Preliminary Datasheet LP28019 10V/1.2A Single-chip Li-ion and Li-POL Charge General Description Features The LP28019 is a complete constant-current/ constantvoltage linear charger for single cell lithium-ion batteries. Its TDFN-10 package and low external component count make the LP28019 ideally suited for portable applications. Furthermore, the LP28019 is specifically designed to work within USB power specifications. Its have a over voltage protection in input with 6.5V and support over zero voltages of battery can charge enable. No external sense 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 ISET rammed externally with a single resistor. The LP28019 automatically terminates the charge cycle when the charge current drops to 1/10th the ISET rammed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the LP28019 automatically enters a low current state, dropping the battery drain current to less than 2µA. The LP28019 can be put into shutdown mode, reducing the supply current to 25µA. Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. z Very Low Power Dissipation z Vin Over Voltage Protection:6.5V z Short-circuit protection z Programmable Charge Current Up to 1500mA z No MOSFET, Sense Resistor or Blocking Diode Required z Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charge Rate Without Risk of Overheating z Charges Single Cell Li-Ion Batteries Directly from USB Port z 25µA Supply Current in Shutdown z Time Pre-charge Conditioning With Safety Timer Reverse Leakage Protection Prevents Battery z Drainage Charge Current Thermal Regulation Status Outputs for LED or System Interface z Indicates Charge and Fault Conditions z Optional Battery Temperature Monitoring Before and During Charge Automatic Sleep Mode for Low-Power z Consumption Available in SOP-8P Package z RoHS Compliant and 100% Lead (Pb)-Free Typical Application Circuit VIN Order Information 1 RED LP28019 □ □ □ F: Pb-Free 10uF 2 4 9 Package Type SP: ESOP-8(P) SO:SOP-8 ACIN BATT CHRG_S GND NC ISETA 8 7 5 GND LP28019SPF ISet=1000/Rset Applications Portable Media Players/MP3 players Cellular and Smart mobile phone PDA/DSC Marking Information Please see website. Bluetooth Applications LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com Page 1 of 9 10uF BATTERY Preliminary Datasheet LP28019 Functional Pin Description P a c k a g e Ty p e Pin Configurations ACIN 1 8 BATT 7 NC 6 NC 5 ISETA LP28019 SOP-8(P) CHG_S 2 NC 3 GND 4 9 PGND Pi n Desc ript ion PIN PIN Number VIN 1 STAT 2 NC 3,6,7 VSS/PGND 4,9 DESCRIPTION VIN is the input power source. Connect to a wall adapter. Open-Drain Charge Status Output. When the battery is charging, the STAT pin is pulled low by an internal N-channel MOSFET. When the charge cycle is completed, the pin is pulled High. No connector. VSS is the connection to system ground. Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is programmed by connecting a 1% resistor(RPROG)to ground. When charging in constant-current ISET 5 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 BATT 8 VBAT is the connection to the battery. Typically a 1µF Tantalum capacitor is needed for stability when there is no battery attached. When a battery is attached, only a 0.1µF ceramic capacitor is required. LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com Page 2 of 9 Preliminary Datasheet LP28019 Function Block Diagram VIN VSS ISET STAT LP28019 Absolute Maximum Ratings Input Voltage to GND (VIN) ----------------------------------------------------------------------------- 2.6V to 10V BAT, ISET, STAT (VX) ---------------------------------------------------------------------- 0.3V to VIN+0.3V BAT Short-Circuit Duration ---------------------------------------------------------------------------- Continuous BAT Pin Current ------------------------------------------------------------------------------------------ 1500mA Maximum Junction Temperature ---------------------------------------------------------------------------- 125°C Operating Junction Temperature Range (TJ) ----------------------------------------------------- -40℃ to 85°C Maximum Soldering Temperature (at leads, 10 sec) ------------------------------------------------------ 260°C Thermal Information Maximum Power Dissipation (PD,TA<40°C) -------------------------------------------------------------- 1.5W Thermal Resistance (JA) --------------------------------------------------------------------------------- 46℃/W LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com Page 3 of 9 Preliminary Datasheet LP28019 Electrical Characteristics (The specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted.) SYMBOL VIN ICC VFLOAT PARAMETER CONDITIONS Adapter/USB Voltage Range Input Supply Current Regulated Output (Float) Voltage MIN 2.65 Charge Mode (Note 4), RISET = 10k Standby Mode (Charge Terminated) Shutdown Mode (RISET Not Connected, VCC < VBAT, or VCC < VUV) 0°C ≤ TA ≤ 85°C, IBAT = 40mA 4.158 RISET = 1k, Current Mode RISET = 2k, Current Mode IBAT BAT Pin Current Standby Mode, VBAT = 4.2V Shutdown Mode (RISET Not Connected) Sleep Mode, VCC = 0V ITRIKL Trickle Charge Current VBAT < VTRIKL, RISET = 2k (Note 5) VTRIKL Trickle Charge Threshold Voltage RISET = 10k, VBAT Rising (Note 5) VTRHYS Trickle Charge Hysteresis Voltage RISET = 10k (Note 5) VUV VUVHYS VMSD VASD ITERM VISET ISTAT VSTAT ΔVRESTAT TLIM RON tSS IISET VIN OVP VCC Undervoltage Lockout Threshold From VCC Low to High VCC Undervoltage Lockout Hysteresis Manual Shutdown Threshold Voltage VCC – VBAT Lockout Threshold Voltage ISET Pin Rising ISET Pin Falling VCC from Low to High VCC from High to Low RISET = 10k (Note 6) C/10 Termination Current Threshold RISET = 2k ISET Pin Voltage STAT Pin Weak Pull-Down Current RISET = 10k, Current Mode VSTAT = 5V STAT Pin Output Low Voltage ISTAT = 5mA Recharge Battery Threshold Voltage VFLOAT - VRESTAT 0 2.8 60 3.7 150 1.15 0.9 70 5 0.085 0.085 0.9 8 100 Junction Temperature in Constant Temperature Mode Power FET “ON” Resistance (Between VCC and BAT) Soft-Start Time IBAT = 0 to IBAT =850V/RISET ISET Pin Pull-Up Current 5.9 Over voltage protection LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com TYP. 5 MAX UNITS 7 V 300 2000 200 500 25 50 4.2 4.242 1000 50 -2.5 -6 ±1 ±2 ±1 ±2 50 2.9 3.0 80 110 3.8 3.95 200 300 1.21 1.30 1.0 1.1 100 140 30 50 0.10 0.115 0.10 0.115 1.0 1.1 20 35 0.35 0.6 150 200 120 600 100 3 6.2 6.5 Page 4 of 9 uA V mA uA mA V mV V mV V V mV mV mA/mA mA/mA V uA V mV °C mΩ uS uA V Preliminary Datasheet LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com LP28019 Page 5 of 9 Preliminary Datasheet LP28019 Typical Operating Characteristics LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com Page 6 of 9 Preliminary Datasheet LP28019 Operation The LP28019 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 1200mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The LP28019 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 LP28019 is capable of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the VCC pin rises above the UVLO threshold level and a 1% ISET ram resistor is connected from the ISET 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 LP28019 supplies approximately 1/10 the ISET rammed charge current to bring the battery voltage up to a safe level for full current charging. (Note: The LP28019X does not include this trickle charge feature). When the BAT pin voltage rises above 2.9V, the charger enters constant-current mode, where the ISET rammed charge current is supplied to the battery. When the BAT pin approaches the final float voltage (4.2V), the LP28019 enters constant-voltage mode and the charge current begins to decrease. When the charge current drops to 1/10 of the ISET rammed value, the charge cycle ends. ISET ramming Charge Current The charge current is ISET rammed using a single resistor from the ISET pin to ground. The battery charge current is 1000 times the current out of the ISET pin. The ISET ram resistor and the charge current are calculated using the following equations: RSET=1000V/ICHG，ICHG= 1000V/RSET The charge current out of the BAT pin can be determined at any time by monitoring the ISET pin voltage using the following equation: IBAT= VSET x 1000/RSET Charge Termination A charge cycle is terminated when the charge current falls to 1/10th the ISET rammed value after the final float voltage is reached. This condition is detected by using an internal, filtered comparator to monitor the ISET pin. When 1 the ISET pin voltage falls below 100mV for longer than tTERM (typically 1ms), charging is terminated. The charge LP28019 – 000 Version 1.0 Datasheet FEB.-2012 current is latched off and the LP28019 enters standby mode, where the input supply current drops to 200µA. (Note: C/10 termination is disabled in trickle charging and thermal limiting modes). When charging, transient loads on the BAT pin can cause the ISET pin to fall below 100mV for short periods of time before the DC charge current has dropped to 1/10th the ISET rammed 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 1/10th the ISET rammed value, the LP28019 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 LP28019 constantly monitors the BAT pin voltage in standby mode. If this voltage drops below the 4.05V recharge threshold (VRESTAT), 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 ISET pin. Figure 1 shows the state diagram of a typical charge cycle. Charge Status Indicator (STAT) The charge status output has three different states: strong pull-down (~10mA), weak pull-down (~20µA) and high impedance. The strong pull-down state indicates that the LP28019 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 LP28019 is ready to charge. High impedance indicates that the LP28019 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. A microprocessor can be used to distinguish between these three states—this method is discussed in the Applications Information section. Thermal Limiting An internal thermal feedback loop reduces the ISET rammed charge current if the die temperature attempts to rise above a preset value of approximately 120°C. This feature protects the LP28019 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 LP28019. The charge current can be set according to typical (not worst-case) ambient temperature with the www.lowpowersemi.com Page 7 of 9 Preliminary Datasheet assurance that the charger will automatically reduce the current in worst-case conditions. TDFN power considerations are discussed further in the Applications Information section. Undervoltage Lockout (UVLO) LP28019 Where PD is the total power dissipated within the IC, ADP is the input supply voltage, VBAT is the battery voltage, IBAT is the charge current and PD_BUCK is the power dissipation due to the regulator. PD_BUCK can be calculated as: An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of 200mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO 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 rises 100mV above the battery voltage. Where VOUTB is the regulated output of the switching regulator, IOUTB is the regulator load and is the regulator efficiency at that particular load. It is not necessary to perform worst-case power dissipation scenarios because the LP28019 will automatically reduce the charge current to maintain the die temperature at approximately 125°C. However, the approximate ambient temperature at which the thermal feedback begins to rotect the IC is: Manual Shutdown At any point in the charge cycle, the LP28019 can be put into shutdown mode by removing RISET thus floating the ISET 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 ISETram resistor. In manual shutdown, the STAT pin is in a weak pull-down state as long as VCC is high enough to exceed the UVLO conditions. The STAT pin is in a high impedance state if the LP28019 is in undervoltage lockout mode: either VCC is within 100mV of the BAT pin voltage or insufficient voltage is applied to the VCC pin. Automatic Recharge Once the charge cycle is terminated, the LP28019 continuously monitors the voltage on the BAT pin using a comparator with a 2ms filter time (tRECHARGE). 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. STAT output enters a strong pull-down state during recharge cycles. Example: Consider the extreme case when an LP28019 is operating from a 6V supply providing 250mA to a 3V Li-Ion battery, the switching regulator and the LDO are off. The ambient temperature above which the LP28019 will begin to reduce the 250mA charge current is approximately: (Correctly soldered to a 2500mm2 double-sided 1 oz. copper board, the LP28019 has a thermal resistance of approximately 43°C/W.) T= If there is more power dissipation due to the switching regulator or the LDO, the thermal regulation will kick in at a somewhat lower temperature than this. In the above circumstances, the LP28019 can be used above 82.75°C, but the charge current will be reduced from 250mA. The approximate current at a given ambient temperature can be calculated: o o o Power Dissipation The conditions that cause the LP28019 battery charger to reduce charge current through thermal feedback can be approximated by considering the total power dissipated in the IC. For high charge currents, the LP28019 power dissipation is approximately: LP28019 – 000 Version 1.0 Datasheet FEB.-2012 Note: 1V = 1J/C = 1W/A Furthermore, the voltage at the ISET pin will change proportionally with the charge current as discussed in the ISET ramming Charge Current section. www.lowpowersemi.com Page 8 of 9 Preliminary Datasheet LP28019 Packaging Information LP28019 – 000 Version 1.0 Datasheet FEB.-2012 www.lowpowersemi.com Page 9 of 9