Preliminary Datasheet LP78090 Smart Charger With Power Path General Description Features The LP78090 is a monolithic linear battery charger whit smart power path switch for single-cell Li-ion batteries in a wide range of tablet and other portable devices. It integrates a linear regulated voltage for power the system and charging the battery at the same time. This device supports both USB and high power DC adapter input. Its charger is a complete constant-current constant voltage linear charger with adjustable charge current up to 1000mA. 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 LP78090 automatically enters a low current state, dropping the battery drain current to less than 15µA. When connecting a high power DC adapter, the smart power path management allows LP78090 power the system with VIN voltage or BAT voltage by switching the voltage level on SC pin and charge the battery simultaneously. This allows immediate system operation even under moving away or deeply discharged battery. When the input current limit is reached, the voltage applied on the SYS pin would pull down to the battery voltage making the charge current decrease. If the current out of SYS pin is more than charge current plus 1200mA, LP78090 with turn power adapter and battery support the system load together. The LP78090 provides an internal path from battery to system in the event the input is removed. 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. Marking Information Device □ □ □ F: Pb-Free Marking LP78090QVF Package Shipping QV:TDFN10 3K/REEL Applications Order Information LP78090 Programmable Charge Current Up to 1000mA Smart Power Path Management 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 15µA Leakage Current in Shutdown Charging Operation and Charge Complete Indicator Thermal Limiting Regulation on Chip Internal Soft Start Function Built-in Short-Circuit Protection Consumption Available in TDFN-10 Package RoHS Compliant and 100% Lead (Pb)-Free MID/Pad Automobile Data Recorder or Event Data Recorder Power Bank Smart Phone Bluetooth Applications Package Type QV:TDFN-10 LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 1 of 10 Preliminary Datasheet LP78090 Functional Pin Description P acka ge Type P i n Co n fi gur a ti ons TDFN-10 Pin Description PIN No. PIN DESCRIPTION 1,3 SYS Output of power supply for system. 2,5 VIN Power supply input for system and charge. BAT is the connection to the battery. Typically a 10µF Tantalum capacitor is needed for stability 4,6 BAT when there is no battery attached. When a battery is attached, only a 0.1µF ceramic capacitor is required. 7 CHRG 8 STDBY 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. Open-Drain Complete 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. Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is programmed by connecting a 1% resistor(R PROG)to ground. When charging in constant-current 9 ISET 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.LP78090: Iset=1200/RPROG. 10 SC 11 GND Smart controller. Ground pin. LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 2 of 10 Preliminary Datasheet LP78090 Application Circuit VCC C1 10uF VIN VIN R1 1K SY S SY S SY S C2 10uF D1-Red CHRG ZENER BAT BAT BAT D2-Green C3 10uF STDBY SC R2 2K LP78090 – 00 Version 1.0 Feb.-2014 GND 4.3V ISET LP78090 Email: [email protected] R3 2K www.lowpowersemi.com Page 3 of 10 Preliminary Datasheet LP78090 Function Block Diagram LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 4 of 10 Preliminary Datasheet LP78090 Absolute Maximum Ratings Input Voltage to GND (VIN) --------------------------------------------------------------------------------------- -0.3V to 6.5V V SYS -------------------------------------------------------------------------------------------------------------------------- -0.3V to 6V BAT, ISET, STAT ------------------------------------------------------------------------------------------- -0.3V to VIN+0.3V BAT Short-Circuit Duration -------------------------------------------------------------------------------------------- Continuous BAT Pin Current ------------------------------------------------------------------------------------------------------------ 1200mA 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) ---------------------------------------------------------------------------------------------------- 68℃/W LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 5 of 10 Preliminary Datasheet LP78090 Electrical Characteristics (The specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN1/2=BVIN = 5V, unless otherwise noted.) SYMBOL PARAMETER CONDITIONS MIN TYP. MAX UNITS 3.9 5 5.5 V Charge Mode, RISET = 10k 330 2000 Standby Mode (Charge Terminated) 230 500 40 60 Charge VIN IQ Adapter/USB Voltage Range Input Supply Current Shutdown Mode (RISET Not Connected, VIN < VBAT, or VIN < VUV and SC=0V) VFLOAT IBAT Regulated Output (Float) Voltage Current Input to Battery 0°C ≤ TA ≤ 85°C, IBAT = 40mA 4.158 4.2 4.242 RISET = 1.2k, Current Mode 800 1000 1200 RISET = 2k, Current Mode 500 600 700 Standby Mode, VBAT = 4.2V Shutdown Mode V mA -2.5 -6 ±1 ±2 ±1 ±2 1100 1250 1400 mA 100 120 mA 2.9 3.0 (RISET Not Connected) 0 Sleep Mode, VIN = 0V uA ISYS Current Limit ITRIKL Trickle Charge Current VBAT < V TRIKL, R ISET = 1.2k 80 VTRIKL Trickle Charge Threshold Voltage RISET = 10k, VBAT Rising 2.8 VTRHYS Trickle Charge Hysteresis Voltage RISET = 10k 120 mV VIN From Low to High 3.9 V VUV VUVHYS VMSD VASD form BAT or VIN to SYS uA VIN Under voltage Lockout Threshold for Charge VIN Under voltage Lockout Hysteresis for 150 200 VIN from Low to High 70 300 mV 100 140 mV VIN from High to Low 5 30 50 mV RISET = 10k, ITERM / ICharge 0.085 0.10 0.115 mA/mA RISET = 2k, ITERM / ICharge 0.085 0.10 0.115 mA/mA Charge Manual Shutdown Charge Threshold Voltage ISET Pin Falling VIN – VBAT Lockout Threshold Voltage ITERM C/10 Charge Termination Current Threshold VSET ISET Pin Voltage RISET = 10k, Current Mode V STAT CHRG、STDBY Pin Output Low Voltage ISTAT = 5mA VRESTAT Recharge Battery Voltage ΔVRESTAT RON R DS(ON) VFLOAT - VRESTAT 100 Path Switch NMOS R DS(ON) Logic-Low Voltage VSCH Logic-High Voltage V 150 200 mV 300 mΩ V mΩ 0.4 1 4.3V＜VIN Voltage on SYS pin V 0.6 130 VIN=VSC=5V ISC V 2 0.35 Power FET “ON” Resistance (Between VIN and BAT) VSCL VSYS 2.2 4.05 Recharge Battery Threshold Voltage V V V -1 1 uA VIN VIN=FLOAT VBAT VIN < 4.3V VBAT V TLT Thermal Limit Temperature 120 ℃ TSD Thermal Shutdown 150 ℃ Charge Characteristics LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 6 of 10 Preliminary Datasheet LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com LP78090 Page 7 of 10 Preliminary Datasheet LP78090 Application Information The LP78090 is a linear switching charger IC with smart power Normal Charge Cycle path management integrated for powering the system and A charge cycle begins when the voltage at the VIN pin rises charging a single cell lithium-ion battery simultaneously. It can above the UVLO threshold level and a 1% ISET ram resistor is deliver up to 1000mA of charge current (using a good thermal connected from the ISET pin to ground or when a battery is PCB layout) with a final float voltage accuracy of ±1%. The connected to the charger output. If the BAT pin is less than 2.9V, LP78090 includes an internal P-channel power MOSFET and the charger enters trickle charge mode. In this mode, the thermal regulation circuitry. No blocking diode or external LP78090 supplies approximately 1/10 the ISET rammed charge current sense resistor is required; thus, the basic application current to bring the battery voltage up to a safe level for full circuit requires only four external components. Furthermore, the current charging. LP78090 is capable of operating from a USB power source， When the BAT pin voltage rises above 2.9V, the charger enters 500mA for USB 2.0 and 850mA for USB3.0 with resistor change constant-current mode, where the ISET rammed charge current on ISET pin. is supplied to the battery. When the BAT pin approaches the It has precious average input current limit and average current final float voltage (4.2V), the LP78090 enters constant-voltage limit form battery to system, to make maximum use of the mode and the charge current begins to decrease. When the allowable input power. And LP78090 would give priority to charge current drops to 1/10 of the ISET rammed value, the ensuring the system load approximately up to 2.4A, which charge cycle ends. contains 1.2A form VIN and 1.2A form battery. LP78090 will reduce charging current or even power from battery to satisfy the system load when its demand is over the input current limit. In low system load situation, the remaining current is supply for charger programmed by an external resistor connected from ISET pin to GND. The device would reduce the charge current when the die temperature exceeds 120℃. 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 500 times the current out of the ISET pin. The ISET ram resistor and the charge current are calculated using the following equations: LP78090: RSET=1200V/ICHG，ICHG= 1200V/RSET Two 130mΩ MOSFET integrated work as an ideal diode to connecting the battery and VIN to the system load, and one of this two MOSFET will turn on allowing the battery to power up the system when the input is removed with circuit in page 3. The charge current out of the BAT pin can be determined at any time by monitoring the ISET pin voltage using the following equation: SYS Pin Voltage Switch IBAT= VSET x 600/RSET The voltage on the SYS pin is set by the SC voltage, VIN Note: Vset is 2Volts. voltage and battery voltage. VIN<4.3V condition, voltage power for system always keeps with battery voltage. 4.3V < VIN condition, voltage power for system always keeps with VIN voltage Charge Termination 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 Current Limit value. The 1ms filter time (tTERM) on the termination comparator The current limit regulate in two directions: from VIN to system ensures that transient loads of this nature do not result in and from battery to system, each one is limited to 1.2A. When premature charge cycle termination. Once the average charge the system load needs the current above 1.2A, LP78090 would current drops below 1/10th the ISET rammed value, the divert part of charge current to system. And the device would LP78090 terminates the charge cycle and ceases to provide power system from VIN and battery when the system current is any current through the BAT pin. In this state, all loads on the more than charge current plus 1.2A. BAT pin must be supplied by the battery. LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 8 of 10 Preliminary Datasheet LP78090 The LP78090 constantly monitors the BAT pin voltage in Thermal Limiting standby mode. If this voltage drops below the 4.05V recharge An internal thermal feedback loop reduces the ISET rammed threshold (VRESTAT), another charge cycle begins and current is charge current if the die temperature attempts to rise above a once again supplied to the battery. To manually restart a charge preset value of approximately 120°C. This feature protects the cycle when in standby mode, the input voltage must be LP78090 from excessive temperature and allows the user to removed and reapplied, or the charger must be shut down and push the limits of the power handling capability of a given circuit restarted using the ISET pin. Figure 2 shows the state diagram board without risk of damaging the LP78090. The charge of a typical charge cycle. current can be set according to typical (not worst-case) ambient temperature with Charge Status Indicator the assurance that the charger will automatically reduce the current in worst-case conditions. The charge status output has two different states: strong pull-down (~10mA) and high impedance. The strong pull-down state indicates that the LP78090 is in a charge cycle. Once the TDFN power considerations are discussed further in the Applications Information section. charge cycle has terminated, the pin state is determined by Automatic Recharge under voltage lockout conditions. High impedance indicates that Once the charge cycle is terminated, the LP78090 continuously the LP78090 is in under voltage lockout mode: either VIN is less monitors the voltage on the BAT pin using a comparator with a than 100mV above the BAT pin voltage or insufficient voltage is 2ms filter time (tRECHARGE). A charge cycle restarts when the applied to the VIN pin. battery voltage falls below 4.05V (which corresponds to A microprocessor can be used to distinguish between these two states—this method is discussed in the Applications Information section. 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 Function CHRG(pin8) STDBY(pin7) Charging Low High charge completed High Low LP78090 – 00 Version 1.0 Feb.-2014 output enters a strong pull-down state during recharge cycles. Email: [email protected] www.lowpowersemi.com Page 9 of 10 Preliminary Datasheet LP78090 Packaging Information TDFN-10 LP78090 – 00 Version 1.0 Feb.-2014 Email: [email protected] www.lowpowersemi.com Page 10 of 10