Features

Complete integrated 2 series, 3 series, and 4 series lithium ion or lithium polymer battery pack management and protection

compensation for compensation ending over the end Voltage (CEDV) measurement

High-voltage side N-CH protection FET driver

Integrated unit balance

Low-power mode [ 123]

- Low power: lt; 180 Wei'an

- Sleep lt; 76 Wei'an

- Current

- Temperature

Complex charge algorithm

- jeita

- Enhanced charging

-Adaptive charging

Support the dual-line SMBUS V1.1 interface

SHA-1 certification

compact Type packaging: 30 lead TSSOP

Application

Remembrance Computer and Internet Book

Medical and testing equipment

# 8226; Portable Instrument

Description

BQ3055

The device is a complete, single -chip -based solution, which is 2 series, 3 series and 4 series lithium -ion batteries The gas measurement, protection and certification of the Harbin polymer battery pack provides a rich functional array.

The BQ3055 device uses its integrated high -performance simulation peripheral equipment, measures and maintains accurate records of capacity, voltage, current, temperature, and other key parameters in lithium ions or lithium polymer batteries, and through SMBUS V1. 1 Compatible interface reports this information to the main controller of the system.

BQ3055 provides software -based first -level and second -level overvoltage, underwriting voltage, overheating and over -charging safety protection conditions, as well as hardware -based discharge current and short circuit protection conditions.

SHA-1 identity verification has a safe memory for authentication key, and can undoubtedly identify the real battery pack.

The compact 30 lead TSSOP package minimizes the cost and volume of the solution of smart batteries, and at the same time provides the maximum function and security for the battery measurement application.

typical features

Parameter measurement information

ElectricPond parameter measurement

Charging and discharge meter

BQ3055 uses the integral Delta-Sigma modulus converter (ADC) to measure the current, use the second Delta-Sigma ADC Temperature measurement.

Points DELTA-SIGMA ADC By measuring the voltage on a small sensor resistance between SR1 and SR2 pins, the voltage of the battery is measured to measure the battery. Integrated ADC measurement from -0.25 V to 0.25 V. When VSR V (SRP) -v (SRN) is positive, the BQ3055 detects charge activity. When VSR V (SRP) -v (SRN) is negative, detect the discharge activity. BQ3055 uses an internal counter to integrate signals over time. The basic rate of counter is 0.65 nvh.

Voltage

BQ3055 updates a single series unit voltage at a interval of 0.25 seconds. The internal ADC measurement voltage of BQ3055 is properly scaled and calibrated. The data is also used to calculate battery impedance for CEDV gas measurement.

current

BQ3055 uses SRP and SRN input, use 5-mΩ to 20-mΩ type measurement and calculate battery charging and discharge current. Sensor resistance.

Automatic calibration

BQ3055 provides automatic calibration functions to eliminate voltage offset errors between SRN and SRP, thereby obtaining the maximum charge measurement accuracy. The BQ3055 performs automatic calibration when the SMBUS line continues to maintain a low level at least 5 seconds.

Temperature

BQ3055 has an internal temperature sensor and input of two external temperature sensors. All three temperature sensor options are enabled separately and configured the temperature of the battery or field effect transistor. Two configurable thermal resistance models are provided in addition to the FET temperature (probably higher temperature type), and the battery temperature can also be monitored.

Communication

BQ3055 uses SMBUS V1.1 to provide the main mode and packet error check (PEC) options according to the SBS specification.

SMBUS opens and close status

When SMBC and SMBD are as low as two seconds or more, the BQ3055 detect the SMBUS shutdown state. Clear this state requires SMBC or SMBD to be transformed into high. The communication bus will restore the activity within 1 millisecond.

Detailed instructions

Overview

BQ3055 equipment measurement voltage, temperature and current to determine the battery capacity and charging status (SOC). BQ3050 passes the induction SRP and SRN pinA small resistance (5 mΩ to 20 mΩ, typical values) between a small resistance (5 mΩ to 20 mΩ, typical values) is connected with the battery to monitor the charging activity. By integrating the charge of the battery, the battery SOC is adjusted during the battery charging or discharge. The measurement of OCV and charge points has determined chemical SOC.

QMAX is valued at the number of data tables from the battery manufacturer by the number of parallel batteries, which is also used for design capacity values. It uses OCV and QMAX values to determine the Charge () state when battery insertion, device resetting or command opening. FullChargeCapAcity () reports the learning capacity available from completely charging to voltage () to reaches EDV0 threshold. When the voltage () is lower than the shutdown

voltage for shutdown time, and withdrawing from the shutdown mode at least within the shutdown time, PF Flags1 () [vShut] bit will be set. For more details, see BQ3055 Technology Reference Manual (SLU440).

The fuel metering is based on the compensation discharge end voltage (CEDV) method, and uses the mathematical model to associate the remaining charging status (RSOC) and the voltage close to the end of the discharge. This requires a single -point FCC update complete discharge cycle. This implementation has a function that models the battery voltage (OCV) into a function of the battery SOC, temperature and current. Impedance is also a function of SOC and temperature, which can be satisfied by using seven parameters: EMF, C0, R0, T0, R1, TC, and C1.

Configuration

oscillator function

BQ3055 fully integrates the system oscillator and does not require any external components to support this function.

System active operation

BQ3055 regularly check the pressure pipe (1s). If the external system is pulled to the ground, the BQ3055 detects the system.

2, 3 or 4 configuration

In the 2 unit configuration, VC1 pairs of VC2 and VC3 short circuits. In the 3 unit configuration, VC1 is short -circuited to VC2.

Battery balance

This device supports battery balance by bypassed the current of each battery by bypassing each battery during charging or standing. If you use the internal bypass of the device, you can bypass 10 mAh, and at the same time you can bypass multiple units. Using an external unit balance circuit can obtain higher unit balance current. In the external unit balance mode, only one unit can be balanced at a time.

The unit balance algorithm determines the amount of charge that needs to be bypassed to balance the capacity of all units.

Internal unit balance

When configuring the internal unit balance, the unit balance current is defined by the external resistor RVC at the VCX input. See Figure 4.

External battery balance

Configure the external unit levelAt the time of balance, the unit balance current is defined by RB. See Figure 5. It can only balance one unit at a time.

Figure Figure

Feature description

Main (first) security feature

BQ3055 supports a variety of battery and system protection functions, which can be easily configured. The main safety functions include:

battery overvoltage and underwriting protection

charging and discharge over current

short circuit

High charging and discharge temperature

AFE watch the door dog

Two (level) safety facilities

BQ3055 secondary secondary time Safety functions can be used to indicate more serious faults through the fuse. The insertable pin can be used for melting series fuses and permanently prohibit the battery pack from charging or discharge. The secondary safety protection function includes:

Safe overvoltage

safe over current charging

Charging field effect tube, discharge field effect tube and pre -charging field effect tube failure

cell imbalance detection

fuse wire Follow the secondary voltage protection IC

AFE register integrity failure (AFE_P)

AFE communication failure (AFE_C)

Charging control characteristics [ 123]

BQ3055 charging control function includes:

support Jeita temperature range. Report the charging voltage and charging current according to the effective temperature range

process a more complex charging mode. The standard temperature range is allowed to be divided into two sub -range, and the charging current is allowed to change the charging current based on the battery voltage

use SMBUS broadcast to report the appropriate charging current and constant voltage charging site required to report the constant charger to the smart charger. The required proper charging voltage

During the charging process, use a voltage -based battery balance algorithm to gradually reduce the charging difference in the battery under the complete charging state of the battery pack. The voltage threshold can be set to make the unit balance in a state of activity. This can prevent over -charging the battery full and cause excessive degradation. It can also increase the available battery pack energy by preventing premature charging.

Support pre -charging and zero voltage charging

Stop charging and suspension of charging

Report charging failure, and indicate charging status through charging and discharge alarm

Gas metering The available capacity in the battery. BQ3055 collects the measurement values of charging and discharge current, and compensate the charging current measurement value according to the temperature and charging status of the battery. The BQ3055 estimates the self -discharge of the battery and adjusts the self -discharge estimate based on the temperature. See BQ3055 Technology Reference Manual (SLU440).

Life data recording function

BQ3055 provides limited life data records for the following key battery parameters:

life highest temperature

# 8226; Life minimum temperature

Life maximum battery voltage

Life minimum battery voltage

Certification

BQ3055 supports the host using SHA-1 for identity verification.

For Kaifeng and fully enter, the SHA-1 certification is required through the gas meter.

Equipment function mode

BQ3055 supports three power modes to reduce power consumption:

under normal mode, BQ3055 performs measurement in 0.25 seconds interval, and measured, and measurement, measurement, measurement, and measurement, and measurement, measurement, and measurement, and measurement, and measurement, measurement, measurement, and measurement, and measurement, and measurement, measurement, and measurement, and measurement, measurement, measurement, and measurement, and measurement, and measurement, measurement, measurement, and measurement of 0.25 seconds. Calculate, protect decision -making and data update. During these intervals, the BQ3055 is in the stage of power reduction.

In sleep mode, BQ3055 performs measurement, calculation, protection decision -making and data update in the adjustable time interval. During these intervals, the BQ3055 is in the stage of power reduction. The BQ3055 has a wake -up function. When the current or failure is detected, the dormant mode can be exited.

In the shutdown mode, BQ3055 is completely disabled.

Application and implementation

Note

The information in the application part of the following application is not part of the TI component specification, TI does not guarantee its accuracy or integrity. TI's customers are responsible for determining whether the part is suitable for its purpose. Customers should verify and test their design implementation to confirm the system function.

Application information

BQ3055 gas meter is a main protection device that can be used with the 2 series, 3 series or 4 series lithium or lithium polymer battery packs. In order to achieve and design a set of comprehensive parameters of a set of specific battery packs, the user needs the BQEVSW tool, which is a graphical user interface tool installed on the PC during the development process. The firmware installed in the product has the default value. These values are in the BQ3055 technology reference manual (SLU440) Summary. Using the BQEVSW tool, once you know the system parameters (for example, the FaultTRigger threshold for protecting, the enable or disable specific function, unit configuration, etc.) can be changed to meet these default values to meet the needs of specific applications in the development process.

Typical application

In typical applications, BQ3055 is usually paired with the second -level overvoltage protection device to provide independent voltage protection levels. Figure 6 shows a typical application.

Design requirements

For BQ3055 design examples, the parameters in Table 1 are used as the input parameter.

Detailed design program

Large current path

High -current path starts with the battery set of the battery pack. When the charging current is through the battery pack, it will return to the battery pack terminal by protecting FET, chemical fuse, lithium -ion battery and battery connection, and sensor. In addition, some components are placed on PACK+and PACK-terminals to reduce the effects of electrostatic discharge.

Protect FET

You must select the N channel to charge and discharge FET for a given application (Figure 7). The application of most portable batteries is a good matching CSD17308Q3. Ti CSD17308Q3 is a 47A-A and 30-V device. When the gate driver voltage is 10V, the RDS (open) is 8.2MΩ.

If the pre -charging field effect tube is used, calculate the R28 to limit the pre -charged current to the required rate. Be sure to consider the power consumption of the string resistor. The pre -charged current is limited to (VCHARGER – Vbat)/R28, and the maximum power consumption is (VCHARGER – Vbat) 2/R28.

All the gate that protects the FET is pulled to the source pole through the high value between the gate and the source to ensure that they are closed when the gate driver is opened.

Capacitor C16 and C17 help protect FET during the ESD incident. If one of them is short -circuit, two devices can ensure normal work. In order to have good electrostatic discharge protection, the copper tracking inductance of the capacitor lead must be designed as short and wide as possible. Make sure that the rated voltage of C16 and C17 is enough to maintain an external voltage when one capacitor is short -circuit.

Chemical melting

Chemical fuse (Sony Chemical, Uchihashi, etc.) is controlled by BQ294705 secondary voltage protection IC or gas meter. Any event will apply a positive voltage to the gate of Q1, as shown in Figure 8, and then Q1 receives current from the third terminal of the fuse, which causes it to click on itBurn and open permanently.

Be sure to carefully check the fuse specifications and match the required ignition current with the ignition current provided by the N -channel FET. Make sure that the device uses the correct voltage, current, and RDS (open) rated value. Discuss the querium control circuit in the querium circuit.

Lithium -ion battery connection

The important point of remembering the battery connection is that the high current flow is connected by the top and the bottom; therefore, these points, these points The voltage induction lead must be connected to the Kelvin to avoid any errors caused by the decline in high -current copper marks. Figure 9 The position of the bid in FIG. 9 indicates that the Kaelvin connection of the battery positive pole node. The connection marked as 1N is equally important. VC5 tube foot (grounding reference for battery voltage measurement) is not in the BQ3055 device, it is in the old generation of equipment. Therefore, one -point connection is needed at 1N to ground with low -current grounding to prevent the voltage drop that does not expect through the long record channel when the battery voltage at the bottom battery is measured at the gas pressure meter.

Sensor

Like the unit connection, the quality of the connection of Kelvin connecting at the sensing resistance is very important. The temperature coefficient of the sensor must be not greater than 75ppm to reduce the drift of the current measurement with the temperature (Figure 10). Select the value of the inductive resistance to the available current and short circuit range corresponding to the BQ3055. Choose a possible minimum value to minimize the negative voltage generated on the BQ3055 VSS node during a minimum short circuit period. The absolute minimum value of this pin is -0.3 V. For a battery pack with two parallel cylindrical batteries, the ideal value is 10 MΩ. As long as you can ensure good Kelvin induction, you can use parallel resistance.

The ground plan of BQ3055 is different from the old generation of equipment. In the previous device, the equipment ground (or low -current grounding) is connected to the SRN side of the RSENSE resistance board. However, the BQ3055 connects the low -current ground ground on the SRP side of the RSENSE resistance board, near the 1N terminal of the battery (see lithium -ion battery connection). This is because compared with previous devices, the VC pin (ground reference pin VC5) of BQ3055 is one less. Nails were removed and combined with SRP internally.

ESD relief

Place a pair of 0.1 μF series ceramic capacitors on Pack+and Pack-terminals to help reduce external static discharge. If one of the capacitors is short -circuit, the two series devices can ensure that the battery pack continues to run.

Optional land can be placed on the terminal to further increase the ESD resistance.

Gas meter circuit

The gas meter circuit includes BQ3055 and its peripheral components. These components are divided into the following groups: poorLow -pass filter, power supply decoupling/RBI, system existence, SMBUS communication, fuse circuit and LED.

Differential low -pass filter

As shown in Figure 11, the differential filter must be input before the current of the gas pressure gauge. The filter eliminates the impact of unnecessary digital noise, which will cause the offset of the measurement current. Even the best differential amplifier has less co -mode suppression under high frequency. Without the filter, the amplifier input level can correct the RF signal, and then the DC offset error may occur.

Due to the capacitor C15 diversion C12/C13, the communication co -mode caused by the component lost matches, the 5%tolerance of the component is sufficient. It has also proven to reduce the offset and noise errors by maintaining the symmetrical placement mode of μA and adding ground shielding to the differential filter network.

Power supply decoupling and RBI

Power decoupling is an important link for the optimization operation of the advanced gas meter BQ3055. As shown in Figure 12, a single 1-μF ceramic container from REG33 to VSS and REG25 to VSS must be placed near the IC pin.

RBI pins are used to provide spare RAM voltage during a short -term transient power disconnection. Some reset mechanisms use RAM to restore key CPU registers after temporary power off. A standard 0.1-μF ceramic capacitor is grounded from the RBI pin, as shown in Figure 12.

The system exists

The system display signal is used to notify whether the gas meter component is installed in the system or removed from the system. In the host system, this pin is connected. The pressure tube foot of BQ3055 occasionally exists the sampling test system. In order to save power, the gas meter provided an internal pull -up resistor during the sampling pulse of 4 μs per second.

Since the current signal of the system is part of the component interface connected to the outside world, it must be protected from the impact of the external static discharge event. The integrated ESD protection on the pressure device pins reduces the external protection requirements of the 8-KV ESD contact rate to only R25 (Figure 13). However, if the system existing signals may be short -circuited to PACK+, it must include R18 and D3 for high -voltage protection.

SMBUS Communication

Similar to the existing pin of the system, the SMBUS clock and data pin integrated high -voltage ESD protection circuit, reducing external Qina The demand for diodes protection. When using the circuit shown in FIG. 14, the communication line can withstand 8-KV (contact) ESD shock. The selected C23 and C24 have a 100 PF value to meet the SMBUS specifications. If you need to use a larger input resistance and/or Qina diode to provide higher protection, please study the most carefullyThe signal quality of the SMBUS signal under bad communication conditions.

SMBUS clock and data cable have internal drop -down lists. When the gas meter detects that both lines are low (for example, during the process of unloading the battery pack), the device will perform automatic offset calibration, and then enter the dormant mode to save power.

The fuse circuit

BQ3055's fuse selling design is used to ignite chemical fuse at the time of violating various safety standards (Figure 15). Insure wire led feet also monitor the status of secondary voltage protection IC. When the gate of Q3 is high, it will ignite chemicalk. The 7-V output of BQ29705 is divided into R13 and R14, which provides sufficient gate drivers for Q1. At the same time, when the fuse signal is high, excessive reverse currents are prevented from entering the BQ29705.

Use C14 is usually a good practice, especially for RFI immunity. If necessary, you can remove C14 because chemical fuse is a relatively slow device and is not affected by any sub -microsecond failure that may produce any sub -microseconds that may be produced during the battery connection.

When the BQ3055 was instructed to ignite the chemical fuse, the fuse was activated to provide a typical 8 -volt output. The new design makes it possible to use higher VGS field effects in the first quarter. This improves the stability of the system and has also broaden the scope of the first quarter.

PFIN detection

As mentioned earlier, the fuse plug -in foot has a dual effect on this device. When the BQ3055 is not ordered to ignite the chemical fuse, the fuse's feet defaults to the output pins of the secondary voltage protector. When the secondary voltage protector ignitions the chemical fuse, the fuse pins are induced to high voltage, and the BQ3055 sets the PFIN logo accordingly.

Secondary current protection

BQ3055 provides secondary over current and short -circuit protection, unit balance, unit voltage reuse and voltage conversion. The following parts check the battery and battery input, battery pack and field effect control control, regulator output, temperature output and battery balance.

Battery and battery input

Each unit input is adjusted with a simple RC filter. This filter provides ESD protection during the unit connection and is used for filtering unwanted voltage instantaneous instantaneous instantaneous instantaneous instantaneous time. Change. The resistance value allows weighing between battery balance and safety protection.

The internal unit balance in BQ3055 usually provides about 310Ω (unit voltage ≥2V is 310Ω. Unit balanced FET RDS ON is reduced to 125Ω when the unit voltage ≥4V), which can be used in the single unit of bypass units The charging current may be over -charged relative to other units (Figure 16). The purpose of this bypass path is to reduce the electricity that enters any battery during the charging period.Stream, make the series components reach the same voltage. The series resistors between the input pins and the nodes of the positive tandem component control the bypass current value. The design of the BQ3055 device can withstand a battery balance current of up to 10 mA. It is recommended to use the series input resistors between 100Ω and 1kΩ for effective unit balance.

BAT input uses diode (D1) and 1-μF ceramic capacitors (C9) to isolate and disconnect with the battery when the voltage decreases instantly.

In addition, as mentioned earlier, in the high current path, the top and bottom nodes of the battery must be sensing at the battery connection to prevent the voltage sensor errors caused by the decline in the decline in high current PCB copper lines. Essence

External battery balance

Internal battery balance can only support 10 mA. External unit balance provides another choice for faster unit balance. For details, please refer to the application description and use the fast unit balance of the external MOSFET (SLUA420).

Packaging and field effect control control

Battery set and VCC input power from the charger to BQ305X. The battery pack also provides a way to measure and detect the existence of the charger. The component input uses a 10-kΩ resistor, and the VCC input uses a diode to prevent the input from entering the transient and prevent the data drive from failing during short circuit events (Figure 17).

The FET is controlled by the 5.1-KΩ series grid resistance, and the switching time constant is a few micro seconds. 3.01-mΩ resistor ensure that the FET is closed when the FET drive is disconnected. Q4 is used to protect the discharge (Q3) when the charger is reversed. If there is no Q4, Q3 can be driven to its linear area, and if the Pack+input becomes slightly negative, it will be severely damaged.

In this case, Q4 will open to protect Q3 through short circuit gates to source. To use a simple ground grid circuit, the field -effect transistor must have a low grille on the threshold. If you want to use more standard devices, such as 2n7000 as a reference schematic, a high -value resistance should be used to bias the gate to 3.3V. The BQ3055 device uses an external P channel pre -charged FET controlled by GPOD. When choosing an external load resistor, the user should consider the maximum charger voltage and the internal pre -charged RDSON.

The regulator output

As described in the power supply decoupling and RBI, the two low -voltage differential regulators in BQ3055 need to compensate the output capacitor. The output must have a 1 μF ceramic capacitor placed in a local terminal pin near the integrated circuit.

Temperature output

For BQ3055 installationSet, TS1 and TS2 provide heat -sensitive resistance drive under program control (Figure 18). Each pin can use a integrated 18-kΩ (typical) linear pull-up resistor to support 10-kΩ at 25 ° C (103) NTC external thermistor (such as Mitsubishi BN35-3H103). The reference design includes two 10 kΩ thermistor: RT1 and RT2.

Second overvoltage protection

BQ29705 provides secondary overvoltage protection, and order the chemical fuse to ignite when any battery exceeds the internal reference threshold. The peripheral components are unit input and delay capacitors.

Unit input

Provide an input filter for each unit input. This includes resistors R5, R6, R7, and R9, as well as capacitor C5, C6, C7 and C8 (Figure 19). The input network is completely independent of the filter network for BQ3055 input. In order to ensure independent security functions, these two devices must have a separate input filter.

Because the filter capacitor is implemented, a low -pressure device can be used in each case.

delay capacitor

C10 sets the time delay of activating output after any unit exceeds the threshold voltage. Time delay calculation is: TD 1.2V × DelayCap (μF)/0.18μA.

Application curve

System example

Power suggestion

Power solution Coupling is of great significance to the optimization operation of the BQ3055 gas meter. A single 1.0 μF ceramic container from REG33 to VSS and REG25 to VSS must be sold near the integrated circuit (IC).

RBI pins are used to provide spare RAM voltage during a short -term transient power disconnection. Some reset mechanisms use RAM to restore key CPU registers after temporary power off. A standard 0.1 μF ceramic capacitor is grounded from the RBI pin.

Layout

Layout Guide

The main layout of BQ3055 is related to the measurement of the Kulun counter. Consider the external components and PCB layout around SRP and SRN pin carefully.

layout example

As shown in Figure 24, the differential filter must be in front of the current of the gas pressure gauge. The filter eliminates the impact of unnecessary digital noise, which will cause the offset of the measurement current. Even the best differential amplifier has less co -mode suppression under high frequency. Without the filter, the amplifier input level can correct the RF signal, and then the DC offset error may occur.1