Features

Complete compatible USB charger

- optional 100 mAh and 500 mAh maximum input current

- 100 MA maximum current current Limit to ensure that the USB-IF standard

-The input-based dynamic power management (VIN-DPM) can prevent bad USB sources

28-v input rated value, with with the withdrawal value, with with the withdrawal value, band Overvoltage protection

Integrated dynamic power path management (DPPM) function can be independently powered at the same time and charge the battery

And current monitoring output (ISET)

The programmable input current limit of the wall adapter is as high as 1.5 a

battery output voltage (BQ72)

programmable terminal current (BQ24074)

Battery disconnection function (BQ24075, BQ24079)

Charging safety timer

Inverse current, short circuit and thermal protection

NTC thermistor input

Order restrictions Empty current

Status indication -charging/completion, good power supply

smartphone

#8226; Portable media player

Portable navigation equipment

Low -power hand holding equipment

] BQ2407X

series equipment is an integrated lithium ion linear charger and system power path management equipment, which is a portable application with limited space. The device can run from the USB port or AC adapter, supporting a charging current up to 1.5 A. The input voltage range with input overvoltage protection supports an unsettled adapter. USB input current limit accuracy and start-up order allows BQ2407X to meet USB-IF influx current specifications. In addition, input the USB source to prevent the charger from crashing error configuration.

BQ2407X has the function of dynamic power path management (DPPM) function, which can supply the system at the same time to charge the battery at the same time. When the input current limits the system output to the DPPM threshold, the DPPM circuit will reduce the charging current; therefore, while monitoring the charging current aloneAlways supply power on the system. This function can reduce the number of battery charging and discharge cycles, allow correct charging to terminate, and enable the system to run without damage or lack of batteries.

Equipment information

(1) For all available software packages, please refer to the appointment of the doctor's order content at the end of the data table.

Typical application circuit

Typical features

vin 6 v, EN1 1, EN2 0, BQ24073 application circuit, TA, TA 25 ° C, unless there is another explanation.

Detailed explanation

Overview

] BQ2407X device is an integrated lithium ion linear charger and system power path management equipment, which is a portable application with limited space. The device is powered by the system and is independent of the battery charging. This function can reduce the number of battery charging and discharge cycles, allow correct charging to terminate, and enable the system to run without damage or lack of batteries. This function also allows the system to start the system immediately, even if the battery is completely discharged. The input power supply for the battery charging and running system can be an AC adapter or USB port. These devices have a dynamic power path management (DPPM), which shared the power current between the system and the battery charging, and automatically reduce the charging current when the system load increases. When charging from the USB port, if the input voltage is lower than the threshold, the input dynamic power management (VIN-DPM) circuit will reduce the input current, thereby preventing the USB port from collapse. The power path architecture also allows the battery to supplement the system current requirements when the adapter cannot provide peak system current.

Function box diagram

Feature description

IOU lock (UVLO)

When UVLO (UVLO) is lower, the BQ2407X series is still in the power -off mode.

In the power off mode, the host command of the control input (CE, EN1, and EN2) was ignored. The Q1 effect transistor connected between the input and output pins is closed, and the state output CHG and PGOOD are high impedance.

The Q2 effect transistor connected to BAT and OUT is connected. If the system Q2 is closed, it is closed. In the power -off mode, the Vout (SC2) circuit is in a state of activity and monitor the overload during the output.

Power

When Vin exceeds the UVLO threshold, BQ2407X is powered on. When VIN is lower than VBAT+VIN (DT), control input (The host command of CE, EN1, and EN2) is ignored. The connection between the output and the output end is high impedance and high impedance. The Q2 -field effect transistor connected to BAT and OUT is connected. (If Sysoff is high, Q2 is off). In this mode, the Vout (SC2) circuit is in a state of activity and monitor the output overload.

Once VIN rises to VBAT+VIN (DT), PGOOD is driven to a low level to indicate the valid power status and read CE, EN1 and EN2 input. If (EN1 EN2 Hi) or the input overvoltage occurs, the device enters the standby mode. In the standby state, Q1 is closed and Q2 is opened, so OUT is connected to the battery input end. (If Sysoff is high, FET Q2 is closed). In this mode, the Vout (SC2) circuit is in a state of activity and monitor the output overload.

When the input voltage at the IN is within the valid range: vin gt; Uvlo and vin gt; vbat+vin (dt) and vin lt; vovp, and the EN1 and EN2 pin indicate the USB pause mode [(EN1111 (EN1111 , EN2) i (Hi, Hi)], all internal timers and other circuit blocks are activated. The device checks whether the ISET and Ilim pins are short -circuited. If there is no short -circuit situation, the device will open the input FET Q1 with a 100mA current to check whether the out of the short circuit. When VOUT is higher than VSC, FET Q1 is switched to the current limits threshold set by EN1, EN2 and Rilim settings, and the device enters the normal working state. When running normally, the system is powered by the input power supply (q1 adjustment), and the device continuously monitor CE, EN1, EN2 status and input voltage.

Overvoltage protection (OVP)

BQ2407X can accept inputs up to 28V without damage. In addition, a overvoltage protection (OVP) circuit is also implemented. When the time of VIN GT; VOVP exceeds TDGL (OVP), the internal LDO is turned off and the charging is stopped. When in an OVP state, the system output (OUT) is connected to the battery, and PGOOD is high impedance. Once the OVP conditions are eliminated, the new order of power starts (see startup). Safety timer reset, the new charging cycle will be output by CHG.

Dynamic power path management

BQ2407X has output output to power the external load connected to the battery. When the power is connected to IN or BAT, the output is activated. The following sections will discuss the behavior of OUT (output) and IN (input), so that only the battery and battery power supply can be charged.

The input source of the connection (adapter or USB)

After the power supply is connected, the dynamic power of BQ2407XSource path management (DPPM) circuit continuously monitor input current. The output of BQ24073/74/75/79 was adjusted to a fixed voltage (VO (REG)). For BQ24072, OUT adjustment is higher than BAT voltage 200 MV. When the BAT voltage drops below 3.2 V, OUT is cut to 3.4 V. This allows the system load correctly even with battery discharge. The input current is shared between the battery charging and the system load output. The BQ2407X has an internal optional current limit that can be charged from the USB port and the internal optional current limit of the 500 ma (USB500), and the programmable input current limit.

BQ2407X is a USB, if it meets the surging current test. The USB specification allows up to up to 10 μF to start. When more than 100 mA, set 50 μC to a maximum charge value. The input current limit of BQ2407X can prevent the input current from exceeding this limit, even if the system capacitor is greater than 10 μF. The input capacitance of the device must be selected enough to prevent violations ( lt; 10μF) because the current is not limited. Figure 17 demonstrates the startup process of BQ2407X and compares it with the USB-IF specification.

The input current limit Selection is controlled by the status of the EN1 and EN2 pin, such as the entry configuration and function of the EN1/EN2 setting table. When the programmable current limit is used, the input current limit is set from the resistance value of the resistance from ILIM pins to VSS, and the following formal formula is given:

] Input current limit can be adjusted to 1.5 A. The effective resistance range is 1.1 k #8486; to 8 k #8486;.

When the input source is connected, the system load is preferred. DPPM and battery supplement mode are used to maintain system loads. Figure 19 and 20 illustrate examples of DPPM and supplementary modes. These models will be explained in detail in the following chapters.

Enter the DPM mode (VIN-DPM)

BQ2407X uses the VIN-DPM mode to operate from the current limited USB port. When the EN1 and EN2 configuration is USB100 (EN2 0, EN1 0) or USB500 (EN2 0, EN2 1) mode, the input voltage will be monitored. If VIN drops to Vin-DPM, the input current limit will be reduced to prevent the input voltage from further decrease. This prevents the BQ2407X collapse design or improper configuration USB source. FIG. 18 shows the current-limited source VIN-DPM behavior. In this figure, the input source has a current of 400 mAh, and the device is in the USB500 mode (EN1 1, EN2 0).

DPPM mode

When the sum of charging and system load current exceeds the maximum input current (programming with EN1, EN2, and Ilim pin), the output voltage is reduced. Once the voltage on the OUT pin drops to VDPPM, BQ2407X enters the DPPM mode. In this mode, the charging current decreases as the output current increases to keep the system output. In DPPM mode, the battery terminal is banned.

Battery supplement mode

If the current is further reduced in the charging mode, and in the charging mode, the current will be further reduced. When the output voltage drops below the VBSUP1 threshold, the battery supplement system load. When the output voltage is higher than the VBSUP2 threshold, the battery stops the supplementary system load.

In the supplementary mode, the battery supplementary current is not adjusted (BAT-FET is completely opened), but the built-in short-circuit protection circuit. Figure 35 demonstrates the supplementary mode. If the voltage at the OUT is dropped to VO (SC2) below the BAT voltage in the battery supplement mode, if there is an overload after TDGL (SC2), the output of the OUT output is closed. Short -circuit recovery timer then counted. After TREC (SC2), OUT opens and tries to restart. If the short circuit still exists, OUT is closed, and the counter is restarted. In the supplementary mode, the battery terminal is disabled.

Input source is not connected

When there is no power connection to the input terminal, the output end is strictly powered by the battery. In this mode, similar to the battery supplement mode, the input and output current is not adjusted, but the short -circuit circuit is activated. If the output voltage is lower than the BAT voltage 250 millivoltage time exceeding TDGL (SC2), the output is closed. Short -circuit recovery timer then counted. After TREC (SC2), OUT opens and tries to restart. If the short circuit still exists, OUT is closed, and the counter is restarted. This opening/off cycle will continue until the overload conditions are eliminated.

Battery charging

Set the CE low -boot battery charging. First, the device provides IBAT (SC) to the battery and monitors the voltage to check whether there is a short circuit on the BAT pin. When the battery voltage exceeds VBAT (SC), the battery continues to charge. The battery is charged in three stages: adjustment of pre -charging, rapid current charging (current adjustment) and constant voltage decrease (voltage adjustment). In all charging stages, the internal control loop monitoring IC knot temperature and reducing the charging current when exceeding the internal temperature threshold.

FIG. 21 shows a normal lithium ion charging cycle using BQ2407X:

In the pre -charging phase, use IPRECHG (IPRECHG) to charge the battery to charge the battery. Essence Once the battery voltage exceeds VLOWV threshold, the battery will be charged by fast charging current (ICHG). When the battery voltage reaches VBAT (REG), the battery will be kept under the constant VBAT (REG) voltage. When the battery is close to fully charging, the charging current gradually decreases. When the battery current reaches ITERM, the CHG pin indicates that it is charged through high impedance.

Please note that when the charging rate is reduced due to the role of thermal circuit, DPPM loop or Vin (low) loop, terminal testing will be disabled.

The value of the fast charging current is set from the resistor set from the ISET pin to the VSS, and it is given from the following formal formula:

The charging current Restrictions can be adjusted to 1.5 A. The effective resistance range is 590 #8486; to 5.9 k #8486;. If ICHG programming is more than the input current limit, the battery will not charge at a rate of ICHG, but IIn (MAX) at a slower rate (minus the load current on the OUT pin, if so). In this case, the charger timer will slow down in proportion.

Charging current converter

When the charger is enabled, the current generated by the internal circuit is proportional to the charging current of the ISET input terminal. The Iset output current is 1/400 (± 10%) of the charging current. When the external charging current programming resistor RISET is applied, the current generates an analog voltage, which can be monitored by the external host to calculate the current from BAT.

The adjustable termination threshold (ITERM input, BQ24074)

The terminal current threshold in BQ24074 is the user's programmable can be programmed. of. Set the terminal current by connecting a resistor from ITERM to VSS. For the USB100 mode (EN1 EN2 LOW), the terminal current value is calculated as follows:

In other input current limit mode (EN1 ≠ EN2), the calculation of the terminal current value is as follows as follows :

The terminal current is programmable to 50%of the high -speed charging current. Riterm resistor must be less than 15 k #8486;. Keep iterm unconnect to select the default internal settings to terminate the current.

Terminal disable (TD input, BQ24072, BQ24073)

BQ24072 and BQ24073 include TD inputs that allow enabled/disable terminals. Connect the TD to the logic high level to disable the charging terminal. When the terminal is disabled, the device will experience pre -charging, fast charging and constant stream phase, and then keep in the constant stream phase. In the CV stage, the output voltage of the charger keeps the BAT is equal toVBAT (reg), the charging current will not end. The charging current is set by ICHG or IINMAX, which is subject to smaller. Battery detection is not performed. Once the current drops below ITERM, the CHG output is high impedance, and it will not turn lower before switching input power or CE. When the terminal is disabled, the pre -charging and fast charging safety timer will also be disabled. If the TD pin is high and the TS pin is not connected or pulled to VIN, the battery pack temperature induction (TS pin function) will be disabled.

Battery detection and charging

BQ2407X automatically detect whether the battery is connected or removed. After the charging cycle is completed, the battery voltage will be monitored. When the battery voltage is lower than the VRCH, the battery detection program runs.

During the battery detection process, the current (IBAT (DET)) is drawn from the battery for a period of time to check whether the voltage on the battery is lower than Vlowv. Otherwise, charging starts. If so, it means that the battery is lost or the protector is opened. Next, if possible, apply a pre -charged current to TDET to turn off the protection device. If VBAT LT; VRCH, the protector is closed and the charging is started. If VBAT GT; VRCH, determine the lack of battery and the detection program continues.

Discovery battery (sysoff input, BQ24075, BQ24079)

BQ24075 and BQ24079 have a Sysoff input, allowing users to turn off the FET Q2 and disconnect the connection between the battery and the OUT pin. This is a factory programming for disconnecting the system load from the battery, without the installation of the battery, or for the host's side impedance rail fuel measurement (such as BQ27500), before the battery is charged or discharged. Very useful. When Sysoff is high, the/chg output remains low. Connect Sysoff to VSS to open Q2 for normal operations. Sysoff passes through ~ 5 m #8486; the resistor is pulled inside VBAT.

Dynamic charging timer (TMR input)

BQ2407X device contains internal safety timers in the pre -charging and fast charging phase to prevent potential damage to the battery and system. The timer starts from each charging cycle. The timer value is programmed by connecting a resistor from TMR to VSS. The resistance value is calculated in the following formulas:

Keep TMR Unconnect to select the internal default timer. Disable the timer by connecting TMR to VSS.

By switching the CE pin or by switching EN1 and EN2 pin, the device enters and exits the USB hanging mode (EN1 Hi, EN2 Hi) to reset the timer.

Please note that when the device is in the heat barrierWhen the machine is state, the timer will be suspended and when the device enters the heat, the speed of the timer will slow down proportional to the charging current. For BQ24072 and BQ24073, when TD is connected to high -logic electricity, the timer is disabled.

In the fast charging stage, several events increase the duration of the timer.

System load current activation DPPM circuit to reduce the available charging current;

Since the input voltage has dropped to VIN (low), the input current decreases; [123 123 ]

Since the IC knot temperature exceeds TJ (reg), the device has entered thermal regulation. In these events, the speed of the internal timer slows down with the reduction of the charging current. For example, if the charging current is reduced by half in two minutes, the timer clock will be reduced to half of the frequency, the counter counting speed is half, and the ""counting"" time is only one minute. If the pre -charged timer expires before the battery voltage reaches Vlowv, the BQ2407X will indicate the failure state. In addition, if the battery current does not drop to ITERM before the fast charging timer expires, it will indicate the failure. CHG output flashes at a frequency of about 2 Hz to indicate the failure state. Clear failure by switching CE or input power, entering/exit USB hanging mode or OVP event.

Status indicator (PGOOD, CHG)

BQ2407X contains two drain opening outputs for indicating its state. When an effective input source is connected, the output signal is good. When (vbat+vin (dt)) lt; vin lt; vovp, PGOOD is low. When the input voltage exceeds this range, PGOOD is high impedance.

The charging cycle after the power of power, CE becomes lower or exited OVP is expressed as CHG pin (Low-LED lit), and all refresh (subsequent) charging will cause the CHG pin (Open-LED Outside). In addition, CHG flickered at a frequency of about 2 Hertz, thus issuing a timer fault signal.

Heat regulation and heat shutdown

BQ2407X contains a hot -regulating circuit for monitoring mold temperature. If the temperature exceeds TJ (reg), the device will automatically reduce the charging current to prevent the mold temperature from rising further. In some cases, despite the operation of the heat circuit, the temperature of the mold will continue to rise, especially when the high VIN and the system load are heavier. Under these conditions, if the temperature of the mold rises to TJ (level), enter FET Q1 to close. FET Q2 is opened to ensure that the battery is still powered by load. Once the temperature of the device chip is cooled through TJ (OFF-HYS), the FET Q1 is opened, and the device returnsHot -toned. Continuous ultra -temperature state can lead to the ""snoring"" mode. In the process of thermal regulation, the speed of the safe timer decreases accordingly as the current limit is reduced.

Note that this feature monitor the mold temperature of BQ2407X. This is not a synonym for ambient temperature. Due to the linear characteristics of the battery charging algorithm and the LDO related to OUT, the power consumption in IC will cause spontaneous heat. Figure 23 shows the improved charging cycle when the thermal circuit activates. During the heat stitch, the battery terminal was disabled.

The temperature monitoring of the battery pack

BQ2407X has the temperature monitoring input of the external battery pack. TS input NTC thermistor connected to the battery pack to monitor the temperature of the battery and prevent the danger from ultra -temperature. During the charging process, INTC originated from TS and continued to monitor the voltage at TS. If at any time, the voltage at the TS exceeds the working range (Vcold to VHOT), and the charging will be suspended. The timer keeps its value, but the count is suspended. When the voltage detected at the TS is returned to the operating window, the charging is recovered, and the timer continues to count. When charging was suspended due to the temperature failure of the battery pack, the CHG pin kept low level and continued to indicate the charging.

For BQ24072 and BQ24073, when the terminal is disabled (TD high) and the voltage at the TS is greater than VDIS (TS), the temperature sensing of the battery pack is disabled. For applications that do not need TS monitoring function, connect a 10-k #8486; the resistor is connected from TS to VSS to set the TS voltage as an effective level and keep charging.

The allowable temperature range of the heating resistance of 103AT-2 is 0 ° C to 50 ° C. However, users can increase the temperature range by adding two external resistors. For more information about the circuit, see Figure 24. The values u200bu200bof RS and RP use the following formula calculations:

Among them

RTH: Thermist resistance in thermal resistance data table Value

RTC: The thermistor -cold braching value in the thermistor Data table

vh: IC's thermal sliding threshold 0.3 v nominal value [v 123]

VC: IC's cold start threshold 2.1 v nominal value ITS: IC output current bias 75μA nominal value ] ntc thermsitor Semi Tek 103AT-4

Select the RS and RP 1%values u200bu200bthat are closest to the calculated values u200bu200bin Table 3.

Rhot and RCOLD are the thermist resistance resistors at the required heat and cold temperature, respectively. Temperature windowThe tightening of the mouth cannot exceed the thermistor that is only connected to the TS, and it can only be extended.

Equipment function mode

Sleep mode

When entering between UVLO and vin (dt), the device enters the sleep mode. After entering the dormant mode for more than 20 milliseconds, the internal FET connection between the input and output pin is banned. Pulling the input to the ground will not discharge the battery, except the leakage on the battery pin. If there is a complete 1000 mAh battery, the leakage volume is 10 Weire, then it requires 1000 mAh/10 Weian 100,000 hours (11.4 years). The self -discharge of the battery is usually five times the value of this value. Explanation of muddy time and comparative device lag

Note

Figure 25 to 29 does not zoom in proportion.

Application and Implement For part of, TI does not guarantee its accuracy or integrity. TI's customers are responsible for determining the applicability of the component. Customers should verify and test their design implementation to confirm the system function.

Application information

BQ2407X device is power supply, and at the same time, it is independent of battery charging. The input power supply for the battery charging and running system can be an AC adapter or USB port. These devices have a dynamic power path management (DPPM), which shared the power current between the system and the battery charging, and automatically reduce the charging current when the system load increases. When charging from the USB port, if the input voltage is lower than the threshold, the input dynamic power management (VIN-DPM) circuit will reduce the input current limit to prevent the USB port from crash. The power path architecture also allows the battery to supplement the system current requirements when the adapter cannot provide peak system current.

BQ2407X can be configured as host control, which is used to select different input current limits based on the input source of the connection, or for applications that do not support multiple types of input sources. It is a completely independent device.

Typical application

vin UVLO to VOVP, if g 800 mAh, IIN (maximum value) 1.3 A, battery temperature charging range 0 ° C to 50 ° C, 6.25 hours of fast charging safety timer.

TS function

Use 10-k #8486; NTC thermistor in the battery pack (103AT-2). For applications that do not need TS monitoring function, connect a 10-k #8486; the resistor is connected from TS to VSS to set the TS voltage as an effective level and keep charging.

CHg and pgood

LED status: connect a 1.5-k #8486; resistor between OUT and CHG to indicate the charging status. A 1.5-k #8486; resistor is connected between OUT and PGOOD to indicate the time for the connection to the effective input source.

The processor monitoring status: connect a pull -up resistor between the power rail of the processor and CHG and PGOOD (about 100 k #8486;).

Select the IN, OUT, and BAT pin capacitor

In most applications, you only need to install a high -frequency decoupling on the power pin, input end, output end and battery pins Capacitor (ceramic). It is recommended to use the value displayed on the application relationship diagram. After evaluating these voltage signals with the actual system operation conditions, you can determine whether the capacitance value can be adjusted to the minimum recommended value (DC load application) or higher value to use it for fast high -sharing pulse load applications. Note: If a high input voltage source is designed (the adapter is poor or the adapter error) is designed, the capacitor needs to be appropriately rated. The test value of ceramic capacitors is twice the rated value, so the 16 -volt power container may be sufficient to withstand 30 volts of transients (the rated value of the test with the capacitor manufacturer).

Application curve

System Example

Independent charger

[[

123] VIN UVLO to VOVP, if g 800 mAh, IIN (maximum) 1.3 a, iterm 110 mAh, battery temperature charging range 0 ° C to 50 ° C, and the safety timer is disabled.