Method for Improving the Accuracy of Asynchronous Communication in Battery Management Systems

Abstract

According to various embodiments of the present document, a method of operating a sensing IC may include: a length measurement step of storing a length measurement value obtained by measuring the time length of a synchronization byte transmitted by an MCU (Micro Controller Unit) based on a clock generated by an internally provided oscillator; a frequency comparison step of comparing the length measurement value with a reference length value obtained when the time length of the synchronization byte is measured at a reference frequency; and a frequency adjustment step of adjusting the frequency of the clock generated by the oscillator by adjusting a control signal that adjusts the amount of current supplied to the oscillator based on the result of the frequency comparison step.

Description

Technology Field

[0001] The present invention relates to a battery monitoring system, and more specifically to a method for improving the accuracy of communication between ICs within a battery monitoring system. Background Technology

[0003] Unlike conventional internal combustion engine vehicles, electric vehicles operate by obtaining driving energy from electrical energy stored in battery cells rather than fossil fuels.

[0004] Generally, a Battery Management System (BMS) that manages the batteries of an electric vehicle monitors the charge and discharge status of battery cells, as well as current voltage and current, and plays a role in adjusting the cells to maintain uniform voltage and state in the event of imbalances between them. To perform this role, the Battery Management System is equipped with multiple sensing ICs. Each sensing IC acquires information from the battery cells and transmits it to the Micro Controller Unit (MCU). At this time, since each sensing IC (integrated circuit) receives power from the connected battery cells, the operating voltage may differ for each sensing IC. Therefore, to prevent electrical damage that may occur due to differences in operating voltage between sensing ICs during communication, isolated communication is performed using isolation devices (e.g., transformers, capacitors, etc.).

[0005] In isolated communication, sensing ICs can communicate with the MCU in both synchronous and asynchronous ways. Asynchronous communication is widely used in battery management systems due to the advantage of reducing the number of pins by eliminating the need for a clock pin; however, it has the disadvantage that data must be transmitted and received at a precisely agreed-upon speed. The problem to be solved

[0007] Therefore, the objective of the present invention is to provide a method for improving the accuracy of asynchronous communication during isolated communication between a sensing IC and an MCU in a battery management system.

[0008] The technical tasks intended to be accomplished in this document are not limited to those mentioned above, and other technical tasks not mentioned will be clearly understood by those skilled in the art to which this document belongs from the description below. means of solving the problem

[0010] According to various embodiments, a method of operating a sensing IC may include a length measurement step of storing a length measurement value obtained by measuring the time length of a synchronization byte transmitted by an MCU (Micro Controller Unit) based on a clock generated by an internally provided oscillator; a frequency comparison step of comparing the length measurement value with a reference length value obtained when the time length of the synchronization byte is measured at a reference frequency; and a frequency adjustment step of adjusting the frequency of the clock generated by the oscillator by adjusting a control signal that adjusts the amount of current supplied to the oscillator based on the result of the frequency comparison step.

[0011] According to one embodiment, the synchronization byte is included in a synchronization frame transmitted by the MCU, and the synchronization frame may include a start bit in the first bit indicating the start of the synchronization frame, a synchronization byte of the next 8 bits, and an end bit in the last bit indicating the end of the synchronization frame.

[0012] According to one embodiment, the length measurement step may include the step of measuring the time length of the synchronization byte using a counter that increases by 1 based on the clock while receiving the synchronization byte.

[0013] According to one embodiment, the length measurement step may include: a step of increasing the counter by 1 based on the clock after recognizing the time of transition from the start bit to the first bit of the synchronization byte in the synchronization frame; a step of terminating the increase of the counter by 1 based on the clock when recognizing the time of transition from the last bit of the synchronization byte to the end bit in the synchronization frame; and a step of storing the value of the counter as the length measurement value.

[0014] According to one embodiment, the frequency adjustment step may include: a step of adjusting the control signal so that the frequency of the clock generated by the oscillator decreases if, as a result of comparison in the frequency comparison step, the length measurement value is greater than the reference length value; a step of adjusting the control signal so that the frequency of the clock generated by the oscillator increases if, as a result of comparison in the frequency comparison step, the length measurement value is smaller than the reference length value; and a step of maintaining the control signal as is so that the frequency of the clock generated by the oscillator is maintained if, as a result of comparison in the frequency comparison step, the length measurement value is equal to the reference length value.

[0015] According to one embodiment, the frequency adjustment step is capable of supplying current to the oscillator based on the control signal composed of N bits. N 2 current mirrors, each capable of turning on / off N The method includes a step of converting into a second control signal, wherein the converting step may include a step of converting the control signal into the second control signal such that a current mirror is turned on for a value represented by the control signal composed of N bits, thereby supplying current to the oscillator.

[0016] According to one embodiment, the frequency adjustment step may include: a step of decreasing the value of the control signal by 1 if, as a result of comparison in the frequency comparison step, the length measurement value is greater than the reference length value; a step of increasing the value of the control signal by 1 if, as a result of comparison in the frequency comparison step, the length measurement value is smaller than the reference length value; and a step of maintaining the control signal as is if, as a result of comparison in the frequency comparison step, the length measurement value is the same as the reference length value.

[0017] According to one embodiment, the sensing IC can perform the steps whenever it receives the synchronization byte to correct the frequency of the clock generated by the oscillator.

[0018] According to various other embodiments, the system may include a communication unit configured to transmit and receive data with an MCU and receive a synchronization frame transmitted by the MCU, an oscillator that generates a system clock used by internal logic, a length measuring unit that measures the time length of a synchronization byte included in the synchronization frame based on the clock and stores the measured length value, a frequency comparison unit that compares the length value with a reference length value when the time length of the synchronization byte is measured at a reference frequency, and a control signal generating unit that generates a control signal to adjust the amount of current supplied to the oscillator based on the comparison result of the frequency comparison unit in order to adjust the frequency of the clock generated by the oscillator.

[0019] According to one embodiment, the synchronization frame may include a start bit in the first bit indicating the start of the synchronization frame, a synchronization byte of the next 8 bits, and an end bit in the last bit indicating the end of the synchronization frame.

[0020] According to one embodiment, the length measuring unit can measure the time length of the synchronization byte using a counter that increases by 1 based on the clock while receiving the synchronization byte.

[0021] According to one embodiment, the length measuring unit may increase the counter by 1 based on the clock after recognizing the transition point from the start bit to the first bit of the synchronization byte in the synchronization frame, and stop increasing the counter by 1 based on the clock when recognizing the transition point from the last bit of the synchronization byte to the end bit in the synchronization frame, and store the value of the counter as the length measuring value.

[0022] According to one embodiment, the control signal generating unit may adjust the control signal so that the frequency of the clock generated by the oscillator decreases when the length measurement value is greater than the reference length value based on the comparison result of the frequency comparison unit, adjust the control signal so that the frequency of the clock generated by the oscillator increases when the length measurement value is smaller than the reference length value based on the comparison result of the frequency comparison unit, and maintain the control signal as is so that the frequency of the clock generated by the oscillator is maintained when the length measurement value is equal to the reference length value based on the comparison result of the frequency comparison unit.

[0023] According to one embodiment, the control signal generating unit is capable of supplying current to the oscillator, 2 N Based on the control signal composed of N bits, including current mirrors, the 2 N 2 current mirrors, each capable of turning on / off N Converted into two second control signals, the above two N By controlling the current mirrors, the amount of current supplied to the oscillator can be adjusted.

[0024] According to one embodiment, the control signal generating unit can convert the control signal into the second control signal so that a current mirror is turned on by an amount equal to the value represented by the control signal composed of N bits, thereby supplying current to the oscillator.

[0025] According to one embodiment, the control signal generating unit can decrease the value of the control signal by 1 if, as a result of comparison by the frequency comparison unit, the length measurement value is greater than the reference length value; increase the value of the control signal by 1 if, as a result of comparison by the frequency comparison unit, the length measurement value is smaller than the reference length value; and maintain the control signal as is if, as a result of comparison by the frequency comparison unit, the length measurement value is equal to the reference length value.

[0026] According to one embodiment, the oscillator may be an RC oscillator implemented only with a resistor and a capacitor, wherein the frequency of the clock generated by controlling the charging or discharging time by adjusting the amount of current is changed. Effects of the invention

[0028] The present invention can improve data transmission accuracy by correcting errors in the asynchronous communication transmission speed in real time by utilizing MCU transmission data to correct an internal oscillator during asynchronous communication between a sensing IC and an MCU (Micro Controller Unit) in a battery monitoring system.

[0029] The present invention can reduce IC size and lower costs by using an internal oscillator with a small surface area to increase accuracy in a battery monitoring system.

[0030] The technical problems intended to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below. Brief explanation of the drawing

[0032] FIG. 1 is an exemplary diagram showing the schematic configuration of a battery management system performing insulated communication according to the present invention. Figure 2 is a diagram showing the internal configuration of a sensing IC that communicates with the MCU of the present invention. FIG. 3 is a drawing showing a synchronization frame according to one embodiment of the present invention. FIG. 4 is a diagram illustrating an example in which a length measuring unit according to an embodiment of the present invention measures a time length using an 8-bit synchronization byte as a reference frequency. FIG. 5 is a diagram illustrating an example in which a length measuring unit according to an embodiment of the present invention measures the time length of an 8-bit synchronization byte at a frequency faster than the reference frequency. FIG. 6 is a diagram illustrating an example in which a length measuring unit according to an embodiment of the present invention measures the time length of an 8-bit synchronization byte at a frequency slower than the reference frequency. FIG. 7 is a diagram illustrating an example of a control signal generation circuit implemented for precise control of the oscillator frequency of the present invention. FIG. 8 is a flowchart illustrating a method for controlling the oscillator frequency of a sensing IC to improve the asynchronous communication accuracy of the present invention. Specific details for implementing the invention

[0033] Hereinafter, embodiments of the present document will be described in detail with reference to the attached drawings. The structure of the present document and the resulting effects will be clearly understood through the detailed description below. Prior to the detailed description of the present document, it should be noted that identical components are indicated by the same reference numerals whenever possible, even if they are shown in different drawings, and that specific descriptions of known components are omitted if it is determined that such omissions could obscure the essence of the present disclosure.

[0034] Before specifically describing the embodiments of this specification, the objectives appearing in the technical field in which the embodiments of this specification are implemented and the technical means that may be considered to solve them will be introduced in sequence.

[0035] Hereinafter, an embodiment of an apparatus and method for insulating signal stabilization in insulating communication according to the present invention will be described with reference to the attached drawings.

[0036] In this process, the thickness of lines or the size of components depicted in the drawings may be exaggerated for the sake of clarity and convenience of explanation. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intent or convention of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0037] Figure 1 is an example diagram showing the schematic configuration of a battery management system performing isolated communication of the present document.

[0038] As illustrated in FIG. 1, the battery management system may include a plurality of sensing ICs (200) (IC#2 to IC#N) for sensing the voltage of a battery cell, a Micro Controller Unit (110) that controls the plurality of sensing ICs (200) and obtains and processes information about the battery cell from the plurality of sensing ICs (200), and a communication IC (300) (IC#1) that is connected to the MCU (110) and communicates with the plurality of sensing ICs (200) to support data communication between the MCU (110) and the plurality of sensing ICs (200). Here, the plurality of sensing ICs (200) and the communication IC (300) may be connected in a daisy chain. That is, the plurality of sensing ICs (200) and the communication IC (300) are connected sequentially so that a communication signal can be received from the sensing IC (200) at the previous stage and transmitted to the sensing IC (200) at the next stage. Additionally, a transformer (TF) for insulation may be provided in the wire for transmitting communication signals between the communication IC (300) and adjacent sensing ICs (200) (IC#2 to IC#N), and a capacitor (C) for insulation may be provided in the wire for transmitting communication signals between multiple sensing ICs (200).

[0039] Here, the sensing IC (200) and the communication IC (300) have the same configuration for data communication, but the sensing IC (200) has an added function for measuring and managing battery cells, and the communication IC (300) may have an added function for data communication with the MCU (110).

[0040] Since each sensing IC (200) receives operating power from the battery cell to which it is connected, the operating voltage of each sensing IC (200) may differ. Therefore, insulation is required for every wire connected between the sensing ICs (200) to prevent burnout and to ensure communication. In addition, to reduce the size of the battery management system and the overall cost, the wire connecting the communication IC (300) and the sensing IC (200) (IC#2 or IC#N) can be insulated using a transformer (TF), and insulation between each sensing IC (200) (IC#2 ~ IC#N) can be performed using a capacitor (C).

[0041] Figure 2 is a diagram showing the internal configuration of a sensing IC that communicates with the MCU of the present invention.

[0042] Referring to FIG. 2, the sensing IC (200) may include a communication unit (210), an oscillator (220), a length measuring unit (230), a frequency comparison unit (240), and a control signal generating unit (250).

[0043] The communication unit (210) can perform the function of exchanging data with an adjacent sensing IC (200) or MCU (110). When the communication unit (210) receives a command from the MCU (110), it can perform the role of transmitting battery cell status information (voltage, current, temperature, etc.) sensed by the sensing IC (200) to the MCU.

[0044] The oscillator (220) can provide a system clock to internal logics. All internal components of the sensing IC can operate in accordance with the system clock provided by the oscillator (220). Therefore, the system clock provided by the oscillator (220) may be a reference clock for receiving and transmitting data when the communication unit (210) communicates with the MCU (110) using an asynchronous communication method such as UART (Universal Asynchronous Receiver / Transmitter).

[0045] Asynchronous communication is a method in which the transmitting and receiving ends use separate clocks to transmit data, and since the clocks are not shared, a synchronization process may be required during data transmission and reception. As a result, a start bit and an end bit are required to indicate the start and end of data transmission for each data transmission, making the speed relatively slower than synchronous communication, and correction may be required to improve communication accuracy. However, it has the advantage of being implementable at a low cost and having simple wiring, so it can be effectively applied when communicating between the sensing IC (200) and the MCU (110) in a battery management system.

[0046] According to one embodiment, the oscillator (220) may be an RC oscillator implemented to generate an oscillation signal using a plurality of resistors (R) and a plurality of capacitors (C). An RC oscillator is composed only of resistors (R) and capacitors (C), so it has a small implementation area and is inexpensive, but has the disadvantage of low frequency accuracy. To compensate for this disadvantage, a method or device required for frequency correction needs to be provided. For example, the frequency can be corrected by controlling the charging and discharging time by adjusting the amount of current applied to the RC oscillator (220).

[0047] According to one embodiment, a length measuring unit (230) for measuring the length of a synchronization frame or a synchronization byte included in a synchronization frame, a frequency comparison unit (240) for comparing the measured length value with a reference length value according to a reference frequency, and a control signal generating unit (250) for generating a control signal to adjust the frequency of a clock generated by an oscillator (220) based on the result of the comparison may be implemented as a single IC, FPGA (field programmable gate array), or processor. According to another embodiment, the length measuring unit (230), the frequency comparison unit (240), and the control signal generating unit (250) may be implemented using at least two ICs.

[0048] FIG. 3 is a drawing showing a synchronization frame according to an embodiment of the present invention.

[0049] Referring to FIG. 3, a synchronization frame according to one embodiment may be composed of a total of 10 bits, including a start bit indicating the start of the synchronization frame in the first bit, followed by 8 bits of synchronization bits, and a stop bit indicating the end of the synchronization frame in the last bit. For example, if a logic high ('1') signal is maintained on a communication line and a logic low ('0') signal is received, it is recognized that the start bit has been received, and if a logic low signal is maintained for a certain period of time after the last logic high, it is recognized that the stop bit has been received.

[0050] When the MCU (110) communicates with the sensing IC (200) for data, it may first send a synchronization frame. Then, it may send a data frame. Similar to the synchronization frame, the data frame may include a start bit and an end bit at the beginning and end, and have data bits in between.

[0051] The length measuring unit (230) may include a counter or a timer, and upon receiving a synchronization frame transmitted by the MCU (110), it can measure and store the length of time. The length measuring unit (230) can calculate how many internal oscillator (220) clock cycles the synchronization frame transmitted from the MCU (110) consists of and measure the time. Based on this, the sensing IC (200) can help calibrate the internal oscillator (220).

[0052] The length measuring unit (230) can measure the time length of the synchronization byte by counting the synchronization byte using the system clock provided by the internal oscillator.

[0053] FIGS. 4 to 6 illustrate an example in which a length measuring unit measures the time length of an 8-bit synchronization byte at a reference frequency, a frequency faster than the reference frequency, and a frequency slower than the reference frequency.

[0054] Referring to FIGS. 4 through 6, in communication between the MCU (110) and the sensing IC (200), the MCU (110) can transmit a 10-bit synchronization frame at a clock of 2 MHz. The synchronization frame may consist of a 1-bit start bit, a 1-byte synchronization byte, and a 1-bit stop bit. When 8 bits of the synchronization byte are transmitted at a clock of 2 MHz, the time required for the synchronization byte to be fully received by the sensing IC (200) is 8 / 2M = 4000ns.

[0055] As shown in FIG. 4, if the oscillator (220) generates and provides an internal system clock of a reference frequency of 28 MHz, then 112 can be counted by counting with the internal system clock of the sensing IC (200) of 28 MHz while receiving a synchronization byte of 4000 ns.

[0056] Referring to FIG. 4, counting begins with a 28 MHz internal system clock at the point when the start bit ends and the first bit of the synchronization byte begins, that is, at the point when the received signal changes from 0 to 1. Then, when counting ends at the point when the last eighth bit of the synchronization byte ends and the end bit begins, that is, at the point when the received signal changes from 0 to 1 for the fourth time after counting has started, 112 can be recorded in the counter.

[0057] According to one embodiment, as shown in FIG. 5, if the oscillator (220) generates and provides an internal system clock of 29 MHz faster than the reference frequency of 28 MHz, then 116 can be counted by counting with the internal system clock of the sensing IC (200) at 29 MHz while receiving a synchronization byte of 4000 ns.

[0058] Referring to FIG. 5, counting begins at the point when the start bit ends and the first bit of the synchronization byte begins, that is, when the received signal changes from 0 to 1, using a 29 MHz internal system clock. Then, when counting ends at the point when the last eighth bit of the synchronization byte ends and the end bit begins, that is, when the received signal changes from 0 to 1 for the fourth time after counting has started, 116 can be recorded in the counter.

[0059] As such, if the clock provided by the oscillator (220) is faster than the reference frequency, a value greater than the reference value of 112 (e.g., 116) can be recorded in the counter that measures the time length of the synchronization byte.

[0060] According to another embodiment, if the oscillator (220) generates and provides an internal system clock of 27 MHz, which is slower than the reference frequency of 28 MHz as shown in FIG. 6, then 108 can be counted by counting with the internal system clock of the sensing IC (200) at 27 MHz while receiving a synchronization byte of 4000 ns.

[0061] Referring to FIG. 6, counting begins with a 27 MHz internal system clock at the point when the start bit ends and the first bit of the synchronization byte begins, that is, at the point when the received signal changes from 0 to 1. Then, when counting ends at the point when the last eighth bit of the synchronization byte ends and the end bit begins, that is, at the point when the received signal changes from 0 to 1 for the fourth time after counting has started, 108 can be recorded in the counter.

[0062] As such, if the clock provided by the oscillator (220) is slower than the reference frequency, a value smaller than the reference value of 112 (e.g., 108) may be recorded in the counter that measures the time length of the synchronization byte.

[0063] The frequency comparison unit (240) can detect a difference by comparing the reference frequency with the frequency generated by the internal oscillator (220) of the sensing IC (200). That is, the frequency comparison unit (240) can compare the time length reference value (e.g., 112) according to the reference frequency with the time length measurement value (e.g., 116 or 108) of the internal oscillator frequency and send the error (e.g., +4 or -4) to the control signal generation unit (250).

[0064] The control signal generation unit (250) can adjust the current amount of the oscillator (220) to correct the frequency of the oscillator (220) based on the error detected by the frequency comparison unit (240).

[0065] According to one embodiment, when the control signal generation unit (250) receives a result that the time length measurement value is greater than the time length reference value according to the reference frequency, for example, as shown in FIG. 5, the result that the time length measured counter value (e.g., 116) is greater than the reference counter value (112), or the result that the error is positive, it can determine that the frequency of the clock generated by the oscillator (220) is greater than the reference frequency. Based on this, the control signal generation unit (250) can control the current applied to the oscillator (220) to be reduced. When the current applied to the oscillator (220) is reduced by the control signal generation unit (250), the frequency of the clock generated by the oscillator (220) becomes smaller and equal to the reference frequency.

[0066] According to another embodiment, when the control signal generation unit (250) receives a result that the time length measurement value is smaller than the time length reference value according to the reference frequency, for example, as shown in FIG. 6, the time length measured counter value (e.g., 108) is smaller than the reference counter value (112), or the error is negative, it can determine that the frequency of the clock generated by the oscillator (220) is smaller than the reference frequency. Based on this, the control signal generation unit (250) can control the current applied to the oscillator (220) to increase. When the current applied to the oscillator (220) by the control signal generation unit (250) increases, the frequency of the clock generated by the oscillator (220) becomes larger and can become equal to the reference frequency.

[0067] According to another embodiment, the control signal generation unit (250) may determine that the frequency of the clock generated by the oscillator (220) is equal to the reference frequency when the time length measurement value is equal to the time length reference value according to the reference frequency, for example, when receiving a result that the time length measured counter value (e.g., 112) is equal to the reference counter value (112) as shown in FIG. 4, or a result that the error is 0. Based on this, the control signal generation unit (250) may control the current applied to the oscillator (220) to be maintained so that the frequency of the clock generated by the oscillator (220) is maintained to be equal to the reference frequency. And the communication unit (210) may generate a response to be transmitted to the MCU (110) based on the clock generated by the oscillator (220).

[0068] And the sensing IC (200) can use the corrected frequency when generating the response of the MCU (110).

[0069] The control signal generation unit (250) can correct the error by adjusting the current applied to the oscillator (220) when an error occurs by comparing the frequency of the system clock of the sensing IC (200) with the reference frequency during asynchronous communication between the MCU (110) and the sensing IC (200).

[0070] FIG. 7 is a diagram illustrating an example of a control signal generation circuit implemented for precise control of the oscillator frequency in the present invention.

[0071] Referring to FIG. 7, the control signal generating unit (250) is 2 N Two current mirrors (711), based on an N-bit control signal, 2 N 2 that individually turn the current mirrors on / off N It may include a conversion unit (713) that converts into control signals.

[0072] 2 N Each of the current mirrors (711) may be composed of two MOSFETs, and according to one embodiment, 2 N Each of the current mirrors (711) can provide the same amount of current to the oscillator (220) when turned on.

[0073] The conversion unit (713) receives an N-bit control signal and 2 N A control signal can be generated to turn on / off each of the current mirrors (711). According to one embodiment, the N-bit control signal may indicate the number of current mirrors to be turned on. For example, if there are 8 current mirrors, the control signal may be 3 bits. If the value of the 3-bit control signal is "000", only 1 current mirror is turned on; if it is "100", 5 current mirrors are turned on; and if it is "111", all 8 current mirrors are turned on.

[0074] According to one embodiment, even if a control signal to turn on the same number of current mirrors is received, the actual current mirrors turned on may differ.

[0075] FIG. 8 is a flowchart illustrating a method for controlling the oscillator frequency of a sensing IC to improve the asynchronous communication accuracy of the present invention.

[0076] Referring to FIG. 8, the frequency control method of an oscillator (220) of a sensing IC for improving asynchronous communication accuracy according to the present invention may include a length measurement step (S100), a frequency comparison step (S110), and a control signal adjustment step (S120).

[0077] In the length measurement step (S100), the length measurement unit (230) of the sensing IC (200) can measure the temporal length of an 8-bit synchronization byte transmitted by the MCU (110). While receiving the synchronization byte as illustrated in FIGS. 4 to 6, the length measurement unit (230) can measure the number of clocks generated by the oscillator (220). According to one embodiment, while receiving the 8-bit synchronization byte, the length measurement unit (230) can measure the temporal length of the synchronization byte as a final counter value by increasing the counter value by 1 in accordance with the clocks generated by the oscillator (220).

[0078] In the frequency comparison step (S110), the frequency comparison unit (240) of the sensing IC can compare the measured counter value with the reference counter value based on the clock of the reference frequency to compare the frequency of the clock generated by the oscillator (220) with the reference frequency. As shown in FIGS. 4 to 6, the comparison result may include a result where the measured counter value is the same as the reference counter value and the frequency of the clock generated by the oscillator (220) is the same as the reference frequency; a result where the measured counter value is greater than the reference counter value and the frequency of the clock generated by the oscillator (220) is greater (or faster) than the reference frequency; or a result where the measured counter value is smaller than the reference counter value and the frequency of the clock generated by the oscillator (220) is smaller (or slower) than the reference frequency. According to another embodiment, the comparison result may include a result where the error is 0, a result where the frequency of the clock generated by the oscillator (220) is greater than the reference frequency and a result where the frequency of the clock generated by the oscillator (220) is less than the reference frequency and a result where the error is less than the reference frequency.

[0079] In the frequency adjustment step (S120), the control signal generation unit (250) of the sensing IC may generate a control signal to adjust the frequency of the clock generated by the oscillator (220) based on the comparison result in the frequency comparison step (S110). According to one embodiment, the control signal may adjust the amount of current supplied to the oscillator (220). If the value of the control signal increases, more current may be supplied to the oscillator (220) than before, so that the frequency may increase, and if the value of the control signal decreases, less current may be supplied to the oscillator (220) than before, so that the frequency may decrease.

[0080] According to one embodiment, the control signal generating unit (250) of the sensing IC may perform a step of initializing the control signal when the control signal is a maximum value or a minimum value. Here, the initializing step may be a step of initializing the value of the control signal to a preset value. According to one embodiment, in FIG. 6, when N is 4, 2 4 = A 4-bit control signal (binary: 0000 to 1111) can be generated to control the on / off of 16 current mirrors. In this case, 0000 may be the minimum value of the control signal and 1111 may be the maximum value of the control signal. The control signal generation unit (250) of the sensing IC may be initialized to a preset value (e.g., binary 1000) when the value of the control signal is the minimum value or the minimum value.

[0081] According to one embodiment, when initializing a control signal, the amount of current supplied by each of the plurality of current mirrors shown in FIG. 7 can be adjusted. For example, when the control signal is at a maximum value and then initialized, the amount of current supplied by each current mirror can be increased so that the amount of current supplied by the current mirrors that turn on upon initialization (e.g., 8 current mirrors) becomes equal to the amount of current supplied by all current mirrors before initialization.

[0082] As another example, when the control signal is at a minimum value and then initialized, the amount of current supplied by each current mirror can be reduced so that the amount of current supplied by the current mirrors that turn on upon initialization (e.g., four current mirrors) becomes equal to the amount of current supplied by one current mirror before initialization.

[0083] According to one embodiment, the value of the control signal that is initialized when the control signal is at a maximum value and the value of the control signal that is initialized when the control signal is at a minimum value may be different.

[0084] In the frequency adjustment step (S120), the control signal generation unit (250) of the sensing IC can decrease the value of the control signal by 1 if, as a result of the frequency comparison in the frequency comparison step (S100), the measured counter value is greater than the reference counter value, i.e., if a positive error occurs. When the value of the control signal is decreased by 1, the number of current mirrors turned on is reduced by 1, thereby reducing the current supplied to the oscillator (220) and making the frequency of the system clock generated by the oscillator (220) smaller.

[0085] In the frequency adjustment step (S120), the control signal generation unit (250) of the sensing IC can increase the value of the control signal by 1 if, as a result of the frequency comparison in the frequency comparison step (S100), the measured counter value is smaller than the reference counter value, i.e., if a negative error occurs. When the value of the control signal is increased by 1, the number of current mirrors turned on increases by 1, thereby increasing the current supplied to the oscillator (220) and increasing the frequency of the system clock generated by the oscillator (220).

[0086] In the frequency adjustment step (S120), the control signal generation unit (250) of the sensing IC can maintain the value of the control signal as is when, as a result of the frequency comparison in the frequency comparison step (S100), the measured counter value is the same as the reference counter value, that is, when no error occurs. By maintaining the value of the control signal as is, the current supplied to the oscillator (220) remains the same as before, so the frequency of the system clock generated by the oscillator (220) can be maintained at the same as the reference frequency.

[0087] The sensing IC can adjust the frequency of the internal system clock to the reference frequency in real time by performing the method shown in FIG. 8 whenever it receives a synchronization byte.

[0088] And the sensing IC (200) can transmit a response to the MCU (110) based on the clock generated by the oscillator (220).

[0089] The oscillator frequency control method for improving asynchronous communication accuracy between the MCU (110) and the sensing IC (200) of the present invention measures the time length of a synchronization byte included in a synchronization data frame transmitted by the MCU (110), and compares the measured time length (measured counter value) with the time length at a reference frequency (reference counter value) to compare the reference frequency with the frequency of the clock generated by the oscillator (220) inside the sensing IC (200). Based on the comparison result, the clock frequency can be corrected by controlling the amount of current supplied to the oscillator (220).

[0090] As described above, the present invention has been explained by limited embodiments and drawings, but the present invention is not limited to the above embodiments and modifications or variations of the described matters are possible. Therefore, the scope of the invention is not limited to the described embodiments but should be defined by the claims set forth below as well as equivalents thereof.

[0091] Those skilled in the art related to the embodiments described above will understand that they may be implemented in modified forms without departing from the essential characteristics of the description. Therefore, the disclosed methods should be considered in an illustrative rather than a limiting sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalence should be interpreted as being included in the invention. Explanation of the symbols

[0093] 110: MCU (micro controller unit) 200: Sensing IC 210: Communications Department 220: Oscillator 230: Control unit 230: Length measuring section 240: Frequency Comparison Unit 250: Control signal generation unit

Claims

Claim 1 A method of operation of a sensing IC comprising: a length measurement step of storing a length measurement value obtained by measuring the time length of a synchronization byte transmitted by an MCU (Micro Controller Unit) based on a clock generated by an internally provided oscillator; a frequency comparison step of comparing the length measurement value with a reference length value obtained when the time length of the synchronization byte is measured at a reference frequency; and a frequency adjustment step of adjusting the frequency of the clock generated by the oscillator by adjusting a control signal that adjusts the amount of current supplied to the oscillator based on the result of the frequency comparison step. Claim 2 A method of operation of a sensing IC according to claim 1, wherein the synchronization byte is included in a synchronization frame transmitted by the MCU, and the synchronization frame includes a start bit indicating the start of the synchronization frame in the first bit, a synchronization byte of the next 8 bits, and a termination bit indicating the end of the synchronization frame in the last bit. Claim 3 A method of operation of a sensing IC according to paragraph 2, wherein the length measuring step comprises the step of measuring the time length of the synchronization byte using a counter that increases by 1 based on the clock while receiving the synchronization byte. Claim 4 A method of operation of a sensing IC according to claim 2 or 3, wherein the length measurement step comprises: a step of increasing the counter by 1 based on the clock after recognizing the time of transition from the start bit to the first bit of the synchronization byte in the synchronization frame; a step of terminating increasing the counter by 1 based on the clock when recognizing the time of transition from the last bit of the synchronization byte to the end bit in the synchronization frame; and a step of storing the value of the counter as the length measurement value. Claim 5 A method of operation of a sensing IC according to claim 1, wherein the frequency adjustment step comprises: a step of adjusting the control signal such that the frequency of the clock generated by the oscillator becomes smaller when the length measurement value is greater than the reference length value as a result of comparison in the frequency comparison step; a step of adjusting the control signal such that the frequency of the clock generated by the oscillator becomes larger when the length measurement value is smaller than the reference length value as a result of comparison in the frequency comparison step; and a step of maintaining the control signal as is so that the frequency of the clock generated by the oscillator is maintained when the length measurement value is equal to the reference length value as a result of comparison in the frequency comparison step. Claim 6 In paragraph 5, the frequency adjustment step is capable of supplying current to the oscillator based on the control signal composed of N bits, 2 N 2 current mirrors, each capable of turning on / off N A method of operation of a sensing IC, comprising a step of converting to a second control signal, wherein the converting step comprises a step of converting the control signal to the second control signal such that a current mirror is turned on for a value represented by the control signal composed of N bits, thereby supplying current to the oscillator. Claim 7 A method of operation of a sensing IC according to claim 6, wherein the frequency adjustment step comprises: a step of decreasing the value of the control signal by 1 if, as a result of comparison in the frequency comparison step, the length measurement value is greater than the reference length value; a step of increasing the value of the control signal by 1 if, as a result of comparison in the frequency comparison step, the length measurement value is smaller than the reference length value; and a step of maintaining the control signal as is if, as a result of comparison in the frequency comparison step, the length measurement value is the same as the reference length value. Claim 8 A method of operation of a sensing IC according to claim 1, wherein the sensing IC performs the steps whenever it receives the synchronization byte to correct the frequency of the clock generated by the oscillator. Claim 9 A sensing IC comprising: a communication unit configured to transmit and receive data with an MCU and receiving a synchronization frame transmitted by the MCU; an oscillator that generates a system clock used by internal logics; a length measuring unit that measures the time length of a synchronization byte included in the synchronization frame based on the clock and stores the measured length value; a frequency comparison unit that compares the length measured value with a reference length value when the time length of the synchronization byte is measured at a reference frequency; and a control signal generating unit that generates a control signal to adjust the amount of current supplied to the oscillator based on the comparison result of the frequency comparison unit in order to adjust the frequency of the clock generated by the oscillator. Claim 10 In claim 9, the synchronization frame comprises a start bit indicating the start of the synchronization frame in the first bit, a synchronization byte of the next 8 bits, and an end bit indicating the end of the synchronization frame in the last bit, a sensing IC. Claim 11 In claim 9, the length measuring unit is a sensing IC that measures the time length of the synchronization byte using a counter that increases by 1 based on the clock while receiving the synchronization byte. Claim 12 A sensing IC according to claim 10 or 11, wherein the length measuring unit increments the counter by 1 based on the clock after recognizing the transition point from the start bit to the first bit of the synchronization byte in the synchronization frame, and terminates incrementing the counter by 1 based on the clock when recognizing the transition point from the last bit of the synchronization byte to the end bit in the synchronization frame, and stores the value of the counter as the length measuring value. Claim 13 In claim 11, the control signal generating unit adjusts the control signal so that the frequency of the clock generated by the oscillator decreases when the length measurement value is greater than the reference length value based on the comparison result of the frequency comparison unit, adjusts the control signal so that the frequency of the clock generated by the oscillator increases when the length measurement value is smaller than the reference length value based on the comparison result of the frequency comparison unit, and maintains the control signal as is so that the frequency of the clock generated by the oscillator is maintained when the length measurement value is equal to the reference length value based on the comparison result of the frequency comparison unit. Claim 14 In paragraph 13, the control signal generating unit is capable of supplying current to the oscillator, 2 N It includes current mirrors, and based on the control signal composed of N bits, the 2 N 2 current mirrors, each capable of turning on / off N Converted into two second control signals, the above two N A sensing IC that controls the amount of current supplied to the oscillator by controlling two current mirrors. Claim 15 In claim 14, the control signal generating unit is a sensing IC that converts the control signal into the second control signal so that a current mirror is turned on for a value represented by the control signal composed of N bits, thereby supplying current to the oscillator. Claim 16 In claim 15, the control signal generating unit comprises: a step of decreasing the value of the control signal by 1 if, as a result of comparison by the frequency comparison unit, the length measurement value is greater than the reference length value; a step of increasing the value of the control signal by 1 if, as a result of comparison by the frequency comparison unit, the length measurement value is smaller than the reference length value; and a sensing IC that maintains the control signal as is if, as a result of comparison by the frequency comparison unit, the length measurement value is equal to the reference length value. Claim 17 In claim 9, the oscillator is a sensing IC that is an RC oscillator implemented only with a resistor and a capacitor, wherein the frequency of the clock generated by controlling the charging or discharging time by adjusting the amount of current is changed.

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