Temperature sensing methods, temperature sensors and chips

Abstract

This disclosure provides a temperature sensing method, a temperature sensor, and a chip. The temperature sensing method includes: charging a first capacitor and a second capacitor; discharging the first capacitor through a first transistor while simultaneously discharging the second capacitor through a second transistor; stopping the discharge of the second capacitor through the second transistor and instead connecting the second capacitor in parallel with a third capacitor to cause the voltage of the second capacitor to drop; in response to the voltage of the first capacitor starting to exceed the voltage of the second capacitor, starting a counter to count, and determining the time at which the counting begins as a first moment; determining the time when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor as a second moment; and determining the sensed temperature based on the first moment, the second moment, and a preset functional relationship. This disclosure can achieve relatively high temperature accuracy without the need for prior calibration.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of integrated circuits, and relates to a temperature sensing method, a temperature sensor and a chip. BACKGROUND

[0002] An on-chip integrated temperature sensor, also known as a silicon sensor or a monolithic integrated temperature sensor, is a special IC (Integrated Circuit) that integrates a temperature sensor on a chip to complete temperature measurement and analog signal output functions.

[0003] Current temperature sensors have various implementation manners, such as a temperature sensor based on a bandgap reference and a temperature sensor based on TDC (Time-to-Digital Converter) quantization of a delay time, but the implementation manners are relatively complex, occupy a large chip area, and have high power consumption. In addition, most temperature implementation manners need one or two point temperature calibrations, and each device in the chip needs to be calibrated separately, which is very time-consuming and will generate an unignorable cost. SUMMARY

[0004] The present disclosure provides a temperature sensing method, a temperature sensor and a chip, which are used to reduce the chip area and power consumption while ensuring high precision of the temperature sensor.

[0005] In a first aspect, an embodiment of the present disclosure provides a temperature sensing method. The temperature sensing method comprises: charging a first capacitor and a second capacitor; discharging the first capacitor through a first transistor while discharging the second capacitor through a second transistor; stopping discharging the second capacitor through the second transistor, and instead connecting the second capacitor and a third capacitor in parallel to make the voltage of the second capacitor drop; in response to the voltage of the first capacitor starting to be higher than the voltage of the second capacitor, starting counting by a counter, and determining a time when the counting starts as a first time; determining a time when the voltage of the first capacitor is discharged to the voltage of the second capacitor through the first transistor as a second time; and determining a sensed temperature according to the first time, the second time and a preset function relationship.

[0006] In an implementation manner of the first aspect, determining the time when the voltage of the first capacitor is discharged to the voltage of the second capacitor through the first transistor as the second time comprises: when the voltage of the first capacitor is discharged to the voltage of the second capacitor through the first transistor, stopping counting by the counter, and obtaining a counting value of the counter; and determining the second time according to the first time, the counting value and a clock signal period.

[0007] In an implementation form of the first aspect, determining the second time instant based on the first time instant, the count value and a clock signal period comprises: inputting the voltage of the first capacitor and the voltage of the second capacitor into the non-inverting terminal and the inverting terminal of a comparator respectively, taking the output of the comparator as a first signal; taking the output of a flip-flop controlled by a clock signal as a second signal, the clock signal being further used to control the second capacitor and the third capacitor to be electrically coupled in parallel to share electric charge so that the voltage of the second capacitor drops to a set voltage; performing AND operation on the first signal and the second signal to output an enable signal for the counter; outputting a time interval by the counter based on the clock signal period and the enable signal; and adding the time interval to the first time instant to obtain the second time instant.

[0008] In an implementation form of the first aspect, the temperature sensing method further comprises: establishing a lookup table between the count value and the temperature according to a pre-acquired mapping relationship between the count value and the temperature, so as to directly determine the corresponding temperature in the lookup table according to the acquired count value.

[0009] In an implementation form of the first aspect, the preset function relationship is represented as: wherein the constant term is a relationship formula composed of the band gap voltage of silicon, the crystal management factor, the Boltzmann constant and the unit charge amount; x represents a multiple relationship between the sampling voltage of the transistor at the second time instant and a sampling voltage difference, the sampling voltage difference being the difference between the sampling voltage of the transistor at the first time instant and the sampling voltage of the transistor at the second time instant; and N represents a proportional relationship formula of the capacitance value of the first capacitor, the capacitance value of the second capacitor, the first time instant and the second time instant.

[0010] In an implementation form of the first aspect, N in the preset function relationship is represented as: N = (the capacitance value C1 of the first capacitor x the second time instant ts2) / (the capacitance value C2 of the second capacitor x the first time instant ts1).

[0011] In an implementation form of the first aspect, x in the preset function relationship is represented as: x = (the voltage VC1 of the second capacitor at the first time instant - the voltage VC2 of the second capacitor at the second time instant) / the voltage VC1 of the second capacitor at the first time instant, and x = the capacitance value C3 of the third capacitor / (the capacitance value C2 of the second capacitor + the capacitance value C3 of the third capacitor).

[0012] In an implementation form of the first aspect, the first transistor and the second transistor comprise a diode or a bipolar junction transistor.

[0013] In an implementation form of the first aspect, the first capacitor and the second capacitor are of the same specification, and the first transistor and the second transistor are of the same specification.

[0014] In a second aspect, the embodiments of the present disclosure provide a temperature sensor. The temperature sensor comprises: a first capacitor electrically coupled between a first voltage terminal and a ground; a second capacitor electrically coupled between a second voltage terminal and the ground; a third capacitor electrically coupled in parallel with the second capacitor; a first transistor electrically coupled in parallel with the first capacitor; a second transistor electrically coupled in parallel with the second capacitor; a control unit configured to: charge the first capacitor and the second capacitor; discharge the first capacitor through the first transistor while discharging the second capacitor through the second transistor; stop discharging the second capacitor through the second transistor, and instead discharge the second capacitor in parallel with the third capacitor so that a voltage of the second capacitor drops; and a temperature sensing unit electrically coupled to the first voltage terminal and the second voltage terminal, and configured to: start counting using a counter in response to a voltage of the first capacitor starting to be higher than a voltage of the second capacitor, determine a time when the counting starts as a first time; determine a time when the voltage of the first capacitor drops to the voltage of the second capacitor through discharging by the first transistor as a second time; and determine a sensed temperature according to the first time, the second time, and a preset function relationship.

[0015] In an implementation form of the second aspect, the temperature sensing unit is configured to: stop counting using the counter when the voltage of the first capacitor drops to the voltage of the second capacitor through discharging by the first transistor, and obtain a count value of the counter; and determine the second time according to the first time, the count value, and a clock signal period.

[0016] In an implementation form of the second aspect, the temperature sensing unit is configured to: receive the voltage of the first capacitor from the first voltage terminal using a non-inverting input terminal of a comparator, receive the voltage of the second capacitor from the second voltage terminal using an inverting input terminal of the comparator, and use an output of the comparator as a first signal; receive a clock signal using an enable terminal of a flip-flop, and use an output of the flip-flop as a second signal, the clock signal being further used to control the second capacitor to be electrically coupled in parallel with the third capacitor to share charge so that the voltage of the second capacitor drops to a set voltage; perform AND operation on the first signal and the second signal and output an enable signal for the counter; output a timing time interval based on the clock signal period and the enable signal using the counter; and obtain the second time by adding the timing time interval to the first time.

[0017] In an implementation form of the second aspect, the temperature sensing unit is configured to establish a lookup table between the count value and the temperature according to a pre-acquired mapping relationship between the count value and the temperature, so as to directly determine the corresponding temperature in the lookup table according to the acquired count value.

[0018] In an implementation form of the second aspect, the preset function relationship is represented as: wherein the constant term is a relationship composed of a band gap voltage of silicon, a crystal management factor, a Boltzmann constant and a unit charge amount; x refers to a multiple relationship between a sampling voltage of the transistor at the second time and a sampling voltage difference, the sampling voltage difference refers to a sampling voltage difference of the transistor at the first time and the second time; N refers to a proportional relationship formed by a capacitance value of the first capacitor, a capacitance value of the second capacitor, the first time and the second time.

[0019] In an implementation form of the second aspect, N in the preset function relationship is represented as: N = (capacitance value of the first capacitor * second time) / (capacitance value of the second capacitor * first time).

[0020] In an implementation form of the second aspect, the first transistor and the second transistor include a diode or a bipolar junction transistor.

[0021] In an implementation form of the second aspect, the first capacitor and the second capacitor are of the same specification, and the first transistor and the second transistor are of the same specification.

[0022] In an implementation form of the second aspect, the temperature sensor further includes: a first charge-discharge switch switching unit, a second charge-discharge switch switching unit and a third charge-discharge switch switching unit controlled by the control unit, the first charge-discharge switch switching unit is electrically coupled with the first capacitor, the second charge-discharge switch switching unit is electrically coupled with the second capacitor, and the third charge-discharge switch switching unit is electrically coupled with the third capacitor.

[0023] In an implementation form of the second aspect, the first charge-discharge switch switching unit comprises a second MOS transistor, a third MOS transistor and a fourth MOS transistor, the second charge-discharge switch switching unit comprises a sixth MOS transistor, a seventh MOS transistor and an eighth MOS transistor, the third charge-discharge switch switching unit comprises a ninth MOS transistor and a tenth MOS transistor; one end of the first capacitor is electrically coupled with a source of the fourth MOS transistor and a drain of the third MOS transistor respectively, the other end of the first capacitor is electrically coupled with the ground, a drain of the second MOS transistor is electrically coupled with a source of the third MOS transistor and one end of the first transistor respectively, a source of the second MOS transistor is electrically coupled with the ground, the other end of the first transistor is electrically coupled with the ground, a drain of the fourth MOS transistor is electrically coupled with a preset voltage; one end of the second capacitor is electrically coupled with a source of the eighth MOS transistor and a drain of the seventh MOS transistor respectively, the other end of the second capacitor is electrically coupled with the ground, a drain of the sixth MOS transistor is electrically coupled with a source of the seventh MOS transistor and one end of the second transistor respectively, a source of the sixth MOS transistor is electrically coupled with the ground, the other end of the second transistor is electrically coupled with the ground, a drain of the eighth MOS transistor is electrically coupled with the preset voltage; one end of the third capacitor is electrically coupled with a source of the ninth MOS transistor and a drain of the tenth MOS transistor respectively, the other end of the third capacitor is electrically coupled with the ground, a drain of the ninth MOS transistor is electrically coupled with one end of the second capacitor, a source of the tenth MOS transistor is electrically coupled with the ground.

[0024] In an implementation form of the second aspect, the control unit is configured to: in a charging period, control the second MOS transistor, the fourth MOS transistor, the sixth MOS transistor, the eighth MOS transistor and the ninth MOS transistor to be closed, control the third MOS transistor, the seventh MOS transistor and the tenth MOS transistor to be opened, so that the preset voltage charges the first capacitor and the second capacitor, and the first transistor and the second transistor discharge and clear; from the discharge start time to the first time, control the second MOS transistor, the fourth MOS transistor, the sixth MOS transistor, the eighth MOS transistor and the ninth MOS transistor to be opened, control the third MOS transistor, the seventh MOS transistor and the tenth MOS transistor to be closed, so that the first capacitor discharges through the first transistor, the second capacitor discharges through the second transistor, and the third capacitor discharges and clears through the tenth MOS transistor; after the first time, control the seventh MOS transistor and the tenth MOS transistor to be opened, control the ninth MOS transistor to be closed, so that the first capacitor continues to discharge through the first transistor, the second capacitor is connected in parallel with the third capacitor, causing the voltage of the second capacitor to drop.

[0025] In a third aspect, the embodiments of the present disclosure provide a chip. The chip comprises the temperature sensor, and a memory configured to store a lookup table corresponding to the preset function relationship.

[0026] An integrated temperature sensor based on discharge time TDC quantization is implemented according to the present disclosure. Since the relative matching of the first capacitor and the second capacitor, the first transistor and the second transistor can be well achieved in the process, and the comparator can be achieved with high resolution, fast speed and low delay. In addition, the preset function relationship of the present disclosure needs to take the logarithm of time, so it is not sensitive to the error of timing. Therefore, a relatively high temperature precision is obtained without the need for early calibration. The temperature sensor of the present application also has the advantages of low power consumption, small chip area, and low mismatch requirement, which saves the high-precision ADC (Analog-to-Digital Converter, Digital-to-Analog Converter), and avoids the disadvantages of large occupied area and high power consumption of high-precision ADC. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A flow chart of the temperature sensing method according to the embodiments of the present disclosure is shown.

[0028] Figure 2 A second time determination flow chart of the temperature sensing method according to the embodiments of the present disclosure is shown.

[0029] Figure 3 A structural schematic diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0030] Figure 4 A structural diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0031] Figure 5 A circuit diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0032] Figure 6 A counting circuit diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0033] Figure 7 A temperature monitoring timing diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0034] Figure 8 A monitoring effect diagram of the temperature sensor according to the embodiments of the present disclosure is shown.

[0035] Figure 9 A structural schematic diagram of the chip according to the embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0036] Following, the embodiments of the present disclosure are described through specific examples, and other advantages and effects of the present disclosure can be easily understood by those skilled in the art from the disclosure. The present disclosure can also be implemented or applied through other different embodiments, and various modifications or changes can be made to the details based on different views and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0037] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concepts of the present disclosure, and only the components related to the present disclosure are shown in the diagrams, not the number, shape and size of the components when actually implemented. The shapes, numbers and proportions of the components when actually implemented can be arbitrarily changed, and the layout of the components can be more complex.

[0038] The technical solutions in the embodiments of the present disclosure will be described in detail below with reference to the drawings of the embodiments of the present disclosure.

[0039] Figure 1 A flowchart of a temperature sensing method according to an embodiment of the present disclosure is shown. As shown in Figure 1 The temperature sensing method according to an embodiment of the present disclosure is applied to a circuit of a temperature sensor, which includes a first capacitor, a second capacitor, a third capacitor, a first transistor and a second transistor. The first capacitor is discharged through the first transistor, and the second capacitor is discharged through the second transistor. The temperature sensing method includes the following steps S11-S16.

[0040] In step S11, the first capacitor and the second capacitor are charged.

[0041] In some embodiments, the first capacitor and the second capacitor have the same specifications.

[0042] In step S12, the first capacitor is discharged through the first transistor, and the second capacitor is discharged through the second transistor.

[0043] In some embodiments, the first transistor and the second transistor include a diode or a bipolar junction transistor. In some embodiments, the first transistor and the second transistor have the same specifications.

[0044] In step S13, the discharging of the second capacitor through the second transistor is stopped, and the second capacitor is connected in parallel with the third capacitor so that the voltage of the second capacitor decreases.

[0045] In some embodiments, the second capacitor and the third capacitor are electrically coupled in parallel to share electric charges, so that the voltage of the second capacitor drops to a set voltage. The set voltage can be determined by the capacitance of the second capacitor and the third capacitor.

[0046] In step S14, in response to the voltage of the first capacitor being higher than the voltage of the second capacitor, the counter starts counting, and the time when the counting starts is determined as a first time.

[0047] In some embodiments, before obtaining the count value of the counter, the method can further include: establishing a lookup table between the count value and the temperature according to a mapping relationship between the count value and the temperature obtained in advance, so as to directly determine the corresponding temperature in the lookup table according to the obtained count value.

[0048] In step S15, the time when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor is determined as a second time. In an embodiment, when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor, the counter stops counting, the count value of the counter is obtained, and the second time is determined according to the first time, the count value and the period of the clock signal.

[0049] In step S16, the sensing temperature is determined according to the first time, the second time and a preset function relationship.

[0050] In some embodiments, the preset function relationship is represented as:

[0051] The constant term is a relationship formula composed of the band gap voltage of silicon, the crystal management factor, the Boltzmann constant and the unit charge amount; x refers to the multiple relationship between the sampling voltage of the transistor at the second time and the sampling voltage difference, the sampling voltage difference refers to the difference between the sampling voltage of the transistor at the first time and the sampling voltage of the transistor at the second time; N refers to a proportional relationship formula formed by the capacitance of the first capacitor, the capacitance of the second capacitor, the first time and the second time.

[0052] In some embodiments, N in the preset function relationship is represented as: N=(capacitance C1 of the first capacitor x second time ts2) / (capacitance C2 of the second capacitor x first time ts1).

[0053] In some embodiments, x in the preset functional relationship is represented as: x = (voltage VC1 of the second capacitor at the first moment - voltage VC2 of the second capacitor at the second moment) / voltage VC1 of the second capacitor at the first moment = capacitance C3 of the third capacitor / (capacitance C2 of the second capacitor + capacitance C3 of the third capacitor).

[0054] According to the embodiments of this disclosure, based on the first time, the second time and the preset relationship, the sensing temperature can be determined by looking up a table through the relationship between the preset time and the temperature, thereby obtaining relatively high temperature accuracy without calibration, and has the advantages of low power consumption, small chip area and low mismatch requirements.

[0055] Figure 2 This diagram illustrates the second moment determination flowchart of the temperature sensing method described in an embodiment of this disclosure. Figure 2 As shown, in step S15, determining the second time based on the first time, the count value, and the clock signal period includes the following steps S151 to S155.

[0056] In step S151, the voltage of the first capacitor and the voltage of the second capacitor are respectively input to the non-inverting and inverting inputs of a comparator, and the output of the comparator is used as the first signal.

[0057] In step S152, the output of a clock signal-controlled flip-flop is used as a second signal. The clock signal is further used to control the second capacitor and the third capacitor to be electrically coupled in parallel to share charge, so that the voltage of the second capacitor drops to a set voltage.

[0058] In step S153, the first signal and the second signal are ANDed together and then an enable signal for the counter is output.

[0059] In step S154, the counter outputs a timing time interval based on the clock signal period and the enable signal.

[0060] In step S155, the timing time interval is added to the first time point to obtain the second time point.

[0061] Figure 3 The diagram shown is a structural schematic of the temperature sensor described in an embodiment of this disclosure. Figure 3 As shown, this embodiment of the present disclosure provides a temperature sensor, which includes: a first capacitor 11, a second capacitor 21, a third capacitor 31, a first transistor 12 and a second transistor 22, as well as a control unit and a temperature sensing unit.

[0062] The first capacitor 11 is electrically coupled between the first voltage terminal and ground. The second capacitor 21 is electrically coupled between the second voltage terminal and ground. The third capacitor 31 is electrically coupled in parallel with the second capacitor 21. The first transistor 12 is electrically coupled in parallel with the first capacitor 11. The second transistor 22 is electrically coupled in parallel with the second capacitor 21. The first capacitor 11 discharges through the first transistor 12, and the second capacitor 21 discharges through the second transistor 22.

[0063] The control unit is configured to charge the first capacitor and the second capacitor, discharge the first capacitor through the first transistor, discharge the second capacitor through the second transistor, stop the second capacitor from discharging through the second transistor, and instead connect the second capacitor in parallel with the third capacitor to reduce the voltage of the second capacitor.

[0064] The temperature sensing unit is electrically coupled to the first voltage terminal and the second voltage terminal. The temperature sensing unit is configured to start counting using a counter in response to the voltage of the first capacitor starting to be higher than the voltage of the second capacitor, to determine the start time of counting as a first moment, to determine the moment when the voltage of the first capacitor drops to the voltage of the second capacitor through the discharge of the first transistor as a second moment, and to determine the sensed temperature based on the first moment, the second moment and a preset functional relationship.

[0065] Additionally, the temperature sensing unit is configured to stop counting using the counter when the voltage of the first capacitor drops to the voltage of the second capacitor through the discharge of the first transistor, and to acquire the count value of the counter, and to determine the second time based on the first time, the count value, and the clock signal period.

[0066] In some embodiments, the first transistor and the second transistor comprise diodes or bipolar junction transistors (BJTs). A common characteristic of diodes and BJTs is that their current and voltage have an exponential relationship.

[0067] In some embodiments, the first capacitor and the second capacitor have the same specifications, and the first transistor and the second transistor have the same specifications.

[0068] Figure 4 The diagram shown is a structural diagram of the temperature sensor described in an embodiment of this disclosure. Figure 4As shown, in addition to the first capacitor 11, the second capacitor 21, the first transistor 12 and the second transistor 22 described above, the temperature sensor also includes: a first charge / discharge switch switching unit 13, a second charge / discharge switch switching unit 23 and a third charge / discharge switch switching unit 32 controlled by the control unit.

[0069] The first charge / discharge switch unit 13 is electrically coupled to the first capacitor 11, the second charge / discharge switch unit 23 is electrically coupled to the second capacitor 21, and the third charge / discharge switch unit 32 is electrically coupled to the third capacitor 31.

[0070] Figure 5 The diagram shown is a circuit diagram of a temperature sensor according to an embodiment of this disclosure. Figure 5 As shown, the first capacitor 11 refers to C1, the second capacitor 21 refers to C2, the first transistor 12 refers to Q1, and the second transistor 22 refers to Q5. The first charge / discharge switching unit 13 includes a second MOSFET Q2, a third MOSFET Q3, and a fourth MOSFET Q4; the second charge / discharge switching unit 23 includes a sixth MOSFET Q6, a seventh MOSFET Q7, and an eighth MOSFET Q8; and the third charge / discharge switching unit 32 includes a ninth MOSFET Q9 and a tenth MOSFET Q10.

[0071] One end of the first capacitor C1 is electrically coupled to the source of the fourth MOSFET Q4 and the drain of the third MOSFET Q3, respectively. The other end of the first capacitor C1 is electrically coupled to ground GND. The drain of the second MOSFET Q2 is electrically coupled to the source of the third MOSFET Q3 and one end of the first transistor Q1, respectively. The source of the second MOSFET Q2 is electrically coupled to ground GND. The other end of the first transistor Q1 is electrically coupled to ground GND. The drain of the fourth MOSFET Q4 is electrically coupled to a preset voltage of 0.9V.

[0072] One end of the second capacitor C2 is electrically coupled to the source of the eighth MOS transistor Q8 and the drain of the seventh MOS transistor Q7, respectively. The other end of the second capacitor C2 is electrically coupled to ground GND. The drain of the sixth MOS transistor Q6 is electrically coupled to the source of the seventh MOS transistor Q7 and one end of the second transistor Q5, respectively. The source of the sixth MOS transistor Q6 is electrically coupled to ground. The other end of the second transistor Q5 is electrically coupled to ground GND. The drain of the eighth MOS transistor Q8 is electrically coupled to a preset voltage of 0.9V.

[0073] One end of the third capacitor C3 is electrically coupled to the source of the ninth MOS transistor Q9 and the drain of the tenth MOS transistor Q10, respectively. The other end of the third capacitor C3 is electrically coupled to ground GND. The drain of the ninth MOS transistor Q9 is electrically coupled to one end of the second capacitor C2. The source of the tenth MOS transistor Q10 is electrically coupled to ground GND.

[0074] In practical applications, combined with Figure 5 and Figure 6 The circuit schematic shown below illustrates the derivation process of the preset functional relationship.

[0075] The first capacitor C1 discharges through the first transistor Q1, and the second capacitor C2 discharges through the second transistor Q5. When Q1 and Q5 are BJTs, their bases and collectors are connected and electrically coupled to ground. When Q1 and Q5 are diodes, their anodes correspond to the emitter of the BJT, and their cathodes correspond to the base and collector of the BJT. The relationship between the voltage (or diode voltage) VD between the emitter and base of Q1 or Q5 and time t (after tens of nanoseconds) is expressed as:

[0076]

[0077] Where η is the ideality factor of the BJT or diode, V T It is thermal voltage, I S It is the saturation current, and C is the capacitance value of C1 or C2.

[0078] At the second time point ts2, the voltage of the BJT or diode is sampled to obtain a voltage Vctat that is inversely proportional to the absolute temperature.

[0079] V ctat =V G0 +α·T≡V D (ts2) (2)

[0080] Among them, V G0 It is the bandgap voltage of silicon, and α is the temperature coefficient.

[0081] The voltage of the BJT or diode is sampled at the first time ts1 and the second time ts2, respectively. The voltage difference Vptat between the two samples is proportional to the absolute temperature.

[0082]

[0083] Where C1 and C2 are the capacitance values ​​of the first and second capacitors, respectively, η is the ideality factor of the BJT or diode, and V T It is thermal voltage.

[0084] Reducing Vctat to a factor of x yields the voltage xVctat. Equating xVctat with Vptat gives the preset functional expression for temperature T:

[0085]

[0086] Where η is the ideality factor of the BJT or diode, V G0 α is the bandgap voltage of silicon, α is the temperature coefficient, N = (C1*ts2) / (C2*ts1), kB is the Boltzmann constant, and q is the unit charge.

[0087] As can be seen from formula (4), as long as N is obtained (the other parameters are fixed constants), the temperature T can be obtained.

[0088] Since VG0, kB, and q are physical constants, C1, C2, ts1, and x are design values, and η and α are less affected by process fluctuations, high-precision temperature measurement can be obtained as long as the second moment ts2 is accurately measured.

[0089] Regarding "x times", in Figure 5 In the example, before switch Q9 is turned on, the voltage across the second capacitor C2 is assumed to be VC1. After switch Q9 is turned on (at which time switch Q10 is turned off), the third capacitor C3 shares the charge on C2, and the voltage across the second capacitor C2 is VC2. Therefore, x = (VC1 - VC2) / VC1 = C3 / (C2 + C3).

[0090] The second time step ts2 is obtained from the counter. The clock signal period is T. After measurement, the counter count value is Nc. Then ts2 = ts1 + Nc * T. The only signal needed to calculate the temperature is the counter count value Nc. According to formula (4), VG0 and kB are constants, η and α are device parameters provided by the semiconductor device model; x, C1, C2, and ts1 are design values, and ts2 is obtained by counter measurement. There is a one-to-one mapping relationship between the counter count value Nc and the temperature T. The temperature can be obtained by establishing a look-up table of the relationship between Nc and temperature.

[0091] In some embodiments, the control unit is configured to perform the following operations (1) to (3).

[0092] (1) During the charging period, the second MOSFET Q2, the fourth MOSFET Q4, the sixth MOSFET Q6, the eighth MOSFET Q8 and the ninth MOSFET Q9 are controlled to close, and the third MOSFET Q3, the seventh MOSFET Q7 and the tenth MOSFET Q10 are controlled to open, so that the preset voltage of 0.9V charges the first capacitor C1 and the second capacitor C2, and the first transistor Q1 and the second transistor Q5 are discharged and cleared.

[0093] (2) From the start of discharge to the first moment, control the second MOS transistor Q2, the fourth MOS transistor Q4, the sixth MOS transistor Q6, the eighth MOS transistor Q8 and the ninth MOS transistor Q9 to be disconnected, and control the third MOS transistor Q3, the seventh MOS transistor Q7 and the tenth MOS transistor Q10 to be closed, so that the first capacitor C1 discharges through the first transistor Q1, the second capacitor C2 discharges through the second transistor Q5, and the third capacitor C3 discharges to zero through the tenth MOS transistor C10.

[0094] (3) After the first moment, the seventh MOSFET Q7 and the tenth MOSFET Q10 are turned off, and the ninth MOSFET Q9 is turned on, so that the first capacitor C1 continues to discharge through the first transistor Q1, and the second capacitor C2 is connected in parallel with the third capacitor C3, causing the voltage of the second capacitor C2 to drop. In some embodiments, the voltage VC2 on the second capacitor C2 will drop due to the parallel connection of C2 and C3, and the magnitude of the voltage drop is Vptat.

[0095] Figure 6 The diagram shows a counting circuit diagram of a temperature sensor according to an embodiment of this disclosure. In some embodiments, the temperature sensing unit may include a comparator, a flip-flop, an AND gate, and a counter. In some embodiments, the process by which the temperature sensing unit determines the second time based on the first time, the count value, and the clock signal period includes the following (1.1) to (1.5).

[0096] (1.1) The voltage of the first capacitor 11 from the first voltage terminal is received using the non-inverting input terminal of the comparator, the voltage of the second capacitor 21 from the second voltage terminal is received using the inverting input terminal of the comparator, and the output of the comparator is used as the first signal.

[0097] like Figure 6As shown, the voltage VC1 of the first capacitor 11 and the voltage VC2 of the second capacitor 21 are respectively input to the non-inverting and inverting inputs of a comparator U1, and the output of the comparator serves as the first signal. When voltages VC1 and VC2 are equal, the output of comparator U1 flips (switches from 1 to 0), and the time at this moment is recorded as the second time ts2.

[0098] Since the capacitance values ​​of C1 and C2 are equal, and Q1 and Q5 are the same BJT, if there is no process error, VC1 and VC2 are equal before the first moment ts1. Even if there is a process error, the difference between the two is very small.

[0099] (1.2) The clock signal is received by the enable terminal of the flip-flop, and the output of the flip-flop is used as the second signal. The clock signal is further used to control the second capacitor 21 and the third capacitor 31 to be electrically coupled in parallel to share charge so that the voltage of the second capacitor 21 drops to a set voltage.

[0100] like Figure 6 As shown, the output of flip-flop U3, controlled by a clock signal CLK2_b, is used as the second signal.

[0101] (1.3) Perform an AND operation on the first signal and the second signal and output the enable signal Enable for the counter.

[0102] Specifically, the rising edge of CLK2_b is ANDed with the output of the D flip-flop and the output of the comparator to obtain an enable signal with a time interval of Δt.

[0103] (1.4) The counter outputs a timing interval based on the clock signal period CLK and the enable signal Enable.

[0104] Specifically, under the clock signal period CLK signal, Enable triggers the counter to complete the digital quantization of Δt, and outputs D0 to D11.

[0105] (1.5) Add the timing time interval to the first time to obtain the second time.

[0106] Specifically, Δt plus the first time step ts1 equals the second time step ts2. Different temperatures correspond to different Δt values, and the counter quantizes Δt to obtain the second time step ts2.

[0107] In some embodiments, the temperature sensing unit is configured to establish a lookup table between the count values ​​and temperatures based on a pre-acquired mapping relationship between each count value and temperature, so as to directly determine the corresponding temperature in the lookup table based on the acquired count value.

[0108] In some embodiments, the preset functional relationship is represented as:

[0109] The constant term is a relationship between the bandgap voltage of silicon, the ideality factor of the transistor, the Boltzmann constant, and the unit charge; x refers to the multiple relationship between the sampling voltage of the transistor at the second time moment and the sampling voltage difference, where the sampling voltage difference refers to the sampling voltage difference of the transistor at the first time moment and the second time moment; N refers to the proportional relationship formed by the capacitance of the first capacitor, the capacitance of the second capacitor, the first time moment, and the second time moment.

[0110] In the preset functional relationship, N is represented as:

[0111] N = (capacitance of the first capacitor C1 × ts2 at the second time) / (capacitance of the second capacitor C2 × ts1 at the first time).

[0112] In the preset functional relationship, x is represented as:

[0113] x = (Voltage of the second capacitor at the first moment VC1 - Voltage of the second capacitor at the second moment VC2) / Voltage of the second capacitor at the first moment VC1 = Capacitance of the third capacitor C3 / (Capacitance of the second capacitor C2 + Capacitance of the third capacitor C3).

[0114] Figure 7 The diagram shown is a timing diagram of temperature monitoring by the temperature sensor according to an embodiment of this disclosure. Figure 7 As shown, a 0.9V power supply charges capacitors C1 and C2 through switches Q4 and Q8. Then, switches Q4 and Q8 are turned off, and Q3 and Q7 are turned on, allowing capacitors C1 and C2 to discharge through the BJT. Voltages VC1 and VC2 on capacitors C1 and C2 change over time. When VC1 is less than VC2, the time is defined as the second moment ts2. The counter starts counting at the first moment ts1 and stops counting at the second moment ts2, where ts2 = ts1 + Nc * T, where Nc is the counter value and T is the clock period. CLK1, CLK1_b, CLK2, and CLK2_b are as follows... Figure 7 As shown.

[0115] Combination Figure 5 As shown, VC1 is equal to the base-emitter voltage V of the BJT. BE VC1 is a voltage inversely proportional to absolute temperature, while the voltage difference between VC2 and VC2 at times ts1 and ts2 is a voltage directly proportional to temperature. The relationship between VC1 and VC2 and discharge time t conforms to formula (1).

[0116] CLK1, CLK1_b, CLK2, and CLK2_b can be digital control signals generated by the system clock, including high and low levels. When the control signal is high, it acts on the N-channel MOSFET, turning it on; when the control signal is low, the N-channel MOSFET is turned off.

[0117] The charging period is from time ts to ts0, and ts0 is the start of the discharge. At time ts0, CLK1_b and CLK2 go from low to high, switches Q3 and Q7 are turned on, and the voltage across capacitors C1 and C2 is greater than the BJT's turn-on voltage, so the BJT is turned on, and capacitors C1 and C2 discharge through the BJT. At time ts1, CLK2 goes from high to low, and CLK2_b goes from low to high. Capacitor C2 cannot discharge through the BJT, but instead shares charge through C3, reducing the original voltage VC2 on C2 to C2 / (C2+C3) times, and then capacitor C2 retains this voltage unchanged.

[0118] Figure 8 The diagram shown illustrates the monitoring effect of the temperature sensor according to an embodiment of this disclosure. Figure 8 As shown, under the tt process angle, within the temperature range of -40 to 120℃, without any calibration, the temperature error is between -1℃ and +1.7℃, and under all process angles, the error is between -3.3℃ and +2.8℃. This disclosure achieves this advantage because the relative matching of capacitors C1 and C2, and BJTQ1 and Q5, can be well achieved in the manufacturing process; the comparator can achieve high resolution, high speed, and low delay; and as shown in formula (4), it requires taking the logarithm of time, thus being insensitive to timing errors. Therefore, the temperature sensor of this disclosure also has the advantages of small area (2000um2) and low power consumption (less than 900uW). This is mainly because it eliminates the need for a high-precision ADC (digital-to-analog converter), which typically occupies a large area and consumes a lot of power.

[0119] Figure 9 The diagram shown is a structural schematic of the chip described in an embodiment of this disclosure. Figure 9 As shown, this disclosure provides a chip including the temperature sensor described above and a memory. The memory is configured to store a lookup table corresponding to the preset functional relationship.

[0120] Reference Figure 5 and Figure 6 In the temperature sensor, a first capacitor is electrically coupled between a first voltage terminal and ground, a second capacitor is electrically coupled between a second voltage terminal and ground, a third capacitor is electrically coupled in parallel with the second capacitor, a first transistor is electrically coupled in parallel with the first capacitor, and a second transistor is electrically coupled in parallel with the second capacitor.

[0121] Additionally, the control unit is configured to: charge the first capacitor and the second capacitor; discharge the first capacitor through the first transistor while simultaneously discharging the second capacitor through the second transistor; stop discharging the second capacitor through the second transistor and instead connect the second capacitor in parallel with the third capacitor, causing the voltage of the second capacitor to drop.

[0122] Furthermore, the temperature sensing unit is electrically coupled to the first voltage terminal and the second voltage terminal. The temperature sensing unit is configured to: in response to the voltage of the first capacitor starting to be higher than the voltage of the second capacitor, start counting using a counter and determine the start time of counting as a first moment; determine the moment when the voltage of the first capacitor drops to the voltage of the second capacitor through the discharge of the first transistor as a second moment; and determine the sensed temperature based on the first moment, the second moment, and a preset functional relationship.

[0123] The protection scope of the temperature sensing method described in this disclosure is not limited to the execution order of the steps listed in this embodiment. Any solution implemented by adding, subtracting, or replacing steps in the prior art based on the principles of this disclosure is included within the protection scope of this disclosure.

[0124] The temperature sensor and chip provided in this disclosure can implement the temperature sensing method described in this disclosure. However, the implementation device of the temperature sensing method described in this disclosure includes, but is not limited to, the structure of the temperature sensor and chip listed in this embodiment. Any structural modifications and substitutions of the prior art made in accordance with the principles of this disclosure are included within the protection scope of this disclosure.

[0125] In the several embodiments provided in this disclosure, it should be understood that the disclosed temperature sensor device or method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules / units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or units may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or modules or units may be electrical, mechanical, or other forms.

[0126] The modules / units described as separate components may or may not be physically separate. The components shown as modules / units may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules / units can be selected to achieve the objectives of the embodiments of this disclosure, depending on actual needs. For example, the functional modules / units in the various embodiments of this disclosure may be integrated into one processing module, or each module / unit may exist physically separately, or two or more modules / units may be integrated into one module / unit.

[0127] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0128] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0129] The above embodiments are merely illustrative of the principles and effects of this disclosure and are not intended to limit this disclosure. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this disclosure. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this disclosure should still be covered by the claims of this disclosure.

Claims

1. A temperature sensing method, characterized by, The method comprises: charging a first capacitor and a second capacitor; discharging the first capacitor through a first transistor while discharging the second capacitor through a second transistor; stopping discharging the second capacitor through the second transistor and instead connecting the second capacitor in parallel with a third capacitor so that the voltage of the second capacitor drops; starting a counter in response to the voltage of the first capacitor starting to be higher than the voltage of the second capacitor, and determining a first time point as the time point when the counter starts; determining a second time point as the time point when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor; and determining a sensing temperature according to the first time point, the second time point and a preset function relationship, wherein the preset function relationship is represented as: , the constant term is a relationship composed of a band gap voltage of silicon, a crystal management factor, a Boltzmann constant and a unit charge amount, x represents a multiple relationship between a sampling voltage of the transistor at the second time and a sampling voltage difference, the sampling voltage difference refers to a sampling voltage difference of the transistor at the first time and the second time, and N represents a proportional relationship of a capacitance value of the first capacitor, a capacitance value of the second capacitor, the first time and the second time. wherein N in the preset function relationship is represented as: N = (a capacitance value C1 of the first capacitor x the second time point ts2) / (a capacitance value C2 of the second capacitor x the first time point ts1), wherein x in the preset function relationship is represented as: x = (the voltage VC1 of the second capacitor at the first time point - the voltage VC2 of the second capacitor at the second time point) / the voltage VC1 of the second capacitor at the first time point, and x = a capacitance value C3 of the third capacitor / (the capacitance value C2 of the second capacitor + the capacitance value C3 of the third capacitor).

2. The temperature sensing method of claim 1, wherein, The step of determining the second time point as the time point when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor comprises: stopping the counter when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor, and obtaining a count value of the counter; and determining the second time point according to the first time point, the count value and a clock signal period.

3. The temperature sensing method of claim 2, wherein, The step of determining the second time point according to the first time point, the count value and a clock signal period comprises: inputting the voltage of the first capacitor and the voltage of the second capacitor into an in-phase terminal and an inverse-phase terminal of a comparator respectively, and taking an output of the comparator as a first signal; taking an output of a flip-flop controlled by a clock signal as a second signal, the clock signal being further used to control the second capacitor to be electrically coupled in parallel with the third capacitor to share electric charges so that the voltage of the second capacitor drops to a set voltage; performing AND operation on the first signal and the second signal to output an enable signal for the counter; outputting a timing time interval by the counter based on the clock signal period and the enable signal; and adding the timing time interval to the first time point to obtain the second time point.

4. The temperature sensing method of claim 1, wherein, The method further comprises: establishing a lookup table between the count value and the temperature according to a mapping relationship between each count value and the temperature obtained in advance, so as to directly determine the corresponding temperature in the lookup table according to the obtained count value.

5. The temperature sensing method according to claim 1, wherein: the first transistor and the second transistor comprise a diode or a bipolar junction transistor.

6. The temperature sensing method according to claim 1, wherein: The first capacitor and the second capacitor are of the same specification, and the first transistor and the second transistor are of the same specification.

7. A temperature sensor, characterized by Comprise: a first capacitor, electrically coupled between a first voltage terminal and ground; a second capacitor, electrically coupled between a second voltage terminal and ground; a third capacitor, electrically coupled in parallel with the second capacitor; a first transistor, electrically coupled in parallel with the first capacitor; a second transistor, electrically coupled in parallel with the second capacitor; a control unit configured to: charge the first capacitor and the second capacitor; discharge the first capacitor through the first transistor while discharging the second capacitor through the second transistor; stop discharging the second capacitor through the second transistor and instead discharge the second capacitor in parallel with the third capacitor so that the voltage of the second capacitor drops; and a temperature sensing unit electrically coupled to the first voltage terminal and the second voltage terminal and configured to: start counting with a counter in response to the voltage of the first capacitor starting to be higher than the voltage of the second capacitor, determine a first time as the time when the counting starts; determine a second time as the time when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor; and determine a sensed temperature according to the first time, the second time, and a preset functional relationship, wherein the preset function relationship is represented as: , the constant term is a relationship composed of a band gap voltage of silicon, a crystal management factor, a Boltzmann constant and a unit charge amount, x represents a multiple relationship between a sampling voltage of the transistor at the second time and a sampling voltage difference, the sampling voltage difference refers to a sampling voltage difference of the transistor at the first time and the second time, and N represents a proportional relationship of a capacitance value of the first capacitor, a capacitance value of the second capacitor, the first time and the second time. wherein N in the preset functional relationship is represented as: N = (the capacitance C1 of the first capacitor x the second time ts2) / (the capacitance C2 of the second capacitor x the first time ts1), wherein x in the preset functional relationship is represented as: x = (the voltage VC1 of the second capacitor at the first time - the voltage VC2 of the second capacitor at the second time) / the voltage VC1 of the second capacitor at the first time, and x = the capacitance C3 of the third capacitor / (the capacitance C2 of the second capacitor + the capacitance C3 of the third capacitor).

8. The temperature sensor of claim 7, wherein, The temperature sensing unit is configured to: stop counting with the counter and obtain the count value of the counter when the voltage of the first capacitor drops to the voltage of the second capacitor through the first transistor; and determine the second time according to the first time, the count value, and the period of a clock signal. The temperature sensing unit is configured to:

9. The temperature sensor of claim 8, wherein, receive the voltage of the first capacitor from the first voltage terminal with the non-inverting input of a comparator, receive the voltage of the second capacitor from the second voltage terminal with the inverting input of the comparator, and use the output of the comparator as a first signal; receive a clock signal with the enable terminal of a flip-flop, and use the output of the flip-flop as a second signal, the clock signal being further used to control the second capacitor to be electrically coupled in parallel with the third capacitor to share charge so that the voltage of the second capacitor drops to a set voltage; perform AND operation on the first signal and the second signal and output the result as an enable signal for the counter; output a timing time interval based on the period of the clock signal and the enable signal with the counter; ​ Add the time interval to the first time to obtain the second time.

10. The temperature sensor of claim 7, wherein, The temperature sensing unit is configured to: According to the mapping relationship between the pre-acquired count value and temperature, a lookup table between the count value and temperature is established to directly determine the corresponding temperature in the lookup table according to the acquired count value.

11. The temperature sensor of claim 7, wherein: The first transistor and the second transistor include a diode or a bipolar junction transistor.

12. The temperature sensor of claim 7, wherein: The first capacitor and the second capacitor are of the same specification, and the first transistor and the second transistor are of the same specification.

13. The temperature sensor of claim 7, wherein, Further comprising: A first charge-discharge switch switching unit, a second charge-discharge switch switching unit, and a third charge-discharge switch switching unit controlled by the control unit, The first charge-discharge switch switching unit is electrically coupled with the first capacitor, the second charge-discharge switch switching unit is electrically coupled with the second capacitor, and the third charge-discharge switch switching unit is electrically coupled with the third capacitor.

14. The temperature sensor of claim 13, wherein, The first charge-discharge switch switching unit includes a second MOS tube, a third MOS tube, and a fourth MOS tube, the second charge-discharge switch switching unit includes a sixth MOS tube, a seventh MOS tube, and an eighth MOS tube, and the third charge-discharge switch switching unit includes a ninth MOS tube and a tenth MOS tube; One end of the first capacitor is electrically coupled with the source of the fourth MOS tube and the drain of the third MOS tube, respectively, the other end of the first capacitor is electrically coupled with the ground, the drain of the second MOS tube is electrically coupled with the source of the third MOS tube and one end of the first transistor, respectively, the source of the second MOS tube is electrically coupled with the ground, the other end of the first transistor is electrically coupled with the ground, and the drain of the fourth MOS tube is electrically coupled with a preset voltage; One end of the second capacitor is electrically coupled with the source of the eighth MOS tube and the drain of the seventh MOS tube, respectively, the other end of the second capacitor is electrically coupled with the ground, the drain of the sixth MOS tube is electrically coupled with the source of the seventh MOS tube and one end of the second transistor, respectively, the source of the sixth MOS tube is electrically coupled with the ground, the other end of the second transistor is electrically coupled with the ground, and the drain of the eighth MOS tube is electrically coupled with a preset voltage; One end of the third capacitor is electrically coupled with the source of the ninth MOS tube and the drain of the tenth MOS tube, respectively, the other end of the third capacitor is electrically coupled with the ground, the drain of the ninth MOS tube is electrically coupled with one end of the second capacitor, and the source of the tenth MOS tube is electrically coupled with the ground.

15. The temperature sensor of claim 14, wherein, The control unit is configured to: In the charging period, the second MOS tube, the fourth MOS tube, the sixth MOS tube, the eighth MOS tube and the ninth MOS tube are controlled to be closed, the third MOS tube, the seventh MOS tube and the tenth MOS tube are controlled to be opened, so that the preset voltage charges the first capacitor and the second capacitor, and the first transistor and the second transistor are discharged and cleared; From the start of the discharging to the first moment, the second MOS tube, the fourth MOS tube, the sixth MOS tube, the eighth MOS tube and the ninth MOS tube are controlled to be opened, the third MOS tube, the seventh MOS tube and the tenth MOS tube are controlled to be closed, so that the first capacitor is discharged through the first transistor, the second capacitor is discharged through the second transistor, and the third capacitor is discharged and cleared through the tenth MOS tube; After the first moment, the seventh MOS tube and the tenth MOS tube are controlled to be opened, and the ninth MOS tube is controlled to be closed, so that the first capacitor continues to be discharged through the first transistor, the second capacitor is connected in parallel with the third capacitor, and the voltage of the second capacitor decreases.

16. A chip, characterized by Comprise: The temperature sensor according to any one of claims 7 to 15; And The memory is configured to store a lookup table corresponding to a preset function relationship.

Images