BL4056 1A Lithium Ion Battery Linear Charger BL4056 General Description Features BL4056 is a complete constant-current/constant voltage ●Protection of battery cell reverse connection linear charger for single cell lithium-ion batteries. With a ● Programmable charge current up to 1A thermally enhanced 8-PIN SOP package on the bottom ●No MOSFET sense resistor or blocking diode and low external component count make the BL4056 ideally suited for portable applications. Furthermore the required ●Complete linear Charger in SOP8 Package for BL4056 is specifically designed to work within USB power specifications. No external sense resistor is needed and no blocking diode is required due to the internal single Cell Lithium-Ion Batteries. ●Constant-Current/Constant-Voltage with thermal regulation to maximize Rate PMOSFET Typical charge （1000mAh battery） ） Without risk of cycle（ overheating. architecture .Thermal feedback regulates the charge current to limit the die temperature during high power operation ● Preset 4.2V/4.34V charge voltage with ±1% accuracy operation or high ambient temperature .The charge voltage is fixed at 4.2V/4.34V,and the charge current can be ● Automatic Recharge programmed externally with a single resistor. The BL4056 ● Two Status Indication for Charge status, no automatically terminates the charge cycle when the charge th battery and battery failure indicators current drops to 1/10 the programmed value after the final ● C/10 charge termination float voltage is reached. ● 55µA supply current in shutdown When the input supply (wall adapter or USB supply) is removed the BL4056 automatically enters a low current state dropping the battery drain current to less than ● 2.9V trickle current charge threshold ● Soft-Start limits inrush current ● Battery Temperature Sensing 2µA.The BL4056 can be put into shutdown mode reducing the supply current to 55µA. Applications Other features include Battery temperature monitor, under-voltage lockout, automatic recharge and two status ●Cellular Telephones pins to indicate charge and charge termination. ●Digital Still Cameras ●MP3 Players ●Bluetooth Applications ●Portable Devices ●USB Bus-Powered Chargers Page1 www.belling.com.cn V1.4 BL4056 Typical charge cycle（ （1000mAh battery） ） Ordering Information Package Information BL4056- VV X XX Package: EP: ESOP8 Features: P: Standard (default, lead free) C: Customized Part Number Top Mark BL4056-42 4056 AXYY ZZ BL4056-43 4056 BXYY ZZ Remark X: Year YY: Week ZZ: Internal Code Output Voltage 42:4.2V 43:4.34V Page2 www.belling.com.cn V1.4 BL4056 Pin Configuration Pin Assignment Pin Num. 1 2 Symbol Function TEMP Temperature sense input Connecting TEMP pin to NTC thermistor’s output in Lithium ion battery pack. If TEMP pin’s voltage is below 45% or above 80% of supply voltage VCC, this means that battery’s temperature is too low or too high, charging is suspended. The temperature sense function can be disabled by grounding the TEMP pin. PROG Constant Charge Current Setting and Charge Current Monitor Pin The charge current is programmed by connecting a resistor RPROG from this pin to GND. When in precharge mode, the PROG pin’s voltage is regulated to 0.1V. When charging in constant-current mode this pin’s voltage is regulated to 1V. In all modes during charging, the voltage on this pin can be used to measure the charge current using the following formula: 3 4 5 GND Ground VCC Positive input supply voltage Provides power to the internal circuit. When VCC drops to within 80mV of the BAT pin voltage, the BL4056 enters low power sleep mode, dropping IBAT to less than 2µA. BAT Battery connection Pin Connect the positive terminal of the battery to this pin. Dropping BAT pin’s current to less than 2µA when IC in disable mode or in sleep mode. BAT pin provides charge current to the battery and provides regulation voltage of 4.2V/4.34V. Charge terminated status output is pulled low by an internal switch to indicate a battery charge terminated; this means Charge termination. Otherwise pin is in high impedance state. Open-Drain charge status output pin is pulled low by an internal switch, When the battery is being charged, the otherwise, pin is in high impedance state. 6 7 8 CE Chip enable input A high input will put the device in the normal operating mode. Pulling the CE pin to low level will put the BL4056 into disable mode. The CE pin can be driven by TTL or CMOS logic level. Page3 www.belling.com.cn V1.4 BL4056 Block Diagram Absolute Maximum Ratings Parameter Rating Unit Input supply voltage : VCC -0.3～8 V PROG pin voltage -0.3～VCC+0.3 V BAT pin voltage -0.3～7 V TEMP pin voltage -0.3～10 V pin voltage -0.3～10 V pin voltage CE pin voltage -0.3～10 V -0.3～10 V BAT pin current 1200 mA PROG pin current 1200 µA Maximum junction temperature 145 ℃ Operating ambient temperature :Topa -40～85 ℃ Storage temperature :Tstr -65～125 ℃ Soldering temperature and time +260（Recommended 10S） ℃ Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Page4 www.belling.com.cn V1.4 BL4056 Electrical Characteristics Symbol VCC ICC -IBAT VFLOAL IBAT Parameter Condition Min Typ. Max Unit 4.0 5.0 8.0 V ●Charge mode, RPROG=1.1K - 150 500 µA ●Standby mode(charge end) - 55 100 µA ●Shutdown mode（RPROG not connected, VCC<VBAT, or VCC<VUV） - 55 100 µA 0℃≤TA≤85℃ BL4056-42 4.158 4.2 4.242 V 0℃≤TA≤85℃ BL4056-43 4.3 4.34 4.38 V ●RPROG=2.2K, current mode 450 500 550 mA ●RPROG=1.1K,current mode 950 1000 1050 mA 0 -2.5 -6 - ±1 ±2 µA - -1 -2 µA ● Input supply voltage static current Regulated output voltage BAT pin current (The condition of current mode is VBAT=3.9V) ●Standby mode: VBAT=4.2V ●Standby mode: VBAT =4.34V Shutdown mode, RPROG not connected Sleep mode, VCC=0V µA µA ITRIKL Trickle charge current ●VBAT<VTRIKL, RPROG=1.1K 120 130 140 mA VTRIKL Trickle charge threshold voltage RPROG=1.1K, VBAT rising 2.8 2.9 3.0 V VTRHYS Trickle voltage hysteresis voltage RPROG=1.1K 150 200 250 mV VUV VCC under voltage lockout threshold ● VCC from low to high 3.5 3.7 3.9 V VUVHYS VCC under voltage lockout hysteresis ● 150 200 300 mV VASD VCC-VBAT lockout threshold voltage VCC from low to high 100 140 180 VCC from high to low 50 80 110 ITERM C/10 termination current threshold ●RPROG=2.2K 60 70 80 ●RPROG=1.1K 120 130 140 VPROG PROG pin voltage ●RPROG=1.1K，current mode 0.9 1.0 1.1 V =5mA - 0.3 0.6 V =5mA - 0.3 0.6 V VCHRG Pin output low voltage mV mA VSTDBY Pin output low voltage VTEMP-H The voltage at TEMP increase - 80 83 %VCC VTEMP-L The voltage at TEMP decrease 42 45 - %VCC ∆VRECHRG Recharge battery threshold voltage 120 180 240 mV TLIM Thermal protection temperature The resistance of power FET ”ON” （between VCC and BAT） - 145 - ℃ - 650 - mΩ - 20 - µS RON VFLOAT -VRECHRG tSS Soft-start time IBAT=0 to IBAT=1100V/RPROG tRECHARGE Recharge comparator filter time VBAT from high to low 0.8 1.8 4 mS tTERM Termination comparator filter time IBAT below ICHG/10 0.8 1.8 4 mS Page5 www.belling.com.cn V1.4 BL4056 IPROG PROG pin pull-up current - 2.0 - µA Note: The ● denotes specifications which apply over the full operating temperature rang, otherwise specifications are at TA=25℃，VCC=5V，unless otherwise specified. Typical performance characteristics RPROG=11KΩ，TA=25℃ VBAT=3.9V，RPROG=11KΩ，TA=25℃ VCC=5V，VBAT=3.9V，RPROG=11KΩ VCC=5V，RPROG=11KΩ Page6 www.belling.com.cn V1.4 BL4056 Description of the Principle The BL4056 is a complete constant-current/constant-voltage linear charger for single cell lithium-ion batteries. Constant-current/constant-voltage to charger batter by internal MOSFET .It can deliver up to 1A of charge current .No blocking diode or external current sense resistor is required. BL4056 include two Open-Drain charge status Pins: Charge status indicator and battery failure status output . The internal thermal regulation circuit reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 145℃. This feature protects the BL4056 from excessive temperature, and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the BL4056 or the external components. Another benefit of adopting thermal regulation is that charge current can be set according to typical, not worst-case, ambient temperatures for a given application with the assurance that the charger will automatically reduce the current in worst-case conditions. The charge cycle begins when the voltage at the VCC pin rises above the UVLO level, a current set resistor is connected from the PROG pin to ground, and the CE pin is pulled above the chip enable threshold. The pin outputs a logic low to indicate that the charge cycle is on going. At the beginning of the charge cycle, if the battery voltage is below 2.9V, the charge is in precharge mode to bring the cell voltage up to a safe level for charging. The charger goes into the fast charge constant-current mode once the voltage on the BAT pin rises above 2.9 V. In constant current mode, the charge current is set by RPROG. When the battery approaches the regulation voltage 4.2V/4.34V, the charge current begins to decrease as the BL4056 enters the constant-voltage mode. When the current drops to charge termination threshold, the charge cycle is terminated, and impedance state to indicate that the charge cycle is terminated and pin assumes a high pin is pulled low. The charge termination threshold is 10% of the current in constant current mode. To restart the charge cycle, remove the input voltage and reapply it, or momentarily force CE pin to 0V. The charge cycle can also be automatically restarted if the BAT pin voltage falls below the recharge threshold. The on-chip reference voltage, error amplifier and the resistor divider provide regulation voltage with 1% accuracy which can meet the requirement of lithium-ion and lithium polymer batteries. When the input voltage is not present, or input voltage is below VBAT, the charger goes into a sleep mode, dropping battery drain current to less than 3µA. This greatly reduces the current drain on the battery and increases the standby time. The charger can be shutdown by forcing the CE pin to GND. The charging profile is shown in the following figure: Page7 www.belling.com.cn V1.4 BL4056 Programming charge current The charge current is programmed using a single resistor from the PROG pin to ground. The program resistor and the charge current are calculated using the following equations.: Charge termination A charge cycle is terminated when the charge current falls to 1/10th the programmed value after the final float voltage is reached. This condition is detected by using an internal filtered comparator to monitor the PROG pin. When the PROG pin voltage falls below 100mV for longer than tTEMP (typically 1.8mS), Charging is terminated. The charge current is latched off and the BL4056 enters standby mode, where the input supply current drops to 55µA (Note:C/10 termination is disabled in trickle charging and thermal limiting modes). When charging, transient loads on the BAT pin can cause the PROG pin to fall below 100mV for short periods of time before the DC charge current has dropped to 1/10th the programmed value. The 1.8mS filter time (tTEMP) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termination. Once the average charge current drops below 1/10th the programmed value, the BL4056 terminated the charge cycle and ceases to provide any current through the BAT pin. In this state all loads on the BAT pin must be supplied by the battery. The BL4056 constantly monitors the BAT pin voltage in standby mode. If this voltage drops below the 4.02V recharge threshold (VRECHRG ),another charge cycle begins and current is once again supplied to the battery. To manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied or the charger must be shut down and restarted using the PROG pin. Figure 1 shows the state diagram of a typical charge cycle. Charge status indicator BL4056 has two open-drain status indicator output and . is pull-down when the BL4056 in a charge cycle. In other status in high impedance. and are all in high impedance when the battery out of the normal temperature. Represent in failure state, when TEMP pin in typical connecting, or the charger with no battery: red LED and Page8 www.belling.com.cn V1.4 BL4056 green LED all don’t light. The battery temperature sense function is disabled by connecting TEMP pin to GND. If battery is not connected to charger, pin outputs a PWM level to indicate no battery. If BAT pin connects a flicker about 1-4S, If not use status indicator should set status indicator 10µF capacitor, the frequency of output connected to GND. charger’s status Red led Green led Charging light dark Battery in full state dark light Under-voltage, battery’s temperature is to high or too low, or not connect to battery(use TEMP) dark dark BAT pin is connected to 10uF capacitor ， No battery mode (TEMP=GND) Green LED bright, Red LED flicker F=1-4 S Thermal limiting An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 140℃(BL4056B is approximately 105℃). The feature protects the BL4056 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the BL4056. The charge current can be set according to typical (not worst-case) ambient temperature with the assurance that the charger will automatically reduce the current in worst-case conditions. To prevent the damage caused by the very high or very low temperature done to the battery pack, the BL4056 continuously senses battery pack temperature by measuring the voltage at TEMP pin determined by the voltage divider circuit and the battery’s internal NTC thermistor as shown in Figure 1. The BL4056 compares the voltage at TEMP pin (VTEMP) against its internal VLOW and VHIGH thresholds to determine if charging is allowed. In BL4056, VLOW is fixed at (45%×Vcc), while VHIGH is fixed at (80%×Vcc). If VTEMP<VLOW or VTEMP>VHIGH , it indicates that the battery temperature is too high or too low and the charge cycle is suspended. When VTEMP is between VLOW and VHIGH, charge cycle resumes. The battery temperature sense function can be disabled by connecting TEMP pin to GND. Selecting R1 and R2 The values of R1 and R2 in the application circuit can be determined according to the assumed temperature monitor range and thermistor’s values. The Follows is an example: Assume temperature monitor range is TL～TH， （ TL＜TH)；the thermistor in battery has negative temperature coefficient（NTC） ，RTL is thermistor’s resistance at TL， RTH is the resistance at TH，so RTL＞RTH，then at temperature TL, the voltage at TEMP pin is: At temperature TH, the voltage at TEMP pin is: We know VTEMPL＝VHIGH＝K2×Vcc (K2=0.8)；VTEMPH＝VLOW＝K1×Vcc (K1=0.45) Then we can have： Likewise, for positive temperature coefficient thermistor in battery, we have RTH＞RTL and we can calculate: Page9 www.belling.com.cn V1.4 BL4056 We can conclude that temperature monitor range is independent of power supply voltage VCC and it only depends on R1, R2, RTL and RTH: The values of RTH and RTL can be found in related battery handbook or deduced from testing data. In actual application, if only one terminal temperature is concerned (normally protecting overheating), there is no need to use R2 but R1. It becomes very simple to calculate R1 in this case. Under Voltage lockout (UVLO) An internal under voltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the under voltage lockout threshold . If the UVLO comparator is tripped, the charger will not come out of shutdown mode until VCC rises 140mV above the battery voltage. Manual terminate At any time of the cycle of charging will put the BL4056 into disable mode to pull CE pin to GND, or remove RPROG （PROG pin is float）. This made the battery drain current to less than 2µA and reducing the supply current to 55µA. To restart the charge cycle, set CE pin in high level or connect a programming resistor. If BL4056 in the under voltage Lockout mode, the and are all in high impedance state, or VCC is above BAT pin 140mV, or VCC is too low. Auto restart Once charge is been terminated, BL4056 immediately use a 1.8ms filter time（ tRECHARGE ）on the termination comparator to constant monitor the voltage on BAT pin. If this voltage drops below the 4.02V recharge threshold (about between 80% and 90% of VCC), another charge cycle begins. This ensured the battery maintained (or approach) to a charge full status and avoid the requirement of restarting the periodic charging cycle. In the recharge cycle, pin enters a pulled down status. Page10 www.belling.com.cn V1.4 BL4056 Fig.1 State diagram of a typical charge cycle Fig.2 Isolating with capacitive load on PROG Pin Stability Considerations In constant-current mode, the PROG pin is in the feedback loop, not the battery. The constant-current mode stability is affected by the impedance at the PROG pin. With no additional capacitance on the PROG pin, the charger is stable with program resistor values as high as 20K. However, additional capacitance on this node reduces the maximum allowed program resistor. Therefore, if IPROG pin is loaded with a capacitance C, the following equation should be used to calculate the maximum resistance value for RPROG： As user, may think charge current is important, not instantaneous current. For example, to run a low current mode switch power which parallel connected with battery, the average current from BAT pin usually importance to instantaneous current. In this case, In order to measure average charge current or isolate capacitive load from IPROG pin, a simple RC filter can be used on PROG pin as shown in Figure 2. In order to ensure the stability add a 10K resistor between PROG pin and filter capacitor. Page11 www.belling.com.cn V1.4 BL4056 Power dissipation The conditions that cause the BL4056 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the IC. Nearly all of this power dissipation is generated by the internal MOSFET-this is calculated to be approximately: PD =(VCC − VBAT ) X I BAT The approximate ambient temperature at which the thermal feedback begins to protect the IC is: TA = 145°C − PDθJA ; TA = 145°C − (VCC − VBAT ) X IBAT X θJA For example: The BL4056 with 5V supply voltage through programmable provides full limiting current 800mA to a charge lithium-ion battery with 3.75V voltage. If θJA is 150℃/W ( reference to PCB layout considerations), When BL4056 begins to decrease the charge current, the ambient temperature about: TA = 145°C − (5V− 3.75V ) X (800mA) χ150°C / W TA =145°C −0.5W X 150°C / W =145°C − 75°C TA =65°C BL4056 can work in the condition of the temperature is above 65℃, but the charge current will pull down to below 800mA. In a fixed ambient temperature, the charge current is calculated to be approximately : Just as Description of the Principle part talks about so, the current on PROG pin will reduce in proportion to the reduced charge current through thermal feedback. In BL4056 design applications don’t need to considerate the worst case of thermal condition, this point is importance, because if the junction temperature up to 145℃ ,IC will auto reduce the power dissipation. Thermal considerations Because of the small size of the thin SOP8 package, it is important to use a good thermal PC board layout to maximize the available charge current. The thermal path for the heat generated by the IC is from the die to the copper lead frame, through the package leads, (especially the ground lead) to the PC board copper. The PC board copper is the heat sink. The footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipate the heat to the surrounding ambient. Other heat sources on the board, not related to the charger, must also be considered when designing a PC board layout because they will affect overall temperature rise and the maximum charge current. Add thermal regulation current It will effective to decrease the power dissipation through reduce the voltage of both ends of the inner MOSFET. In the thermal regulation, this action of transporting current to battery will raise. One of the measure is through an external component(as a resistor or diode) to consume some power dissipation. For example: The BL4056 with 5V supply voltage through programmable provides full limiting current 800mA to a charge lithium-ion battery with 3.75V voltage. If θJA is 125℃/W, so that at 25℃ ambient temperature, the charge current is calculated to be approximately : In order to increase the thermal regulation charge current, can decrease the power dissipation of the IC through reducing the voltage (as show fig.3) of both two ends of the resistor which connecting in series with a 5V AC adapter. With square equation to calculate I BAT ： Page12 www.belling.com.cn V1.4 BL4056 If RCC=0.25Ω, VS=5V, VBAT=3.75V, TA=25℃ and θJA =125℃/W, we can calculate the thermal regulation charge current: IBAT＝948mA. It means that in this structure it can output 800mA full limiting charge current at more high ambient temperature environment. Although it can transport more energy and reduce the charge time in this application, but actually spread charge time, if BL4056 stay in under-voltage state, when VCC becomes too low in voltage mode. Fig.4 shows how the voltage reduced with increase RCC value in this circuit. This technique will act the best function when in order to maintain the minimize the dimension of the components and avoid voltage decreased to minimize RCC . Fig.3:A circuit to maximum the thermal regulation charge current Fig.4:The relationship curve between charge current with RCC VCC bypass capacitor Many types of capacitors can be used for input bypassing, however, caution must be exercised when using multilayer ceramic capacitors. Because of the self-resonant and high Q characteristics of some types of ceramic capacitors, high voltage transients can be generated under some start-up conditions, such as connecting the charger input to a live power source. Adding a 1.5Ω resistor in series with a ceramic capacitor will minimize start-up voltage transients. Charging Current Soft Start BL4056 includes a soft start circuit which used to maximize to reduce the surge current in the begging of charge cycle. When restart a new charge cycle, the charging current ramps up from 0 to the full charging current within 20µs. In the start process it can maximize to reduce the action which caused by surge current load. USB and Wall Adapter Power BL4056 allows charging from a USB port, a wall adapter can also be used to charge Li-Ion/Li-polymer batteries. Figure 5 shows an example of how to combine wall adapter and USB power inputs. A P-channel MOSFET, M1, is used to prevent back conducting into the USB port when a wall adapter is present and Schottky diode, D1, is used to prevent USB power loss through the 1KΩ pull-down resistor. Generally, AC adaptor is able to provide bigger much current than the value of specific current limiting which is 500mA for USB port. So can rise charge current to 600mA with using a N-MOSFET (MN1) and an additional set resistor value as high as 10K. Page13 www.belling.com.cn V1.4 BL4056 Fig.5:Combining Wall Adapter and USB Power Typical Application Mainly used in Cellular telephones, MP3, MP4 players, digital still cameras, electronic dictionary, GPS, portable devices and vary chargers. 1. Suitable for the function of battery’s temperature detection, the application of the indicator of battery’s temperature anomaly and charge status. 2. Suitable for the application of USB power and the charge of wall adapter Page14 www.belling.com.cn V1.4 BL4056 3. Suitable for charge status indicator, which 4. Suitable for the application which not the need charge status indicator and battery’s application not temperature detection. need battery’s temperature detection. 5. Add a resistor for power dissipation, Red LED for charge status, green LED for charge terminate state Page15 www.belling.com.cn V1.4 BL4056 Board Layout Considerations ●RPROG at PROG pin should be as close to BL4056 as possible, also the parasitic capacitance at PROG pin should be kept as small as possible. ●The capacitance at VCC pin and BAT pin should be as close to BL4056 as possible. ● During charging, BL4056’s temperature may be high, the NTC thermistor should be placed far enough to BL4056 so that the thermistor can reflect the battery’s temperature correctly. ● It is very important to use a good thermal PC board layout to maximize charging current. The thermal path for the heat generated by the IC is from the die to the copper lead frame through the package lead (especially the ground lead) to the PC board copper, the PC board copper is the heat sink. The footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipate the heat to the surrounding ambient. Feed through vias to inner or backside copper layers are also useful in improving the overall thermal performance of the charger. Other heat sources on the board, not related to the charger, must also be considered when designing a PC board layout because they will affect overall temperature rise and the maximum charge current. ●The ability to deliver maximum charge current under all conditions require that the exposed metal pad on the back side of the BL4056 package be soldered to the PC board ground. Failure to make the thermal contact between the exposed pad on the backside of the package and the copper board will result in larger thermal resistance. Page16 www.belling.com.cn V1.4 BL4056 Packaging Information: Packaging Type: SOP8-PP Dimension (mm) Dimension (Inches) Character Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.1 0.3 0.004 0.012 B b Page17 1.27(Typ.) 0.330 0.05(Typ.) 0.510 0.013 0.020 c 0.9(Typ.) 0.035(Typ.) c1 1.0(Typ.) 0.039(Typ.) D 5.8 6.2 0.228 0.244 D1 3.202 3.402 0.126 0.134 E 3.800 4.000 0.150 0.157 E1 2.313 2.513 0.091 0.099 F 4.7 5.1 0.185 0.201 L 0.675 0.725 0.027 0.029 G 0.32(Typ.) 0.013(Typ.) R 0.15(Typ.) 0.006(Typ.) θ1 7 θ 8 ° ° www.belling.com.cn 7 8 ° ° V1.4