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2022-09-16 16:00:09
BQ27350 is a single battery lithium -ion battery manager for impedance tracking fuel metering technology
Introduction
Features
Comprehensive battery fuel meter suitable for single batteries and 1 series lithium ion applications
use SHA-1 /HMAC encryption for security battery certification
Calculation and report
- The remaining battery capacity
- Battery voltage and temperature Current
- Four empty predictions
Based on patented battery orbital impedance #8482; Technology
- Moderate for battery discharge curve to accurately predict the empty empty empty empty empty Time
- Auto -adjustment of battery aging, battery self -discharge and temperature/rate inefficient adjustment
-The low -value detection resistor (10m or smaller)
96 bytes of non -easy -to -lose sexual notebook data memory
Host's i2C communication interface
20 -needle tssop packaging
Application
Motion sales point terminal
Industrial data collection
smartphone
#8226 ; PDA system
Digital camera
Handheld terminal
Instructions
Texas Instrument CompanyBQ27350 [123
] It is a battery fuel meter that supports the safety certification of a single battery lithium ion battery pack. It is designed for the integration of the battery group. The device only requires a small number of host microcontroller firmware to support the implementation of the main processor of the system. BQ27350 also provides integration and external support, using SHA-1/HMAC certification algorithm for safety battery pack certification.Typical implementation
General description 
BQ27350 accurately predicts the battery capacity and other working characteristics of a single lithium -based rechargeable battery. The host processor can ask it to provide unit information, such as charging status (SOC), clearing time (TTE) and full time(TTF).
Information is accessed by a series of commands called standard commands. The additional extended command set provides more functions. These two sets of commands are used by general format commands () to indicate the control registers and status registers that read and write to BQ27350 and information in the position of the data flash memory position. Using the I2C engine of the BQ27350, the command can be sent from the host to the instrument, which can be executed during application development, packaging manufacturing or terminal device operation.
Unit information is stored in non -easy -to -sex flash memory inside BQ27350. During application development and component manufacturing, many locations of these data flash memory can be accessed. During the running of the terminal device, they usually cannot access them directly. By using the BQ27350 supporting assessment software, through a separate command, or through a series of data flash memory access commands to achieve access to these locations. To access the required data flash memory position, you must know the correct data flashing subclasses and offset.
BQ27350 provides a 96 -byte user programming data flash memory, divided into 3 32 -byte blocks: manufacturer information A, manufacturer information B, and manufacturer information C. This data space is accessible through the data flash memory interface. For more information on access to data flash memory, see the Data Flash Data Interface section.
The key to BQ27350 high -precision gas metering prediction is the excretion trajectory of Texas Instruments #8482; algorithm. This algorithm combines battery measurement, characteristics, and characteristics to create a charge state prediction, which can reach accuracy of more than 1%under various operating conditions.
The BQ27350 is measured by monitoring the small -value series resistance between the battery negative polar end and the low -voltage side to protect the FET (5 m to 20 m ) to measure the charging/discharge activity. When a load of an application is applied, the battery impedance is measured by comparing its opening voltage (OCV) and measurement voltage under the load conditions.
BQ27350 can use an external NTC thermistor (default Semitic 103AT) for temperature measurement, or it can also be configured to use its internal temperature sensor. The BQ27350 uses the temperature monitoring of the battery set environment for fuel measurement and battery protection function.
In order to reduce power consumption, the BQ27350 has several power modes: normal, dormant, dormant and shutdown. BQ27350 is automatically passed between these modes according to the occurrence of specific events, although the host processor can directly start some of these modes. More details can be found in the Power Mode section.
The battery pack authentication function was also implemented on the BQ27350. The draft area is used to receive inquiry information from the host and export the SHA-1/HMAC encryption response. The BQ27350 can be executed directly, or it can also be passed on the BQ26100 independent certification IC. Specific detailsFound in the section of Identity Verification .
Comment format practice:
Command: oblique body, with parentheses, without spaces, such as RemainingCapAcity ().
Data flashing: oblique body, coarse body, and separators, such as design capacity,
Stock position and logo: only brackets, such as [TDA] mode and status: all uppercase letters, such as unkncel sealing model.
Data flash memory interface
Access data flash memory
BQ27350 Data flash memory is a non -easy -to -miss memory, including BQ27350 initialization, default value, unit status, calibration, configuration and user users information. Data flash memory can be accessed in several different ways, depending on the working mode and access data of the BQ27350.
The data flash memory position that is usually accessed is often read by the host. It can be easily accessible by specific instructions. These instructions have been described in the data command part. These commands are available when the BQ27350 is in an unclean or sealing mode.
However, most data flash memory positions can only be accessed in non -sealing mode by using BQ27350 evaluation software or transmitting data flashing blocks. In the process of development and manufacturing, these positions should be optimized and/or fixed. They become part of the golden packet file, and then they can be written into multiple battery packs. Once determined, these values usually remain unchanged during the terminal equipment.
To access the data flashing position separately, the block containing the required data flash memory position must be transmitted to the command register position, where they can be read to the host or directly change. This is achieved by sending the setting command BlockDataControl () (code 0x61) with data 0x00. You can read the data of up to 32 bytes from the BlockData () command position 0x40 ... 0x5F, change the outside, and then rewrite the blockdata () command space. Alternatively, if the corresponding offset of a specific location is used for indexing blockdata () command space, you can read, change, and rewrite it to a specific location. Finally, once the correct verification of the entire block and being written into the blockdatachecksum () (command number 0x60), the data staying in the command space is transmitted to the Data Flash.
Sometimes, the data flash memory category will be greater than 32 bytes. In this case, the DataFLASHBLOCK () command is used to specify the 32 -byte block where the required location is located. Then, 0x40+offset 32 gives the correct command address. For example, in order to access the terminal voltage in the gas meter class, the DataFLASHClass () 80 (0x50) is emitted to set this class. Because the offset is 48, it must be located in the second 32 wordsIn the block. Therefore, the DataFlashblock () 0x01 is emitted to set the offset to indexes the offset of the BlockData () memory area of 0x40+48 mold 32 u003d 0x40+16 u003d 0x40+0x10 u003d 0x50.
Reading and writing subclass data is a 32 -byte manner operation. However, data can be written with shorter blocks. The length of the block can be less than 32 bytes. These blocks of data backgrounds do not cover data that exceeds the actual block length.
All the data written in the memory are not limited by BQ27350-Gas pressure gauges will not reject these values. Due to the invalid data of the firmware program, writing an error value may cause hardware failure. The written data is permanent, so the power -on reset cannot solve the failure.
Manufacturer's information block
BQ27350 users with 96 -byte users programming data flash memory: manufacturer information block A, manufacturer information block B, manufacturer information block C. The method of accessing these memory positions is slightly different, depending on whether the device is in a non -sealing mode or a sealing mode.
When the non -sealing mode and 0x00 were written into the BlockDataControl (), the access to the manufacturer's information block was the same as accessing the general data flash memory position. First, the DataFLASHClass () command is used to set the subclass, and then the dataflashblock () command sets the offset of the first data flash address in the subclass. BlockData () command code contains the referenced data flash memory data. When writing data flash memory, Blockdatachecksum () will receive a verification. Only when the verification is received and verified, the data is really written into the data flash memory.
As an example, the data flash memory position of the manufacturer's information block B is defined as a subclass u003d 58 and offset u003d 32 to 63 (32 -byte blocks). Class u003d System Data specifications do not need to be used to handle manufacturer information block B, but for grouping when viewing data flash memory information in BQ27350 evaluation software.
When the seal mode or 0x01 has been written in the blockDataControl (), the data flash memory is no longer available in the method of non -sealing mode. Use the DataFlashBlock () command to select the specified manufacturer's information block instead of publishing subclass information. Use this command to send 0x01, 0x02, or 0x03 to cause the corresponding information blocks (A, B, or C) to the command space 0x40 ... 0x5F for host editing or reading. After successfully writing the verification and information into the blockdatachecksum (), the modified block will be returned to Data Flash. Note: Manufacturer's information block A is read only in the seal mode.
Function description
Fuel measurement
BQ27350 measures the battery voltage, temperature and current to determine the battery SOC. The BQ27350 is monitored and charged and discharge through the voltage between the SRP and SRN pins and the voltage between the small resistance (5m to 20mm ) through the sensor (5M to 20mm ). By integrating the charge of the battery, the battery SOC is adjusted during the battery charging or discharge process.
The total capacity of the battery was obtained by comparing the charging status before and after the load and the power passed. When applying an application load, the battery is measured by comparing the OCV and the voltage measured under the load by comparing the predetermined function of the current SOC to measure the resistance of the battery. The measurement of OCV and charge points determines the state of chemical charge and chemical capacity (QMAX). The initial QMAX value is taken from the number of data tables of the battery manufacturer by the number of parallel batteries. It is also used to calculate the value of the design capacity. The BQ27350 obtains and updates the battery impedance curve during the use of normal batteries. It uses this configuration file and the SOC and QMAX values to determine the complete charging capacity () and charging status () at the current load and temperature. Full of capacity () refers to the available capacity of the battery that is fully charged at the current load and temperature at the voltage (). NominaLavaability () and FullavailableCapAcity () are the unparalleled (non -load or light load) versions of RemainingCapAcity () and FullChargeCapAcity (), respectively.
The BQ27350 has two signs, which is accessed by the Flags () function. When the SOC of the battery drops to the critical level, a warning is issued. When the remaining capacity () is lower than the first capacity threshold specified in the RCA set, the [RCA] ( remaining capacity alert ) logo will be set. Once the remaining capacity () is higher than the RCA settings, the sign is cleared. All units are in Naza.
When the charging status () is lower than the second capacity threshold TDA SET%, set the [TDA] ( Termid Downside Alarm ) logo as a final discharge warning. If the TDA settings%u003d -1, the sign is not available in the discharge process.
Similarly, when Stateofcharge () rises to TDA Clear%or more and has set the [TDA] logo, the [TDA] logo will be cleared, provided that the TDA SET%≠ -1 will be. All units are expressed in percentage.
Resistance trajectory variables
BQ27350 have several data flash memory variables, allowing users to customize impedance tracking algorithms to optimize performance. These variables depend on the power characteristics of the application and the unit itself.
load mode
The load mode is usedIn the selection of the constant current or constant power model #8482; load the algorithm used in the selection (see loading selection). When the load mode is 0, the constant current model (default). When it is 1, a constant power model is used.
Loading
Loading Selection Definition to calculate the type of power or current model #8482; algorithm that is used to calculate the power or current model in the impedance trajectory. If the load mode u003d 0 ( Hengliu ), the options in Table 5-1 are available.
The upper limit of the reserve MAH 
The upper limit of the reserve MAH is determined that after reaching 0 remaining capacity (), before reaching the termination voltage, the actual remaining capacity is available How many. The reserve uses air load compensation.
The upper limit of the reserves MWH
The upper limit of the reserve MWH determined that after reaching 0 Availablenergy (), the actual surplus capacity before reaching the termination voltage. The spare capacity uses air load compensation.
DSG current threshold
Many functions in BQ27350 use the register as a threshold to determine whether the actual discharge current flows or flows out of the battery. The default value of this register is 100mA, which should be enough for most applications. This threshold should be set enough to be lower than any normal application load current, but it should be high enough to prevent noise or drift affect measurement.
Change current threshold
This register is used as a threshold by many functions in BQ27350 to determine whether the actual charge current flows or flows out of the battery. The default value of this register is 50mA, which should be enough for most applications. This threshold should be set enough to be lower than any normal charging current, but it should be high enough to prevent noise or drift affect measurement.
Exit current, DSG relaxation time, CHG relaxation time, exit relaxation time
Exit current as part of the impedance trajectory #8482; determine when the BQ27350 will from the current in the charging direction or discharge direction of the current. The flow mode enters the algorithm of the relaxation mode. The exit current value is set to the default value 10mA, which should be higher than the standby current of the host system, but it cannot exceed the C/20 rate. Essence
It must meet any of the following conditions to enter the relaxation mode:
1. | average current () | lt; | exit current | to DSG relaxation time.
2. | AveragraRrent () | lt; | Exit current | Used to change the relaxation time.
After about 30 minutes in the relaxation mode, when the voltage changes meet the standard DV/DT LT; 4UV/SEC, the BQ27350 attempts to obtain the accurate OCV reading. When reading a new reading, if the charging status(SOC) Compared with the previous OCV reading more than 37%, the total battery capacity is updated. These updates are used for impedance tracking #8482; algorithms. During the OCV reading period, the battery voltage should be relaxed and the current should not be higher than C/20 when trying to enter the relaxation mode.
Give up the relaxation time specify the averagerRrent () Keep the shortest time above the quitcurrent threshold before exiting the relaxation mode.
Maximum urinary flow rate
The maximum urinary flow rate contains the maximum chemical capacity of the battery, which is determined by comparing the charge status before and after the load. It also corresponds to the capacity under extremely low flow, such as C/20. In order to obtain high accuracy, the BQ27350 updates the value regularly during operation. The initial value of QMAX should be set to the battery unit capacity specified in its data table.
Update status
There are two digits in the register that are important
- Bit 1 (0x02) indicate that the BQ27350 has learned a new QMAX parameter and is accurate.
- Bit 2 (0x04) indicates whether the impedance tracking is #8482; the algorithm has been enabled.
The rest are retained. Bit 1 and position 2 are configured by users; however, bit 1 can also be set by BQ27350. Unless you create a gold image file, you should not modify these bits, such as the application description the default flash memory constant of the optimization for specific battery types (see SLUA334.pdf). Bit 1 is updated by BQ27350 according to needs, and bit 2 is set by the control () command 0x0021.
The average value of the last operation
BQ27350 records from the average current from each discharge cycle to the end. It stores the average current of the last discharge cycle in the register. This register should not be modified. It is updated by the BQ27350 when needed.
The average P
BQ27350 recorded from each discharge cycle to the end of the average power. It stores the average power of the last discharge cycle in the register. Multiplying the instantaneous power to the average power of 27bq () to obtain a continuous average power. Then record these data to get the average power. This register should not be modified. It is updated by the BQ27350 when needed.
RA Table
This data is automatically updated during the operation of the device. In addition to the reading values from another preview package for creating Gold Image Files , any user changes should not be made. The format of the configuration file is Cell0 R_A M, where M is the number of charge state corresponding to the value of the value.
Temperature measurement
BQ27350 can pass the filmThe temperature sensor or TS input measurement temperature depends specifically on the setting of the [TEMPS] package configuration () settings.
Temperature measurement is achieved by calling the TEMPERATURE () function (for specific information, see the standard command).
When using an external thermistor input, TOUT (pin 7) is powered by thermistor, TS (pin 3) is used to measure thermistor voltage. BQ27350 then associates the voltage with temperature, assuming the thermistor is Semitic 103AT or similar device.
Ultra -temperature instructions
BQ27350 can set safety signs in the measurement temperature according to the measurement temperature in the state of charging and discharge.
Excessive temperature: Charging
If the temperature () exceeds the OT CHG threshold for a period of time during the charging process, and the average current () gt; the changing current threshold, the set signs () [) [) [) [) [) [) [) [) [) [) [) [) [) [) [) [) [) OTC] bit. Note: If OT CHG TIME u003d 0, the function is completely disabled.
When the temperature () is lower than the OT CHG recovery, the [OTC] of the sign () is reset.
Ultra -temperature: discharge
If the temperature () exceeds the threshold of OT DSG for a period of time during the discharge process, and the average current () ≤ Essence Note: If OT DSG time u003d 0, the function will be completely disabled. -DSG current threshold When the temperature () is lower than the OT DSG recovery, the [OTD] bit of the sign () is reset.
Charging and charging termination instructions
In order to correctly operate the BQ27350, the battery charging voltage must be specified by the user. The default value of this variable is the charging voltage u003d 4200mv.
When (1) During the current cone -shaped window of two consecutive cycles, the average current () is less than the cone current, (2) in the same time period, the cumulative change of the capacitor gt; 0.25mAh/cone In the form current window, (3) voltage () gt; charging voltage-charging cone voltage, the BQ27350 detects the charging termination. When this happens, the [FC] bit of the sign () is set and the [CHG] bit is cleared. In addition, if the [RMFCC] bit of the package configuration is set, the RemainingCapAcity () is set to a full load capacity ()
BQ27350 has four power modes: normal, dormant, dormant, and dormant and Shut off (arranged in order of power consumption). Under normal mode, the BQ27350 is completely powered on and can perform any allowable tasks. In the dormant mode, the gas meter is in a low power state, and regular measurement and calculation are performed. In the dormant mode, the gas meter is in the minimum power state and will only be awakened by communication activities or increased battery current. Finally, in the shutdown mode, turn off all BQ27350 circuit and cut off the equipment power supply; you can restart the IC by re -applied to the device.
The relationship between these modes is shown in Figure 5-1.
Mode 6.1 
average current (), perform voltage () and temperature () measurement, and update the interface data set. The decision to change the state will also be made. Exit this mode by activating different power modes.
Sleep mode
When (1) average current () is lower than the programmable level dormant current, and (2) If you set the [bus low] bit with a block configuration (), And the data bus (SCL and SDA low pins) lasted 5s at a low level, and entered the dormant mode. When the BQ27350 enters the dormant mode, set the [dormant] bit of control status (). Once the dormant state is confirmed, the BQ27350 will be automatically calibrated to minimize the offset before entering the dormant mode. By setting the [Sleep] bit of Pack Configuration (), you can disable the sleep mode, where 0 u003d disable, 1 u003d enable. In the dormant mode, the BQ27350 will periodically wake up to measure and update the data set, and then it will return directly to the sleep state. If any entry condition is destroyed, the protection state changes, or the current that the current exceeds iWake Through RSense, the BQ27350 will withdraw from dormant.
Dormation mode
To enter the dormant mode, you need to set the [dormant] bit of PackConfiguration () when the device enters the dormant mode. If (1) detect communication, (2) device reset, or (3) the current through RSENSE is higher than IWAKE, the dormant mode is exited. If the Pack Configuration [Hibernate] bit is cleared, the BQ27350 will not enter the dormant mode. After exiting the dormant mode, the device will return to normal mode.
Shipping mode
The closing mode needs to use an external LDO with enlightenment (low activation). To enter the shutdown state, you need to set the PackConfiguration () [Shutdown] bit when the BQ27350 enters the dormant state. The charger must not appear, and the DSG FET of the protector must be closed. If [Shut off] set up the PackConfiguration () bit, BQ27350 will increase it when entering Hibernate. Together with the loss of DSG FET (low -side protection device), close the LDO to close the BQ27350. When charging more than 2 secondsLDO recovers.
Power Control
reset function
When the BQ27350 detects hardware or software reset (starting the MRST pin driver low or control () bit), it, it), it), it, it), it), it, respectively. Determine the type of reset and add the corresponding counter. This information can be accessed by sending the Command Control () function by using the RESET_DATA subtra command.
As shown in Figure 5-2, if partial reset is detected, the RAM verification is generated and compared with previously stored verifications and comparison. If the verification and value do not match, RAM will be re -initialized ( completely reset ). Every time RAM changes, the storage verification and update will be updated.
Awakening comparator 
Flash memory update 
Automatic calibration
BQ27350 provides an automatic calibration function. When the working conditions change, it will measure the voltage offset error between SRP and SRN. It reduces the offset error from normal sensing resistance voltage VSR to obtain the maximum measurement accuracy.
When the interface line remained at a low level at a low time at the lowest bus, and (2) VSR GT; in the dead area, the gas meter executing unilateral offset calibration.
When the average current () ≤ and (2) {) The voltage change after the last offset calibration ≥} or {The temperature change after the last offset calibration is greater than ≥} The gas meter also executed a single offset.
Automatic minimum current
When these measurements cannot be performed, the capacity and current measurement should be continued at the final measurement rate during the offset calibration. If the battery voltage drops during the offset calibration exceeding the calibration, the load current may increase significantly; therefore, the offset calibration will be in Chinaend.
Communication
BQ27350 uses the same I2C communication as BQ27200, and directly with Ti-OMAP and other standard I2C main device interfaces.
BQ27350 also uses SDQ interface to communicate with security products (such as BQ26100).
BQ27350 only acts as a format converter between I2C and SDQ.
I2C interface
Gas meter supports standard I2C read, incremental reading, single -byte writing quickly read and function. The 7 -bit device address (ADDR) is the most effective 7 -bit in the hexadecimal address, which is fixed to 1010101. Therefore, for writing or reading, the 8 -bit device address is 0xaa or 0xab, respectively.
Data at the address indicated by the Quick Read return address pointer. Whenever the BQ27350 or I2C host confirm the data, the address pointer (the register inside the I2C communication engine) increases. The quick writing function is the same as this, which is a convenient way to send multiple bytes (for example, two bytes that require two bytes of data) to the continuous command position. 
Try to read the address of 0x7F or more (NACK command): [123 123 ]
Try incremental writing (all additional data bytes sent by nack):
Certification
BQ27350 can be used as SHA-1/HMAC identity verification slave, its internal engine, or external BQ26100 (including safety memory). In these two implementations, sending 160 SHA-1 inquiries to BQ27350 will cause IC to return 160 digits based on the inquiry message and hidden pure text authentication key. When this summary is matched with the same summary of the host or dedicated verification host, the verification process will be successful. The host or dedicated verification host operates the same inquiry message and uses the same pure text key.
BQ27350 contains a default pure text authentication key 0x0123456789abcdeffedcba987654321. If using BQ27350's internal authentication engine can be used for development purposes by default, but before investing in the package, it should be changed to the key and seal the part immediately. If you use BQ26100 for external identity verification, the key must be changed to 16 bytes of 0x00 .
Key programming
When using the SHA-1/HMAC internal engine using BQ27350, the authentication key is stored in memory in a clear text. The pure text authentication key can only be written into BQ27350 when IC is in a non -sealing mode. Once the IC is unblocked, it will be written to the BlockDataControl () to write the 0x00 to enable the verification data command. Next, write 0x70 and 0x00 to DataFlashClass () and DataFlashblock () to specify the subclass ID and offset. The BQ27350 is now ready to receive a 16 -byte pure text key, which must start with the command position 0x4C. Once the verification and writing are successfully written into Blockdatachecksum (),