sensing architecture provided by the invention does not need an energy-consuming analog-digital converter (ADC), a complex time-digital signal converter (TDC) and trimming, and has the advantages of low power consumption, low complexity, small layout area and low chip cost.

Drawings

FIG. 1 is a schematic diagram of a prior art voltage domain temperature sensing integrated circuit;

FIG. 2 is a schematic diagram of a prior art time domain temperature sensing integrated circuit;

FIG. 3 is a schematic diagram of a prior art frequency domain temperature sensing integrated circuit;

FIG. 4 is a schematic structural diagram of a CMOS self-compensated temperature sensing IC according to the present invention;

FIG. 5 is a schematic diagram of a circuit configuration of a reference current source;

FIG. 6 is a graph of the current output characteristics of the reference current source;

FIG. 7 is a schematic circuit diagram of a current-carrying ring oscillator;

FIG. 8 is a graph of temperature-frequency conversion characteristics of a current-loaded ring oscillator;

FIG. 9 is a schematic diagram of a circuit configuration including a reference current source, a current mirror, and a current-loaded ring oscillator;

FIG. 10 is a schematic diagram of a temperature-frequency conversion curve after NMOS process corner self-compensation;

fig. 11 is a schematic structural diagram of a CMOS process self-compensated temperature sensing integrated circuit according to the present invention.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Referring to fig. 4, a schematic structural diagram of a CMOS self-compensated temperature sensing integrated circuit according to an embodiment of the present invention is provided, where the temperature sensing integrated circuit mainly includes three parts: the reference current source, the current load type ring oscillator and the ring oscillator drive the voltage stabilizing circuit. The reference current source is respectively and electrically connected with the current load type ring oscillator and the ring oscillator driving voltage stabilizing circuit through the current mirror, and the ring oscillator driving voltage stabilizing circuit is electrically connected with the current load type ring oscillator.

In the embodiment of the invention, the reference current I output by the reference current source_REFLinearly increases with temperature and is only influenced by the process corner of the NMOS tube, wherein I is under fast _ n process_REFSmall, i.e. in slow _ n process_REF2, partial enlargement; oscillation frequency f of current-load type ring oscillator_outLinearly increases with temperature and is only affected by the process corner of the NMOS tube, wherein f is the fast _ n process_outIs linearly larger, and f is under slow _ n process_outIs linear and small. The influence of an NMOS process angle on the temperature-frequency conversion of the current load type ring oscillator is counteracted by adjusting the current mirror proportion coefficient, and the power supply rejection ratio of the temperature-frequency conversion of the current load type ring oscillator is improved by driving the voltage stabilizing circuit to stabilize the power supply voltage of the current load type ring oscillator through the ring oscillator.

The invention designs a temperature-frequency converter (TFC) only related to an NMOS (N-channel metal oxide semiconductor) process, and counteracts the influence of the NMOS process on the TFC conversion result by adjusting the current mirror proportionality coefficient of a reference current source, thereby realizing the self-compensation of the NMOS process. In addition, in order to improve the power supply rejection ratio of the TFC, a ring oscillator driving voltage stabilizing circuit is designed, and the influence of the system power supply voltage on the TFC conversion result is eliminated. The ultra-low power consumption temperature sensing architecture provided by the invention does not need an energy-consuming analog-digital converter (ADC), a complex time-digital signal converter (TDC) and trimming, and has the advantages of low power consumption, low complexity, small layout area and low chip cost.

In a possible embodiment, the reference current source comprises three NMOS transistors, M1, M2 and M3 respectively, three PMOS transistors, M4, M5 and M6 respectively, the source of M1 is grounded through a resistor Rs, the drain of M1 is connected with the drain of M6, the gate of M1 is connected with the drain of M1 and the gate of M2 respectively, the source of M2 is grounded, and the drain of M2 is connected with the drain of M5 and the gate of M3 respectively; the source of M3 is grounded, the drain of M3 is connected with the grid of M4 and the drain of M4 respectively, the grid of M4 is connected with the grids of M5 and M6 respectively, the sources of M4, M5 and M6 are grounded, and the reference current source outputs reference currentStream I_REF。

It is understood that, as shown in fig. 5, two NMOS (M1, M2) and two PMOS (M5, M6) constitute a main circuit of the reference current source. The PMOS channel should be as long as possible to reduce the channel length modulation effect, thereby reducing the output current I to the system power supply VDD_REFThe negative feedback is introduced by M3 and M4, which can further improve the power supply rejection ratio.

According to V_GS2＝V_GS1+I_REF×R_SThe reference current output of the reference current source can be obtained:

wherein, V_GS2Denotes the voltage between the gate and source of M2, V_GS1Represents the voltage between the gate and source of M1, μ_nFor the carrier mobility of NMOS, k is the ratio of width-to-length ratios of M1 and M2, Cox is the gate-oxide capacitance per unit area, and R is_SIs a precision resistor. Wherein the other parameters can be considered as constant values, only mu_nWith temperature and process variations. On the one hand, the higher the temperature, the higher the carrier mobility μ_nThe lower, the_REFThe larger. On the other hand, the closer the NMOS is to the slow process corner, the carrier mobility μ_nThe lower, the_REFThe larger. Vice versa, the current output characteristic of the reference current source shown in FIG. 6, i.e., the reference current I, can thus be obtained_REFLinearly increasing with temperature, and fast _ n Process I_REFSmall, slow _ n Process I_REFIs larger.

In a possible embodiment, the ring oscillator of current load type includes three current sources E1, E2 and E3 and three NMOS transistors, M7, M8 and M9.

The output end of the current source E1 is connected with the drain of M7 and the gate of M8 respectively, the output end of the current source E2 is connected with the drain of M8 and the gate of M9 respectively, the output end of the current source E3 is connected with the drain of M9 and the gate of M7, and the sources of M7, M8 and M9 are all grounded; wherein each current sourceCharging current of n × I_REF。

Referring to fig. 7, a schematic structural diagram of the current-loaded ring oscillator is shown, and compared with the resistive-loaded ring oscillator and the multi-stage inverter cascaded ring oscillator, a temperature-frequency curve of the current-loaded ring oscillator is only related to an NMOS process, and self-compensation of a process corner is easily achieved. Therefore, the present invention employs a current-load type ring oscillator as a core circuit for temperature-frequency conversion, as shown in fig. 7.

In fig. 7, the capacitors C1, C2, and C3 are parasitic capacitors of three cascade nodes in the current-load-type ring oscillator, respectively, and the oscillation phenomenon can be regarded as a continuous cycle of the processes of sequentially charging the three cascade nodes, reaching the threshold voltage, and turning over the output, so that the turning period (i.e., 1/f) is set_out) And the driving current n × I_REFThreshold voltage V of NMOS flip_{th_n}There is a linear relationship:

wherein, V_th0M is a threshold voltage offset, and m is a threshold voltage sensitivity coefficient. Note that f_outAnd current nxi_REFIs proportional to the driving current n × I_REFIn the case of constant, f_outAnd V_{th_n}The linear relationship of negative correlation is presented. On the one hand, because of V_{th_n}Decreases with increasing temperature, so f_outAnd will slowly rise as the temperature increases; on the other hand, when NMOS is close to fast process corner, V_{th_n}Will also decrease, resulting in f_outIs higher. Vice versa, the frequency output characteristic of the current load type ring oscillator shown in FIG. 8, i.e., f, can be obtained_outLinearly increasing with temperature, and f under fast _ n process_outLarge, slow _ n process f_outIs small.

In one possible embodiment, the current mirror includes two NMOS transistors, M10 and M11, respectively, and two PMOS transistors, M12 and M20, respectively. Wherein the gate of M20 is connected to the gate of M4, the source of M20 is connected to VDD, and that of M20The drain electrode is the reference power supply output end of the reference current source and outputs a reference power supply I_REFThe grid and the drain of M10 are connected with a reference current I_REFM10 source is grounded, M11 gate is connected with reference current I_REFThe drain of M11 is connected to the gate and drain of M12, the source of M11 is connected to ground, and the source of M12 is connected to VDD.

It can be understood that, as can be seen from the above equations (1) and (2), the NMOS process corner pair f_outAnd I_REFIs in the opposite direction, so that the reference current I can be set_REFAfter proportional mirroring, the current load is used as the current load of the ring oscillator, and the influence of the NMOS process corner on the temperature-frequency conversion is finally offset by adjusting the proportional coefficient n of the current mirror, as shown in fig. 9.

For example, when the NMOS is close to the fast process corner, I_REFWill be smaller. On the one hand, f_outWill be due to f_out∝n×I_REFBut is rather small; on the other hand, f_outMay be large because the NMOS of the ring oscillator is close to the fast process corner. Therefore, by properly adjusting the current mirror scaling factor n, the NMOS process corner pair f can be obtained_outThe influence of (2) is eliminated. When the NMOS is close to the slow process corner, the same analysis can be done. Therefore, the invention can finally realize the self-compensation of the NMOS process angle without additional trimming, and the temperature-frequency conversion curve after the process angle self-compensation is shown in figure 10.

It should be noted that, the current source E1 in the current-load ring oscillator is a PMOS transistor M13, the current source E2 is a PMOS transistor M14, and the current source E3 is a PMOS transistor M15, as shown in fig. 9, the sources of M13, M14, and M15 are connected to VDD, the drain of M13 is connected to the drain of M7, the drain of M14 is connected to the drain of M8, the drain of M15 is connected to the drain of M9, and the gates of M13, M14, and M15 are all connected to the gate of M12 in the current mirror.

In one possible implementation, the ring oscillator drives a voltage regulator circuit, which includes a current source E4, two NMOS transistors, M16 and M17, respectively, and a BUF buffer.

Wherein, the driving current of the current source E4 is the reference current I_REFThe output ends of the current sources E4 are respectively connected with the drain electrode of the M17A first terminal of the BUF buffer, a gate; the source of M17 is connected with the drain of M16 and the gate of M16 respectively; the source of M16 is grounded; the second end of the BUF buffer is connected with VDD, the third end is grounded, and the fourth end is connected with V of the current load type ring oscillator_DRIVEEnd, V_DRIVEThe end is a power supply end of the current load type ring oscillator. The BUF buffer can be an operational amplifier in a voltage follower connection mode.

It will be appreciated that in the circuit shown in figure 9, the system supply voltage VDD is applied to the reference current I_REFAlmost has no influence, but V_DRIVEWill slightly change the output frequency f of the ring oscillator_out. This is because VDD affects the drain parasitic capacitance of M13, M14, M15, resulting in f_outFluctuating. Therefore, the invention adopts a ring oscillator to drive a voltage stabilizing circuit, and utilizes I which is not influenced by VDD_REFThe voltage generated by NMOS flowing through two diode connection modes (V is obtained by BUF buffering_DRIVE) As a power supply for the ring oscillator, thereby improving the power supply rejection ratio of the temperature-frequency converter, as shown in fig. 11.

It should be noted that, in the temperature sensing integrated circuit provided in the embodiment of the present invention, the reference current source I_REFRelated only to the process corner of NMOS, and the closer to fast _ n process corner, I_REFThe smaller; oscillation frequency f of current load type wake-up oscillator_outRelated only to NMOS process corner, and the closer to fast _ n process corner, f_outThe larger, based on this, the reference current I_REFThe current load of the ring oscillator is used after the proportional mirror image, and the process self-compensation can be realized by properly adjusting the proportional coefficient n of the current mirror, so that the later-stage trimming is not needed.

Ring oscillator drive voltage regulator circuit utilizing I unaffected by VDD_REFThe voltage generated by NMOS flowing through two diode connection modes (V is obtained by BUF buffering_DRIVE) The ring oscillator is powered, thereby improving the power supply rejection ratio of the current load type ring oscillator.

The CMOS process self-compensating temperature sensing integrated circuit provided by the embodiment of the invention does not need an energy consumption ADC, so that the system complexity is low, the power consumption is low, and the chip layout area is small; a complex TDC is not required, so that the system integration level is high, and the cost of the flow sheet is low; the temperature-frequency curve of the current load type ring oscillator is only related to the NMOS process angle, so that the process angle self-compensation is easy to realize, the trimming is not needed, and the cost is low.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (8)

1. A CMOS technology self-compensating temperature sensing integrated circuit is characterized by comprising a reference current source, a current load type ring oscillator and a ring oscillator driving voltage stabilizing circuit, wherein the reference current source is respectively and electrically connected with the current load type ring oscillator and the ring oscillator driving voltage stabilizing circuit through a current mirror, and the ring oscillator driving voltage stabilizing circuit is electrically connected with the current load type ring oscillator;

reference current I output by reference current source_REFLinearly increases with temperature and is only influenced by the process corner of the NMOS tube, wherein I is under fast _ n process_REFSmall, i.e. in slow _ n process_REF2, partial enlargement; oscillation frequency f of current-load type ring oscillator_outLinearly increases with temperature and is only affected by the process corner of the NMOS tube, wherein f is the fast _ n process_outIs linearly larger, and f is under slow _ n process_outIs linear and small;

the influence of an NMOS process angle on the temperature-frequency conversion of the current load type ring oscillator is counteracted by adjusting the proportionality coefficient of the current mirror, and the power supply rejection ratio of the temperature-frequency conversion of the current load type ring oscillator is improved by stabilizing the power supply voltage of the current load type ring oscillator through the ring oscillator driving voltage stabilizing circuit.

2. The temperature sensing integrated circuit of claim 1, wherein the reference current source comprises three NMOS transistors, M1, M2 and M3 respectively, three PMOS transistors, M4, M5 and M6 respectively, the source of M1 is grounded through a resistor Rs, the drain of M1 is connected to the drain of M6, the gate of M1 is connected to the drain of M1 and the gate of M2 respectively, the source of M2 is grounded, and the drain of M2 is connected to the drain of M5 and the gate of M3 respectively; the source of M3 is grounded, the drain of M3 is connected with the grid of M4 and the drain of M4 respectively, the grid of M4 is connected with the grids of M5 and M6 respectively, the sources of M4, M5 and M6 are grounded, and the reference current source outputs reference current I_REF。

3. The temperature sensing integrated circuit of claim 2, wherein V is a function of_GS2＝V_GS1+I_REF×R_SAnd obtaining the reference current output of the reference current source:

wherein, mu_nFor the carrier mobility of NMOS, k is the ratio of width-to-length ratios of M1 and M2, Cox is the gate-oxide capacitance per unit area, and R is_SIs a precision resistor;

μ_nthe higher the temperature, the higher the carrier mobility, mu, with temperature and process variations_nThe lower, I_REFThe larger; the lower the temperature, the carrier mobility μ_nThe higher, I_REFThe smaller; the closer the NMOS is to the slow process corner, the carrier mobility μ_nThe lower, the_REFThe larger; the closer the NMOS is to the fast process corner, the carrier mobility mu_nThe higher, so I_REFThe smaller.

4. The temperature-sensing integrated circuit of claim 1, wherein the current-load type ring oscillator comprises three current sources E1, E2, and E3 and three NMOS transistors, M7, M8, and M9;

the output end of the current source E1 is respectively connected with the drain of M7 and the gate of M8, the output end of the current source E2 is respectively connected with the drain of M8 and the gate of M9, the output end of the current source E3 is connected with the drain of M9 and the gate of M7, and the sources of M7, M8 and M9 are all grounded; wherein the charging current of each current source is n × I_REF。

5. The temperature-sensing integrated circuit of claim 4, wherein the capacitors C1, C2, and C3 are parasitic capacitors of three cascaded nodes of the current-loaded ring oscillator, respectively, and the oscillation phenomenon of the current-loaded ring oscillator is regarded as a continuous cycle of the three cascaded nodes being sequentially charged, reaching the threshold voltage, and turning over the output, and the turning over period is 1/f_outAnd the driving current n × I_REFThreshold voltage V of NMOS flip_{th_n}There is a linear relationship:

wherein, V_th0Is the threshold voltage offset, m is the threshold voltage sensitivity coefficient, f_outAnd current nxi_REFIs proportional to the driving current n × I_REFIn the case of constant, f_outAnd V_{th_n}A linear relationship with negative correlation;

when NMOS is close to fast process corner, V_{th_n}Will also decrease, resulting in f_outThe height is higher; when the NMOS is close to slow process corner, V_{th_n}Will also rise, resulting in f_outLow; f. of_outLinearly increasing with temperature, and f under fast _ n process_outLarge, slow _ n process f_outIs small.

6. The temperature sensing integrated circuit of claim 4, wherein the current mirror comprises two NMOS transistors, M10 and M11, respectively, and two PMOS transistors, M12 and M20, respectively;

the grid of M20 is connected with the grid of M4, the source of M20 is connected with VDD, the drain of M20 is the reference power supply output end of the reference current source, and the reference power supply I is output_REFThe grid and the drain of M10 are connected with a reference current I_REFM10 source is grounded, M11 gate is connected with reference current I_REFThe drain of M11 is connected to the gate and drain of M12, the source of M11 is connected to ground, and the source of M12 is connected to VDD.

7. The temperature-sensing integrated circuit of claim 4, wherein the current source E1 is a PMOS transistor M13, the current source E2 is a PMOS transistor M14, and the current source E3 is a PMOS transistor M15;

the sources of M13, M14 and M15 are connected with VDD, the drain of M13 is connected with the drain of M7, the drain of M14 is connected with the drain of M8, the drain of M15 is connected with the drain of M9, and the gates of M13, M14 and M15 are connected with the gate of M12 in the current mirror.

8. The temperature sensing integrated circuit of claim 1, wherein the ring oscillator drive voltage regulator circuit comprises a current source E4, two NMOS transistors, M16 and M17, respectively, and a BUF buffer;

the driving current of the current source E4 is a reference current I_REFThe output end of the current source E4 is respectively connected with the drain electrode and the grid electrode of the M17 and the first end of the BUF buffer; the source of M17 is connected with the drain of M16 and the gate of M16 respectively; the source of M16 is grounded; the second end of the BUF buffer is connected with VDD, the third end is grounded, and the fourth end is connected with V of the current load type ring oscillator_DRIVEEnd of said V_DRIVEThe end is a power supply end of the current load type ring oscillator.

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