TWI734531B - Code shift calculation circuit and method for calculating code shift value - Google Patents

Abstract

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

Description

Code shift calculation circuit and calculation method of code shift value

The present invention relates to ZQ calibration, and particularly relates to adjusting the drive strength code through ZQ calibration according to voltage changes and temperature changes.

As the operating speed of the electronic device increases, the swing width of the signal transferred between the semiconductor storage devices in the electronic device decreases to minimize the delay time taken to transfer the signal. However, as the swing width decreases, signal transmission is affected by external noise to a greater extent, 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). The impedance mismatch will distort the signal output from the semiconductor storage device, and may cause failures such as set up/hold failure or misjudgment of signal level in the corresponding semiconductor storage device receiving the distorted signal. In order to match the impedance of the transmission line with the output impedance of the output circuit, the output impedance of the semiconductor memory device must be adjusted to match the impedance of the transmission line.

The ZQ calibration circuit is used to adjust the output impedance of the semiconductor memory device and improve The ZQ pin is used as the ZQ calibration terminal in the semiconductor storage device. External ZQ calibration commands, such as ZQCS (ZQ Calibration Short) commands are input into the ZQ pin. When an external ZQ calibration command is input, the ZQ calibration operation is executed within the period defined by the command to use the generated code to change the resistance value of the output driver. In order to improve the resistance accuracy of the output driver after ZQ calibration, the method of improving resolution can be adopted, that is, the method of increasing the code. However, since the period defined by the ZQCS command is shorter, if the width of the code that can be moved by the ZQCS command is increased to increase the resolution, it may lead to the risk of signal transmission not conforming to the specification (that is, the period defined by the ZQCS command). In contrast, if the resolution is increased 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 changes or voltage changes.

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 changes or voltage changes, that is, temperature changes or The deviation of the drive strength code caused by the voltage change.

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

The code shift calculation circuit of the present invention is used to generate a shift value to adjust the pass The drive strength code for ZQ calibration. The code shift calculation circuit includes a first arithmetic circuit, a second arithmetic circuit, and a third arithmetic circuit. The first arithmetic circuit is used for generating the first output value according to the temperature difference and the first rate of change of the drive strength code to the temperature. The temperature difference is the difference between the previous temperature when the previous ZQ command is acquired and the current temperature when the current ZQ command is acquired. The second arithmetic circuit is used for generating a second output value according to the voltage difference and the second rate of change of the drive strength code to the voltage. Wherein, the voltage difference is the difference between the previous working voltage when the previous ZQ command is acquired and the current working voltage when the current ZQ command is acquired. The third arithmetic circuit is used for summing the first output value and the second output value to generate a displacement value, thereby adjusting the drive strength code.

The code displacement value calculation method of the present invention is used to generate a displacement value to adjust the drive strength code calibrated by ZQ. The method includes: generating a first output value according to a temperature difference value and a first rate of change of the drive strength code to temperature, wherein the temperature difference value is the difference between the previous temperature when the previous ZQ command is acquired and the current temperature when the current ZQ command is acquired The second output value is generated according to the voltage difference and the second rate of change of the drive strength code to the voltage, where the voltage difference is the previous working voltage when the previous ZQ command is obtained and the current working when the current ZQ command is obtained The difference between the voltages; and summing the first output value and the second output value to generate a displacement value, thereby adjusting the drive strength code.

Based on the above, the present invention can generate the displacement value of the code according to the temperature difference and the voltage difference of the working voltage, thereby adjusting the drive strength code calibrated by ZQ. Therefore, the present invention can improve the resolution while eliminating temperature The deviation of the drive strength code caused by changes or voltage changes.

100: Code shift calculation device

110: Resistance divider circuit

120: Or gate

130: Temperature change and voltage change calculation circuit

140: Code shift calculation circuit

150: Fuse

300: Code shift calculation circuit

310: The first arithmetic circuit

311: proportional calculation circuit

3111, 3115: divider

3112~3114, 3116~3118: Multiplier

312: Multiplier

320: second arithmetic circuit

321: proportional calculation circuit

3211, 3215: divider

322: Multiplier

330: Adder

a1~a20: value

AD1, AD2: adder

CSV1: The first output value

CSV2: Second output value

CSV3: Displacement value

CT: current temperature

CV: current voltage

DT: Temperature change

DV: voltage change

FF0~FF4: flip-flop

HT: high temperature

HV: high voltage

LT: low temperature

LV: low pressure

OP: Amplifier

PU/PD: pull-up/pull-down signal

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

S1~S4: Multiplexer

S610~S630: steps

SF: shifter

SUB1, SUB2: subtractor

T0~T3: temperature

T_C: temperature code

V0~V3: Voltage

VBGR: reference voltage

VDD: working voltage

VDD_C: voltage code

ZQCL: Command

ZQCS: Command

FIG. 1 is a block diagram of the code shift calculation device of the present invention.

Figure 2A is a graph showing the relationship between the rate of change of code versus temperature and voltage.

FIG. 2B is a graph showing the relationship between the rate of change of the code and the voltage with respect to the temperature.

FIG. 3 is a block diagram of the code shift calculation circuit of the present invention.

FIG. 4 is a block diagram of the ratio calculation circuit 311 according to an embodiment of the invention.

FIG. 5 is a block diagram of the ratio calculation circuit 321 according to an embodiment of the invention.

Fig. 6 is a flowchart showing the steps of the code displacement value calculation method of the present invention.

FIG. 1 is a block diagram of the code shift calculation device of the present invention. Please refer to Figure 1. The code shift calculation device 100 includes a resistor divider circuit 110, an amplifier OP, or (OR) gate 120, a temperature change and voltage change calculation circuit 130, a code shift calculation circuit 140, a fuse 150, and a Positioner SF and 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 operating voltage VDD and the reference voltage VBGR to output a voltage code VDD_C representing the voltage value of the operating voltage VDD.

The temperature change and voltage change calculation circuit 130 receives the voltage code VDD_C and the temperature code T_C representing the temperature value. The temperature change and voltage change calculation circuit 130 includes flip-flops FF0 to FF3 and subtractors SUB1 and SUB2. The flip-flops FF0~FF3 are triggered by the ZQCS command or 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 time point corresponding to the previous rising edge of the ZQCS command The voltage code of VDD_C is used as the previous voltage. The subtractor SUB1 calculates the voltage variation DV from the time point of the previous rising edge to the time point of the current rising edge according to 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.

The code shift calculation circuit 140 can calculate the displacement value used to adjust the drive strength code calibrated through the ZQ based on the current voltage CV, the voltage change amount DV, the current temperature CT, and the temperature change amount DT. In this way, the present invention can adjust (or displacement) the drive strength code calibrated through ZQ in response to temperature changes or voltage changes. It should be noted that the rate of change of drive strength code to temperature under high/low voltage and the rate of change of drive strength code to voltage under high/low temperature required for code shift calculation can be through the fuse 150 Stored in advance. However, the present invention does not only use fuses to store the above-mentioned rate of change. Any storage device (such as a memory circuit) with a storage function should fall within the protection scope of the present invention.

The shifter SF receives the displacement value calculated by the code shift calculation circuit 140 and the up/down signal PU/PD. Shifter SF according to The pull-up/pull-down signal PU/PD is adjusted according to the displacement value, and the adjusted pull-up/pull-down signal PU/PD is output to the flip-flop FF4. The flip-flop FF4 outputs the adjusted pull-up/pull-down signal PU/PD (code format) after being triggered. In an embodiment, the shifter SF can be implemented as an adder.

Figure 2A is a graph showing the relationship between the rate of change of code versus temperature and voltage. Please look at Figure 2A, R(T)_LV represents the rate of change of code to voltage under low voltage LV, and R(T)_HV represents the rate of change of code to voltage under high voltage HV. Among them, the above-mentioned "high voltage" and "low voltage" can be the two extreme values of the normal operating voltage range. The values of the rate of change R(T)_LV and the rate of change R(T)_HV can be obtained by experiments and stored in the fuse 150 in advance. The code shift calculation circuit 140 may assume that the rate of change of the code to temperature is linear with respect to the change of voltage, thereby depending on the received value 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) to calculate the rate of change of the corresponding code to the voltage (for example, any one of the rate of change R(T)_V0 to R(T)_V3). It should be noted that although FIG. 2A only exemplifies the voltages V0 to V3, the present invention is not limited thereto. In other embodiments, more voltage values can be distinguished between the voltage LV and the voltage HV.

FIG. 2B is a graph showing the relationship between the rate of change of the code and the voltage with respect to the temperature. Please look at Figure 2B, R(V)_LT represents the rate of change of code to voltage at low temperature LT, and R(V)_HT represents the rate of change of code to voltage at high temperature HT. Among them, the above-mentioned "high temperature" and "low temperature" can be the two extreme values of the normal operating temperature range. The values of the rate of change R(V)_LT and the rate of change R(V)_HT can be obtained through experiments and stored in the fuse 150 in advance. The code shift calculation circuit 140 can assume the generation The code-to-voltage change rate is linear with respect to the temperature change, so that it depends on the received change rate R(V)_LT, the value of the change rate R(V)_HT, and the current temperature CT (for example, the temperature T0~T3 Any one) to calculate the rate of change of the corresponding code to the voltage (for example, any one of the rate of change R(V)_T0~R(V)_T3). It should be noted that although FIG. 2B only illustrates the temperature T0~T3, 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.

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

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

FIG. 4 is a block diagram of the ratio calculation circuit 311 according to an embodiment of the invention. 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. The divider 3111 receives the rate of change R(T)_HV, and divides the rate of change R(T)_HV by 8 to obtain the value a1. The multipliers 3112~3114 receive the value a1, and multiply the value a1 by 3, 5, and 7, respectively, to obtain the values a2~a4. The multiplexer S1 is used to select a value corresponding to the current voltage CV from the values a1 to a4 to output according to the current voltage CV, which is called the value a5.

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 the value a6. The multipliers 3116 to 3118 receive the value a6, and perform the operations of multiplying the value a6 by 3, multiplying by 5, and multiplying by 7, respectively, to obtain the values a7 to a9. The multiplexer S2 is used to select a value corresponding to the current voltage CV from the values a6 to a9 to output according to the current voltage CV, which is called the value a10. The adder AD1 is used to add the value a5 and the value a10 to obtain the code-to-temperature change rate R(T)_CV corresponding to the current voltage CV.

Please refer to FIGS. 2A and 4 at the same time. When the value of the current voltage CV is equal to the value of the voltage V0, the multiplexers S1 and S2 will respectively select the values a1 and a6 as output. When the value of the current voltage CV is equal to the value of the voltage V1, the multiplexers S1 and S2 will respectively select the values a2 and a7 as output. When the value of the current voltage CV is equal to the value of the voltage V2, the multiplexers S1 and S2 will respectively select the values a3 and a8 as output. Dangdang When the value of the previous voltage CV is equal to the value of the voltage V3, the multiplexers S1 and S2 will respectively select the values a4 and a9 as outputs.

FIG. 5 is a block diagram of the ratio calculation circuit 321 according to an embodiment of the invention. Please refer to FIG. 5. In 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. The 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. The multipliers 3212 to 3214 receive the value a11, and multiply the value a11 by 3, 5, and 7 respectively to obtain the values a12 to a14. The multiplexer S3 is used to select a value corresponding to the current temperature CT from the values a11 to a14 to output according to the current temperature CT, which is called the value a15.

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

Please refer to FIG. 2B and FIG. 5 at the same time. When the value of the current temperature CT is equal to the value of the temperature T0, the multiplexers S1 and S2 will respectively select the values a11 and a16 as output. When the value of the current temperature CT is equal to the value of the temperature T1, the multiplexers S1 and S2 will respectively select the values a12 and a17 as output. When the value of the current temperature CT is equal to the value of the temperature T2, the multiplexers S1 and S2 will respectively select the values a13 and a18 as output. When the value of the current temperature CT is equal to the value of the temperature T3, the multiplexers S1 and S2 will respectively select the values a14 and a19 as output.

In particular, the number of multipliers and dividers in FIGS. 4 and 5 and the corresponding operations are related to the high/low temperature, high/low pressure range setting, and the distinction between 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.

Fig. 6 is a flowchart showing the steps of the code displacement value calculation method of the present invention. Please refer to Figure 3 and Figure 6 at the same time. Step S610 is to generate the first output value according to the temperature difference (ie the temperature change amount DT) and the first rate of change of the drive strength code to the temperature (ie the rate of change R(T)_CV) CSV1. Wherein, the temperature change DT is the difference between the previous temperature when the previous ZQ command is acquired and the current temperature when the current ZQ command is acquired. Step S620 is to generate the second output value CSV2 according to the voltage difference value (the amount of voltage change DV) and the second rate of change of the drive strength code to the voltage (ie, the rate of change R(V)_CT). Wherein, the voltage variation DV is the difference between the previous working voltage when the previous ZQ command is acquired and the current working voltage when the current ZQ command is acquired. Step S630 is to add the first output value CSV1 and the second output value CSV2 to generate a displacement value CSV3, thereby adjusting the drive strength code.

In summary, the present invention can generate the displacement value of the code according to the temperature difference and the voltage difference of the working voltage, thereby adjusting the drive strength code calibrated by ZQ. Therefore, the present invention can eliminate the deviation of the drive strength code caused by the temperature change or the voltage change under the premise of improving the resolution.

300: Code shift calculation circuit

310: The first arithmetic circuit

311: proportional calculation circuit

312: Multiplier

320: second arithmetic circuit

321: proportional calculation circuit

322: Multiplier

330: Adder

CT: current temperature

CV: current voltage

DT: Temperature change

DV: voltage change

R(V)_CT, R(T)_CV, R(T)_HV, R(T)_LV, R(V)_HT, R(V)_LT: rate of change

CSV1: The first output value

CSV2: Second output value

CSV3: Displacement value

Claims (14)

A code shift calculation circuit is used to generate a displacement value to adjust a drive strength code calibrated by ZQ. A rate of change to generate a first output value, wherein the temperature difference is the difference between a previous temperature when a previous ZQ command is acquired and a current temperature when a current ZQ command is acquired; a second arithmetic circuit , For generating a second output value according to a voltage difference value and a second rate of change of the drive strength code to the voltage, wherein the voltage difference value is a previous operating voltage when the previous ZQ command is obtained and Acquiring the difference between a current operating voltage at the time of the current ZQ command; and a third arithmetic circuit for summing the first output value and the second output value to generate the displacement value , Thereby adjusting the drive strength code. The code shift calculation circuit according to claim 1, wherein the first arithmetic circuit is further configured to calculate the product of the temperature difference and the first rate of change to obtain the first output value, and The second arithmetic circuit is also used to calculate the product of the voltage difference and the second rate of change to obtain the first output value. The code shift calculation circuit according to claim 1, wherein the first arithmetic circuit is further used for: according to the current operating voltage, the drive strength code is a first extreme operating voltage for temperature Extreme rate of change, and a second extreme rate of change of the drive strength code with respect to temperature at a second extreme operating voltage to calculate the The first rate of change; the second arithmetic circuit is also used to: according to the current temperature, the drive strength code at a first extreme temperature of the voltage at a third extreme rate of change, and the drive strength code A fourth extreme rate of change of voltage at a second extreme temperature is used to calculate the second rate of change. The code shift calculation circuit according to claim 3, wherein the first arithmetic circuit is further used to: compare the first extreme rate of change to a first ratio and the second extreme rate of change to a second ratio Performing summation to generate the first rate of change, wherein the first ratio and the second ratio are determined according to the current operating voltage; the second arithmetic circuit is also used to: compare a third ratio The third extreme rate of change and a fourth ratio of the fourth extreme rate of change are summed to generate the second rate of change, wherein the third ratio and the fourth ratio are based on the current temperature To decide. The code shift calculation circuit according to claim 4, wherein the first arithmetic circuit is further used for: selecting the first extreme change rate from a plurality of different ratios of the first extreme change rate according to the current operating voltage A proportional change rate of the first extreme, and the second extreme change rate of the second proportion is selected from the plurality of different proportions of the second extreme change rate according to the current operating voltage; The second arithmetic circuit is further used for: according to the current temperature, change from the third extreme of the plurality of different proportions The third extreme change rate of the third ratio is selected from the transformation rate, and the fourth extreme change rate of the fourth ratio is selected from the plurality of different ratios of the fourth extreme change rate according to the current temperature. The fourth extreme rate of change. The code shift calculation circuit according to claim 5, wherein the plurality of different ratios include (1/8), (5/8), and (7/8). The code shift calculation circuit according to claim 3, wherein the first arithmetic circuit includes: a first multiplexer for changing from a plurality of different ratios of the first extremes according to the current operating voltage Select and output a first ratio of the first extreme change rate among the ratios; a second multiplexer for selecting from the plurality of different ratios of the second extreme change rate according to the current operating voltage Output a second ratio of the second extreme change rate; a first adder for adding the first extreme change rate of the first ratio and the second extreme change of the second ratio To obtain the first rate of change; wherein the second arithmetic circuit includes: a third multiplexer for changing the rate of change from the plurality of different ratios to the third extreme according to the current temperature Selecting and outputting a third ratio of the third extreme change rate; a fourth multiplexer for selecting and outputting a fourth extreme change rate of the plurality of different ratios according to the current temperature The fourth extreme of the fourth ratio Rate of change; a second adder for summing the third extreme rate of change of the third ratio and the fourth extreme rate of change of the fourth ratio to obtain the second rate of change. The code shift calculation circuit according to claim 7, wherein the plurality of different ratios include (1/8), (5/8), and (7/8). A method for calculating code displacement value is used to generate a displacement value to adjust a drive strength code calibrated by ZQ. The method includes: according to a temperature difference and a first rate of change of the drive strength code to temperature A first output value is generated, wherein the temperature difference is the difference between a previous temperature when a previous ZQ command is acquired and a current temperature when a current ZQ command is acquired; according to a voltage difference and the drive A second rate of change of the intensity code to the voltage is used to generate a second output value, where the voltage difference is a previous operating voltage when the previous ZQ command is acquired and a current operating voltage when the current ZQ command is acquired And summing the first output value and the second output value to generate the displacement value, thereby adjusting the drive strength code. The method for calculating the code displacement value according to claim 9, further comprising: calculating the product of the temperature difference and the first rate of change to obtain the first output value; and Calculate the product of the voltage difference and the second rate of change to obtain the first output value. The method for calculating the code displacement value according to claim 9, further comprising: a first extreme rate of change of temperature at a first extreme operating voltage according to the current operating voltage and the drive strength code, and the A second extreme rate of change of the drive strength code with respect to temperature under a second extreme operating voltage is used to calculate the first rate of change; A third extreme rate of change of the voltage and a fourth extreme rate of change of the drive strength code to voltage at a second extreme temperature are used to calculate the second rate of change. The code displacement value calculation method according to claim 11, further comprising: summing the first extreme change rate of a first proportion and the second extreme change rate of a second proportion to generate the A first rate of change, wherein the first rate and the second rate are determined according to the current operating voltage; and the third extreme rate of change for a third rate and the first rate for a fourth rate The four extreme change rates are summed to generate the second change rate, wherein the third ratio and the fourth ratio are determined according to the current temperature. The method for calculating the code displacement value according to claim 12 further includes: changing from a plurality of different proportions of the first extreme according to the current operating voltage. The first extreme change rate of the first ratio is selected from the conversion rate, and the second extreme change rate of the second ratio is selected from the plurality of different ratios of the second extreme change rate according to the current operating voltage. The second extreme change rate; and the third extreme change rate of the third proportion is selected from the plurality of different proportions of the third extreme change rate according to the current temperature, and the third extreme change rate is selected according to the current temperature The fourth extreme rate of change of the fourth proportion of temperature is selected from the plurality of different proportions of the fourth extreme rate of change. The method for calculating the code displacement value according to claim 13, wherein the multiple different ratios include (1/8), (5/8), and (7/8).

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