Impedance calibration device and method and chip

Abstract

The invention discloses an impedance calibration device and method and a chip, and belongs to the technical field of display. The device comprises an adjustable impedance network module which is used for providing a sampling point of a measured voltage and a sampling point of a reference voltage, and the measured voltage and the reference voltage are logic values of multiple bits; the comparison module is used for sampling the measured voltage and the reference voltage and comparing the logic value difference between the measured voltage and the reference voltage to obtain a comparison result; the calibration module is used for carrying out impedance adjustment on the adjustable impedance network module according to the comparison result so as to enable the measured voltage to approach the reference voltage; and the detection module is used for detecting whether the detected voltage approaching the reference voltage is accurate or not based on the comparison result. Therefore, self-adaptive calibration is realized.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an impedance calibration device, method and chip. Background Technology

[0002] For chips, such as display control chips, signal integrity must be ensured during operation. Signal integrity refers to the ability of a signal to maintain its shape, amplitude, and timing during transmission. A prerequisite for ensuring signal integrity is setting the impedance values ​​of the chip's physical layer (PHY) according to the specifications (spec). The PHY is the module within the chip responsible for processing physical signal transmission; examples of PHYs include High Definition Multimedia Interface (HDMI) and Mobile Industry Processor Interface Display Serial Interface (MIPI DSI).

[0003] However, due to the influence of temperature, humidity and process parameter changes, the actual impedance of the PHY often fails to reach the set value, which damages signal integrity and causes problems such as reflection, crosstalk, and delay deviation, ultimately leading to data transmission errors. Summary of the Invention

[0004] This application provides an impedance calibration device, method, and chip, capable of adaptively calibrating the impedance of the chip's PHY. The technical method is as follows.

[0005] In a first aspect, this application provides an impedance calibration device, comprising: an adjustable impedance network module for providing sampling points of a measured voltage and a reference voltage, wherein the measured voltage and the reference voltage are logic values ​​of multiple bits; a comparison module for sampling the measured voltage and the reference voltage, comparing the logic value differences between the measured voltage and the reference voltage, and obtaining a comparison result; a calibration module for adjusting the impedance of the adjustable impedance network module according to the comparison result, so that the measured voltage approaches the reference voltage; and a verification module for verifying, based on the comparison result, whether the measured voltage approaching the reference voltage is accurate.

[0006] In some possible implementations, the adjustable impedance network module includes a fixed impedance unit and an adjustable impedance unit. The fixed impedance unit includes multiple fixed impedance elements connected in series, and its output terminal serves as a sampling point for the reference voltage. The adjustable impedance unit includes an external impedance element connected in series and an adjustable impedance element, and its output terminal serves as a sampling point for the voltage being measured. The impedance value of the external impedance element is equivalent to the standard impedance setting value.

[0007] In some possible implementations, the calibration module includes a digital logic processing unit, which is used to: input a digital control word to the adjustable impedance unit, the digital control word representing a voltage value, and the control signal used to instruct the adjustable impedance unit to adjust the impedance based on the voltage value to obtain the corresponding measured voltage; and a comparison module, which is used to: sample the logic values ​​of the measured voltage and the reference voltage bit by bit, compare the values ​​of N bits between the measured voltage and the reference voltage, and obtain a comparison result between N bits, where N does not exceed the bit width of the logic value, and the comparison result between N bits is used to trigger the digital logic processing unit to adjust the impedance of the adjustable impedance unit so that the measured voltage approaches the reference voltage.

[0008] In some possible implementations, the calibration module is used to: adjust the impedance of the adjustable impedance unit according to the comparison results between N bits, through a difference successive approximation processing strategy, so that the measured voltage approaches the reference voltage.

[0009] In some possible implementations, the measured voltage approaching the reference voltage is obtained based on a first digital control word output by the calibration module, which instructs the adjustable impedance network module to adjust the impedance. The verification module is used to: fine-tune the first digital control word according to a reference amplitude based on the comparison result corresponding to the measured voltage approaching the reference voltage, to obtain a second digital control word; adjust the impedance of the adjustable impedance network module based on the second digital control word to obtain an updated measured voltage and the corresponding comparison result; and verify the accuracy of the measured voltage approaching the reference voltage based on the M updated measured voltages and the corresponding M comparison results obtained from the M-th fine-tuning operation, where M is a positive integer.

[0010] In some possible implementations, the comparison result output by the comparison module is represented by a first logic value or a second logic value. The first logic value indicates that the corresponding measured voltage is higher than the reference voltage, and the second logic value indicates that the corresponding measured voltage is lower than the reference voltage. In the process of obtaining a second digital control word by fine-tuning the first digital control word according to a reference amplitude based on the comparison result corresponding to the measured voltage approaching the reference voltage, the verification module is used to: decrease the first digital control word according to the reference amplitude when the comparison result corresponding to the measured voltage approaching the reference voltage is the first logic value, to obtain the second digital control word; and increase the first digital control word according to the reference amplitude when the comparison result corresponding to the measured voltage approaching the reference voltage is the second logic value, to obtain the second digital control word.

[0011] In some possible implementations, in verifying the accuracy of a measured voltage approaching a reference voltage based on M updated measured voltages obtained from the M-th fine-tuning operation and the corresponding M comparison results, the verification module is configured to: after obtaining M updated measured voltages from the M-th fine-tuning operation and the corresponding M comparison results, determine that the measured voltage approaching the reference voltage is accurate if the M comparison results include alternating first and second logic values; and determine that the measured voltage approaching the reference voltage has not met the accuracy condition if the M comparison results include consecutive first or second logic values.

[0012] Secondly, an impedance calibration method is provided, the method comprising: sampling the measured voltage and reference voltage corresponding to the object to be calibrated, wherein the measured voltage and reference voltage are logic values ​​of multiple bits; comparing the logic value difference between the measured voltage and the reference voltage to obtain a comparison result; adjusting the impedance of the object to be calibrated according to the comparison result so that the measured voltage approaches the reference voltage; and verifying whether the measured voltage approaching the reference voltage is accurate based on the comparison result.

[0013] In some possible implementations, before sampling the measured voltage and reference voltage corresponding to the object to be calibrated, the method further includes: inputting a digital control word to the object to be calibrated, the digital control word representing a voltage value, and a control signal used to instruct the object to adjust its impedance based on the voltage value to obtain the corresponding measured voltage; comparing the logic value difference between the measured voltage and the reference voltage to obtain a comparison result, including: sampling the logic values ​​of the measured voltage and the reference voltage bit by bit; performing a bit-by-bit comparison of the values ​​of N bits between the measured voltage and the reference voltage to obtain a comparison result between N bits, wherein N does not exceed the bit width of the logic value, and the comparison result between N bits is used to trigger impedance adjustment of the object to be calibrated to make the measured voltage approach the reference voltage.

[0014] In some possible implementations, the impedance of the object to be calibrated is adjusted according to the comparison results to make the measured voltage approach the reference voltage. This includes adjusting the impedance of the object to be calibrated according to the comparison results between N bits using a difference successive approximation processing strategy to make the measured voltage approach the reference voltage.

[0015] In some possible implementations, the measured voltage approaching the reference voltage is obtained based on a first digital control word, which is used to instruct the object to be calibrated to adjust its impedance. Based on the comparison results, the accuracy of the measured voltage approaching the reference voltage is verified, including: based on the comparison results corresponding to the measured voltage approaching the reference voltage, the first digital control word is numerically fine-tuned according to a reference amplitude to obtain a second digital control word; the impedance of the object to be calibrated is adjusted based on the second digital control word to obtain an updated measured voltage and the corresponding comparison results; the accuracy of the measured voltage approaching the reference voltage is verified based on the M updated measured voltages obtained from the M-th adjustment operation and the corresponding M comparison results, where M is a positive integer.

[0016] In some possible implementations, the comparison result is represented by a first logic value or a second logic value, where the first logic value indicates that the corresponding measured voltage is higher than the reference voltage, and the second logic value indicates that the corresponding measured voltage is lower than the reference voltage. Based on the comparison result corresponding to the measured voltage approaching the reference voltage, the first digital control word is numerically fine-tuned according to a reference amplitude to obtain the second digital control word, including: when the comparison result corresponding to the measured voltage approaching the reference voltage is the first logic value, decreasing the first digital control word according to the reference amplitude to obtain the second digital control word; when the comparison result corresponding to the measured voltage approaching the reference voltage is the second logic value, increasing the first digital control word according to the reference amplitude to obtain the second digital control word.

[0017] In some possible implementations, based on the M updated measured voltages obtained from the M-th fine-tuning operation and the corresponding M comparison results, the accuracy of the measured voltage approaching the reference voltage is checked. This includes: after obtaining the M updated measured voltages and the corresponding M comparison results from the M-th fine-tuning operation, if the M comparison results include alternating first and second logic values, it is determined that the measured voltage approaching the reference voltage is accurate; if the M comparison results include consecutive first or second logic values, it is determined that the measured voltage approaching the reference voltage has not met the accuracy condition.

[0018] Thirdly, a chip is provided that includes an impedance calibration device as described in the first aspect and any implementation thereof.

[0019] Fourthly, a display device is provided, including the chip provided in the third aspect.

[0020] Fifthly, a computer-readable storage medium is also provided, wherein at least one computer program is stored therein, the at least one computer program being loaded and executed by a processor to enable a computer to implement the method provided in the second aspect above.

[0021] Sixthly, a computer program product or computer program is also provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the method provided in the second aspect above.

[0022] The technical solution provided in this application brings at least the following beneficial effects: In this application, feedback control is used to adjust the voltage output (i.e., the measured voltage) of the object to be calibrated (e.g., an adjustable impedance network module) in the PHY of the chip, making the measured voltage as close as possible to the reference voltage. This ensures that the actual impedance value of the object to be calibrated is close to the standard impedance setting value, thus achieving impedance calibration. Furthermore, to avoid inaccurate calibration results due to deviations in the circuit structure of the device, the accuracy of the measured voltage after calibration is verified, which helps to obtain reliable impedance calibration results and ensure the signal integrity of the chip's PHY. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of an implementation environment provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of an impedance calibration device provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an impedance calibration device provided in an embodiment of this application; Figure 4 This is a schematic diagram of the calibration process of an impedance calibration device provided in an embodiment of this application; Figure 5 This is a schematic flowchart of an impedance calibration method provided in an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0026] In related technologies, the PHY of chips such as display control chips is often affected by changes in temperature, humidity and process parameters, resulting in the actual impedance value not reaching the set standard (set value), which leads to errors in the PHY output data.

[0027] This application proposes an impedance calibration device that uses feedback control of the voltage output (i.e., the measured voltage) of the object to be calibrated (e.g., an adjustable impedance network module) in the PHY of a chip to make the measured voltage as close as possible to a reference voltage. This ensures that the actual impedance value of the object to be calibrated is close to the standard impedance setting value, thereby achieving the purpose of impedance calibration. Furthermore, to avoid inaccurate calibration results due to deviations in the circuit structure of the device, the accuracy of the measured voltage after calibration is verified, which helps to obtain reliable impedance calibration results and ensure the signal integrity of the chip PHY.

[0028] To facilitate understanding of the technical solution of this application, an implementation environment provided by an embodiment of this application is described below.

[0029] For example, Figure 1 A schematic diagram of an implementation environment provided in an embodiment of this application is shown. For example... Figure 1 As shown, the implementation environment includes a display device 00, which includes a communication interface 110, a display control chip 120, and a display panel 130.

[0030] For example, the display panel 130 may be a liquid crystal panel, such as a thin film transistor liquid crystal display (TFT-LCD), an organic light-emitting semiconductor (OLED) panel, or other types of liquid crystal panels, but is not limited thereto.

[0031] For example, the display control chip 120 is, but is not limited to, a timing controller (TCON) or a television system on chip (TVSOC).

[0032] For example, the communication interface 110 may be a physical layer (PHY) communication interface of the display control chip 120 for connecting to an external signal source or display panel 130. The external signal source may be, for example, a graphics processing unit (GPU) or a system on a chip (SoC). The communication interface 110 may be, for example, a high-definition multimedia interface (HDMI), a low-voltage differential signaling (LVDS) interface, a mobile industry processor interface display serial interface (MIPI DSI), or a display interface DP (DisplayPort), but is not limited to these.

[0033] In this example, data signals from an external signal source can be input to the display control chip 120 via a communication interface 110 such as HDMI. The display control chip 120 then inputs the received data signals onto the display panel 130 for display according to a timing sequence. However, given that variations in temperature, humidity, and process parameters can cause different deviations in the impedance values ​​corresponding to this type of communication interface 130, an impedance calibration device can be used in this example to adaptively calibrate the impedance on the differential lines of the communication interface 110 to ensure signal integrity, resulting in high reliability.

[0034] Next, in conjunction with the above-described implementation environment, an impedance calibration device provided in the embodiments of this application will be introduced.

[0035] For example, Figure 2 The diagram shows a schematic representation of an impedance calibration device according to an embodiment of this application. This impedance calibration device can be applied to similar... Figure 1 The display control chip 120 shown is not limited to this.

[0036] like Figure 2 As shown, the impedance calibration device 200 may include an adjustable impedance network module 201, a calibration module 202, a comparison module 203, and a verification module 204. The working principle of the impedance calibration device 200 will be described in detail below, combining the functions of the adjustable impedance network module 201, calibration module 202, comparison module 203, and verification module 204.

[0037] In this embodiment, since impedance values ​​are difficult to quantify, closed-loop feedback control of voltage values ​​can be used to make the actual output voltage (i.e., the measured voltage) vrep of the communication interface 110 as close as possible to the reference voltage vref. In this way, the actual impedance value of the communication interface 110 is close to the standard impedance setting value, thereby achieving the purpose of impedance calibration.

[0038] In some possible implementations, the adjustable impedance network module 201 may include a fixed impedance unit and an adjustable impedance unit. The fixed impedance unit provides a sampling point for the reference voltage, while the adjustable impedance unit provides a sampling point for the voltage being measured. That is, the fixed impedance unit provides a fixed, non-adjustable impedance value, which can be used as a reference impedance. The voltage at the output of the fixed impedance unit can be used as a reference voltage, therefore, the output of the fixed impedance unit can be used as a sampling point for the reference voltage. Similarly, the adjustable impedance unit provides an adjustable impedance value, and the output of the adjustable impedance unit can be used as a sampling point for the voltage being measured.

[0039] As an example, a fixed impedance unit may include multiple fixed impedance elements (such as standard resistors or fixed inductors) connected in series, such as... Figure 3 The fixed impedance unit shown includes fixed resistors R1 and R2 connected in series, with the voltage at the series junction of R1 and R2 serving as the reference voltage. The adjustable impedance unit may include an external impedance element connected in series and an adjustable impedance element, such as... Figure 3 The external impedance element shown is resistor R3 connected to the external resistance pin REXT of communication interface 110. For example, the impedance value of R3 is 1.62 kΩ. The adjustable impedance element is, for example, an adjustable resistor R4 connected in series with R3. In this example, the external impedance element is equivalent to the standard impedance setting value of communication interface 110. When the voltage (i.e., the measured voltage) at the series node of the external impedance element and the adjustable impedance element is close to the reference voltage, it indicates that the impedance distribution between the adjustable impedance unit and the external resistor is 1:1. That is, the actual impedance of communication interface 110 is equivalent to the standard impedance setting value, thereby realizing the impedance calibration of communication interface 110.

[0040] For example, refer to Figure 3 The calibration module 202 may include a digital logic processing unit. This unit can input a digital control word into the adjustable impedance unit of the adjustable impedance network module 201 to control the adjustable impedance unit to adjust its impedance based on the voltage value represented by the digital control word, thereby obtaining the corresponding measured voltage. Both the measured voltage and the reference voltage can be represented as logic values ​​of multiple bits.

[0041] Next, the comparison module 203 can be used to sample the measured voltage and the reference voltage, compare the logic value difference between the measured voltage and the reference voltage, that is, to perform a bitwise logic value comparison between the measured voltage and the reference voltage to obtain a comparison result. Then, the calibration module 202 is used to adjust the impedance of the adjustable impedance unit according to the comparison result, so that the measured voltage approaches the reference voltage. Thus, the verification module 204 can be used to verify whether the measured voltage approaching the reference voltage is accurate based on the comparison result.

[0042] If accurate, the impedance value corresponding to the measured voltage that approximates the reference voltage (such as the value of R4) can be applied to the Transition Minimized Differential Signaling (TMDS) differential pair of the communication interface 110. This is equivalent to feeding back external factors to the data differential line to obtain an accurate impedance value, thereby ensuring signal integrity during data transmission. Conversely, if inaccurate, the calibration operation can be repeated.

[0043] A specific example of the impedance calibration process described above is that the calibration module 202 can adjust the digital control word using a Successive Approximation (SAR) processing strategy (that is, starting from the most significant bit (MSB) of the digital control word, it attempts to adjust the value of each bit sequentially), to control the adjustable impedance unit to adjust the impedance based on the adjusted digital control word, thereby obtaining the corresponding measured voltage. The comparison module 203 can sample the logic values ​​of the measured voltage and the reference voltage bit by bit, performing a bit-by-bit comparison of the N bits between the measured voltage and the reference voltage to obtain a comparison result between N bits, where N does not exceed the bit width of the aforementioned logic value. The comparison result between the N bits is used to trigger the calibration module 202 to execute the SAR processing strategy until the measured voltage approaches the reference voltage.

[0044] Let's illustrate this with a specific example. For example... Figure 4 The impedance calibration process shown involves the calibration module 202 first acquiring the top-level control signal rcal_en. This rcal_en signal, issued by the display control chip 120, indicates the IDEL status and is used to enable or disable the impedance calibration function. The IDEL status indicates whether the display control chip 120 is in an idle / inactive state. If the IDEL status is valid, it means that the display control chip 120 is not currently transmitting data and there is no interference. Therefore, the impedance calibration function is enabled, triggering an impedance calibration operation on the communication interface 110 to ensure the accuracy of the impedance calibration.

[0045] After enabling the impedance calibration function (Rcal IDEL), the digital logic processing unit (DLU) can receive the calibration mode selection signal `sup_comp_mode` and the calibration loop power enable signal `sup_comp_rt_pwron` configured by the display control chip 120 through a register. The calibration mode selection signal `sup_comp_mode` is used to switch the state of the impedance calibration process (Rcal PU). For example, if `sup_comp_mode=1`, the DLU enters the impedance calibration process; conversely, if `sup_comp_mode=0`, the impedance calibration process exits. Similarly, the value of `sup_comp_rt_pwron` (1 or 0) indicates whether power is supplied to the current calibration loop (such as the adjustable impedance network module mentioned above). Therefore, when `sup_comp_mode=1` and `sup_comp_rt_pwron=1`, the current impedance calibration process is entered, and the adjustable impedance network module 201 is powered on.

[0046] Next, the digital logic processing unit outputs a control signal carrying the digital control word sup_dac_n<6:0>=0111111 to the aforementioned adjustable impedance unit. This control unit adjusts the impedance based on the voltage value represented by the digital control word to obtain the corresponding measured voltage vrep. The logic value 0111111 (i.e., code0) is the default voltage value in this example (close to the reference voltage). However, due to the influence of temperature, humidity, or process parameters, the measured voltage vrep may not actually equal the logic value 0111111. Therefore, the obtained measured voltage vrep will subsequently be compared and adjusted with the reference voltage vref.

[0047] Next, the digital logic processing unit triggers (e.g., outputs a trigger signal sample_clk) the comparison module 203 to perform sampling. The comparison module 203 first performs a first sampling. The digital logic processing unit inputs a loop status signal sup_comp_rt=1 to the comparison module 203 via a register. The comparison module 203 then acquires the most significant bit of the logic value of the reference voltage vref output by the fixed impedance unit. Then, the digital logic processing unit inputs the loop status signal sup_comp_rt=0 to the comparison module 203, and the comparison module 203 acquires the most significant bit of the logic value of the measured voltage vrep output by the adjustable impedance unit. The comparison module then performs a bit-by-bit comparison of the most significant bits of the logic values ​​of the measured voltage vrep and the reference voltage vref to obtain the comparison result sup_comp_rt_result. As an example, the impedance calibration device also includes a counting module (…). Figure 2(Not explicitly stated in the text) The counting module is used to record the number of samples. For example, the counting module is a counter. Therefore, in this example, after the first sample is completed, the counting module can record the sampling count as bit_cnt=1, meaning one sample was taken.

[0048] Next, based on the comparison result sup_comp_rt_result of the first sampling, impedance calibration is attempted using the SAR processing strategy. Specifically, if sup_comp_rt_result = 0, the comparison module 203 transmits a corresponding feedback signal to the digital logic processing unit, causing the digital logic processing unit to oversample according to the feedback signal, remove glitches, and determine whether the comparison result corresponding to the highest bit of the current code0 is "0" or "1". If the judgment result sup_comp_rt_result(dig) = 1 (dig represents the number of bits currently approximated, which in the current example is the highest bit in 0111111), it means that the current measured voltage vrep < the reference voltage vref, the value of the i-th bit of the current calibration (i.e., the highest bit in 0111111) remains unchanged, and the (i-1)-th bit is connected to 0. If sup_comp_rt_result(dig) = 0, then vrep > vref, the i-th bit is flipped (that is, from 0 to 1, or from 1 to 0), and the (i-1)-th bit is connected to 0. Thus, a new code1 is obtained. The adjustable impedance unit is controlled to adjust the impedance value according to code1 to obtain a new measured voltage. The new measured voltage is then compared with the reference voltage vref by the comparison module 203 to obtain the corresponding comparison result sup_comp_rt_result. Based on the comparison result, it is determined whether to continue (for example, by determining whether to continue by judging whether the preset number of sampling N has been reached). An impedance calibration is attempted using the SAR processing strategy. If so, the digital logic processing unit performs oversampling and glitching processing, and determines whether the second most significant bit of code1 is "0" or "1". If sup_comp_rt_result(dig)=1, the value of the i-th bit (i.e., the second most significant bit in code1) remains unchanged, and the (i-1)-th bit is set to 0. If sup_comp_rt_result(dig)=0, then vrep>vref, the i-th bit is flipped, and the (i-1)-th bit is set to 0, resulting in a new code2. This is used to continue controlling the adjustable impedance unit to adjust the impedance value and obtain a new measured voltage again. Repeat the above process until the obtained measured voltage vrep approaches the reference voltage vref, or until the values ​​of the 7 bits of the obtained measured voltage are compared and calibrated one by one, and the calibration process ends. At this time, the measured voltage corresponding to the last codeN will be very close to the reference voltage, and the counting module will count the number of sampling bit_cnt=N, where N is equal to or less than the bit width of the measured voltage.

[0049] Next, since the above process mainly obtains a measured voltage that reaches (or is close to) the reference voltage by comparing the voltage values, and the actual comparison module and other devices may also have noise, nonlinearity or other errors, which will also lead to a deviation between the final result and the ideal value, in this embodiment, after the impedance calibration is completed and the sampling number bit_cnt statistical result is reset, the detection is started by the inspection module 204 to detect the measured voltage that has reached the reference voltage and determine whether the measured voltage that has reached the reference voltage is accurate.

[0050] For example, the detection process can be as follows. After obtaining a measured voltage that approximates the reference voltage vref based on the digital control word codeN (also referred to herein as the first digital control word), the verification module 204 can be used to perform a numerical fine-tuning operation on codeN, and determine the accuracy of the measured voltage corresponding to codeN based on the result of the fine-tuning operation.

[0051] During impedance calibration, the comparison module can only output a comparison result of 1 (also referred to as the first logic value in this paper) or 0 (also referred to as the second logic value in this paper). If 1 and 0 appear alternately, it indicates that the voltage is in a dynamic equilibrium state, that is, the current measured voltage is just near the reference voltage, the system is stably approaching the target impedance, and the calibration accuracy is high. Conversely, if the output of the comparison module is stable at 1 or 0, it indicates that the measured voltage is far from the reference voltage or the system is not sensitive enough to small changes.

[0052] Therefore, the detection module 204 performs detection based on the comparison result of the Nth comparison and codeN. Specifically, if the comparison result corresponding to the measured voltage that approaches the reference voltage, i.e., the Nth comparison result sup_comp_rt_result=1, then the current digital control word sup_dac_n (i.e., codeN, also referred to as the first digital control word in this document) is reduced by the reference amplitude, for example, the reference amplitude = 1, thereby slightly subtracting 1 from the value of sup_dac_n to obtain the second digital control word, which is the updated digital control word sup_dac_n-1. If the Nth comparison result sup_comp_rt_result=0, then the first digital control word sup_dac_n is increased by the reference amplitude, for example, by 1, to obtain the second digital control word, which is the updated digital control word sup_dac_n+1. Then, based on the updated digital control word, the impedance of the adjustable impedance unit is adjusted again, and the sampling and comparison process of the impedance calibration stage described above is repeated through the comparison module 203, etc., to obtain a new comparison result. By repeating this process M times (where M is a positive integer greater than 1), the digital control word sup_dac_n is finely tuned to obtain M updated measured voltages and the corresponding M comparison results.

[0053] Analyze the M comparison results sup_comp_rt_result. If the M comparison results include alternating first and second logic values, that is, if the M comparison results sup_comp_rt_result alternate between 1, 0, 1, 0, ... or 0, 1, 0, 1, ..., then the measured voltage corresponding to codeN is considered accurate, the accuracy judgment result is output, and the detection operation ends.

[0054] If the M comparison results include consecutive first or second logic values, for example, if at least two consecutive comparison results are the same, i.e., the M comparison results sup_comp_rt_result are similar to 0, 0, 1, 1, ... or 1, 1, 0, 0, ..., then it indicates that the measured voltage corresponding to codeN is not accurate enough (the accuracy condition has not been met). Then, the digital control word codeX obtained from the Mth value fine-tuning operation can be taken as the logic control word for the next SAR processing, and a valid detect_en signal can be output to instruct the device 200 to perform impedance calibration and the corresponding detection operation again.

[0055] For example, during the detection phase, the code value after the first fine-tuning is 10, and the corresponding comparison result is 0; the code value after the second fine-tuning is 11, and the corresponding comparison result is 0; the code value after the third fine-tuning is 12, and the corresponding comparison result is 1; the code value after the fourth fine-tuning is 11, and the corresponding comparison result is 1. If two consecutive comparison results are the same, the code value of the last (i.e., the fourth) fine-tuning, 11, is used as the starting digital control word for the next SAR processing. This value is sent to the adjustable impedance unit for impedance adjustment to obtain a new measured voltage. The above calibration process is repeated until the measured voltage approaches the reference voltage accurately.

[0056] For example, the detection operation can be performed by setting a preset number of detection cycles. If the preset number of detection cycles, such as 10 cycles, is reached and the detect_en signal is still not valid (i.e., the measured voltage approaching the reference voltage is inaccurate), then the SAR processing is returned. If the detect_en signal is still not valid after re-executing the SAR processing for a total of loop count P, then an execution failure (fail_en) signal is output, and the loop processing is exited.

[0057] In other words, if the detection result indicates that the measured voltage is accurate and approaches the reference voltage, a valid detect_en enable signal is output, and the logic returns to the IDLE state (top-level integration). Otherwise, it returns to the Rcal PU stage for re-comparison. If the detection enable signal (detect_en) remains invalid for P consecutive SAR processing cycles (P can be customized, for example, P belongs to the value of 0~31), the impedance calibration logic exits.

[0058] Therefore, through the above testing process, if the measured voltage approaching the reference voltage is inaccurate, it indicates that the impedance calibration effect has not met expectations, and fine-tuning is performed. If the measured voltage approaching the reference voltage is accurate, it indicates that the impedance calibration effect has met expectations, and the impedance corresponding to the measured voltage at this time is considered equivalent to the standard impedance setting value. This adaptive fine-tuning operation improves the reliability of impedance calibration.

[0059] It should be noted that the above embodiments only illustrate the division of the above functional modules when implementing their functions. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the display device can be divided into different functional modules to complete all or part of the functions described above.

[0060] Those skilled in the art will understand that Figure 2 The structure shown does not constitute a limitation on device 200, which may include components such as... Figure 2 It can show more or fewer components, or combine certain components, or use different component arrangements.

[0061] Next, an impedance calibration method provided by an embodiment of this application will be described.

[0062] For example, Figure 5 The diagram illustrates a flowchart of an impedance calibration method provided in an embodiment of this application. This method can be executed on any suitable device, equipment, or platform, for example... Figure 1 The display device 00 shown, or Figure 2 The impedance calibration is performed on the impedance calibration device 200 shown, but is not limited thereto.

[0063] like Figure 5 As shown, this method may include steps S510 to S540.

[0064] S510 samples the measured voltage and reference voltage corresponding to the object to be calibrated. The measured voltage and reference voltage are logic values ​​of multiple bits.

[0065] S520 compares the logic value difference between the measured voltage and the reference voltage to obtain the comparison result.

[0066] S530 adjusts the impedance of the object to be calibrated based on the comparison results so that the measured voltage approaches the reference voltage.

[0067] S540 verifies the accuracy of the measured voltage that approaches the reference voltage based on the comparison results.

[0068] In some possible implementations, before the S510 samples the measured voltage and reference voltage corresponding to the object to be calibrated, the method may further include: inputting a digital control word to the object to be calibrated, the digital control word representing a voltage value, and a control signal used to instruct the object to be calibrated to adjust the impedance based on the voltage value to obtain the corresponding measured voltage.

[0069] For example, S520 compares the logic value difference between the measured voltage and the reference voltage to obtain a comparison result, which may include the following sub-steps: sampling the logic values ​​of the measured voltage and the reference voltage bit by bit; performing a bit-by-bit comparison of the values ​​of N bits between the measured voltage and the reference voltage to obtain a comparison result between N bits, wherein N does not exceed the bit width of the logic value, and the comparison result between N bits is used to trigger impedance adjustment of the object to be calibrated so that the measured voltage approaches the reference voltage.

[0070] In some possible implementations, S530 adjusts the impedance of the object to be calibrated based on the comparison results to make the measured voltage approach the reference voltage. This may include the sub-step: adjusting the impedance of the object to be calibrated based on the comparison results between N bits using a difference successive approximation processing strategy to make the measured voltage approach the reference voltage.

[0071] In some possible implementations, the measured voltage approaching the reference voltage is obtained based on a first digital control word, which is used to instruct the object to be calibrated to adjust its impedance. Therefore, S540, based on the comparison result, verifies the accuracy of the measured voltage approaching the reference voltage, which may include: fine-tuning the first digital control word according to a reference amplitude based on the comparison result corresponding to the measured voltage approaching the reference voltage, to obtain a second digital control word; adjusting the impedance of the object to be calibrated based on the second digital control word to obtain an updated measured voltage and the corresponding comparison result; and verifying the accuracy of the measured voltage approaching the reference voltage based on the M updated measured voltages obtained from the M-th adjustment operation and the corresponding M comparison results, where M is a positive integer.

[0072] In some possible implementations, the comparison result is represented by a first logic value or a second logic value, where the first logic value indicates that the corresponding measured voltage is higher than the reference voltage, and the second logic value indicates that the corresponding measured voltage is lower than the reference voltage. Based on the comparison result corresponding to the measured voltage approaching the reference voltage, the first digital control word is numerically fine-tuned according to a reference amplitude to obtain the second digital control word, including: when the comparison result corresponding to the measured voltage approaching the reference voltage is the first logic value, decreasing the first digital control word according to the reference amplitude to obtain the second digital control word; when the comparison result corresponding to the measured voltage approaching the reference voltage is the second logic value, increasing the first digital control word according to the reference amplitude to obtain the second digital control word.

[0073] In some possible implementations, based on the M updated measured voltages obtained from the M-th fine-tuning operation and the corresponding M comparison results, the accuracy of the measured voltage approaching the reference voltage is checked. This includes: after obtaining the M updated measured voltages and the corresponding M comparison results from the M-th fine-tuning operation, if the M comparison results include alternating first and second logic values, it is determined that the measured voltage approaching the reference voltage is accurate; if the M comparison results include consecutive first or second logic values, it is determined that the measured voltage approaching the reference voltage has not met the accuracy condition.

[0074] It should be noted that, for information regarding the function or beneficial effects of each step in the above impedance calibration method, please refer to the description of the impedance calibration device in the foregoing embodiments, which will not be repeated here.

[0075] In an exemplary embodiment, a computer device is also provided, comprising a processor and a memory, wherein at least one computer program is stored in the memory. The at least one computer program is loaded and executed by one or more processors to enable the computer device to implement any of the impedance calibration methods described above.

[0076] In an exemplary embodiment, a computer-readable storage medium is also provided, storing at least one computer program. This computer program is loaded and executed by a processor of a computer device to enable the computer to implement any of the impedance calibration methods described above. The computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, or optical data storage device, etc.

[0077] In an exemplary embodiment, a computer program product or computer program is also provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform any of the impedance calibration methods described above.

[0078] It should be understood that "multiple" as used in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0079] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. An impedance calibration device, characterized in that, The device includes: An adjustable impedance network module is used to provide sampling points for the measured voltage and the reference voltage, wherein the measured voltage and the reference voltage are logic values ​​of multiple bits. The comparison module is used to sample the measured voltage and the reference voltage, compare the logic value difference between the measured voltage and the reference voltage, and obtain a comparison result; A calibration module is used to adjust the impedance of the adjustable impedance network module according to the comparison result, so that the measured voltage approaches the reference voltage. The verification module is used to verify, based on the comparison results, whether the measured voltage that approaches the reference voltage is accurate.

2. The apparatus according to claim 1, characterized in that, The adjustable impedance network module includes a fixed impedance unit and an adjustable impedance unit; The fixed impedance unit includes multiple fixed impedance elements connected in series, and its output terminal serves as the sampling point of the reference voltage. The adjustable impedance unit includes an external impedance element and an adjustable impedance element connected in series. Its output terminal serves as the sampling point for the measured voltage. The impedance value of the external impedance element is equivalent to the standard impedance setting value.

3. The apparatus according to claim 2, characterized in that, The calibration module includes a digital logic processing unit, which is used to: output a digital control word to control the adjustable impedance unit to adjust the impedance based on the voltage value represented by the digital control word, so as to obtain the corresponding measured voltage; The comparison module is configured to: sample the logic values ​​of the measured voltage and the reference voltage bit by bit, perform bit-by-bit comparison of the values ​​of N bits between the measured voltage and the reference voltage, and obtain a comparison result between the N bits, wherein N does not exceed the bit width of the logic value, and the comparison result between the N bits is used to trigger the digital logic processing unit to adjust the digital control word, so as to control the adjustable impedance unit to adjust the impedance based on the adjusted digital control word, so that the measured voltage approaches the reference voltage.

4. The apparatus according to claim 3, characterized in that, The calibration module is used for: Based on the comparison results between the N bits, the digital control word is adjusted through a difference successive approximation processing strategy to control the adjustable impedance unit to adjust the impedance based on the adjusted digital control word, so that the measured voltage approaches the reference voltage.

5. The apparatus according to any one of claims 1-4, characterized in that, The measured voltage that approximates the reference voltage is obtained based on the first digital control word output by the calibration module; The inspection module is used for: Based on the comparison result corresponding to the measured voltage that is close to the reference voltage, the first digital control word is numerically fine-tuned according to the reference amplitude to obtain the second digital control word. The impedance of the adjustable impedance network module is adjusted based on the second digital control word to obtain the updated measured voltage and the corresponding comparison result. Based on the M updated measured voltages obtained from the M numerical fine-tuning operations and the corresponding M comparison results, the accuracy of the measured voltage that approaches the reference voltage is verified, where M is a positive integer.

6. The apparatus according to claim 5, characterized in that, The comparison result output by the comparison module is represented by a first logic value or a second logic value. The first logic value indicates that the corresponding measured voltage is higher than the reference voltage, and the second logic value indicates that the corresponding measured voltage is lower than the reference voltage. Based on the comparison result corresponding to the measured voltage that approaches the reference voltage, the first digital control word is numerically fine-tuned according to the reference amplitude to obtain the second digital control word. The verification module is used to: If the comparison result corresponding to the measured voltage that approaches the reference voltage is the first logic value, the first digital control word is reduced according to the reference amplitude to obtain the second digital control word; If the comparison result corresponding to the measured voltage that approaches the reference voltage is the second logic value, the first digital control word is increased according to the reference amplitude to obtain the second digital control word.

7. The apparatus according to claim 6, characterized in that, In verifying the accuracy of the measured voltage approaching the reference voltage based on M updated measured voltages obtained from M numerical fine-tuning operations and the corresponding M comparison results, the verification module is used to: If the M comparison results include alternating first and second logic values, it is determined that the measured voltage that approaches the reference voltage is accurate. If the M comparison results include consecutive first or second logic values, it is determined that the measured voltage approaching the reference voltage has not reached the accuracy condition.

8. An impedance calibration method, characterized in that, The method includes: The measured voltage and reference voltage corresponding to the object to be calibrated are sampled, and the measured voltage and the reference voltage are logic values ​​of multiple bits; The difference in logic values ​​between the measured voltage and the reference voltage is compared to obtain the comparison result; Based on the comparison results, the impedance of the object to be calibrated is adjusted so that the measured voltage approaches the reference voltage. Based on the comparison results, verify whether the measured voltage that approaches the reference voltage is accurate.

9. The method according to claim 8, characterized in that, Before sampling the measured voltage and reference voltage corresponding to the object to be calibrated, the method further includes: Output a digital control word to control the object to be calibrated to adjust its impedance based on the voltage value represented by the digital control word, so as to obtain the corresponding measured voltage; The step of comparing the logic value difference between the measured voltage and the reference voltage to obtain a comparison result includes: The logic values ​​of the measured voltage and the reference voltage are sampled bit by bit. The values ​​of N bits between the measured voltage and the reference voltage are compared bit by bit to obtain the comparison result between the N bits, wherein N does not exceed the bit width of the logic value. The comparison result between the N bits is used to adjust the digital control word to control the object to be calibrated to adjust the impedance based on the adjusted digital control word, so that the measured voltage approaches the reference voltage.

10. The method according to claim 9, characterized in that, The step of adjusting the impedance of the object to be calibrated based on the comparison result to make the measured voltage approach the reference voltage includes: Based on the comparison results between the N bits, the digital control word is adjusted through a difference successive approximation processing strategy to control the impedance of the object to be calibrated to adjust based on the adjusted digital control word, so that the measured voltage approaches the reference voltage.

11. The method according to any one of claims 8-10, characterized in that, The measured voltage that approaches the reference voltage is obtained based on the first digital control word; The step of verifying the accuracy of the measured voltage that approximates the reference voltage based on the comparison result includes: Based on the comparison result corresponding to the measured voltage that is close to the reference voltage, the first digital control word is numerically fine-tuned according to the reference amplitude to obtain the second digital control word. The impedance of the object to be calibrated is adjusted based on the second digital control word to obtain an updated measured voltage and the corresponding comparison result. Based on the M updated measured voltages obtained from the M numerical fine-tuning operations and the corresponding M comparison results, the accuracy of the measured voltage that approaches the reference voltage is verified, where M is a positive integer.

12. The method according to claim 11, characterized in that, The comparison result is represented by a first logic value or a second logic value, wherein the first logic value indicates that the corresponding measured voltage is higher than the reference voltage, and the second logic value indicates that the corresponding measured voltage is lower than the reference voltage. Based on the comparison result corresponding to the measured voltage that approaches the reference voltage, the first digital control word is numerically fine-tuned according to the reference amplitude to obtain the second digital control word, including: If the comparison result corresponding to the measured voltage that approaches the reference voltage is the first logic value, the first digital control word is reduced according to the reference amplitude to obtain the second digital control word; If the comparison result corresponding to the measured voltage that approaches the reference voltage is the second logic value, the first digital control word is increased according to the reference amplitude to obtain the second digital control word.

13. The method according to claim 12, characterized in that, Based on the M updated measured voltages obtained from the M numerical fine-tuning operations and the corresponding M comparison results, the accuracy of the measured voltage approaching the reference voltage is verified, including: If the M comparison results include alternating first and second logic values, it is determined that the measured voltage that approaches the reference voltage is accurate. If the M comparison results include consecutive first or second logic values, it is determined that the measured voltage approaching the reference voltage has not reached the accuracy condition.

14. A chip comprising the impedance calibration device as described in any one of claims 1 to 7.

15. A display device comprising the chip as claimed in claim 14.

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