Temperature sensing apparatus and method having calibration mechanism

Abstract

A temperature sensing method is provided. A first and a second voltage digital codes are configured corresponding to a first and a second temperatures. A base temperature that makes a voltage across a component of a temperature sensing circuit to be a constant is configured. A temperature difference and a digital code difference are calculated to further calculate a predetermined slope to establish a relation equation. A sensing is performed corresponding to the first temperature to generate an actual voltage digital code. A base temperature difference is calculated between the first temperature and the base temperature and an actual digital code difference between the actual voltage digital code and the first voltage digital code are calculated to further calculate a slope variation to modify the relation equation to perform temperature sensing by using the temperature sensing circuit according to the modified equation.

Description

[Technical Field]

[0001] This invention relates to temperature sensing technology, and more particularly to a temperature sensing device and temperature sensing method with a correction mechanism. [Previous Technology]

[0002] In integrated circuits, temperature sensing circuits can be used to detect the temperature of a chip or the environment, and adjust the chip's operation based on the detection results to prevent damage to the chip in inappropriate temperature environments. Common temperature sensing circuits can utilize temperature-related parameters in electronic components, such as the voltage across semiconductor components, to achieve the sensing purpose.

[0003] However, due to process variations, the component voltage across different temperature sensing circuits may change to varying degrees with temperature. Without a calibration mechanism that can be executed quickly while maintaining calibration accuracy, the calibration time cost of the temperature sensing circuit will increase. [Summary of the Invention]

[0004] In view of the problems of the prior art, one object of the present invention is to provide a temperature sensing method with a correction mechanism to improve the prior art.

[0005] This invention includes a temperature sensing method with a correction mechanism, comprising: setting a first voltage digital code by a processing circuit corresponding to a first temperature; setting a second voltage digital code by a processing circuit corresponding to a second temperature; setting a reference temperature by a processing circuit, wherein the reference temperature makes the voltage across the circuit elements of the temperature sensing circuit constant; calculating a preset temperature difference between the first temperature and the second temperature and a preset digital code difference between the first voltage digital code and the second voltage digital code by a processing circuit, and then calculating a preset slope based on a first ratio between the preset digital code difference and the preset temperature difference, and establishing a preset temperature and digital code relationship equation based on the preset slope; and sensing the temperature... The circuit senses the first temperature corresponding to the voltage across the circuit element to generate an actual voltage digital code; the processing circuit calculates the reference temperature difference between the first temperature and the reference temperature; the processing circuit calculates the actual voltage digital code and the actual digital code difference between the first voltage digital code, and then calculates the slope variation based on the second ratio between the actual digital code difference and the reference temperature difference; the processing circuit corrects the preset slope based on the slope variation to generate a corrected slope to replace the preset slope in the preset temperature and digital code relationship equation to generate the actual temperature and digital code relationship equation; and the temperature is sensed through the temperature sensing circuit based on the actual temperature and digital code relationship equation.

[0006] The present invention includes a temperature sensing device with a correction mechanism, comprising: a temperature sensing circuit and a processing circuit. The processing circuit is configured to perform a temperature sensing method, comprising: setting a first voltage digital code corresponding to a first temperature; setting a second voltage digital code corresponding to a second temperature; setting a reference temperature, wherein the reference temperature makes the voltage across the circuit elements of the temperature sensing circuit constant; calculating a preset temperature difference between the first temperature and the second temperature and a preset digital code difference between the first voltage digital code and the second voltage digital code, and then calculating a preset slope based on a first ratio between the preset digital code difference and the preset temperature difference, and establishing a preset temperature-digital code relationship equation based on the preset slope; causing the temperature sensing circuit to sense the first temperature to generate an actual voltage digital code; calculating a reference temperature difference between the first temperature and the reference temperature; calculating the actual voltage digital code and the actual digital code difference between the first voltage digital code, and then calculating a slope variation based on a second ratio between the actual digital code difference and the reference temperature difference; correcting the preset slope based on the slope variation to generate a corrected slope to replace the preset slope in the preset temperature-digital code relationship equation to generate an actual temperature-digital code relationship equation; and performing temperature sensing through the temperature sensing circuit based on the actual temperature-digital code relationship equation.

[0007] Regarding the features, implementation and effects of this case, the preferred embodiments are described in detail below with reference to the drawings.

Implementation Method

[0008] One objective of the present invention is to provide a temperature sensing method with a correction mechanism. By utilizing the characteristic that the voltage across circuit elements is constant at a reference temperature close to absolute zero, the method only needs to sense the digital code of the temperature to be corrected once and then calculate it with a preset digital code. This can maintain the correction accuracy while significantly reducing the correction time cost.

[0009] Please refer to Figure 1. Figure 1 shows a block diagram of a temperature sensing device 100 with a calibration mechanism according to an embodiment of the present invention. The temperature sensing device 100 includes a temperature sensing circuit 110 and a processing circuit 120.

[0010] In one embodiment, the voltage across a circuit element of the temperature sensing circuit 110 is temperature-dependent, enabling the temperature sensing circuit 110 to generate a corresponding digital code based on the magnitude of the voltage across this circuit element at different temperatures. In one embodiment, the voltage across this circuit element is the base-emitter voltage difference (VBE) of a bipolar junction transistor (BJT) made of silicon.

[0011] The processing circuit 120 is electrically coupled to the temperature sensing circuit 110 and includes computer executable commands to perform temperature sensing with a calibration mechanism.

[0012] Please refer to Figure 2. Figure 2 shows a schematic diagram of the relationship between temperature and the voltage across the circuit elements of the temperature sensing circuit 110 in one embodiment of the present invention. In Figure 2, the horizontal axis represents temperature in absolute temperature (K), and the vertical axis represents the voltage across the circuit elements in digital measurement units.

[0013] The temperature sensing performed by the processing circuit 120 and the temperature sensing circuit 110 will be described in detail below with reference to both FIG1 and FIG2.

[0014] The processing circuit 120 sets a first voltage digital code DC1 corresponding to the first temperature TP1 in FIG2. In one embodiment, the first temperature TP1 is, for example, room temperature with an absolute temperature of 303.15 (30 degrees Celsius). The processing circuit 120 may set a first voltage digital code DC1 corresponding to the first temperature TP1.

[0015] The processing circuit 120 sets a second voltage digital code DC2 corresponding to the second temperature TP2 in FIG2. In one embodiment, the second temperature TP2 is, for example, room temperature with an absolute temperature of 323.15 degrees (50 degrees Celsius). The processing circuit 120 may set a second voltage digital code DC2 corresponding to the second temperature TP2.

[0016] The processing circuit 120 sets a reference temperature TPB corresponding to FIG2, wherein the reference temperature TPB causes the circuit elements of the temperature sensing circuit 110 to have a constant reference voltage across them. In one embodiment, the difference between the reference temperature TPB and absolute zero (0K, i.e., approximately -273.15 degrees Celsius) is less than a first temperature range, for example, but not limited to, a value within a range of less than 5 degrees. In one embodiment, the reference temperature TPB is very close to absolute zero. In one embodiment, the reference temperature TPB may be absolute zero.

[0017] As shown in Figure 2, the voltage across the base-emitter voltage difference circuit element is 1.2 volts when the temperature is close to absolute zero. However, as the temperature rises, different temperature sensing circuits 110 will have different linear relationships LR1~LR2 with different slopes as shown in Figure 2 due to process variations, and will have different voltages across the circuit element at the first temperature TP1, thereby generating different digital codes.

[0018] Therefore, corresponding to an ideal temperature sensing circuit 110, the processing circuit 120 can set a reference temperature TPB, and the reference temperature TPB makes the voltage across the circuit elements constant, for example, 1.2 volts. For ease of explanation, the reference temperature TPB is directly plotted as absolute zero in Figure 2. More specifically, even if different temperature sensing circuits 110 have slight variations in manufacturing processes, causing variations in the voltage across the circuit elements at higher temperatures, the voltage across the circuit elements in these temperature sensing circuits 110 will not vary when extremely close to absolute zero, and will all be 1.2 volts.

[0019] It should be noted that the above values ​​are only examples. In practice, the actual value of the reference voltage may vary slightly depending on the actual configuration of the reference temperature TPB.

[0020] The processing circuit 120 first senses the first voltage digital code DC1 and the second voltage digital code DC2 obtained from the first temperature TP1 and the second temperature TP2 on the linear relationship LR1, and then calculates the preset temperature difference between the first temperature TP1 and the second temperature TP2 and the preset digital code difference between the first voltage digital code DC1 and the second voltage digital code DC2, and then calculates the preset slope SLP according to the first ratio between the preset digital code difference and the preset temperature difference.

[0021] SLP= (DC2-DC1) / (TP2-TP1) (Equation 1)

[0022] The processing circuit 120 then establishes a constant and a preset temperature-digit code relationship equation based on the preset slope SLP to ensure the relationship between the temperature and voltage digit codes of the two points is valid. When the voltage digit code is DC, the temperature is T, the constant is C, and the preset slope is SLP, the preset temperature-digit code relationship equation between the voltage digit code DC and the temperature T can be expressed by the following equation:

[0023] DC=SLP×T+C (Equation 2)

[0024] The temperature sensing circuit 110 senses the first temperature TP1 to generate the actual voltage digital code DCA. More specifically, as described above, due to process variations, the actual voltage digital code DCA sensed by the actual temperature sensing circuit 110 corresponding to the first temperature TP1 corresponds to the linear relationship LR2 in Figure 2.

[0025] The processing circuit 120 calculates the actual digital code difference between the actual voltage digital code DCA and the first voltage digital code DC1. Furthermore, the processing circuit 120 calculates the reference temperature difference between the first temperature TP1 and the reference temperature TPB. The processing circuit 120 then calculates the slope variation SLV based on a second ratio between the actual digital code difference and the reference temperature difference. The slope variation SLV can be expressed by the following formula:

[0026] SLV=(DCA-DC1) / (TP1-TPB) (Equation 3)

[0027] The processing circuit 120 corrects the preset slope SLP based on the slope variation SLV to generate a corrected slope CLP. In one embodiment, the processing circuit 120 adds the slope variation SLV to the preset slope SLP to obtain the corrected slope CLP, which can be expressed by the following formula:

[0028] CLP=SLV+SLP (Equation 4)

[0029] This process of correcting the slope is to correct the slope of the linear relationship LR1 to be close to the linear relationship LR2 through the slope variation SLV.

[0030] The processing circuit 120 replaces the preset slope SLP in the preset temperature-digital code relationship equation (i.e., equation (2)) with the correction slope CLP to generate the actual temperature-digital code relationship equation, which can be expressed by the following equation:

[0031] DC=CLP×T+C (Equation 5)

[0032] The processing circuit 120 senses the temperature through the temperature sensing circuit 110 according to the equation relating the actual temperature to the digital code. More specifically, the temperature sensing performed by the processing circuit 120 first involves the temperature sensing circuit 110 sensing the temperature of the TPU to be measured to generate the digital code DCU of the voltage to be measured. The processing circuit 120 then substitutes the digital code DCU of the voltage to be measured into the voltage digital code DC in the equation relating the actual temperature to the digital code to obtain:

[0033] DCU=CLP×TPU+C (Equation 6)

[0034] After rearranging (Equation 6), the processing circuit 120 can obtain the sensed value of the temperature of the TPU to be measured:

[0035] TPU=(DCU-C) / CLP (Equation 7)

[0036] Therefore, when performing temperature sensing, the processing circuit 120 can generate the temperature to be measured TPU according to the calibration mechanism, corresponding to the linear relationship LR2 actually possessed by the temperature sensing circuit 110.

[0037] The following will use a numerical example to explain the correction mechanism and temperature sensing of the processing circuit 120.

[0038] In this numerical example, the first temperature TP1 is an absolute temperature of 303.15 degrees Celsius (30 degrees Celsius) and the second temperature TP2 is an absolute temperature of 323.15 degrees Celsius (50 degrees Celsius). The first voltage digit DC1 is 100 and the second voltage digit DC2 is 50, then the preset slope SLP can be obtained from (Equation 1) as (50 / -20) = -2.5.

[0039] Based on the preset slope SLP of -2.5, when the calculated constant is 857.88, the preset temperature-digit code relationship equation in (Equation 2) will become:

[0040] DC=(-2.5)×T+857.88

[0041] Furthermore, if the actual voltage digit DCA is 105 and the reference temperature TPB is 0.15, the slope variation SLV can be obtained from (Equation 3) as SLV=(105-100) / (303.15-0.15)=5 / 303=0.0165. Further, the correction slope CLP can be obtained from (Equation 4) as CLP=-2.5+0.0165=-2.4835. This is the correction slope CLP of the actual temperature sensing approximately linear relationship LR2 obtained after correcting the linear relationship LR1 corresponding to the preset slope SLP through the slope variation SLV.

[0042] When performing temperature sensing, if the voltage code DCU to be measured is 90, the temperature TPU to be measured can be obtained from (Equation 7) as TPU = (90 - 857.88) / (-2.4835) = 309.19 degrees. Therefore, the sensed value of the temperature TPU to be measured is an absolute temperature of 309.19 degrees (36.04 degrees Celsius).

[0043] In some technologies, the impact of process differences on different temperature sensing circuits is improved by single-point calibration or two-point calibration. However, with single-point calibration, the digital code corresponding to the temperature further away from the calibration point will become more divergent and lose calibration accuracy, while two-point calibration requires heating and cooling of the chip of each temperature sensing circuit, which increases the calibration time cost.

[0044] The temperature sensing method with correction mechanism of the present invention can take advantage of the characteristic that the voltage across circuit elements is constant at a reference temperature close to absolute zero. It only needs to sense the digital code of the temperature to be corrected once and then calculate it with the preset digital code. It can maintain the correction accuracy while greatly reducing the correction time cost.

[0045] Please refer to Figure 3. Figure 3 shows a flowchart of a temperature sensing method 300 with a correction mechanism according to an embodiment of the present invention.

[0046] This invention discloses a temperature sensing method 300 with a correction mechanism, which is applied, for example, but not limited to, the temperature sensing device 100 of FIG. 1. One embodiment of the temperature sensing method 300 is shown in FIG. 3, and includes the following steps.

[0047] In step S310, the processing circuit 120 sets the first voltage digital code DC1 corresponding to the first temperature TP1.

[0048] In step S320, the processing circuit 120 sets the second voltage digital code DC2 corresponding to the second temperature TP2.

[0049] In step S330, the processing circuit 120 sets the reference temperature TPB, wherein the reference temperature TPB makes the voltage across the circuit elements of the temperature sensing circuit 110 constant.

[0050] In step S340, the processing circuit 120 calculates the preset temperature difference between the first temperature TP1 and the second temperature TP2 and the preset digital code difference between the first voltage digital code DC1 and the second voltage digital code DC2, and then calculates the preset slope SLP based on the first ratio between the preset digital code difference and the preset temperature difference, and establishes the preset temperature and digital code relationship equation based on the preset slope SLP.

[0051] In step S350, the temperature sensing circuit 110 senses the first temperature TP1 to generate the actual voltage digital code DCA.

[0052] In step S360, the processing circuit 120 calculates the reference temperature difference between the first temperature TP1 and the reference temperature TPB.

[0053] In step S370, the processing circuit 120 calculates the actual digital code difference between the actual voltage digital code DCA and the first voltage digital code DC1, and then calculates the slope variation SLV based on the second ratio between the actual digital code difference and the reference temperature difference.

[0054] In step S380, the processing circuit 120 corrects the preset slope SLP according to the slope variation SLV to generate a corrected slope CLP to replace the preset slope SLP in the preset temperature and digital code relationship equation to generate the actual temperature and digital code relationship equation.

[0055] In step S390, the processing circuit 120 performs temperature sensing through the temperature sensing circuit 110 according to the equation relating actual temperature and digital code.

[0056] It should be noted that the above-described implementation is merely an example. In other embodiments, those skilled in the art can make modifications without departing from the spirit of the invention.

[0057] In summary, the temperature sensing method with correction mechanism in this invention utilizes the characteristic that the voltage across circuit elements is constant at a reference temperature close to absolute zero. It only needs to sense the digital code of the temperature to be corrected once and then calculate it with the preset digital code, which can maintain the correction accuracy while greatly reducing the correction time cost.

[0058] Although the embodiments of this case are described above, these embodiments are not intended to limit this case. Those skilled in the art can make changes to the technical features of this case based on the explicit or implicit content of this case. All such changes may fall within the scope of patent protection sought in this case. In other words, the scope of patent protection of this case shall be determined by the scope of the patent application in this specification. [Simplified Explanation of the Diagram]

[0059] [Figure 1] shows a block diagram of a temperature sensing device with a correction mechanism in one embodiment of the present invention; [Figure 2] shows a schematic diagram of the relationship between temperature and the voltage across circuit elements of the temperature sensing circuit in one embodiment of the present invention; and [Figure 3] shows a flowchart of a temperature sensing method with a correction mechanism in one embodiment of the present invention.

Claims

1. A temperature sensing method with a correction mechanism, comprising: setting a first voltage digital code corresponding to a first temperature by a processing circuit; setting a second voltage digital code corresponding to a second temperature by the processing circuit; setting a reference temperature by the processing circuit, wherein the reference temperature causes a circuit element of a temperature sensing circuit to have a constant voltage across it; calculating a preset temperature difference between the first temperature and the second temperature and a preset digital code difference between the first voltage digital code and the second voltage digital code by the processing circuit, and then calculating a preset slope based on a first ratio between the preset digital code difference and the preset temperature difference, and establishing a preset temperature-digit code relationship equation based on the preset slope; sensing the first temperature by the temperature sensing circuit to generate an actual voltage digital code; and calculating a reference temperature difference between the first temperature and the reference temperature by the processing circuit. The processing circuit calculates an actual digital code difference between the actual voltage digital code and the first voltage digital code, and then calculates a slope variation based on a second ratio between the actual digital code difference and the reference temperature difference; the processing circuit corrects the preset slope based on the slope variation to generate a corrected slope to replace the preset slope in the preset temperature-digit code relationship equation to generate an actual temperature-digit code relationship equation; and performs temperature sensing through the temperature sensing circuit based on the actual temperature-digit code relationship equation.

2. The temperature sensing method as described in claim 1 further includes: the processing circuit adding the slope variation to the preset slope to generate the correction slope.

3. The temperature sensing method as described in claim 2, wherein the temperature sensing further comprises: sensing a temperature to be measured by the temperature sensing circuit to generate a digital code of a voltage to be measured; and substituting the digital code of the voltage to be measured into the equation relating the actual temperature and the digital code by the processing circuit to obtain a sensed value of the temperature to be measured.

4. The temperature sensing method as described in claim 1, wherein a voltage digital code is DC, a temperature is T, a constant is C, the preset slope is SLP and the correction slope is CLP, the preset temperature and digital code relationship equation is DC=SLP×T+C, and the actual temperature and digital code relationship equation is DC=CLP×T+C.

5. The temperature sensing method as described in claim 1, wherein the difference between the reference temperature and an absolute zero is less than a preset range.

6. The temperature sensing method as described in claim 5, wherein the voltage across the circuit element is the base-emitter voltage difference of a bipolar junction transistor (BJT) formed of silicon.

7. A temperature sensing device with a calibration mechanism, comprising: a temperature sensing circuit; and a processing circuit configured to perform a temperature sensing method, comprising: setting a first voltage digit code corresponding to a first temperature; setting a second voltage digit code corresponding to a second temperature; setting a reference temperature, wherein the reference temperature causes a circuit element of the temperature sensing circuit to have a constant voltage across it; calculating a preset temperature difference between the first temperature and the second temperature and a preset digit code difference between the first voltage digit code and the second voltage digit code, and then calculating a preset slope based on a first ratio between the preset digit code difference and the preset temperature difference, and establishing a preset temperature-digit code relationship equation based on the preset slope; causing the temperature sensing circuit to sense the first temperature to generate an actual voltage digit code; calculating a reference temperature difference between the first temperature and the reference temperature; calculating the actual voltage digit code and an actual digit code difference between the first voltage digit code, and then calculating a slope variation based on a second ratio between the actual digit code difference and the reference temperature difference; The preset slope is corrected according to the slope variation to generate a corrected slope to replace the preset slope in the preset temperature-digital code relationship equation to generate an actual temperature-digital code relationship equation; and a temperature is sensed through the temperature sensing circuit according to the actual temperature-digital code relationship equation.

8. The temperature sensing device as claimed in claim 7 further includes: a processing circuit that adds the slope variation to the preset slope to generate a correction slope.

9. The temperature sensing device as claimed in claim 8, wherein the temperature sensing further comprises: sensing a temperature to be measured by the temperature sensing circuit to generate a digital code of a voltage to be measured; and substituting the digital code of the voltage to be measured into the equation relating the actual temperature and the digital code by the processing circuit to obtain a sensed value of the temperature to be measured.

10. The temperature sensing device as claimed in claim 7, wherein a voltage digital code is DC, a temperature is T, a constant is C, the preset slope is SLP and the correction slope is CLP, the preset temperature and digital code relationship equation is DC=SLP×T+C, and the actual temperature and digital code relationship equation is DC=CLP×T+C.

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