BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The BL4054/BL4054B automatical -ly terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. FEATURES Programmable Charge Current Up to 800mA No MOSFET, Sense Resistor or Blocking Diode Required Preset 4.2V Charge Voltage with ±1% Accuracy Charge Current Monitor Output for Gas Gauging Thermal Regulation Maximizes Charge Rate Without Risk of Overheating Charges Single Cell Li-Ion Batteries Directly from USB Port Over-Voltage Protect Automatic Recharge Charge Status Output Pin C/10 Charge Termination 25µA Supply Current in Shutdown 2.9V Trickle Charge Threshold Soft-Start Limits Inrush Current Available in 5-Lead SOT-23 Package When the input supply (wall adapter or USB supply) is removed, the BL4054/BL4054B automatically enters a low current state, dropping the battery drain current to less than 2µΑ. The BL4054/BL4054B can be put into shutdown mode, reducing the supply current to 25µA. Other features include charge current monitor, under-voltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. APPLICATIONS The only difference between BL4054 and BL4054B is that at power on, BL4054 will check the battery voltage first, it will not start charging unless the battery voltage is below the auto-rechrage threshold. BL4054B does not perform this check. So BL4054B can guarantee the high battery capacity at all time, while BL4054 can prevent the battery from being repeatedly charged in some specific applications. Cellular and Smart Phones Charging Docks and Cradles BlueTooth Applications PDAs MP3/MP4/MP5 Players DESCRIPTION The BL4054/BL4054B is a complete constant current / constant voltage linear charger for single cell Lithium-Ion batteries. No external sense ORDERING INFORMATION TYPICAL APPLICATION VCC 4.5V to 6.5V BL4054/BL4054B – XX X X XXX Package: RN: SOT23-5 TRN: TSOT23-5 VCC 1uF BAT Features: P: Standard (default, lead free) C: Customized 600mA BL4054/BL4054B PROG Trickle Charge: T: Trickle Charge N: No Trickle Charge GND Float Voltage: 42: 4.2V 43: 4.3V 44: 4.4V PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 4.2V Li-Ion Battery 1.65k 600mA Application Circuit www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 1 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Absolute Maximum Rating (Note 1) Input Supply Voltage (VCC) PROG Voltage BAT Voltage CHRGb BAT Short-Circuit Duration BAT Pin Current -0.3V to +10V -0.3V to +VCC -0.3V to 7V -0.3V to 10V Continuous 800mA PROG Pin Current 800µA Maximum Junction Temperature 125°C (Note2) Operating Temperature Range -40°C to 85°C Storage Temperature Range -65°C to 125°C Lead Temperature (Soldering, 10s) 300°C Package Information TSOT23-5/SOT23-5 TOP VIEW CHRGb 1 Part Number PROG 4 VCC MARKING GND 2 BAT 5 3 Top Mark Temp Range (Note3) BL4054-4.2 BAYW BL4054-4.3 BBYW BL4054-4.4 BCYW BL4054B-4.2 BAYW BL4054B-4.3 BBYW BL4054B-4.4 BCYW -40°C to +85°C Thermal Resistance (Note 4) Package TSOT23-5 SOT23-5 ӨJA 220°C/W 250°C/W ӨJC 110°C/W 130°C/W Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The BL4054/BL4054B is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: X: Product Code(BL4054:B,BL4054B:B ) V: Voltage Code(4.2V:A,4.3V:B,4.4V:C) Y: Year of Manufacturing(9:2009) W: Week of Manufacturing(W:A-Z, a-z). Contact Belling marketing for more information in detail. Note 4: Thermal Resistance is specified with approximately 1 square of 1 oz copper. PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 2 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Pin Description PIN NAME 1 CHRGb 2 GND 3 BAT 4 VCC 5 PROG PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 FUNCTION Open-Drain Charge Status Output. When the battery is charging, the CHRGb pin is pulled low by an internal N-channel MOSFET. When the charge cycle is completed, a weak pull-down of approximately 12µA is connected to the CHRGb pin, indicating an “AC present” condition. When the BL4054/BL4054B detects an under-voltage lockout condition, CHRGb is forced high impedance. Ground Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. An internal precision resistor divider from this pin sets the float voltage which is disconnected in shutdown mode. Positive Input Supply Voltage. Provides power to the charger. VCC can range from 4.25V to 6.5V and should be bypassed with at least a 1µF capacitor. When VCC drops to within 30mV of the BAT pin voltage, the BL4054/BL4054B enters shutdown mode, dropping IBAT to less than 2µA. Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is Programmed by connecting a 1% resistor, RPROG, from this pin to ground. When charging in constant-current mode, this pin servos to 1V. In all modes, the voltage on this pin can be used to measure the charge current using the following formula: IBAT = (VPROG / RPROG) • 1000 The PROG pin can also be used to shut down the charger. Disconnecting the Program resistor from ground allows a 3µA current to pull the PROG pin high. When it reaches the 1.21V shutdown threshold voltage, the charger enters shutdown mode, charging stops and the input supply current drops to 25µA. This pin is also clamped to approximately 2.4V. Driving this pin to voltages beyond the clamp voltage will draw currents as high as 1.5mA. Reconnecting RPROG to ground will return the charger to normal operation. www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 3 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Block Diagram 120oC TDIE VCC + 4 TA 1x 1000x 7.0V BAT + - 5µΑ + MA 3 R1 - OVP + VA CA - - + OV_SHDN SHDN C1 R2 REF 1.21V + R3 1V R4 1 + 0.1V - R5 C2 CHRGb STANDBY + C3 - TO BAT BL4054/BL4054B Rev 1.4 5/2009 VCC 2.9V 5 PPMIC BU 3µΑ PROG GND RPROG 2 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 4 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Electrical Characteristics (Note 5) Symbol (VCC = 5V, TA = 25°C, unless otherwise noted.) Parameter Conditions Charge Mode Supply Current ISPLYCHRG (Note6) Min RPROG=2kΩ RPROG =10kΩ Typ 500mA 100mA 2000µA 2000µA 535mA 107mA 1V 1V 1.07V 1.07V 100µA 500µA -2.5µA -6µA 300µA RPROG =2kΩ 465mA RPROG =10kΩ 93mA Max IBATCHRG Charge Mode Battery Current VPROGCHRG PROG Pin Voltage ISPLYSTBY Standby Mode Supply Current IBATSTBY Standby Mode Battery Current ISPLYMSD Manual Shutdown Mode Supply Current IBATMSD Manual Shutdown Mode Battery Current -2µA VPROGCLMP PROG Pin Clamp Voltage 2V ISPLYASD Automatic Shutdown Mode Supply Current IBATASD Automatic Shutdown Mode Battery Current ISPLYUVLO UVLO Mode Supply Current IBATUVLO UVLO Mode Battery Current -2µA 2µA IBATSLEEP Sleep Mode Battery Current -1µA 1µA VFLOAT Float Voltage 4.158V 4.2V 4.242V ITRIKL Trickle Charge Current 20mA 5mA 50mA 10mA 70mA 15mA VTRIKL Trickle Charge Threshold 2.8V 2.9V 3V VTRIKL, HYS Trickle Charge Hysteresis 60mV 100mV 150mV VUVLO UVLO Threshold 3.7V 3.9V 4.1V VUVLO, HYS UVLO Hysteresis 150mV 200mV 300mV VOVP Input Over-Voltage Protect Threshold 6.8V 7V 7.2V VOVP, HYS Input Over-Voltage Protect Hysteresis PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 RPROG =2kΩ RPROG =10kΩ 0.93V 0.93V 0 90µA -2µA RPROG =2kΩ RPROG =10kΩ 2µA 0 3V 25µA 50µA 0 2µA 25µA 50µA 200mV www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 5 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 VMSD, RISE Manual Shutdown Threshold, PROG rising 1.15V 1.21V 1.3V VMSD, FALL Manual Shutdown Threshold, PROG falling 0.95V 1.0V 1.05V VASD, RISE Automatic Shutdown Threshold, BAT rising 5mV 30mV 50mV VASD, FALL Automatic Shutdown Threshold, BAT falling 70mV 100mV 140mV ITERM C/10 Termination Current Threshold 85mV 100mV 115mV VRECHRG Auto Recharge Battery Voltage 4V 4.05V 4.1V ICHRGb CHRGb Pin Weak Pull-down Current 8µA 12µA 35µA VCHRGb CHRGb Pin Output Low Voltage 0.35V 0.6V TLIM Junction Temperature In Constant Temperature Mode 120°C RON Power FET ON Resistance 600mΩ TSS Soft-Start Time TRECHRG Recharge Comparator Filter Time 0.75ms 2ms 4.5ms TTERM Termination Comparator Filter Time 0.4ms 1ms 2.5ms IPROG PROG Pin Pull-up Current 50µs RPROG =2kΩ 3µA Note 5: 100% production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization. Note 6: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to the battery through the BAT pin (approximately 100mA). Typical Performance Characteristics PROG Pin Voltage vs Temperature PROG Pin Voltage vs Supply Voltage (Constant Current Mode) VCC=5V VBAT=4V TA=25°C RPROG=10K 1.0175 1.0150 VCC=5V VBAT=4V RPROG=10K 500 IBAT(mA) 1.0125 300 1.0100 1.000 1.0075 200 1.0050 0.995 100 1.0025 0.990 4.0 4.5 5.0 5.5 VCC(V) PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 VCC=5V TA=25°C RPROG=2K 400 VPROG(V) VPROG(V) 600 1.0200 1.010 1.005 Charge Current vs PROG Pin Voltage 6.0 6.5 7.0 1.0000 -50 -25 0 25 50 TEMPERATURE(°C) 75 100 0 0.00 0.25 0.50 0.75 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 1.00 1.25 VPROG(V) 6 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Typical Performance Characteristics PROG Pin Pull-Up Current vs Temperature and Supply Voltage PROG Pin Current vs PROG Pin Voltage (Clamp Current) PROG Pin Current vs PROG Pin Voltage (Pull-Up Current) 4.5 0 4.0 VBAT=4.3V VPROG=0V 4.2 3.5 -50 3.0 -100 IPROG(µΑ) IPROG(µA) 3.9 3.6 IPROG(µΑ) 2.5 -150 2.0 VCC=4.2V VCC=6.5V 1.5 3.3 -200 VCC=5V VBAT=4.3V TA=25°C 1.0 3.0 0.5 2.7 -50 -25 0 25 50 75 100 125 TEMPERATURE(°C) 0.0 2.0 2.2 2.3 2.4 2.5 -300 2.0 2.6 4.17 4.15 200 300 400 500 600 4.210 4.205 VFLOAT(V) VFLOAT(V) 4.19 4.200 4.190 4.190 4.185 -50 -25 IBAT(mA) 0 25 50 TEMPERATURE(°C) 75 40 38 20 15 5 0 1 2 3 4 VCHRGb(V) PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 5 6 6.5 7.0 CHRGb Pin I-V Curve (Weak Pull-Down State) 15 10 30 28 22 7 6.0 20 32 24 0 5.5 34 26 VCC=5V VBAT=4V TA=25°C 10 5.0 ICHRGb(µA) ICHRGb(mA) ICHRGb(mA) 25 4.5 VCC(V) 36 30 5.5 TA=25°C RPROG=10K 4.185 4.0 100 CHRGb Pin Current vs Temperature (Strong Pull-Down State) 35 5.0 4.200 4.195 40 4.5 4.205 4.195 CHRGb Pin I-V Curve (Strong Pull-Down State) 4.0 4.215 VCC=5V RPROG=10K 4.210 4.21 100 3.5 Regulated Output (Float) Voltage vs Supply Voltage 4.215 VCC=5V TA=25°C RPROG=1.25K 0 3.0 VPROG(V) Regulated Output (Float) Voltage vs Temperature 4.25 4.23 2.5 VPROG(V) Regulated Output (Float) Voltage vs Charge Current VFLOAT(V) 2.1 VCC=5V VBAT=4.3V TA=25°C -250 20 -50 5 VCC=5V VBAT=4V VCHRGb=1V VCC=5V VBAT=4.3V TA=25°C 0 -25 0 25 50 75 TEMPERATURE(°C) 100 125 0 1 2 3 4 5 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 6 7 VCHRGb(V) 7 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Typical Performance Characteristics CHRGb Pin Current vs Temperature (Weak Pull-Down State) 25 Trickle Charge Current vs Supply Voltage Trickle Charge Current vs Temperature 60 60 VCC=5V VBAT=4.3V VCHRGb=5V 20 RPROG=2K 50 40 ITRIKL(mA) ICHRGb(µΑ) ITRIKL(mA) 40 15 RPROG=2K 50 VCC=5V VBAT=2.5V 30 VBAT=2.5V TA=25°C 30 20 20 10 10 10 RPROG=10K 5 -50 -25 0 25 50 75 100 0 -50 125 TEMPERATURE(°C) Trickle Charge Threshold vs Temperature 0 25 50 75 TEMPERATURE(°C) 100 125 4.5 5.0 5.5 6.0 6.5 7.0 VCC(V) Charge Current vs Battery Voltage 3.000 Charge Current vs Supply Voltage 600 600 500 500 400 400 RPROG=2K VCC=5V RPROG=10K 2.975 -25 RPROG=10K 0 4.0 2.925 IBAT(mA) VTRIKL(V) IBAT(mA) 2.950 300 2.900 2.875 200 200 VCC=5V RPROG=2K TA=25°C 2.850 100 2.825 2.800 -50 -25 0 25 50 75 100 0 2.7 125 TEMPERATURE(°C) Charge Current vs Ambient Temperature 4.09 RPROG=2K 3.6 VBAT(V) 3.9 4.2 4.5 VCC=5V RPROG=10K 650 RDS(ON)(mΩ) VRECHRG(V) 4.03 100 4.01 0 25 50 100 125 150 TEMPERATURE(°C) PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 75 3.99 -50 6.0 6.5 7.0 100 125 VCC=4.2V IBAT=100mA RPROG=2K 500 450 400 RPROG=10K 0 -50 -25 5.5 VCC(V) 550 4.05 200 5.0 700 600 VCC=5V VBAT=4V 4.5 Power FET "ON" Resistance vs Temperature 4.07 400 IBAT(mA) 3.3 RPROG=10K 0 4.0 4.11 500 300 3.0 100 Recharge Voltage Threshold vs Temperature 600 VBAT=4V TA=25°C 300 -25 0 25 50 75 TEMPERATURE(°C) 100 125 350 -50 -25 0 25 50 75 TEMPERATURE(°C) www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 8 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Operation The BL4054/BL4054B is a single cell Lithium-Ion battery charger using a constant current / constant voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of 1%. The BL4054/BL4054B includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the BL4054/BL4054B is capable of operating from a USB power source. A charge cycle begins when the voltage at the VCC pin rises above the UVLO threshold level and a 1% program resistor is connected from the PROG pin to ground or when a battery is connected to the charger output. If the BAT pin is less than 2.9V, the charger enters trickle charge mode. In this mode, the BL4054/BL4054B supplies approximately 1/10 the programmed charge current to bring the battery voltage up to a safe level for full current charging. When the BAT pin voltage rises above 2.9V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. If the battery voltage is above 2.9V at power-on, BL4054B enters the constant-current mode immediately, while BL4054 will perform one more check. If the battery voltage is below the auto-recharge threshold, BL4054 enters the constant current mode, otherwise it goes to standby mode. This is the only difference between the BL4054 and BL4054B. Refer to Figure 1a and 1b for more details. BL4054/BL4054B Rev 1.4 5/2009 Programming Charge Current The charge current is programmed using a single resistor from the PROG pin to ground. The battery charge current is 1000 times the current out of the PROG pin. The program resistor and the charge current are calculated using the following equations: R PROG = Normal Charge Cycle PPMIC BU When the BAT pin approaches the final float voltage (4.2V), the BL4054/BL4054B enters constant-voltage mode and the charge current begins to decrease. When the charge current drops to 1/10 of the programmed value, the charge cycle ends. 1000V I CHG I CHG = 1000V R PROG The charge current out of the BAT pin can be determined at any time by monitoring the PROG pin voltage using the following equation: I BAT = VPROG • 1000 R PROG Charge Termination A charge cycle is terminated when the charge current falls to 1/10 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 TTERM (typically 1ms), charging is terminated. The charge current is latched off and the BL4054/BL4054B enters standby mode, where the input supply current drops to 100µA. (Note: C/10 termination is disabled in trickle charging mode). When charging, transient loads on the BAT www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 9 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 pin can cause the PROG pin to fall below 100mV for short periods of time before the DC charge current has dropped to 1/10 the programmed value. The 1ms filter time (TTERM) 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 1/10 the programmed value, the BL4054/BL4054B terminates 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 BL4054 constantly monitors the BAT pin voltage in standby mode. If this voltage drops below the 4.05V 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 1a and 1b shows the state diagram of a typical charge cycle. POWER ON BAT < 2.9V PROG RECONNECTED OR UVLO CONDITION STOPS 1/10 FULL CURRENT CHRGb:STRONG PULL-DOWN BAT > 2.9V 2.9V<BAT<4.05V ICC DROPS TO <25uA CHRGb:Hi-Z IN UVLO WEAK PULL-DOWN OTHERWISE PROG FLOATED OR UVLO CONDITION FULL CURRENT CHRGb:STRONG PULL-DOWN PROG < 100mV NO CHARGE CURRENT CHRGb:WEAK PULL-DOWN POWER ON BAT < 2.9V PROG RECONNECTED OR UVLO CONDITION STOPS 1/10 FULL CURRENT CHRGb:STRONG PULL-DOWN BAT > 2.9V 2.9V<BAT<4.05V ICC DROPS TO <25uA CHRGb:Hi-Z IN UVLO WEAK PULL-DOWN OTHERWISE PROG FLOATED OR UVLO CONDITION FULL CURRENT CHRGb:STRONG PULL-DOWN PROG < 100mV NO CHARGE CURRENT CHRGb:WEAK PULL-DOWN 2.9V < BAT < 4.05V Figure1b. State Diagram of BL4054B Charge Cycle Charge Status Indicator (CHRGb) The charge status output has three different states: strong pull-down (~10mA), weak pull-down (~12µA) and high impedance. The strong pull-down state indicates that the BL4054/BL4054B is in a charge cycle. Once the charge cycle has terminated, the pin state is determined by under-voltage lockout conditions. A weak pull-down indicates that VCC meets the UVLO conditions and the BL4054/BL4054B is ready to charge. High impedance indicates that the BL4054/BL4054B is in under voltage lockout mode: either VCC is less than 100mV above the BAT pin voltage or insufficient voltage is applied to the VCC pin. A microprocessor can be used to distinguish between these three states—the application circuit of this method is shown in the Typical Applications section. 2.9V < BAT < 4.05V Manual Shutdown BAT > 4.05V Figure1a. State Diagram of BL4054 Charge Cycle At any point in the charge cycle, the BL4054/BL4054B can be put into shutdown mode by removing RPROG thus floating the PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 10 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 PROG pin. This reduces the battery drain current to less than 2µA and the supply current to less than 50µA. A new charge cycle can be initiated by reconnecting the program resistor. In manual shutdown, the CHRGb pin is in a weak pull-down state as long as VCC is high enough to exceed the UVLO conditions. The CHRGb pin is in a high impedance state if the BL4054/BL4054B is in under voltage lockout mode: either VCC is within 100mV of the BAT pin voltage or insufficient voltage is applied to the VCC pin. Over-Voltage Protect The BL4054/BL4054B has an internal Over-Voltage Protect comparator, once the input voltage VCC rises above 7V (VOVP), this comparator will shut down the chip. This feature can prevent the BL4054/BL4054B from the over-voltage stress due to the input transient at hot plug in. In this state, the CHRGb pin will be high impedance. Once the VCC falls back to safe range (VOVP - VOVP, HYS), normal operation continues. Automatic Recharge Once the charge cycle is terminated, the BL4054/BL4054B continuously monitors the voltage on the BAT pin using a comparator with a 2ms filter time (TRECHRG). A charge cycle restarts when the battery voltage falls below 4.05V (which corresponds to approximately 80% to 90% battery capacity). This ensures that the battery is kept at or near a fully charged condition and eliminates the need for periodic charge cycle initiations. CHRGb output enters a strong pull-down state during recharge cycles. PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 Applications Information Stability Considerations The constant-voltage mode feedback loop is stable without an output capacitor provided a battery is connected to the charger output. With no battery present, an output capacitor is recommended to reduce ripple voltage. When using high value, low ESR ceramic capacitors, it is recommended to add a 1Ω resistor in series with the capacitor. No series resistor is needed if tantalum capacitors are used. 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 thus it should be avoided. Average, rather than instantaneous, charge current may be of interest to the user. For example, if a switching power supply operating in low current mode is connected in parallel with the battery, the average current being pulled out of the BAT pin is typically of more interest than the instantaneous current pulses. In such a case, a simple RC filter can be used on the PROG pin to measure the average battery current as shown in Figure 2. A 10k resistor has been added between the PROG pin and the filter capacitor to ensure stability. Thermal Limiting An internal thermal feedback loop reduces the programmed charge current if the die www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 11 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 temperature attempts to rise above a preset value of approximately 120°C. This feature protects the BL4054/BL4054B 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 BL4054/BL4054B. 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. 10k CHARGE CURRENT MONITOR CIRCUITRY PROG BL4054 RPROG CFILTER GND from a 5V USB supply is programmed to supply 400mA full-scale current to a discharged Li-Ion battery with a voltage of 3.75V. Assuming θJA is 150°C/W, the ambient temperature at which the BL4054/BL4054B will begin to reduce the charge current is approximately: TA = 120°C − (5V − 3.75V) • 400mA • 150°C / W TA = 45°C The BL4054/BL4054B can be used above 45°C ambient, but the charge current will be reduced from 400mA. The approximate current at a given ambient temperature can be approximated by: I BAT = Figure 2. Isolating Capacitive Load on PROG Pin Power Dissipation The conditions that cause the BL4054/BL4054B 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 ) • I BAT where PD is the power dissipated, VCC is the input supply voltage, VBAT is the battery voltage and IBAT is the charge current. The approximate ambient temperature at which the thermal feedback begins to protect the IC is: TA = 120°C − PD • θ JA TA = 120°C − (VCC − VBAT ) • I BAT • θ JA Example: An BL4054/BL4054B operating PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 120°C − TA (VCC − VBAT ) • θ JA Using the previous example with an ambient temperature of 60°C, the charge current will be reduced to approximately: IBAT = 120°C − 60°C = 320mA (5V − 3.75V) • 150°C / W Moreover, when thermal feedback reduces the charge current, the voltage at the PROG pin is also reduced proportionally as discussed in the Operation section. It is important to remember that BL4054/BL4054B applications do not need to be designed for worst-case thermal conditions since the IC will automatically reduce power dissipation when the junction temperature reaches approximately 120°C. Thermal Considerations Because of the small size of the ThinSOT package, it is very important to use a good www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 12 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 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. 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 following table lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with the device mounted on topside. Table 1. Measured Thermal Resistance (2-Layer Board*) COPPER AREA TOPSIDE BACKSIDE BOARD AREA THERMAL RESISTANCE JUNCTION-TO-AMBIENT 2500mm2 2500mm2 2500mm2 125℃/W 2 2500mm 2 2500mm2 125℃/W 2500mm 2 2 130℃/W 2500mm2 2500mm2 135℃/W 2 2 150℃/W 1000mm 225mm 2 100mm2 50mm 2 2500mm 2500mm 2500mm Table 2. Measured Thermal Resistance (4-Layer Board**) COPPER AREA (EACH SIDE) BOARD AREA THERMAL RESISTANCE JUNCTION-TO-AMBIENT 2500mm2*** 2500mm2 80℃/W **Top and bottom layers use two ounce copper, inner layers use one ounce copper ***10,000mm2 total copper area 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 Ω resistor in series with an X5R ceramic capacitor will minimize start-up voltage transients. Charge Current Soft-Start The BL4054/BL4054B includes a soft-start circuit to minimize the inrush current at the start of a charge cycle. When a charge cycle is initiated, the charge current ramps from zero to the full-scale current over a period of approximately 50µs. This has the effect of minimizing the transient current load on the power supply during start-up. * Each layer uses one ounce copper PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 13 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Typical Applications USB/ USB/Wall Adapter Power LiLi-Ion Charger 5V WALL ADAPTER BAT USB POWER 1k VIN=5V IBAT 3 BL4054 BL4054B 4 VCC 5 PROG GND 2 1uF 10k Full Featured Single Cell LiLi-Ion Charger Li-Ion CELL 2.5k 100mA/ 500mA uC 330Ω 4 VCC 3 BAT BL4054 BL4054B 1 5 CHRGb PROG GND 2 1uF 500mA Li-Ion CELL 2k SHDN Basic LiLi-Ion Charger with Reverse Polarity Input Protection Using a Microprocessor to Determine CHRGb State VDD V+ 4 5V WALL ADAPTER VCC BL4054 BL4054B 1uF 2k OUT CHRGb BAT 3 500mA BL4054 BL4054B uPROCESSOR 800k VCC PROG GND 2 5 Li-Ion CELL 2k IN 800mA 800mA LiLi-Ion Charger with External Power Dissipation VIN=5V 0.25Ω 4 1uF 800mA VCC BAT 3 BL4054 BL4054B 5 PROG GND 2 1.25k PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 Li-Ion CELL www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 14 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Package Description TSOT-23-5 Surface Mount Package PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 www.belling.com.cn Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited ©2009 Belling All Rights Reserved 15 BL4054/BL4054B 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in SOT23-5/TSOT23-5 Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.889 1.295 0.035 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 0.022 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-5 Surface Mount Package PPMIC BU BL4054/BL4054B Rev 1.4 5/2009 www.belling.com.cn Belling Proprietary Information. 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