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Document overview
- Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 8
Technical content
Features
z Programmable Charge Current Up to 800mA z No MOSFET, Sense Resistor or Blocking Diode Required z Constant-Current/Constant-Voltage Operation with Thermal Protection to Maximize Charge Rate without Risk of Overheating z Charges Single Cell Li-ion Batteries Directly from USB Port z Preset 4.2V Charge Volt age with +-1% Accuracy z 20 μA Supply Current in Shutdown z 2.9V Trickle Charge Threshold z Available Without Trickle Charge z Soft-Start Limits Inrush Current z Available in 5-Lead SOT-23 Package
Applications
z Cellular Telephones, PDA, MP3 Players z Charging Docks and Cradles z Bluetooth Applications Pin Configuration Ordering/Marking Information
Ordering Information
Package: B2 = SOT-23-5L F: Lead-Free 016b*
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 2 of 8 2006/05/18 Absolute Maximum Rating (1) Parameter Symbol Value Units Input Supply Voltage V CC 8 V PROG Voltage V PROG VCC+0.3 V BAT Voltage V BAT 7 V CHRG Voltage V CHRG 10 V BAT Short-Circuit Duration — Continuous — Thermal Resistance, Junction-to-Ambient ΘJA 250 (SOT-23-5) °C/W BAT Pin Current I BAT 800 mA PROG Pin Current I PROG 800 μA Maximum Junction Temperature T J 125 °C Storage Temperature T S -65 to +125 °C Lead Temperature (Soldering, 10 sec) — 300 °C Recommended Operating Conditions (2) Parameter Symbol Value Units Supply Input Voltage V IN -0.3 to +8 V Junction Temperature T J -40 to +85 °C
Electrical Characteristics
VIN = 5V; TJ = 25°C; unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit VCC Input Supply Voltage 4.25 — 6 V Charge Mode(3), RPROG = 10k — 110 500 µA Standby Mode (Charge Terminated) — 115 160 µAICC Input Supply Current Shutdown Mode(RPROG Not Connected, VCC < VBAT, or VCC < VUV) — 20 40 µA VFLOAT Regulated Output (Float) Voltage I BAT = 30mA, ICHRG = 5mA 4.158 4.2 4.242 V RPROG = 10k, Current Mode 90 110 130 mA RPROG = 2k, Current Mode — 500 — mA Standby Mode, VBAT = 4.2V 0 +/-1 +/-5 µA Shutdown Mode (RPROG Not Connected) — +/-0.5 +/-5 µA IBAT BAT Pin Current Sleep Mode, V ITRIKL Trickle Charge Current V BAT < VTRIKL, RPROG = 10k 12 18 25 mA VTRIKL Trickle Charge Threshold Voltage R PROG = 10k, VBAT Rising 2.8 2.9 3.0 V
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 3 of 8 2006/05/18 Electrical Characteristics (Continued) VIN = 5V; TJ = 25°C; unless otherwise specified Symbol Parameter Conditions Min Typ Max Unit VUV V CC Undervoltage Lockout Threshold From V CC Low to High — 3.4 — V VUVHYS V CC Undervoltage Lockout Hysteresis — 170 — mV PROG Pin Rising — 1.25 — V VMSD Manual Shutdown Threshold Voltage PROG Pin Falling — 1.2 — V VCC from Low to High — 100 — mV VASD VCC – VBAT Lockout Threshold Voltage VCC from High to Low — 30 — mV RPROG = 10k(4) — 0.1 — mA/mAITERM C/10 Termination Current Threshold RPROG = 2k — 0.1 — mA/mA VPROG PROG Pin Voltage R PROG = 10k, Current Mode 0.9 1.03 1.1 V ICHRG CHRG Pin Weak Pull-Down Current V CHRG = 5V 8 20 40 µA VCHRG CHRG Pin Output Low Voltage I CHRG = 5mA — 0.35 0.8 V ΔVRECHRG Recharge Battery Threshold Voltage V FLOAT - VRECHRG — 100 — mV TLIM Thermal Protection Temperature — 120 — °C tSS Soft-Start Time I BAT = 0 to 1000V/RPROG — 100 — µs tRECHARGE Recharge Comparator Filter Time V BAT High to Low — 2 — ms tTERM Termination Comparator Filter Time I BAT Falling Below ICHG/10 — 1000 — µs IPROG PROG Pin Pull-Up Current — 1 — µA Note 1: Exceeding the absolute maximum rating may damage the device. Note 2: The device is not guaranteed to function outside its operating rating. Note 3: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to the battery through the BAT pin (approximately 100mA). Note 4: ITERM is expressed as a fraction of measured full charge current with indicated PROG resistor.
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 5 of 8 2006/05/18 Operation The EC49016 is a single cell lithium-ion battery charger us ing a constant-current/const ant-voltage algorithm. It can deliver up to 800mA of charge current (using a good therma l PCB layout) with a final float voltage accuracy of ±1%. The EC49016 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is r equired; thus, the basic charger circuit requires only two external components. Furthermore, the EC49016 is capable of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the VCC pin ri ses 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 2.8V, the charger enters trickle charge mode. In this mode, the EC49016 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 2.8V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin app roaches the final float voltage (4.2V), the EC49016 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. Programming Charge Current The charge current is programmed using a single resistor from the PROG pin to ground. The battery charge current is 1100 times the current out of the PROG pin. The program re sistor and the charge current are calculated using the following equations: PROG CHG CHG PROG R VII VR 1100,1100 == , The charge current out of the BAT pin can be determined at any time by moni toring the PROG pin voltage using the following equation: 1100•= PROG PROG BAT R VI 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 tTERM (typically 1ms), charging is terminated. The charge current is latched off and the EC49016 enters standby mode, where t he input supply current drops to 200mA. (Note: C/10 termination is disabled in trickle charging and thermal lim iting 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 1ms filter time (tTERM) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle term ination. Once the average charge current drops below 1/10th the programmed value, the EC49016 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 supp lied by the battery.The EC49016 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 charge r must be shut down and restarted using the PROG pin. Figure 1 shows the state diagram of a typical charge cycle.
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 6 of 8 2006/05/18 Charge Status Indicator (CHRG) The charge status output has three different stat es: strong pull-down (~10mA), weak pull-down (~20 μA) and high impedance. The strong pull-down state i ndicates that the EC49016 is in a charge cycle. Once the charge cycle has terminated, the pin state is determined by undervoltage lockout conditions. A weak pull-down indicates that VCC meets the UVLO conditions and the EC49016 is ready to c harge. High impedance indicates that the EC49016 is in undervoltage lockout mode: either VCC is less than 100mV above the BAT pin voltage or insufficient voltage is applied to the VCC pin. Thermal Limiting An internal thermal feedback loop reduces the programmed ch arge current if the die temperature attempts to rise above a preset value of approximately 120 ℃. This feature protects the EC49016 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 EC49016. The charge current can be set according to typical (not worst-case) ambient temperature with the assurance that the charger will automatically redu ce the current in worst-case conditio ns. Thin SOT power considerations are discussed further in the Applications Information section. Undervoltage Lockout (UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshol d. The UVLO circuit has a built-in hy steresis of 200mV. Furthermore, to protect against reverse current in the power MOSFET, the UV LO circuit keeps the charger in shutdown mode if VCC falls to within 30mV of the battery voltage. If the UVLO comparator is tripped, the charger will not come out of shutdown mode until VCC raises 100mV above the battery voltage. Trickle Charge Mode 1/10TH of Full Current Chrg LED: Strong Pull-Dn CC/CV Charge Mode Full Current Chrg LED: Strong Pull-Dn Standby Mode No Charge Current Chrg LED: Weak Pull-Dn Shutdown Mode ICC Drops to < 20μA Chrg: Hi-Z In UVLO WeakPull-Dn Otherwise VBAT<2.8V VBAT>2.8V VBAT>2.8V VPROG<100mV 4.05V>VBAT>2.8V Power On PROG Reconnected Or UVLO Connection Stops PROG Floated Or UVLO Connection Figure5. State Diagram of a Typical Charge Cycle
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 7 of 8 2006/05/18 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 addition al 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. The pole frequency at the PROG pin should be kept above 100kHz. 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. Power Dissipation The conditions that cause the SE9016 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) • IBAT The approximate ambient temperature at which the thermal feedback begins to protect the IC is: TA = 120°C – PDθJA TA = 120°C – (VCC – VBAT) • IBAT • θJA Thermal Considerations Because of the small size of the thin SOT23 package, it is very 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 lead, (especially the gr ound lead) to the PC board copper. The PC board copper is the heat sink. The footprint copper pads should be as wi de 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 over all temperature rise and the maximum charge current. Application Hints
Standalone Linear Lithium Battery Charger E-CMOS Corp. (www.ecmos.com.tw) Page 8 of 8 2006/05/18 OUTLINE DRAWING SOT-23-5L DIMENSIONS DIMN INCHES MM MIN MAX MIN MAX A 0.110 0.120 2.80 3.05 B 0.059 0.070 1.50 1.75 C 0.036 0.051 0.90 1.30 D 0.014 0.020 0.35 0.50 E – 0.037 – 0.95 F – 0.075 – 1.90 H – 0.006 – 0.15 J 0.0035 0.008 0.090 0.20 K 0.102 0.118 2.60 3.00 B K A F D E C H J