Preliminary Datasheet LP78071 1A Charge+ 1.5A Synchronous Boost PMIC General Description Features The LP78071 is a PMIC，which has 1ch Charger and 1ch Synchronous Boost Converter with ESOP-8 and TDFN10 package. Charger: Programmable Charge Current Up to 1000mA No MOSFET, Sense Resistor or Blocking Diode Required Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charge Rate Without Risk of Overheating Charges Single Cell Li-Ion Batteries Directly from USB Port 8µA Supply Current in Shutdown Drainage Charge Current Thermal Regulation Status Outputs for LED or System Interface Boost: 1.5A Output Current Synchronous Boost Converter 600KHz fixed frequency switching High Switch On Current: 3A Low RDS(ON) Integrated Power Mosfet Efficiency is 94% Built-in OVP, OTP, OCP, Soft-Star Consumption Available in ESOP-8 Package RoHS Compliant and 100% Lead (Pb)-Free Its charger is a complete constant-current constant voltage linear charger for single cell lithium-ion batteries. Furthermore, the LP78071 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 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 charger 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 LP78071 automatically enters a low current state, dropping the battery drain current to less than 4µA. 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. Boost converter is Synchronous current mode boost DC-DC converter. Its PWM circuitry with built-in 3A Current power MOSFET makes this converter highly power efficiently. Selectable high switching frequency allows faster loop response and easy filtering with a low noise output. The non-inverting input and its error amplifier is connected to an internal 800mV precision reference voltage. Order Information LP78071 □ □ □ F: Pb-Free Package Type SP: ESOP-8 Marking Information Device Marking Package Shipping LP78071SPF SP:ESOP-8 3K/REEL LP78071QVF QV:TDFN10 Applications MID/Pad Power Bank Smart Phone Bluetooth Applications QV:TDFN-10 LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 1 of 16 Preliminary Datasheet LP78071 Functional Pin Description Pack ag e Typ e Pin C o n f ig u rat io n s ESOP-8 FB 1 8 EN LX 2 7 VOUT CHRG_B 3 6 BAT ISET 4 5 VIN GND 9 FB 1 LX 2 CHRG_B 3 TDFN-10 10 EN CE 4 GND 11 ISET 5 LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] 9 VOUT 8 BAT 7 VIN 6 GND www.lowpowersemi.com Page 2 of 16 Preliminary Datasheet LP78071 Pin Description TDFN-10 ESOP8 PIN 1 1 FB DESCRIPTION Boost Feedback pin. The pin voltage is 0.8V. Boost Output switching node. SW is the drain of the internal low-side N-Channel MOSFET 2 2 LX and high-side P-Channel MOSFET. Connect the inductor to SW to Complete the step-up converter. Open-Drain Charge Status Output. When the battery is charging, the STAT pin is pulled low 3 3 CHRG_B by an internal N-channel MOSFET. When the charge cycle is completed, the pin is pulled High. 4 CE Charge enable pin. Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is 5 4 ISET programmed by connecting a 1% resistor(RPROG)to ground. When charging in constant-current mode, this pin servos to 2V. In all modes, the voltage on this pin can be used to measure the charge current using the following formula.LP78071: Iset=1000/Rprog. 6,11 9 GND 7 5 Vin Ground Pin. VIN is the input power source. Connect to a wall adapter. BAT is the connection to the battery. Typically a 10µF Tantalum capacitor is needed for 8 6 BAT stability when there is no battery attached. When a battery is attached, only a 0.1µF ceramic capacitor is required. 9 7 VOUT 10 8 EN LP78071 – 00 Version 1.0 Open-Drain Charge Status Output. When the battery is charging, the STAT pin is pulled High by an internal N-channel MOSFET. When the charge cycle is completed, the pin is pulled Low. Boost enable pin. Active High. Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 3 of 16 Preliminary Datasheet LP78071 Application Circuit Vin 5 VIN BAT 6 10uF 10uF 1K 10uF 3 ON OFF CHRG_B LX Vout 8 4 9 1K 2 7 Vout 10uF EN 68K ISET GND FB 1 13K ESOP-8 Vin 7 VIN BAT 8 10uF 10uF 1K 10uF 3 ON OFF 4 10 5 6 1K LX 2 CHRG_B CE Vout 9 Vout 10uF EN 68K ISET GND FB 1 13K TDFN-10 LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 4 of 16 Preliminary Datasheet LP78071 Function Block Diagram ESOP-8: LX 2 EN 8 SLOPE COMPENSATION EN CURRENT SENSE INTERNAL COMPENSATION FB 1 CURRENT LIMIT REF + + CONTROL LOGIC ZCD OSC VHIGH BODY AND VHIGH SELECT VIN 7 VOUT 5 145℃ TDIE TA VCC 1X 1200X - 6 BAT 5μA + MA R1 VA CA - + SHDN C1 - + - R2 REF 1.22V + R3 1V R4 C2 CHRG_B 3 C3 + 0.1V - R5 + - TO BAT Version 1.0 Feb.-2014 VCC 2.9V 24 LP78071 – 00 3μA ISET Email: [email protected] GND 9 www.lowpowersemi.com Page 5 of 16 Preliminary Datasheet LP78071 TDFN-10: LX 2 EN 10 SLOPE COMPENSATION EN CURRENT SENSE INTERNAL COMPENSATION FB 1 CURRENT LIMIT REF + + CONTROL LOGIC ZCD OSC VHIGH BODY AND VHIGH SELECT VIN 9 OUT 7 145℃ TDIE TA VCC 1X 1200X - 8 BAT 5μA + MA R1 VA CA - + CE 4 + - R2 SCHMITT SHDN C1 - REF 1.22V + R3 1V R4 C2 CHRG_B 3 C3 + 0.1V - R5 + - TO BAT Version 1.0 Feb.-2014 VCC 2.9V 25 LP78071 – 00 3μA ISET Email: [email protected] GND 6 www.lowpowersemi.com Page 6 of 16 Preliminary Datasheet LP78071 Absolute Maximum Ratings Input Voltage to GND (VIN) ---------------------------------------------------------------------------------------- -0.3V to 6.5V VOUT--------------------------------------------------------------------------------------------------------------------- -0.3V to 6V BAT, ISET, STAT (VX) ------------------------------------------------------------------------------------------0.3V to VIN+0.3V BAT Short-Circuit Duration -------------------------------------------------------------------------------------------- Continuous BAT Pin Current ------------------------------------------------------------------------------------------------------------ 2000mA 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) ---------------------------------------------------------------------------------------------------- 48℃/W LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 7 of 16 Preliminary Datasheet LP78071 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 PARAMETER CONDITIONS MIN TYP. MAX UNITS V Charge VIN ICC Adapter/USB Voltage Range 2.65 Input Supply Current 5 6 Charge Mode, RISET = 10k 300 2000 Standby Mode (Charge Terminated) 200 500 25 50 4.2 4.242 Shutdown Mode (RISET Not Connected, VCC < VBAT, or VCC < VUV) VFLOAT IBAT Regulated Output (Float) Voltage BAT Pin Current 0°C ≤ TA ≤ 85°C, IBAT = 40mA 4.158 RISET = 1k, Current Mode 1000 RISET = 2k, Current Mode 500 Standby Mode, VBAT = 4.2V Shutdown -6 ±1 ±2 Sleep Mode, VCC = 0V ±1 ±2 50 ITRIKL Trickle Charge Current VBAT < VTRIKL, RISET = 2k VTRIKL Trickle Charge Threshold Voltage RISET = 10k, VBAT Rising VTRHYS Trickle Charge Hysteresis Voltage RISET = 10k VUV VCC Under voltage Lockout Threshold From VCC Low to High VUVHYS VCC Under voltage Lockout Hysteresis VMSD VASD ITERM VISET VSTAT ΔVRESTAT Manual Shutdown Threshold Voltage VCC – VBAT Lockout Threshold Voltage C/10 Termination Current Threshold 0 2.8 2.9 3.0 V mV 3.9 200 uA mA 120 150 V mA -2.5 Mode (RISET Not Connected) uA V 300 mV ISET Pin Rising 2 V ISET Pin Falling 2.2 V VCC from Low to High 70 100 140 mV VCC from High to Low 5 30 50 mV RISET = 10k 0.085 0.10 0.115 mA/mA RISET = 2k 0.085 0.10 0.115 mA/mA ISET Pin Voltage RISET = 10k, Current Mode STAT Pin Output Low Voltage ISTAT = 5mA Recharge Battery Threshold Voltage VFLOAT - VRESTAT 2 100 V 0.35 0.6 V 150 200 mV TLIM Junction Temperature in Constant Temperature Mode 145 °C RON Power FET “ON” Resistance (Between VCC and BAT) 300 mΩ 5.5 V Boost(VBAT=3.5V, Vout=5V, TA=25℃) Vout Output Voltage Range 0.9 UVLO Icc VFB=0.6V,Switch on Supply Current VFB=0.9V,Shutdown Vfb Rds(on) 1.9 V 300 uA 1 0.784 0.8V uA 0.816 V High-Side P-mosfet 100 mΩ Low-Side N-mosfet 60 mΩ Fosc 600 KHz Duty 90 % VENL 0.4 VENH 1.5 V V ILimit Maximum current through SW pin 3 A VOVP Output Pin OVP Threshold Voltage 6 V LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 8 of 16 Preliminary Datasheet LP78071 Typical Operating Characteristics Turn On Through EN VOUT=5V/10mA VOUT=5V/100mA VOUT=5V/500mA VOUT=5V/1A LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 9 of 16 Preliminary Datasheet LP78071 Charge Characteristics LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 10 of 16 Preliminary Datasheet LP78071 Application Information The LP78071 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 1000mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The LP78071 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 LP78071 is capable of operating from a USB power source. 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 the ISET pin voltage falls below 100mV for longer than t TERM (typically 1ms), charging is terminated. The charge current is latched off and the LP78071 enters standby mode, where the input supply current drops to 200µA. (Note: C/10 termination is disabled in trickle charging and thermal limiting modes). Normal Charge Cycle A charge cycle begins when the voltage at the V CC 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 LP78071 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 LP78071 does not include this trickle charge feature). When charging, transient loads on the BAT pin can cause the ISET pin to fall below 200mV 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 LP78071 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. 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 LP78071 enters constant-voltage The LP78071 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 mode and the charge current begins to decrease. When the once again supplied to the battery. To manually restart a charge charge current drops to 1/10 of the ISET rammed value, the cycle when in standby mode, the input voltage must be charge cycle ends. removed and reapplied, or the charger must be shut down and restarted using the ISET pin. Figure 2 shows the state diagram of a typical charge cycle. 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 600 times Charge Status Indicator (STAT) the current out of the ISET pin. The ISET ram resistor and the The charge status output has two different states: strong charge current are calculated using the following equations: pull-down (~10mA) and high impedance. The strong pull-down LP78071: state indicates that the LP78071 is in a charge cycle. Once the RSET=1000V/ICHG，ICHG= 1000V/RSET charge cycle has terminated, the pin state is determined by under voltage lockout conditions. High impedance indicates that The charge current out of the BAT pin can be determined at any the LP78071 is in under voltage lockout mode: either V CC is less time by monitoring the ISET pin voltage using the following than 100mV above the BAT pin voltage or insufficient voltage is equation: applied to the VCC pin. IBAT= VSET x 500/RSET Note: Vset is 2Volts. LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 11 of 16 Preliminary Datasheet A microprocessor can be used to distinguish between these two states—this method is discussed in the Applications Information section. LP78071 Boost Output voltage Setting Set the output voltage by selecting the resistive voltage divider ratio. The voltage divider drops the output voltage to the 0.8V Function CHRG_B(pin3) Voltage Charging Low 0.3V feedback voltage. Use a 100K resistor for R1 of the voltage divider. Determine the high-side resistor R2 by the equation: Vout=(R2/R1+1) x VFB Thermal Limiting Vout=(R2/R1+1) x 0.8V An internal thermal feedback loop reduces the ISET rammed charge current if the die temperature attempts to rise above a Table: preset value of approximately 120°C. This feature protects the Vout R1 R2 C3 LP78071 from excessive temperature and allows the user to 3.3V 100K 312.5K 22pF push the limits of the power handling capability of a given circuit 5V 100K 525V 22pF board without risk of damaging the LP78071. The charge current can be set according to typical (not worst-case) ambient temperature with the assurance that the charger will Power Dissipation automatically reduce the current in worst-case conditions. The conditions that cause the LP78071 battery charger to ESOP power considerations are discussed further in the reduce charge current through thermal feedback can be Applications Information section. approximated by considering the total power dissipated in the IC. For high charge currents, the LP78071 power dissipation is approximately: Automatic Recharge Once the charge cycle is terminated, the LP78071 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. Where PD is the total power dissipated within the IC, ADP is the input supply voltage, V BAT is the battery voltage, I BAT is the charge current and P D_BUCK is the power dissipation due to the regulator. P D_BUCK can be calculated as: Boost Under voltage Lockout (UVLO) An internal under voltage lockout circuit monitors the input voltage is 1.9V and keeps the charger in shutdown mode until VCC rises above the under voltage 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 V CC falls to 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 LP78071 will automatically reduce the charge current to maintain the die temperature at within 30mV of the battery voltage. If the UVLO comparator is approximately 125°C. However, the approximate ambient tripped, the charger will not come out of shutdown mode until temperature at which the thermal feedback begins to protect VCC rises 100mV above the battery voltage. the IC is: LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 12 of 16 Preliminary Datasheet LP78071 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 LP78071 can be used above 82.75°C, but Example: Consider the extreme case when an LP78071 is the charge current will be reduced from 250mA. The operating from a 6V supply providing 250mA to a 3V Li -Ion approximate current at a given ambient temperature can be battery, the switching regulator and the LDO are off. The ambient temperature above which the LP78071 will begin to reduce the 250mA charge current is approximately: (Correctly soldered to a 2500mm 2 double-sided 1 oz. calculated: copper board, the LP78071 has a thermal resistance of approximately 43°C/W.) Note: 1V = 1J/C = 1W/A Furthermore, the voltage at the ISET pin will change proportionally with the charge current as discussed in the T= ISET ramming Charge Current section. LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 13 of 16 Preliminary Datasheet LP78071 PCB Layout Considerations It is important to pay special attention to the PCB layout. The following provides some guidelines: • To obtain optimal performance, the decoupling capacitor from Vin to GND and the output filter capacitors from OUT to GND should be placed as close as possible to the LP78071, with short trace runs to GND pins. • All low-current GND connections should be kept separate from the high-current charge or discharge paths from the battery. Use a single-point ground technique incorporating both the small-signal ground path and the power ground path. • The high-current charge paths into IN and from the OUT pins must be sized appropriately for the maximum charge current in order to avoid voltage drops in these traces. LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 14 of 16 Preliminary Datasheet LP78071 Packaging Information ESOP-8 LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 15 of 16 Preliminary Datasheet LP78071 TDFN-10 LP78071 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 16 of 16