Preliminary Datasheet LP28400 3A/15V Synchronous Switching Mode 1/2cell Li-ion Chargers With Power Path Selector General Description Features The LP28400 is a complete constant-current/ constant- voltage Switch mode charger for 1cell or 2cell lithium-ion batteries. 1.5MHz Synchronous Switching Charger with 3A Integrated MOSFETs. No external blocking diodes is required. The Switch mode charger uses a high switching frequency to reduce power dissipation during charging eliminate heat and allow tiny external components. It can operate from a single input that accepts. All power switches for charging and switching the load between battery and external power are included on-chip that can be embedded in a wide range of handheld applications, Built-in power path controller, easily installation with external MOSFETs, Dynamic power management, better thermal performance. The LP28400 includes complete charge termination circuitry, automatic recharge and a ±1% output voltage. Fault condition protection includes cycle -by -cycle current limiting and thermal shutdown. Other safety features include battery temperature monitoring, charge status indication and programmable timer to cease the charging cycle. The LP28400 is available in a low profile (0.75mm) 10-lead (4mm × 4mm) TDFN package. □ □ Up to 95% efficiency 4.5-15V Operating voltage(Vin) Vin Over Voltage Protection:6.8V/16.5V Short-circuit protection Programmable Charge Current Up to 3000mA Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charge Rate Without Risk of Overheating Charges 1Cell and 2cell Li-Ion Batteries Directly with same chip, Chargers with power path selector Internal Fixed 7Hrs timer Drainage Charge Current Thermal Regulation Status Outputs for LED or System Interface Indicates Charge and Fault Conditions Optional Battery Temperature Monitoring Before and During Charge Automatic Sleep Mode for Low-Power Consumption Available in 4mm × 4mm TQFN-20 Package RoHS Compliant and 100% Lead (Pb)-Free Marking Information Order Information LP28400 □ □ □ F: Pb-Free Package Type Device Marking Package LP28400 LPS QV: TQFN-20 LP28400 QV: TQFN-20 Output voltage Shipping XXXXX X: Batch numbers. Default: 4.2V/8.4V Applications LP28400-00 Version 1.0 May.-2013 Portable Media Players Cellular and Smart mobile phone Car GPS Handheld Battery-Powered Devices Handheld Computers Charging Docks and Cradles Email: [email protected] www.lowpowersemi.com Page 1 of 17 Preliminary Datasheet LP28400 Typical Application Circuit VIN SW SS34 15,16,19,20 2.2uH PVCC/ACP/ACN 22uF BS 22uF 3 13,14 SRP 20mR BATTERY 0.1u 17 22uF 10 AVCC 10R 1uF SRN LP28400 4 1uF 10K VREF CELL 10K 6 1.5K 5 8 ISET REGN 1CELL CELL 7 12 2CELL TS STAT 1uF 10K 10K 9 GND/PGND Figure1. Application Without Power Path Selector LP9006 VIN 20mR LP9006 22uF SYS 10uF 22uF 10R 22uF 0.1uF 0R 1K LP9007 4K AVCC VREF 10K 330 PVCC 2.2uH 20mR SW 0.1uF SS34 NC / 0.1uF 1uF 10K BATDRV ACN ACDRV ACP 4K CMS 1uF 1 cell NC /0.1uH 22uF BATTERY BS CELL LP28400 SRP STAT PGND ISET GND SRN TS REGN 10K 1uF 10K Figure2. Application With Power Path Selector Functional Pin Description P a c k ag e T y pe P in Con f igu ra t ion s TQFN- 20 LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 2 of 17 Preliminary Datasheet LP28400 Pin Description PIN PIN DESCRIPTION NO. Connect to common source of Nch ACFET and reverse blocking Nch RBFET. Place 4K resistor from CMS 1 ACDRV 2 AVCC 3 VREF 4 3.3V reference output. A 1uF MLCC is placed from VREF to GND to make it stable. TS 5 NTC resistor connection. ISET 6 Fast charge current set pin. CELL 7 Cell selection pin. Set CELL pin LOW or floating for 2-cell, HIGH for 1-cell. STAT 8 Open-Drain Charge Status Output. SRN 9 Charge current sense negative input. SRP 10 GND 11 Power ground. REGN 12 5V power supply output, Bypass 1uF MLCC to AGND. SW 13.14 PVCC 15.16 IC power supply of power device of Charger. Put 10uF MLCC from PVCC to PGND. BS 17 CMS pin to the common source of ACFET and RBFET to control the turn-on speed. AC adapter to system switch driver output. IC power supply of internal bias. Put 1uF MLCC from AVCC to AGND. Add 10Ω resistor to filter the noise of power line. Charge current sense positive input. A 0.1-uF is recommended for common mode filtering from SRP to AGND. A 0.1uF is placed from SRP to SRN for differential mode filtering. Switching node, charge current output inductor connection. Connect a 47-nF BS capacitor from SW to BS. Boostrap pin. Place a 0.047u-F MLCC from SW to BS. Battery discharge MOSFET gate driver output. Connect a 1kohm resistor to the gate of the P-channel power MOSFET(BATFET). Connect the source of the BATFET to the system load voltage node. BATDRV 18 Connect the drain gate drive of the BATFET to the battery pack positive is asymmetrical to allow a node. The internal quick turn-off and slower turn-on. The internal break-before-make logic with respect to ACDRV. There is an internal 50k pull-down resistor from BATDRV to ground. ACN 19 ACP 20 LP28400-00 Adaptor current sense resistor negative input. A 0.1-uF from ACN to AGND is recommended for common mode filtering. A 0.1uF is placed from ACN to ACP for differential mode filtering. Adaptor current sense resistor positive input. A 0.1-uF from ACP to AGND is recommended for common mode filtering. A 0.1uF is placed from ACN to ACP for differential mode filtering. Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 3 of 17 Preliminary Datasheet LP28400 Operating Flow Chart LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 4 of 17 Preliminary Datasheet LP28400 Typical Application Circuit LP9006 VIN LP9006 22uF 20mR SYS 10uF 22uF 10R 22uF 0.1uF 0R LP9007 1K BATDRV ACN ACDRV PVCC 4K ACP 4K CMS 1uF AVCC VREF 10K 20mR 0.1uF SS34 NC /0.1uF 1uF 10K 2.2uH SW 22uF NC /0.1uH 2cell BATTERY BS 330 CELL LP28400 SRP STAT GND TS PGND SRN ISET REGN 10K 1uF 10K Figure3. LP28400 application 2CELL circuit LP9006 VIN LP9006 22uF 20mR SYS 10uF 22uF 10R 22uF 0.1uF 0R 1K LP9007 4K BATDRV ACN AVCC VREF 330 PVCC ACDRV ACP 4K CMS 1uF 20mR 0.1uF SS34 1 cell NC / 0.1uF 1uF 10K 2.2uH SW NC / 0.1uH 22uF BATTERY BS 10K 10K CELL LP28400 SRP STAT GND TS ISET LP9006 PGND SRN REGN 10K 1uF 10K Figure4. LP28400 application 2LED circuit LP9006 VIN LP9006 22uF 20mR SYS 10uF 22uF 10R 22uF 0.1uF 0R 4K 1K 10K 330 2.2uH 100K SW 0.1uF SS34 100mR LP9014 10K LP9007 BS CELL Larger Current Charge Select 100mR NC / 0.1uF 1uF 10K BATDRV AVCC VREF PVCC ACDRV ACN 4K ACP LP9007 CMS 1uF 100K NC /0.1uH LP28400 SRP STAT 10K PGND ISET GND SRN TS 1 cell1 REGN 22uF BATTERY 1uF 10K Figure5. LP28400 application of charger circuit and USB Power LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 5 of 17 Preliminary Datasheet LP28400 Function Block Diagram VDD 1 ISET 1 EN1 SHORT CIRCUIT COMP. 10KΩ~100KΩ 2.5A~0.5A UVLO SHUTDOWN CIRCUITRY ADJUSTABLE CURRENT LIMIT 10μA OVP Error Amp. LX OTP FB CONTROL AND DRIVER LOGIC PWM COMP. SOFT START OSCILLATOR CURRENT SENSE AMP. SLOPE COMPENSASION VDD 2 OUT 2 GATE DRIVER EN2 UVLO LP28400-00 VSS Version 1.0 May.-2013 CURRENT LIMIT TSD Email: [email protected] ISET 2 VSS REF www.lowpowersemi.com Page 6 of 17 Preliminary Datasheet LP28400 Absolute Maximum Ratings Input Voltage to GND (VIN) --------------------------------------------------------------------------------------------- 20V ACDRV, BS-------------------------------------------------------------------------------------------------------------------26V ACP, ACN, CMS, STAT, BATDRV, SRP, SRN ,SW --------------------------------------------0.3V to VIN+0.3V REGN, TS, CELL------------------------------------------------------------------------------------------------- -0.3Vto 7V BAT Short-Circuit Duration ------------------------------------------------------------------------------------- Continuous BAT Pin Current ----------------------------------------------------------------------------------------------------- 3000mA ISET Pin Current -------------------------------------------------------------------------------------------------------- 800µA 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) ------------------------------------------------------------------------- 2W Thermal Resistance (JA) ------------- ---------------------------------------------------------------------------- 40℃/W Electrical Characteristics 4.5V≤V(PVCC, AVCC)≤15V, –20°C < TJ + 125°C, typical values are at TA= 25°C, with respect to AGND (unless otherwise noted) SYMBOL PARAMETER VIN Adapter/USB Voltage Range VUVLO AC under-voltage rising VUVLO_HYS AC under-voltage VSLEEP SLEEP mode threshold VSLEEP_HYS CONDITIONS MIN TYP. MAX UNITS 4.5 5 15 V 3.3 V 300 mV VAVCC – VSRN falling 100 mV Hysteresis VAVCC – VSRN rising 200 mV VACSET ACSET Voltage Range RSENSE = 20mΩ IACSET ACSET Input Bias Current Measure on AVCC VACSET=VREF, RSENSE = 20mΩ VACP-ACN AC Current Full Scale VACSET=Float, Sense Voltage RSENSE = 20mΩ VACSET=GND, RSENSE = 20mΩ 0 VREF V 25 -25 uA 95 100 105 mV 71 75 79 mV 46 50 54 mV 1.2 1.5 mA VAVCC > VUVLO, VAVCC > VSRN, VBAT=4.2V/8.4V, Charge disabled Icc VAVCC > VUVLO, VAVCC > Input Supply Current VSRN, Charge 15 mA 15 uA 25 uA enabled, switching Sleep Mode, VAVCC>VUVLO,VSRN>VAVCC BTST, SW, SRP, SRN, VAVCC > VUVLO, VAVCC > VSRN, ISET < 40mV, IBAT LP28400-00 BAT Pin Current Version 1.0 May.-2013 VBAT=4.2V/8.4V, Charge disabled Email: [email protected] www.lowpowersemi.com Page 7 of 17 Preliminary Datasheet BTST, SW, SRP, LP28400 SRN, VAVCC > VUVLO, VAVCC > VSRN, ISET > 25 uA 120mV, VBAT=8.4V, Charge done CELL = VREF, TJ = 0°C to 85°C VFLOAT Regulated Output (Float) Voltage LP28400 CELL = GND, TJ = 0°C to 85°C LP28400 4.158 4.2 4.242 V 8.358 8.4 8.442 V 1.32 1.5 1.68 MHz Fsw PWM Switching Frequency VISET ISET Voltage Range 0 VREF V IISET ISET Input Bias Current 25 -25 uA VSRP-SRN-CC VSRP-SRN-CP TTERM_DEG Charge Current Full Scale Sense Voltage Charge Current Full Scale Sense Voltage in Pre-Charge VISET=VREF 71 75 79 mV VISET=Float 46 50 54 mV VISET=AGND 21 25 29 mV VISET=VREF 7.1 7.5 7.9 mV VISET=Float 4.6 5.0 5.4 mV VISET=AGND 2.1 2.5 2.9 mV VSRN > VRECH and ICHG < Deglitch time CELL = VREF, measured on VLOWV 100 ITERM Precharge to fast charge SRN transition threshold CELL = AGND, measured on SRN 2.85 2.9 2.95 V 5.7 5.8 5.9 V CELL = VREF, measured on VLOWV_HYS Fast charge to precharge SRN hysteresis CELL = AGND, measured on SRN KTERM Termination Termination set factor VRECHG of fast charge Threshold, below regulation voltage limit, VBAT_REG-VSRN 200 mV 400 mV 10% current Recharge mS CELL=VREF ,measured on SRN 100 130 160 mV CELL=GND, measured on SRN 200 260 320 mV TPRE-CHARGE Pre-Charge Timer 1848 2100 2352 S TFAST-CHARGE Fast-Charge Timer 22176 25200 28224 S VVREF_REG VREF regulator voltage VAVCC > VUVLO, No load 3.13 3.3 3.47 V IVREF_LIM VREF current limit VVREF=0V,VAVCC> VUVLO VREGN_REG REGN regulator voltage VAVCC > 10 V IREGN_LIM REGN current limit VREGN = 0 V, VAVCC > 10V High-Side Ron VBS-VSW=5V 110 mΩ Low-Side Ron VREGN=5V 110 mΩ RDS_BAT_OFF BATFET Turn-off Resistance VAVCC > 5V 100 Ω RDS_BAT_ON BATFET Turn-on Resistance VAVCC > 5V 20 KΩ RDS VBATDRV_REG VBATDRV_REG LP28400-00 BATFET Drive Voltage Version 1.0 May.-2013 40 5 =VACN VBATDRV when VAVCC > Email: [email protected] 5.3 mA 5.6 50 - 4.2 www.lowpowersemi.com V mA 7 V Page 8 of 17 Preliminary Datasheet LP28400 5V and BATFET is on IOCP_HSFET VIN OVP VACOV_HYS Current limit on HSFET Measure on HSFET 6 A CELL = VREF 6.4 6.6 6.8 V Over voltage protection CELL = GND 16.1 16.5 16.9 V AC over-voltage falling CELL = VREF 200 mV hysteresis CELL = GND 500 mV AVCC rising 1 µs AVCC falling 25 mS AC Over-Voltage Rising Deglitch TACOV_RISE_DEG TACOV_FALL_DEG VLTF to turn off ACFET and Disable Charge AC Over-Voltage Falling Deglitch to Turn on ACFET Cold Temperature Threshold, TS Charger suspends charge. pin Voltage Rising Threshold As percentage to VREF Hot Temperature Hysteresis, TS VLTF_HYS pin voltage Falling Hot Temperature TS pin voltage VHTF rising Threshold Cut-off VTCO Temperature TS pin voltage falling Threshold TJ_REG Junction Temperature TSHUT Thermal shutdown temperature TSHUT_HYS Thermal shutdown hysteresis LP28400-00 Version 1.0 May.-2013 72.5 73.5 74.5 % As percentage to VVREF 0.2 0.4 0.6 % As percentage to VVREF 46.6 47.2 47.8 % As percentage to VVREF 44.2 44.7 45.2 % Charging Temperature rising Email: [email protected] 125 ℃ 160 ℃ 30 ℃ www.lowpowersemi.com Page 9 of 17 Preliminary Datasheet LP28400 Typical Operating Characteristics Figure6. Power UP Figure7．Power UP(NO BATT) Figure 8. BATFET to ACFET Transition During Powerup LP28400-00 Version 1.0 May.-2013 Figure 9. Over-voltage Protection Email: [email protected] www.lowpowersemi.com Page 10 of 17 Preliminary Datasheet Figure10. Over-voltage Release LP28400 Figure11. Soft Start Figure12. Discontinuous Conduction Mode Switching Figure13. Continuous Conduction Mode Switching LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 11 of 17 Preliminary Datasheet Figure 14. Charge Enable by TS Figure 16. Battery Insertion and Removal LP28400-00 Version 1.0 May.-2013 LP28400 Figure 15. Charge Disable by TS Figure 17. Battery to Ground Short Protection Email: [email protected] www.lowpowersemi.com Page 12 of 17 Preliminary Datasheet LP28400 Typical Charge Profile Efficiency VS Output Current LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 13 of 17 Preliminary Datasheet LP28400 Operation Application The LP28400 is a constant current, constant voltage 1-cell and 2-cell Li-Ion battery charger controller that uses a current mode PWM step-down (buck) switching architecture. The charge current is set by an external sense resistor across the SRP and Under high ambient temperature, the charge current will fold SRN pins. Voltage amplifier and the resistor divider provide back to keep IC temperature not exceeding 125°C regulation with ±1% accuracy. Input Current Regulation Normal Charge Cycle The LP28400 series offers a high accuracy voltage regulator on for the charging voltage. The LP28400 uses CELL pin to select number of cells with a fixed 4.2V/cell. Connecting CELL to AGND or floating CELL sets 2 cell output, and connecting to VREF sets 1 cell output The total input current from an AC adapter or other DC sources is a function of the system supply current and the battery charging current. System current normally fluctuated as portions of the Dynamic systems are powered up or down. Without Power Management (DPM), the source must be able to supply the maximum system current and the maximum ULATION available charger input current simultaneously. By using DPM, CELL PIN VOLTAGE GND or Floating 8.4V the summation of system power and charge power exceeds the VREF 4.2V maximum input power. Therefore, the current capability of the the input current regulator reduces the charging current when AC adapter can be lowered, reducing system cost., the sense Normal Charge Cycle voltage between ACP and ACN is 75mV typ. A charge cycle begins when the voltage at the V CC pin rises The ACP and ACN pins are used to sense across RAC with above the UVLO threshold level and when a battery is default value of 20mΩ. However, resistors of other values can connected to the charger output. If the BAT pin is less than also be used. A larger sense resistor will give a larger sense 2.9V/5.8V, the charger enters trickle charge mode. In this mode, voltage and higher regulation accuracy, at the expense of the LP28400 supplies approximately 1/10 the ISET rammed higher conduction loss. charge current to bring the battery voltage up to a safe level for full current charging. Charge Termination When the BAT pin voltage rises above 2.9V/5.8V, the charger A charge cycle is terminated when the charge current falls to goes into the full- scale constant current charge mode. In 1/10th the SRP and SRN rammed value after the final float constant current mode The charge current is set by an external voltage is reached. This condition is detected by using an sense resistor across the SRP and SRN charge current is internal, filtered comparator to monitor the SRP and SEN pin. supplied to the battery. When the BAT pin approaches the final When the SRP and SEN pin voltage falls below 1/10 for longer float voltage (4.2V/8.4V), LP28400 enters constant-voltage than TTERM_DEG, charging is terminated. The charge current mode and the charge current begins to decrease. When the is latched off and the LP28400 enters standby mode, where the charge current drops to 1/10 of the ISET rammed value, the input supply current drops to 1.2mA. (Note: C/10 termination is charge cycle ends. disabled in trickle charging and thermal limiting modes). When charging, transient loads on the VSRP-SRN can cause Charge Current Regulation The ISET input sets the maximum charging current. Battery current is sensed by current sensing resistor RSR connected between SRP and SRN. The full-scale differential voltage between SRP and SRN is 75mV max. the VSRP-SRN to fall below 1/10 for short periods of time before the DC charge current has dropped to 1/10th the VSRP-SRN rammed value. The 100ms filter time (TTERM_DEG) 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 LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 14 of 17 Preliminary Datasheet LP28400 below 1/10th the VSRP-SRN rammed value, the LP28400 to VTCO thresholds. The controller suspends charge by turning terminates the charge cycle and ceases to provide any current off the PWM charge MOSFETs. through the BAT pin. In this state, all loads on the BAT pin must be supplied by the battery. Charge Status Indicator (STAT) The open-drain STAT output indicate operations as shown in the following table. various charger these status pins can be used to driver LEDs or communicate to the host processor. Note that OFF indicates the open-drain transistor is turned off. A microprocessor can be used to distinguish between these three states—this method is discussed in the Applications Information section. Charge STATE STAT Charging ON Charge done OFF Assuming a NTC thermistor on the battery pack resistance at 0°C and 45°C are RTHCOLD Safety Timers the values of RT1 and RT2 can As a safety backup, the charger also provides an internal fixed equations and have RTHHOT, be determined by using below 35 minutes pre-charge safety timer and an internal fixed 7 hours fast charge timer Soft-Start Charger Current The charger automatically soft-starts the charger regulation current every time the charger goes into fast-charge to ensure there is no overshoot or stress on the output capacitors or the power converter. The soft-start consists of stepping-up the charge regulation current into 8 evenly divided steps up to the Temperature Sensing Configuration programmed charge current. Each step lasts around 1.4ms, for a typical rise time of 11.2ms. No external components are VREF needed for this function. RTC1 LP28400 Battery Temperature Detection TS The controller continuously monitors battery temperature by measuring the voltage between the TS pin and AGND. A negative temperature coefficient resistance (NTC) and an RT2 NTC external voltage divider typically develop this voltage. The controller compares this voltage against its internal thresholds to determine if charging is allowed. To initiate a charge cycle, the battery temperature must be within the VLTF to VHTF thresholds. If battery temperature is outside of this range, the controller suspends charge and waits until the battery temperature is within the VLTF to VHTF range. During the charge cycle the battery temperature must be within the VLTF LP28400-00 Version 1.0 May.-2013 System Power Selector The IC automatically switches adapter or battery power to the system load. The battery is connected to the system by default during power up or during SLEEP mode. When the adapter Email: [email protected] www.lowpowersemi.com Page 15 of 17 Preliminary Datasheet LP28400 plugs in and the voltage is above the battery voltage, the IC keep ACFET off, disconnecting the adapter from system. exits SLEEP mode. The battery is disconnected from the /BATDRV stays at ACN-5V (clamp to ground) to connect system and the adapter is connected to the system after exiting battery to system. SLEEP. An automatic break-before-make logic prevents After the device comes out of SLEEP mode, the system begins shoot-through currents when the selectors switch. The ACDRV to switch from battery to adapter. is used to drive a pair of back-to-back n-channel power When the adapter is removed, the IC turns off ACFET and MOSFETs between adapter and ACP with sources connected enters SLEEP mode to turn on p-channel BATFET, connecting together to CMS. The n-channel FET with the drain connected the battery to the system to the ACP (Q2, RBFET) provides reverse battery discharge protection, and minimizes system power dissipation with its low-RDSON. The other n-channel FET with drain connected to adapter input (Q1, ACFET) separates battery from adapter, and provides a limited dI/dt when connecting the adapter to the system by controlling the FET turn-on time. The /BATDRV controls a p-channel power MOSFET (Q3, BATFET) placed between battery and system with drain connected to battery. Before the adapter is detected, the ACDRV is pulled to CMS to LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 16 of 17 Preliminary Datasheet LP28400 Packaging Information LP28400-00 Version 1.0 May.-2013 Email: [email protected] www.lowpowersemi.com Page 17 of 17