PT4057

ＰＴ４０５７ GENERALDESCRIPTION PT4057 is a complete CC/CV linear charger for single cell lithium-ion batteries. it 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 P-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 4.35V,and the charge current can be programmed externally with a single resistor. The PT4057 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed the PT4057 automatically enters a low current state dropping the battery drain current to less than 2μA.The PT4057 can be put into shutdown mode reducing the supply current to 55μA. Other features include Battery temperature monitor, under-voltage lockout, automatic recharge and two status pins to indicate charge and charge termination. Features               Protection of battery cell reverse connection Programmable charge current up to 1.1A No MOSFET sense resistor or blocking diode required Complete linear Charger for single Cell Lithium-Ion Batteries CC and CV operation with thermal regulation to maximize Rate without risk of overheating Preset 4.35V charge voltage with ±1% accuracy Automatic Recharge Two Status Indication for Charge status, no battery and battery failure indicators C/10 charge termination 55μA supply current in shutdown 2.9V trickle current charge threshold Soft-Start limits inrush current Battery Temperature Sensing Available in ESOP-8 package Applications        Cellular Telephones Mobile Power Supply Digital Still Cameras MP3 Players Bluetooth Applications Portable Devices USB Bus-Powered Chargers 　 www.puolop.com - 1- ＰＴ４０５７ Typical Application Pin Configuration 　 www.puolop.com - 2- ＰＴ４０５７ Pin Assignment PIN Num. 1 2 Symbol Function TEMP Temperature sense input Connecting TEMP pin to NTC thermistor ’s output in Lithium ion battery pack. If TEMP pin’s voltage is below 45% or above 80% of supply voltage VCC, this means that battery ’s temperature is too low or too high, charging is suspended. The temperature sense function can be disabled by grounding the TEMP pin. PROG Constant Charge Current Setting and Charge Current Monitor Pin The charge current is programmed by connecting a resistor RPROG from this pin to GND. When in precharge mode, the PROG pin ’ s voltage is regulated to 0.1V. When charging in constant-current mode this pin’s voltage is regulated to 1V. In all modes during charging, the voltage on this pin can be used to measure the charge current using the following formula: I PROG  3 4 5 VPROG  1450 RPROG GND Ground VCC Positive input supply voltage Provides power to the internal circuit. When VCC drops to within 80mV of the BAT pin voltage, the PT4057 enters low power sleep mode, dropping IBAT to less than 2μA. BAT Battery connection Pin Connect the positive terminal of the battery to this pin. Dropping BAT pin’s current to less than 2μA when IC in disable mode or in sleep mode. BAT pin provides charge current to the battery and provides regulation voltage of 4.35V. Charge terminated status output 6 STDBY STDBY is pulled low by an internal switch to indicate a battery charge terminated; this means Charge termination. Otherwise pin is in high impedance state. Open-Drain charge status output 7 8 CHRG CE When the battery is being charged, the CHRG pin is pulled low by an internal switch,otherwise, CHRG pin is in high impedance state. Chip enable input A high input will put the device in the normal operating mode. Pulling the CE pin to low level will put the PT4057 into disable mode. The CE pin can be driven by TTL or CMOS logic level. 　 www.puolop.com - 3- ＰＴ４０５７ Block Diagram Absolute Maximum Ratings Parameter Rating Unit Input supply voltage : VCC -0.3～8 V PROG pin voltage -0.3～VCC+0.3 V BAT pin voltage -0.3～7 V TEMP pin voltage -0.3～10 V CHRG pin voltage -0.3～10 V STDBY pin voltage -0.3～10 V CE pin voltage -0.3～10 V BAT pin current 1200 mA PROG pin current 1200 uA Maximum junction temperature 150 ℃ Operating ambient temperature -40～85 ℃ Storage temperature -65～125 ℃ Soldering temperature and time +260（Recommended 10S） ℃ Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. 　 www.puolop.com - 4- ＰＴ４０５７ Electrical Characteristics Symbol Parameter Vcc Input supply voltage ICC -IBAT VFLOAL IBAT Static Current Regulated output voltage BAT pin current (The condition of current mode is VBAT=3.9V) Test Condition MAX TPY MIN Unit 4.0 5.0 8.0 V Charge mode, RPROG=1.3K 150 500 uA Standby mode (charge end) 55 100 uA Shutdown mode RPROG not connected, VCC