Tel:86-755-81796865 http://www.stchip.com SL1054 Advanced Lithium-Ion Linear Battery Charger General Description SL1054 is a single Lithium-Ion or Lithium-Polymer cell linear battery charger which is designed for compact and cost-sensitive handheld devices. It combines charge status indication, charge termination, battery temperature monitoring, and high accuracy current and voltage regulation in a SOP-8 package. SL1054 charges the battery in three modes, precharge, constant current, constant voltage. If the battery voltage is below the precharge threshold VO(MIN), the SL1054 precharges the battery with a lower conditioning current. After precharge, the SL1054 applies a constant current to the battery. An external sense-resister sets the charge current. The constant voltage mode continues until the battery reaches the regulation The battery temperature is continuously measured by an external thermistor through the TS pin. SL1054 inhibits charge until the temperature is within the range defined by users. Features For Single Lithium-Ion or Lithium-Polymer Cell Battery Pack 4.2V A Few External Components are Required Precharge, Constant Current, Constant Voltage Modes Battery Temperature Monitor Charge Status Indication Automatic Battery Recharge Charge Termination Detect Auto Low Power Sleep Mode when VDD Power is removed MSOP-8 Package RoHS Compliant and 100% Lead (Pb)-Free Applications Digital Cameras PDAs Cellular Phones Information Appliance Pin Configurations 1 Tel:86-755-81796865 http://www.stchip.com SL1054 Typical Application Circuit Figure1: Application circuit using P-channel MOSFET Figure2: Application circuit using PNP transistor 2 Tel:86-755-81796865 http://www.stchip.com SL1054 Founctinal Pin Description Pin Name VDD Pin Funtion Supply Voltage Input TS Temperature Sense Input. Input from battery temperature monitoring circuit. STAT1 In charge status, this pin is pulled to high; when charge completed, it’s pulled to low; and if temperature fault or disable, it’s in high impedance status. STAT2 In charge status, this pin is pulled to low; when charge completed, it’s pulled to high; and if temperature fault or disable, it’s in high impedance status. GND Gound CC Charge Control Output. Current output to drive on external PNP transistor or P-Channel MOSFET for current and voltage regulation CS Current Sense Input. Charge current is sensed according to the voltage drop from supply voltage to this pin BATT Battery voltage input. Input directly from battery voltage. Absolut Maxmum Ratings(Note 1) Supply Voltage ------------------------------------------------ －0.3V～7V Storage Temperature Range-------------------------------------－65℃～150℃ Power Dissipation, PD@TA＝25℃------------------------------------ 300mW Junction Temperature ----------------------------------------------- 150℃ Operation Juntion Temperature Range------------------------- －40℃～＋125℃ ESD Susceptibility (Note2)------------------------------------------------ 4KV Recommneded Operation Conditions(Note 3) Supply Input Voltage----------------------------------------------4.5V to 7V Junction Temperature Range---------------------------------- －20℃～＋70℃ Electrical Electrical Characteristics(TA＝25℃) Parameter Symbol Test Condition Min Typ Max Units Operating Current IDD(OPE) 4.5V<VDD<7V ---- 1 2 mA Vdd Sleep Current IDD(sleep) VBATT-VDD≥0.2V ---- ---- 3 uA Input Bias Current @ BATT Pin IBATT VBATT = VO(REG), VBATT-VDD≥0.2V ---- 1.5 2.6 uA Input Bias ITS VTS =5V, ---- ---- 1.1 uA 3 VBATT-VDD≥0.2V Current @ TS Pin Input Bias Current @ CS Pin ICS --- --- 1.1 uA Output Voltage VO(REG) 4.160 4.20 4.240 V Current Regulation Threshold VI(SNS) VI(SNS)=VDD-VCS 100 115 130 mV Current Detect Threshold V(PRE) V(PRE)=VDD-VCS 4 12 24 mV Precharge Threshold VO(MIN) 2.7 2.9 3.1 V Recharge Threshold VO(RCH) VO(REG)170mV VO(REG)110mV VO(REG)50mV V Charge Teminated Current Detect Threshold V(TERM) V(TERM)=VDD-VCS 2 12 22 mV Ouput Low Voltage @STAT1Pin VSTAT1(LOW) IOL =10mA ----- 0.4 0.6 V Ouput High Voltage @STAT1Pin VSTAT1(HIGH) IOH=5mA VDD-0.5V ---- ---- V Ouput Low Voltage @STAT2 Pin VSTAT2(LOW) IOL =10mA ----- 0.4 0.6 V Ouput High Voltage @STAT2 Pin VSTAT2(HIGH) IOH=5mA VDD-0.5V ---- ---- V Lower Temperature Threshold VTS1* 28 30 32 %VDD Upper Temperature Threshold VTS2* 68 70 72 %VDD VCS =5V, VBATT-VDD≥0.2V Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for 4 extended periods may remain possibility to affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. Note 3. The device is not guaranteed to function outside its operating conditions. 5 Tel:86-755-81796865 http://www.stchip.com SL1054 Detection First, the FB/CE pin must connect to VDD or a voltage divider to enable the charge function. And then if a battery is already inserted and the input power source is absent, the SL1054 will enter sleep mode to prevent draining power from battery. When input power source and battery are both existed, another detection is the battery temperature. The TS pin voltage must be in the allowed range as shown in Figure 6 and the electrical characteristics, and then the SL1054 will start the charge cycle according to the battery voltage conditions. Precharge Mode When the battery voltage is lower than the precharge threshold VO(MIN), the SL1054 begins to charge the battery in precharge mode. In this condition, the precharge current is set at approximately 10% of the constant regulation current. The purposes of small precharge current are to minimize the power dissipation on the external switch during the precharge period and to revive deeply discharged battery cells. Constant Current Regulation Charge Mode When the battery voltage is between the precharge threshold VO(MIN) and the regulation voltage VO(REG), the SL1054 starts the constant current regulation charge mode. SL1054 monitors charge current with voltage drop between two terminals of a sense-resistor, RCS, which connects to pin VDD and CS. The following equation can calculate the desired charging current. 6 Tel:86-755-81796865 http://www.stchip.com SL1054 Constant Voltage Regulation and Charge Termination Mode When the battery voltage reaches the regulation voltage VO(REG), the constant voltage feedback control starts, and then the charge current begins to decrease as the typical charge profile shown. As the charge current decreases to lower than charge terminated current threshold, the SL1054 will terminate the charge cycle. Recharge Mode After the charge termination mode, if the battery voltage falls to lower than the recharge threshold voltage VO(RCH), the SL1054 will begin a new charge cycle according to the battery voltage. Battery Temperature Detection The SL1054 continuously detects the battery temperature by measuring the TS pin voltage. A NTC or PTC thermistor can parallel with RT2 to deviate the TS pin voltage. (As shown in Figure 5) The TS pin voltage must be within normal temperature voltage range that is shown in Figure 6 and electrical characteristics, and then SL1054 can start working normally. The RT1 and RT2 can be derived from following equations. For NTC Thermistors: Where RTL is the resistance value in lowest desired operation temperature and RTH is the resistance value in highest desired operation temperature. The resistances of thermistors are specified by the thermistor manufacturer. If the temperature monitoring function is not desired, there's an easy method to set RT1 and RT2 at the same value and disconnect the thermistor to disable this function. 7 Tel:86-755-81796865 http://www.stchip.com SL1054 Charge status indication The SL1054 indicates the status of the charger on the 3-state STAT1 and STAT2 pin. The following table shows the statuses of this pin. Condition STAT1 Pin STAT2 Pin In batter charging cycle High Low Charge cycle completed Low High Temperature fault or charge function disable or output shorted High Impedance High Impedance Selecting an External PNP Pass-Transistor or P-Channel MOSFET: The SL1054 drives an external PNP transistor or P-Channel MOSFET to control the charging current. The specifications must be concerned are the voltage and current rating and package power dissipation. The external switch is performed as a linear regulator. The maximum power loss occurs when the constant current regulation starts at the beginning, and it can be calculated approximately from following equation: PD(MAX) =I(SNS)×(VDD -0.1V -2.8V) I(SNS) is the constant regulation current. The minimum voltage drop between the sense-resistor is 100mV, and the minimum precharge threshold voltage is 2.8V. The external pass device with PCB heatsinking must be rated for the maximum power dissipation. Selecting Input/Output Capacitor In analog circuit applications, to place a high-frequency decoupling capacitor nearby the controller IC between input power source and ground is very important. A 0.1uF ceramic is recommended. If a high ripple and noise input power is chosen, it should have enough capacitance to reduce the disturbance. A 0.1uF to 1uF output capacitor is recommended to control the output voltage and keep the output voltage ripple small when the battery is disconnected 8 Tel:86-755-81796865 http://www.stchip.com . 9 SL1054