Code shift calculation circuit and code shift value calculation method

Abstract

The present invention provides a code shift calculation circuit and a method for calculating a code shift value. A first operation circuit of the code shift calculation circuit generates a first output value according to a temperature difference value and a first change rate of a driving strength code to temperature, wherein the temperature difference value is the difference between a previous temperature when a previous ZQ command is obtained and a current temperature when a current ZQ command is obtained. A second operation circuit of the code shift calculation circuit generates a second output value according to a voltage difference value and a second change rate of a driving strength code to voltage, wherein the voltage difference value is the difference between a previous operating voltage when a previous ZQ command is obtained and a current operating voltage when a current ZQ command is obtained. A third operation circuit of the code shift calculation circuit sums the first output value and the second output value to generate a shift value, thereby adjusting the driving strength code calibrated by ZQ.

Description

Technical Field

[0001] The present invention relates to ZQ calibration, and in particular to a code shift calculation circuit and a method for calculating a code displacement value. Background Art

[0002] As the operating speed of electronic devices increases, the swing width of signals transmitted between semiconductor memory devices within the electronic devices decreases to minimize the delay time spent on transmitting signals. However, as the swing width decreases, signal transmission is more affected by external noise, and signal reflection at the interface end increases due to impedance mismatch. Impedance mismatch is caused by changes in the manufacturing process, supply voltage, and operating temperature (Process-Voltage-Temperature, PVT). Impedance mismatch will distort the signal output from the semiconductor memory device, which may cause faults such as set up / hold failure or signal level misjudgment in the corresponding semiconductor memory device that receives the distorted signal. In order to match the impedance of the transmission line and the output impedance of the output circuit with each other, the output impedance of the semiconductor memory device must be adjusted to match the impedance of the transmission line.

[0003] The ZQ calibration circuit is used to adjust the output impedance of the semiconductor memory device, and provides a ZQ pin as a ZQ calibration terminal in the semiconductor memory device. An external ZQ calibration command, such as a ZQCS (ZQ Calibration Short) command, is input into the ZQ pin. When the external ZQ calibration command is input, the ZQ calibration operation is performed within the period defined by the command to change the resistance value of the output driver using the generated code. In order to improve the resistance accuracy of the output driver after ZQ calibration, the resolution can be improved, that is, the code is increased. However, since the period defined by the ZQCS command is short, if the resolution is improved by increasing the width of the code that can be moved by a ZQCS command, there is a risk that the signal transmission does not meet the specification (i.e., the period defined by the ZQCS command). In contrast, if the resolution is improved without increasing the width of the code that can be moved by a ZQCS command, it will be difficult to eliminate the change in output impedance caused by temperature change or voltage change.

[0004] Therefore, other solutions are needed to improve the resolution without increasing the width of the code that can be moved by a ZQCS command, and to eliminate the change in output impedance caused by temperature change or voltage change, that is, the deviation of the drive strength code caused by temperature change or voltage change. Summary of the invention

[0005] The present invention provides a code shift calculation circuit and a code shift value calculation method, which can eliminate the deviation of the driving strength code caused by temperature change or voltage change by shifting the driving strength code calibrated by ZQ.

[0006] The code shift calculation circuit of the present invention is used to generate a shift value to adjust the driving strength code calibrated by ZQ. The code shift calculation circuit includes a first operation circuit, a second operation circuit and a third operation circuit. The first operation circuit is used to generate a first output value based on a temperature difference and a first rate of change of the driving strength code to the temperature. The temperature difference is the difference between the previous temperature when the previous ZQ command is obtained and the current temperature when the current ZQ command is obtained. The second operation circuit is used to generate a second output value based on a voltage difference and a second rate of change of the driving strength code to the voltage. The voltage difference is the difference between the previous operating voltage when the previous ZQ command is obtained and the current operating voltage when the current ZQ command is obtained. The third operation circuit is used to sum the first output value and the second output value to generate a shift value, thereby adjusting the driving strength code.

[0007] The method for calculating the code shift value of the present invention is used to generate a shift value to adjust the driving strength code calibrated by ZQ. The method includes: generating a first output value according to a temperature difference value and a first change rate of the driving strength code to temperature, wherein the temperature difference value is the difference between a previous temperature when a previous ZQ command is obtained and a current temperature when a current ZQ command is obtained; generating a second output value according to a voltage difference value and a second change rate of the driving strength code to voltage, wherein the voltage difference value is the difference between a previous operating voltage when a previous ZQ command is obtained and a current operating voltage when a current ZQ command is obtained; and summing the first output value and the second output value to generate a shift value, thereby adjusting the driving strength code.

[0008] Based on the above, the present invention can generate a code displacement value according to the temperature difference and the voltage difference of the working voltage, thereby adjusting the driving strength code calibrated by ZQ. Therefore, the present invention can improve the resolution while eliminating the deviation of the driving strength code caused by temperature change or voltage change. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and together with the description serve to explain the principles of the present invention.

[0010] Figure 1 is a block diagram of a code shift calculation device of the present invention;

[0011] Figure 2A is a graph showing the relationship between the rate of change of code with temperature and voltage;

[0012] Figure 2B is a graph showing the relationship between the rate of change of code to voltage and temperature;

[0013] Figure 3 is a block diagram of a code shift calculation circuit of the present invention;

[0014] Figure 4 is a block diagram of a ratio calculation circuit 311 according to an embodiment of the present invention;

[0015] Figure 5 is a block diagram of a ratio calculation circuit 321 according to an embodiment of the present invention;

[0016] Figure 6 The present invention is a flowchart of the steps of the method for calculating the code displacement value.

[0017] Description of Figure Numbers

[0018] 100: Code shift calculation device

[0019] 110: Resistor voltage divider circuit

[0020] 120: OR gate

[0021] 130: Temperature change and voltage change calculation circuit

[0022] 140: Code shift calculation circuit

[0023] 150: Fuse

[0024] 300: Code shift calculation circuit

[0025] 310: First operation circuit

[0026] 311: Proportional calculation circuit

[0027] 3111, 3115: Divider

[0028] 3112~3114, 3116~3118: Multiplier

[0029] 312: Multiplier

[0030] 320: Second operation circuit

[0031] 321: Proportional calculation circuit

[0032] 3211, 3215: Divider

[0033] 322: Multiplier

[0034] 330: Adder

[0035] a1~a20: value

[0036] AD1, AD2: Adder

[0037] CSV1: First output value

[0038] CSV2: Second output value

[0039] CSV3: Displacement value

[0040] CT: Current temperature

[0041] CV: Current voltage

[0042] DT: Temperature change

[0043] DV: voltage change

[0044] FF0~FF4:Flip-flop

[0045] HT: high temperature

[0046] HV: High Voltage

[0047] LT: Low Temperature

[0048] LV: Low Pressure

[0049] OP: Amplifier

[0050] PU / PD: pull-up / pull-down signal

[0051] R(V)_CT, R(T)_CV, R(T)_HV, R(T)_LV, R(V)_HT, R(V)_LT, R(V)_T0~R(V)_T3, R(T)_V0~R(T)_V3: change rate

[0052] S1~S4: Multitasker

[0053] S610~S630: Steps

[0054] SF: Shifter

[0055] SUB1, SUB2: Subtractor

[0056] T0~T3: Temperature

[0057] T_C: Temperature code

[0058] V0~V3: voltage

[0059] VBGR: reference voltage

[0060] VDD: operating voltage

[0061] VDD_C: Voltage code

[0062] ZQCL: Commands

[0063] ZQCS: Commands DETAILED DESCRIPTION

[0064] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0065] Figure 1 FIG. 1 is a block diagram of a code shift calculation device of the present invention. Figure 1 The code shift calculation device 100 includes a resistor divider circuit 110, an amplifier OP, an OR gate 120, a temperature change and voltage change calculation circuit 130, a code shift calculation circuit 140, a fuse 150, a shifter SF, and a flip-flop FF4. The resistor divider circuit 110 is used to provide a divided voltage of the working voltage VDD. The amplifier OP receives the divided voltage of the working voltage VDD and a reference voltage VBGR to output a voltage code VDD_C representing the voltage value of the working voltage VDD.

[0066] The temperature change and voltage change calculation circuit 130 receives a voltage code VDD_C and a temperature code T_C representing a temperature value. The temperature change and voltage change calculation circuit 130 includes flip-flops FF0-FF3 and subtractors SUB1 and SUB2. The flip-flops FF0-FF3 are triggered by a ZQCS command or a ZQCL command. For example, at the time point of the current rising edge of the ZQCS command, the flip-flop FF0 outputs the voltage code VDD_C corresponding to this time point as the current voltage CV, and the flip-flop FF1 outputs the voltage code VDD_C corresponding to the time point of the previous rising edge of the ZQCS command as the previous voltage. The subtractor SUB1 calculates the voltage change DV between the time point of the previous rising edge and the time point of the current rising edge based on the current voltage CV and the previous voltage code. Similarly, the flip-flop FF2 outputs the current temperature CT, the flip-flop FF3 outputs the previous temperature, and the subtractor SUB2 is used to generate the temperature change DT.

[0067] The code shift calculation circuit 140 can calculate the shift value for adjusting the driving strength code calibrated by ZQ according to the current voltage CV, the voltage change DV, the current temperature CT and the temperature change DT. In this way, the present invention can adjust (or shift) the driving strength code calibrated by ZQ in response to temperature changes or voltage changes. It should be noted that the rate of change of the driving strength code to temperature at high / low voltages and the rate of change of the driving strength code to voltage at high / low temperatures required for code shift calculation can be pre-stored by the fuse 150. However, the present invention is not limited to storing the above-mentioned change rate by a fuse, and any storage device (such as a memory circuit) with a storage function should be within the protection scope of the present invention.

[0068] The shifter SF receives the shift value calculated by the code shift calculation circuit 140 and the pull-up / pull-down signal PU / PD. The shifter SF adjusts the pull-up / pull-down signal PU / PD according to the shift value, and outputs the adjusted pull-up / pull-down signal PU / PD to the flip-flop FF4. The flip-flop FF4 outputs the adjusted pull-up / pull-down signal PU / PD (in code form) after being triggered. In one embodiment, the shifter SF can be implemented by an adder.

[0069] Figure 2A is a graph of the rate of change of code over temperature versus voltage. Figure 2A , R(T)_LV represents the rate of change of the code to the voltage under the low voltage LV, and R(T)_HV represents the rate of change of the code to the voltage under the high voltage HV. Among them, the above-mentioned "high voltage" and "low voltage" can be two extreme values ​​of the normal working voltage range. The values ​​of the rate of change R(T)_LV and the rate of change R(T)_HV can be obtained by experiment and stored in the fuse 150 in advance. The code shift calculation circuit 140 can assume that the rate of change of the code to the temperature is linear with respect to the change of the voltage, thereby calculating the corresponding rate of change of the code to the voltage (for example, any one of the rates of change R(T)_V0 to R(T)_V3) based on the received values ​​of the rate of change R(T)_LV, the rate of change R(T)_HV and the current voltage CV (for example, any one of the voltages V0 to V3). It should be noted that although Figure 2A The voltages V0 to V3 are merely exemplified, but the present invention is not limited thereto. In other embodiments, more voltage values ​​may be distinguished between the voltage LV and the voltage HV.

[0070] Figure 2B is a graph of the rate of change of code to voltage versus temperature. Figure 2B, R(V)_LT represents the rate of change of the code to the voltage at a low temperature LT, and R(V)_HT represents the rate of change of the code to the voltage at a high temperature HT. Among them, the above-mentioned "high temperature" and "low temperature" can be two extreme values ​​of the normal working temperature range. The values ​​of the rate of change R(V)_LT and the rate of change R(V)_HT can be obtained by experiment and stored in the fuse 150 in advance. The code shift calculation circuit 140 can assume that the rate of change of the code to the voltage is linear with respect to the change of temperature, thereby calculating the corresponding rate of change of the code to the voltage (for example, any one of the rates of change R(V)_T0 to R(V)_T3) based on the received values ​​of the rate of change R(V)_LT, the rate of change R(V)_HT and the current temperature CT (for example, any one of the temperatures T0 to T3). It should be noted that although Figure 2B Only the temperatures T0 to T3 are exemplified, but the present invention is not limited thereto. In other embodiments, more temperature values ​​can be distinguished between the low temperature LT and the high temperature HT.

[0071] Figure 3 FIG. 1 is a block diagram of the code shift calculation circuit of the present invention. Figure 3 The code shift calculation circuit 300 includes a first operation circuit 310, a second operation circuit 320 and an adder 330. The first operation circuit 310 includes a ratio calculation circuit 311 and a multiplier 312. The ratio calculation circuit 311 receives the change rate R(T)_HV, the change rate R(T)_LV and the current voltage CV. The ratio calculation circuit 311 calculates the change rate R(T)_CV of the code corresponding to the current voltage CV to the temperature as the first change rate based on the above three values. The multiplier 312 is used to receive the change rate R(T)_CV and the temperature change DT, and calculate the product of the change rate R(T)_CV and the temperature change DT as the first output value CSV1.

[0072] The second operation circuit 320 includes a ratio calculation circuit 321 and a multiplier 322. The ratio calculation circuit 321 receives the change rate R(V)_HT, the change rate R(V)_LT and the current temperature CT. The ratio calculation circuit 321 calculates the change rate R(V)_CT of the code corresponding to the current temperature CT to the voltage as the second change rate based on the above three values. The multiplier 322 is used to receive the change rate R(V)_CT and the voltage change amount DV, and calculate the product of the change rate R(V)_CT and the voltage change amount DV as the second output value CSV2. Finally, the adder 330 is used to perform an addition operation on the first output value CSV1 and the second output value CSV2 to obtain a displacement value CSV3 for adjusting the drive strength code.

[0073] Figure 4 FIG. 3 is a block diagram of a ratio calculation circuit 311 according to an embodiment of the present invention. Figure 4 In this embodiment, the ratio calculation circuit 311 includes dividers 3111 and 3115, multipliers 3112-3114 and 3116-3118, multiplexers S1 and S2, and adder AD1. Divider 3111 receives the rate of change R(T)_HV and divides the rate of change R(T)_HV by 8 to obtain value a1. Multipliers 3112-3114 receive value a1 and multiply value a1 by 3, 5, and 7, respectively, to obtain values ​​a2-a4. Multiplexer S1 is used to select a value corresponding to the current voltage CV from values ​​a1-a4 according to the current voltage CV and output it, which is called value a5.

[0074] Similarly, the divider 3115 receives the rate of change R(T)_LV and divides the rate of change R(T)_LV by 8 to obtain a6. The multipliers 3116-3118 receive the value a6 and multiply the value a6 by 3, 5 and 7 respectively to obtain values ​​a7-a9. The multiplexer S2 is used to select a value corresponding to the current voltage CV from the values ​​a6-a9 and output it, which is called the value a10. The adder AD1 is used to add the values ​​a5 and a10 to obtain the rate of change R(T)_CV of the code corresponding to the current voltage CV to the temperature.

[0075] Please also refer to Figure 2A and Figure 4 , when the current voltage CV is equal to the voltage V0, multiplexers S1 and S2 will select values ​​a1 and a9 as outputs respectively. When the current voltage CV is equal to the voltage V1, multiplexers S1 and S2 will select values ​​a2 and a8 as outputs respectively. When the current voltage CV is equal to the voltage V2, multiplexers S1 and S2 will select values ​​a3 and a7 as outputs respectively. When the current voltage CV is equal to the voltage V3, multiplexers S1 and S2 will select values ​​a4 and a6 as outputs respectively.

[0076] Figure 5 FIG. 3 is a block diagram of a ratio calculation circuit 321 according to an embodiment of the present invention. Figure 5In this embodiment, the ratio calculation circuit 321 includes dividers 3211 and 3215, multipliers 3212-3214 and 3216-3218, multiplexers S3 and S4, and adder AD2. Divider 3211 receives the rate of change R(V)_HT and divides the rate of change R(V)_HT by 8 to obtain a value a11. Multipliers 3212-3214 receive value a11 and multiply value a11 by 3, 5, and 7, respectively, to obtain values ​​a12-a14. Multiplexer S3 is used to select a value corresponding to the current temperature CT from values ​​a11-a14 according to the current temperature CT and output it, which is called value a15.

[0077] Similarly, the divider 3215 receives the rate of change R(V)_LT and divides the rate of change R(V)_LT by 8 to obtain a value a16. The multipliers 3216-3218 receive the value a16 and multiply the value a16 by 3, 5 and 7 respectively to obtain values ​​a17-a19. The multiplexer S4 is used to select a value corresponding to the current temperature CT from the values ​​a16-a19 according to the current voltage CV and output it, which is called the value a20. The adder AD2 is used to add the value a15 and the value a20 to obtain the rate of change R(V)_CT of the code to the voltage corresponding to the current temperature CT.

[0078] Please also refer to Figure 2B and Figure 5 , when the current temperature CT value is equal to the temperature T0 value, the multiplexers S1 and S2 will respectively select the values ​​a11 and a19 as outputs. When the current temperature CT value is equal to the temperature T1 value, the multiplexers S1 and S2 will respectively select the values ​​a12 and a18 as outputs. When the current temperature CT value is equal to the temperature T2 value, the multiplexers S1 and S2 will respectively select the values ​​a13 and a17 as outputs. When the current temperature CT value is equal to the temperature T3 value, the multiplexers S1 and S2 will respectively select the values ​​a14 and a16 as outputs.

[0079] In particular, Figure 4 and Figure 5 The number of multipliers and dividers and the corresponding operations are related to the range settings of high / low temperature and high / low pressure and the fineness of the distinction of the aforementioned ranges. In other embodiments, a larger number of multipliers and dividers corresponding to different operations can be used to obtain more precise calculation results.

[0080] Figure 6 This is a flowchart of the steps of the code displacement value calculation method of the present invention. Please also refer to Figure 3 and Figure 6, step S610 is to generate a first output value CSV1 according to a temperature difference (i.e., temperature change DT) and a first rate of change of the driving strength code to the temperature (i.e., rate of change R(T)_CV). The temperature change DT is the difference between the previous temperature when the previous ZQ command is obtained and the current temperature when the current ZQ command is obtained. Step S620 is to generate a second output value CSV2 according to a voltage difference (voltage change DV) and a second rate of change of the driving strength code to the voltage (i.e., rate of change R(V)_CT). The voltage change DV is the difference between the previous operating voltage when the previous ZQ command is obtained and the current operating voltage when the current ZQ command is obtained. Step S630 is to sum the first output value CSV1 and the second output value CSV2 to generate a displacement value CSV3, thereby adjusting the driving strength code.

[0081] In summary, the present invention can generate a code displacement value according to the temperature difference and the voltage difference of the working voltage, thereby adjusting the driving strength code calibrated by ZQ. Therefore, the present invention can improve the resolution while eliminating the deviation of the driving strength code caused by temperature change or voltage change.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A code shift calculation circuit for generating a shift value to adjust a drive strength code calibrated by a ZQ, comprising: A first operation circuit is used to generate a first output value according to a temperature difference and a first change rate of the driving strength code to temperature, wherein the temperature difference is a difference between a previous temperature when a previous ZQ command is obtained and a current temperature when a current ZQ command is obtained; a second operation circuit for generating a second output value according to a voltage difference and a second change rate of the driving strength code to the voltage, wherein the voltage difference is a difference between a previous operating voltage when the previous ZQ command is obtained and a current operating voltage when the current ZQ command is obtained; as well as The third operation circuit is used for summing the first output value and the second output value to generate the displacement value, so as to adjust the driving strength code.

2. The code shift calculation circuit according to claim 1, characterized in that: The first operation circuit is further used to calculate the product of the temperature difference and the first change rate to obtain the first output value, and the second operation circuit is further used to calculate the product of the voltage difference and the second change rate to obtain the first output value.

3. The code shift calculation circuit according to claim 1, characterized in that: The first operation circuit is further used for: Calculating the first change rate according to the current operating voltage, a first extreme change rate of the drive strength code to temperature at a first extreme operating voltage, and a second extreme change rate of the drive strength code to temperature at a second extreme operating voltage; The second operation circuit is further used for: The second change rate is calculated according to the current temperature, a third extreme change rate of the drive strength code to the voltage at the first extreme temperature, and a fourth extreme change rate of the drive strength code to the voltage at the second extreme temperature.

4. The code shift calculation circuit according to claim 3, characterized in that: The first operation circuit is further used for: Adding the first extreme change rate of a first ratio and the second extreme change rate of a second ratio to generate the first change rate, wherein the first ratio and the second ratio are determined according to the current operating voltage; The second operation circuit is further used for: The third extreme change rate of the third ratio and the fourth extreme change rate of the fourth ratio are summed to generate the second change rate, wherein the third ratio and the fourth ratio are determined according to the current temperature.

5. The code shift calculation circuit according to claim 4, characterized in that: The first operation circuit is further used for: Selecting the first extreme change rate of the first ratio from a plurality of first extreme change rates of different ratios according to a current operating voltage, and selecting the second extreme change rate of the second ratio from a plurality of second extreme change rates of different ratios according to a current operating voltage; The second operation circuit is further used for: The third extreme change rate of the third ratio is selected from the third extreme change rates of the plurality of different ratios according to the current temperature, and the fourth extreme change rate of the fourth ratio is selected from the fourth extreme change rates of the plurality of different ratios according to the current temperature.

6. The code shift calculation circuit according to claim 5, characterized in that: The multiple different ratios include 1 / 8, 5 / 8 and 7 / 8.

7. The code shift calculation circuit according to claim 3, characterized in that: The first operation circuit comprises: A first multiplexer, configured to select and output the first extreme change rate of a first proportion from a plurality of first extreme change rates of different proportions according to the current working voltage; A second multiplexer, configured to select and output the second extreme change rate of a second proportion from among the plurality of second extreme change rates of different proportions according to the current working voltage; a first adder, configured to sum the first extreme change rate of the first ratio and the second extreme change rate of the second ratio to obtain the first change rate; The second operation circuit comprises: A third multiplexer, configured to select and output the third extreme change rate of a third proportion from among the plurality of third extreme change rates of different proportions according to the current temperature; a fourth multiplexer, configured to select and output the fourth extreme change rate of a fourth ratio from among the plurality of fourth extreme change rates of different ratios according to the current temperature; The second adder is used for summing up the third extreme change rate of the third ratio and the fourth extreme change rate of the fourth ratio to obtain the second change rate.

8. The code shift calculation circuit according to claim 7, characterized in that: The multiple different ratios include 1 / 8, 5 / 8 and 7 / 8.

9. A method for calculating a code shift value, for generating a shift value to adjust a drive strength code calibrated by ZQ, the method comprising: generating a first output value according to a temperature difference value and a first rate of change of the drive strength code to the temperature, wherein the temperature difference value is a difference between a previous temperature when a previous ZQ command is obtained and a current temperature when a current ZQ command is obtained; generating a second output value according to a voltage difference value and a second change rate of the driving strength code to the voltage, wherein the voltage difference value is a difference between a previous operating voltage when the previous ZQ command is obtained and a current operating voltage when the current ZQ command is obtained; as well as The first output value and the second output value are summed to generate the displacement value, thereby adjusting the driving strength code.

10. The method for calculating the code displacement value according to claim 9, characterized in that: Also includes: Calculate the product of the temperature difference and the first change rate to obtain the first output value; as well as The first output value is obtained by calculating the product of the voltage difference and the second change rate.

11. The method for calculating the code displacement value according to claim 9, characterized in that: Also includes: Calculating the first change rate according to the current operating voltage, a first extreme change rate of the drive strength code to temperature at a first extreme operating voltage, and a second extreme change rate of the drive strength code to temperature at a second extreme operating voltage; as well as The second change rate is calculated according to the current temperature, a third extreme change rate of the drive strength code to the voltage at the first extreme temperature, and a fourth extreme change rate of the drive strength code to the voltage at the second extreme temperature.

12. The method for calculating the code displacement value according to claim 11, characterized in that: Also includes: Adding the first extreme change rate of a first ratio and the second extreme change rate of a second ratio to generate the first change rate, wherein the first ratio and the second ratio are determined according to the current operating voltage; as well as The third extreme change rate of the third ratio and the fourth extreme change rate of the fourth ratio are summed to generate the second change rate, wherein the third ratio and the fourth ratio are determined according to the current temperature.

13. The method for calculating the code displacement value according to claim 12, characterized in that: Also includes: Selecting the first extreme change rate of the first ratio from a plurality of first extreme change rates of different ratios according to a current operating voltage, and selecting the second extreme change rate of the second ratio from a plurality of second extreme change rates of different ratios according to a current operating voltage; as well as The third extreme change rate of the third ratio is selected from the third extreme change rates of the plurality of different ratios according to the current temperature, and the fourth extreme change rate of the fourth ratio is selected from the fourth extreme change rates of the plurality of different ratios according to the current temperature.

14. The method for calculating the code displacement value according to claim 13, characterized in that: The multiple different ratios include 1 / 8, 5 / 8 and 7 / 8.

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