LM3658SD

LM3658 Dual Source USB/AC Li Chemistry Charger IC for Portable Applications May 2005 LM3658 Dual Source USB/AC Li Chemistry Charger IC for Portable Applications General Description The LM3658 is a single chip charger IC designed for handheld applications. It can safely charge and maintain a single cell Li-Ion/Polymer battery operating from an AC wall adapter or USB power source. Input power source selection of USB/AC is automatic. With both power sources present, the AC power source has priority. Charge current is programmed through an external resistor when operating from an AC wall adapter allowing charge currents from 50 mA to 1000 mA. When the battery is charged using USB power, charge currents of 100 mA or 500 mA are pin-selectable. The termination voltage is controlled to within ± 0.35% of 4.2V. The LM3658 requires few external components and integrates internal power FETs, reverse current protection and current sensing. The internal power FETs are thermally regulated to obtain the most efficient charging rate for a given ambient temperature. The LM3658 operates in five modes: pre-qualification mode, constant-current mode, constant-voltage mode, top-off mode and maintenance mode. Optimal battery management is obtained through thermal regulation, battery temperature measurement and multiple safety timers. The LM3658 provides two open-drain outputs for LED status indication or connection to GPIOs. Features n Integrated power FETs with thermal regulation n Charges from either an AC wall adapter or USB power source with automatic source selection n 50 mA to 1000 mA charge currents using AC wall adapter n Pin-selectable USB charge currents of 100 mA or 500 mA n Continuous battery temperature monitoring n Built-in multiple safety timers n Charge status indication n Continuous over-current and temperature protection n Near-depleted battery pre-conditioning n Sleep mode with ultra low quiescent current n On-board Kelvin-sensing achieves ± 0.35% termination accuracy n Maintenance mode with automatic recharge n Thermally enhanced 3 mm x 3 mm LLP package Applications n n n n n Smartphones Digital still cameras PDAs Hard Drive and flash-based MP3 players USB-powered devices Typical Application 20128201 © 2005 National Semiconductor Corporation DS201282 www.national.com LM3658 Connection Diagram and Package Mark Information LLP10 Package Drawing 20128202 Note: The actual physical placement of the package marking will vary from part to part. The package marking “X” is the manufacturing plant code. “YY” is a 2-digit date code, and "ZZ" for die traceability. These codes will vary considerably. "L111B” identifies the device (part number, option, etc.). TABLE 1. LM3658 Pin Description Pin # 1 2 3 4 5 6 7 8 9 10 Name CHG_IN USBpwr GND USB_sel EN_b STAT2 STAT1 ISET TS BATT AC wall adapter input pin. USB power input pin. Power and signal ground pin. Pulling this pin low limits the USB charge current to 100 mA. Pulling this pin high limits the USB charge current to 500 mA. Pulling this pin low enables the charger. Pulling this pin high disables the charger. Active low open-drain output. Indicates charger status. This pin is capable of driving an LED as well as GPIOs. See Operation Description section for more detail. Active low open-drain output. Indicates charger status. This pin is capable of driving an LED as well as GPIO. See Operation Description section for more detail. A resistor is connected between this pin and GND. The resistor value determines the full-rate charge current when using the AC source. Battery temperature sense pin. This pin must be connected to battery pack’s temperature sense output pin. See Operation Description section for more detail. Positive battery terminal connection. TABLE 2. Ordering Information Order Number LM3658SD LM3658SDX Package Marking L111B L111B Supplied As 1000 units, Tape-and-Reel 4500 units, Tape-and-Reel Description For more information on the various options, please refer to Operation Description section. www.national.com 2 LM3658 Absolute Maximum Ratings 2) (Notes 1, Operating Ratings (Notes 1, 2) Input Voltage Range for CHG_IN Input Voltage Range for USB_pwr Recommended Load Current Power Dissipation(Note 3) Junction Temperature (TJ) Range Ambient Temperature (TA) Range 4.5V to 6.0V 4.35V to 6.0V 0 to 1000 mA Internally Limited −40˚C to +125˚C −40˚C to +85˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. CHG_IN, USBpwr (VCC) All other pins except GND Power Dissipation (Note 3) Junction Temperature (TJ-MAX) Storage Temperature Range ESD Rating (Note 4) Human Body Model: Machine Model: −0.3V to +6.5V −0.3V to CHG_IN or USBpwr Internally Limited +150˚C −65˚C to +150˚C 2.0 kV 200V Thermal Properties θJA, Junction-to-Ambient Thermal Resistance (Note 5) 54˚C/W Electrical Characteristics Unless otherwise noted, VCC (VCHG_IN and/or VUSBpwr) = 5V, VBATT = 3.5V. CCHG_IN = 1 µF, CUSBpwr = 1 µF, CBATT = 1 µF. Typical values and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in boldface type apply over TJ = 0˚C to +85˚C. (Notes 2, 6, 7) Symbol CHARGER VCHG_IN VUSBpwr ICC_PD ICC_STBY AC Wall Adapter Input Voltage Range USB Input Voltage Range Quiescent Current in Power Down Mode Quiescent Current in Standby Mode Battery Leakage Current in Power Down Mode VBATT > VCC–VOK_CHG VBATT < VCC − VOK_CHG VCC > VPOR EN_b = High VBATT > VCC + VOK_CHG 0.01 STAT1 = off, STAT2 = on, adapter or USB connected, VBATT = 4.2V VCC – VBATT (Rising) VCC – VBATT (Falling) VCC (Rising) VBATT < VCC – VOK_CHG VFULL_RATE < VBATT < VTERM ICHG = 10% of its value when VBATT = 3.5V TA = 25˚C TA = 0˚C to 85˚C VBATT = VTERM, ICHG = 1A VCC > VBATT + VCHG_DO_MAX VBATT = VTERM, USB_sel = high VCC > VBATT + VUSB_DO_MAX 6V ≥ VCC ≥ 4.5V VBATT < VCC – VOK_CHG VFULL_RATE < VBATT < VTERM ICHG = KISET/RISET 500 250 2.0 µA 1 4.5 4.35 6.0 6.0 5 V V µA Parameter Conditions Typ Limit Min Max Units 400 600 µA IBATT_PD IBATT_MAINT Battery Leakage Current in Maintenance Mode VOK_CHG VPOR CHG_IN or USBpwr OK Trip-Point VCC POR Trip-Point 7 200 50 3.0 15 µA mV V VTERM Battery Charge Termination Voltage Battery Charge Termination Voltage Tolerance 4.2 −0.35 −1.5 +0.35 V % +1.5 mV mV VCHG_DO VUSB_DO ICHG CHG_IN Drop-Out Voltage USBpwr Drop-Out Voltage CHG_IN Full-Rate Charge Current Range (see full-rate charge mode description) 50 1000 mA 3 www.national.com LM3658 Electrical Characteristics Unless otherwise noted, VCC (VCHG_IN and/or VUSBpwr) = 5V, VBATT = 3.5V. CCHG_IN = 1 µF, CUSBpwr = 1 µF, CBATT = 1 µF. Typical values and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in boldface type apply over TJ = 0˚C to +85˚C. (Notes 2, 6, 7) (Continued) Symbol CHARGER ICHG CHG_IN Full Rate Charge Current Charge Current Set Coefficient ICHG = KISET/RISET (see full-rate charge mode description) Charge Current Set Voltage USB Full-Rate Charge Low Current USB Full-Rate Charge High Current Pre-Qualification Current VBATT = 2V, for both AC adapter and USB VBATT rising, transition from pre-qualification to full-rate charging VBATT falling RISET = 10kΩ RISET = 5 kΩ RISET = 3.3kΩ KISET 6V ≥ VCC ≥ 4.5V VBATT < VCC – VOK_CHG VFULL_RATE < VBATT < VTERM 245 500 760 220 465 700 270 535 820 mA Parameter Conditions Typ Limit Min Max Units 2500 AΩ VISET 6V ≥ VCC ≥ 4.5V VBATT < VCC – VOK_CHG VFULL_RATE < VBATT < VTERM 2.5 V IUSB_L IUSB_H IPREQUAL 90 450 45 80 400 35 100 500 55 mA mA mA VFULL_RATE Full-Rate Qualification Threshold Full Rate Hysteresis IEOC 3.0 60 9 2.9 50 7 3.1 70 11 V mV % End-of-Charge 6V ≥ VCC ≥ 4.5V Current, Percent from VBATT < VCC – VOK_CHG VFULL_RATE < VBATT < VTERM Full-Range Current Minimum Top-Off Charge Current Restart Threshold Voltage Battery Temperature Sense Comparator Low-Voltage Threshold Battery Temperature Sense Comparator High-Voltage Threshold Battery Temperature Sense Current Regulated Junction Temperature Thermal Shutdown Temperature Power OK Deglitch Time Pre-Qualification Timer 4 ITOPOFF 6V ≥ VCC ≥ 4.5V VBATT < VCC – VOK_CHG VBATT = VTERM VBATT falling, transition from EOC to pre-qualification mode 2.5 1.25 3.75 % VRESTART VTL 4.0 3.94 4.07 V 0.49 0.46 0.52 V VTH 2.49 2.44 2.54 V ITSENSE TREG TSD 100 120 165 94 106 µA ˚C ˚C DETECTION AND TIMING TPOK TPREQUAL VBATT < VCC – VOK_CHG 60 30 40 27 100 33 ms mins www.national.com LM3658 Electrical Characteristics Unless otherwise noted, VCC (VCHG_IN and/or VUSBpwr) = 5V, VBATT = 3.5V. CCHG_IN = 1 µF, CUSBpwr = 1 µF, CBATT = 1 µF. Typical values and limits appearing in normal type apply for TJ = 25˚C. Limits appearing in boldface type apply over TJ = 0˚C to +85˚C. (Notes 2, 6, 7) (Continued) Symbol Parameter Conditions Typ Limit Min Max Units DETECTION AND TIMING TPQ_FULL Deglitch Time for Pre-Qualification to Full-Rate Charge Transition Deglitch Time for Full-Rate to Pre-Qualification Transition Charge Timer Deglitch Time for End-of-Charge Transition Deglitch Time for Battery Temperature Fault Deglitch Time for EN_b and USB_sel Pins Deglitch Time for ITOPOFF Top-Off Charging Timer Low-Level Input Voltage High-Level Input Voltage Low-Level Output Current High-Level Output Current EN_b USB_sel EN_b USB_sel STAT1, STAT2, output voltage = 0.25V STAT1, STAT2, output voltage = 6.0V 25 0.01 1.4 2.5 10 1 mA µA 300 270 330 ms TFULL_PQ 300 270 330 ms TCHG TEOC 300 300 270 270 330 330 min ms TBATTEMP 40 20 80 ms TDGL 40 20 80 ms TITOPOFF TTOPOFF I/O VIL VIH IOL IOH 300 30 270 27 330 33 ms min 0 0.7 1.5 V V Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables. Note 2: All voltages are with respect to the potential at the GND pin. Note 3: The LM3658 has built-in thermal regulation to regulate the die temperature to 120oC. See Operation Description section for more detail. Note 4: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. MIL-STD-883 3015.7 Note 5: Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, special care must be paid to thermal dissipation issues in board design. Please refer to application note AN1187 for more detail. Note 6: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm. Note 7: LM3658 is not intended as a Li-Ion battery protection device; battery used in this application should have an adequate internal protection. 5 www.national.com LM3658 Block Diagram 20128203 www.national.com 6 LM3658 Li-Ion Charging Profile 20128204 7 www.national.com LM3658 LM3658 Operation Description POWER-DOWN MODE The LM3658 will power down automatically when the voltage on the USBpwr or CHG_IN pin drops below the battery voltage with an amount that is equal to VOK_CHG (VBATT > VCC - VOK_CHG). Power-Down mode shuts off the internal power FETs as well as the open-drain pull-down transistors on the status pins STAT1 and STAT2. The only current consumed by the LM3658 is an ultra-low quiescent current of 1 µA typical. POWER-ON RESET As soon as the voltage of one of the power sources rises above VBATT + VOK_CHG, the charger will wake up. However, charging will not be initiated unless the supply voltage source exceeds the VPOR. AUTOMATIC POWER SOURCE DETECTION When the voltage of one of the power sources exceeds the VPOR threshold, the LM3658 detects which power source is a valid charge supply. When both supply voltages are valid and present, CHG_IN will automatically be selected over USBpwr. The USBpwr will be the designated power source only if no CHG_IN is present or when the voltage on the CHG_IN pin is less than the battery voltage. THERMAL POWER FET REGULATION The internal power FETs are thermally regulated to the junction temperature of 120oC to guarantee optimal charging of the battery. At all times is the charge current limited by the ISET resistor setting, the USB 100 mA/500 mA selection, or the 100oC junction temperature of the LM3658. The charge current is therefore a function of the charge current settings, the thermal conductivity of the package and the ambient temperature as described in the following equation: It is recommended to charge Li-Ion batteries at 1C rate, where “C” is the capacity of the battery. As an example, it is recommended to charge a 750 mAh battery at 750 mA, or 1C. Charging at a higher rate can cause damage to the battery. USBpwr FULL-RATE CHARGING MODE The full-rate charge cycle is initiated following the successful completion of the pre-qualification mode. Timer TCHG starts to count when the charger enters full-rate charging, with STAT1 on and STAT2 off. If the USB bus provides the charger supply, then the default full-rate charge current is 100 mA max unless the USB_sel pin is pulled high, which sets the charge current to 500 mA max. CONSTANT-VOLTAGE CHARGING MODE AND END-OF-CHARGE (EOC) DETECTION The battery voltage increases rapidly as a result of full-rate charging and will reach the 4.2V termination voltage, triggering the constant-voltage charge cycle. Timer TCHG continues to count in this cycle. STAT1 is on and STAT2 is off. The charge current gradually decreases during constant-voltage charging until it reaches the End-Of-Charge (EOC), which is equal to 10% of the full-rate current set either by the resistor connected to the ISET pin or the USB_sel pin. If Timer TCHG times out before EOC is reached, charging stops and STAT1 and STAT2 will both be on, indicating a bad battery condition. TOP-OFF CHARGING MODE Once EOC has been reached, a top-off cycle continues to charge the battery. Timed top-off cycle provides optimal battery capacity following a complete charge cycle. During this cycle, charging terminates when ICHG reaches 2.5% of the full-rate charge current or when TTOPOFF times out, whichever occurs first. STAT1 will turn off and STAT2 will turn on once the top-off cycle completes successfully, indicating that charging is done. MAINTENANCE MODE Maintenance mode begins immediately after the charger successfully finishes the top-off cycle. In the maintenance mode, the battery voltage is being monitored by the LM3658 continuously. If the battery voltage drops 200 mV below VTERM, a new full-rate charge cycle starts to replenish the battery. As this new full-rate charge cycle begins, STAT1 will turn on and STAT2 will turn off, and all the timers will reset. Refer to the LM3658 Flowchart. CHARGE STATUS OUTPUTS The LM3658 provides two open-drain outputs STAT1 and STAT2 that can be connected to external LEDs or to General Purpose I/O’s (GPIO) of a peripheral IC. All charge status of the LM3658 is illustrated in Table 3. “ON” means that STATx pin is pulled low as its pull-down transistor is turned on, representing a logic 0. 20128205 Where TA is the ambient temperature and θJA is the thermal resistance of the package. Thermal regulation guarantees maximum charge current and superior charge rate without exceeding the power dissipation limits of the LM3658. PRE-QUALIFICATION MODE During pre-qualification, STAT1 is on and STAT2 is off, and the charger supplies a constant current of 50 mA to the battery. When the battery voltage reaches VFULL_RATE, the charger transitions from pre-qualification to full-rate charging. The pre-qualification mode aborts when the battery doesn’t reach VFULL_RATE within the time allowed in TPREQUAL timer. In this event, charging stops and STAT1 and STAT2 will both be on, indicating a bad battery condition. CHG_IN FULL-RATE CHARGING MODE The full-rate charge cycle is initiated following the successful completion of the pre-qualification mode. Timer TCHG starts to count when the charger enters full-rate charging, with STAT1 on and STAT2 off. When charging with an AC wall adapter, the full-rate charge current is proportional to the value of the resistor that is connected to the ISET pin as described in the following equation: www.national.com 8 LM3658 LM3658 Operation Description (Continued) TABLE 3. Status Pins Summary STAT1 OFF ON OFF ON STAT2 OFF OFF ON ON Condition Power-Down, charging is suspended or interrupted Pre-qualification mode, CC and CV charging, Top-off mode Charge is completed Bad battery (Safety timer expired), or LDO mode If the TS pin is not used in the application, it should be connected to GND through 10kΩ pulldown resistor. When the TS pin is left floating (battery removal), then the charger will be disabled as the TS voltage exceeds the upper temperature limit. SAFETY TIMERS In order to prevent endless charging of the battery, which can cause damage to the battery, there are three safety timers that forcefully terminate charging if the charging mode is not completed within the time allowed. Pre-Qualification Timer (TPREQUAL) The pre-qualification timer starts with the initiation of the pre-qualification mode and allows 30 minutes to transition from pre-qualification to full rate charging. If the battery voltage does not reach VFULL_RATE in 30 minutes, charging stops and status pins STAT1 and STAT2 both turn on to indicate a bad battery status. Charger Timer (TCHG) The charge timer starts with the initiation of full-rate charging and has a duration of 5 hours for the LM3658. If the charge current does not reach EOC, charging stops and STAT1 and STAT2 both turn on to indicate a bad battery status. Once the charge control declares a bad battery, removing the input source is the only means to clear the bad battery status. Top-Off Timer (TTOPOFF) Once the charger successfully completes constant current constant voltage charging, it enters top-off mode and starts TTOPOFF timer. Topoff lasts 30 minutes for the LM3658. During top-off, charging stops when TTOPOFF reaches its count or when ICHG reaches 2.5% of the full-rate charge current. There is no time-out condition in top-off mode. When charging is interrupted either by battery temperature out of range or disabling the LM3658, the applicable safety timer will store its count value for the duration of the interruption and subsequently resumes counting from its stored count value when charging continues, only if the charger resumes to the same operation mode it was in before the interrupt. BATTERY TEMPERATURE MONITORING (Suspend Mode) The LM3658 is equipped with a battery thermistor interface to continuously monitor the battery temperature by measuring the voltage between the TS pin and ground. Charging is allowed only if the battery temperature is within the acceptable temperature range set by a pair of internal comparators inside the LM3658. If the battery temperature is out of range, STAT1 and STAT2 both turn off and charging is suspended. Timer holds its count value. The TS pin is only active during charging and draws no current from the battery when no external power source is present. 9 20128210 The LM3658 battery temperature feature is tailored to use negative temperature coefficient (NTC) 103AT thermistors with 10kΩ impedance. If alternative thermistors need to be used in the system, supplemental external resistors are needed to create a circuit with equivalent impedance. 20128211 DISABLING CHARGER (Charge Interrupt Mode) Charging can be safely interrupted by pulling the EN_b pin high and charging can resume upon pulling the EN_b pin low. The enable pin can be permanently tied to GND with no extra current consumption penalty during power down mode. When the charger is disabled, timer holds its count value, and STAT1 and STAT2 are both off. INPUT/OUTPUT BYPASS CAPACITORS Care should be taken to support the stability of the charge system by connecting a 1 µF capacitor as close as possible to the BATT pin. An input capacitor ranging from 1.0 µF– 10.0 µF must be connected to the CHG_IN and USBpwr input pins. Low cost ceramic capacitors can be selected. THERMAL PERFORMANCE OF THE LLP PACKAGE The LM3658 is a monolithic device with integrated power FETs. For that reason, it is important to pay special attention to the thermal impedance of the LLP package and to the PCB layout rules in order to maximize power dissipation of the LLP package. The LLP package is designed for enhanced thermal performance and features an exposed die attach pad at the bottom center of the package that creates a direct path to the PCB for maximum power dissipation. Compared to the traditional leaded packages where the die attach pad is embedded inside the molding compound, the LLP reduces one layer in the thermal path. www.national.com LM3658 LM3658 Operation Description (Continued) The thermal advantage of the LLP package is fully realized only when the exposed die attach pad is soldered down to a thermal land on the PCB board with thermal vias planted underneath the thermal land. Based on thermal analysis of the LLP package, the junction-to-ambient thermal resistance (θJA) can be improved by a factor of two when the die attach pad of the LLP package is soldered directly onto the PCB with thermal land and thermal vias, as opposed to an alternative with no direct soldering to a thermal land. Typical pitch and outer diameter for thermal vias are 1.27 mm and 0.33 mm respectively. Typical copper via barrel plating is 1 oz, although thicker copper may be used to further improve thermal performance. The LM3658 die attach pad is connected to the substrate of the IC and therefore, the thermal land and vias on the PCB board need to be connected to ground (GND pin). For more information on board layout techniques, refer to Application Note 1187 “Leadless Lead Frame Package (LLP).” This application note also discusses package handling, solder stencil and the assembly process. www.national.com 10 LM3658 LM3658 Operation Description (Continued) 20128207 LM3658 Flowcart 11 www.national.com LM3658 LM3658 Operation Description (Continued) 20128206 LM3658 USBpwr Mode Flowcart 20128208 LM3658 CHG_IN Mode Flowcart www.national.com 12 LM3658 Dual Source USB/AC Li Chemistry Charger IC for Portable Applications Physical Dimensions inches (millimeters) unless otherwise noted LLP10 Package Drawing NS Package Number SDA10A National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. 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