LP4074 POWER | Alldatasheet

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Technical content

Features

 Programmable Charge Current Up to 600mA  No MOSFET, Sense Resistor or Blocking Diode Required  Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize  Charge Rate Without Risk of Overheating  4.2V Charge Voltage with ± 1% Accuracy  Charge Current Monitor Output for Gas Gauging  Automatic Recharge  3V Trickle Charge Threshold  Charging OTP  Package in SOT23-5/SOT23-6 Typical Application Circuit ISET STAT2 VBAT STAT1 Battery CBAT 10uF VIN RSET GND CIN 10uF VIN Marking Information Part Marking Package Shipping LP4074B5F LP4074 YWX SOT23-5 3K/REEL LP4074B6F LP4074 YWX SOT23-6 3K/REEL Marking indication: Y:Production year W:Production week X:Production batch.

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 2 of 8 Preliminary Datasheet LP4074 Functional Pin Description Pin Configurations VIN GND STAT1 BAT ISET1 3 4 Top View VIN GND STAT1 BAT ISET1 3 4 Top View

5 STAT2

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. 2 2 GND Ground. 3 3 BAT Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. 4 4 VIN Positive Input Supply Voltage. Open-Drain Charge 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. 5 6 ISET Charge Current Program and Charge Current Monitor Pin. The charge current is programmed by connecting a 1% resistor, RISET, to ground. When charging in constant-current mode, this pin servos to 1V. In all modes, the voltage on this pin can be used to measure the charge current using the following formula: IBAT=1000/RISET

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 3 of 8 Preliminary Datasheet LP4074 Function Block Diagram STAT1 STAT2 ISET GND BAT VIN CA MA VA REF SHDN TO BAT VCC 1000X Absolute Maximum Ratings Note1 Note1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Thermal Information ESD Susceptibility

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 4 of 8 Preliminary Datasheet LP4074

Electrical Characteristics

(TA = 25℃. VIN = 5V, unless otherwise noted.) SYMBOL PARAMETER CONDITIONS MIN TYP. MAX UNITS VIN Adapter/USB Voltage Range 4.5 5 6.5 V IIN Input Supply Current Standby Mode (Charge Terminated) 50 uA VFLOAT Regulated Output (Float) Voltage IBAT = 40mA 4.158 4.2 4.242 V IBAT BAT Pin Current RISET = 10K，Current Mode 100 mA RISET = 2K，Current Mode 500 Standby Mode, VBAT = 4.2V Sleep Mode, VIN = 0V ±1 uA VTRIKL Trickle Charge Threshold Voltage RISET = 10k, VBAT Rising 3 V VTRHYS Trickle Charge Hysteresis Voltage RISET = 10K 150 mV ITRIKL Trickle charge current VBAT < VTRIKL, RISET =10K 40 mA VBAT < VTRIKL, RISET=2K 200 VUV VIN Undervoltage Lockout Threshold From VIN Low to High 3.8 V VUVHYS VIN Undervoltage Lockout Hysteresis 200 mV VASD VIN–VBAT Lockout Threshold Voltage 150 mV ITERM C/10 Termination Current Threshold 15 % IBAT VISET ISET Pin Voltage RISET = 10K,Charge Mode 1 V VSTAT STAT1/STAT2 Pin Output Low Voltage ISTAT = 5mA 0.5 V ISTAT STAT1/2 Pin Weak Pull-Down Current ICHRG = 5V 5 uA ΔVRECHRG Recharge Battery Threshold Voltage VFLOAT - VRECHRG 200 mV

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 5 of 8 Preliminary Datasheet LP4074 Applications Information The LP4074 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 600mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ± 1%. The LP4074 includes an internal P -channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only three external components. Furthermore, the LP4074 is capable of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the V IN pin rises above the UVLO threshold level and a 1% program resistor is connected from the ISET pin to ground or when a battery is connected to the charger output. If the BAT pin is less than 2.9V, the charger enters trickle charge mode. When the BAT pin voltage rises above 2.9V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin approaches the final float voltage (4.2V), the LP4074 enters constant-voltage mode and the charge current begins to decrease. When the charge curr ent drops to 1 .5/10 of the programmed value the charge cycle ends. Programming Charge Current The charge current is programmed using a single resistor from the ISET pin to ground. The battery charge current is 1000 times the current out of the ISET pin. The program resistor and the charge current are calculated using the following equations: RISET=1000÷IBAT, IBAT=1000÷RISET The charge current out of the BAT pin can be determined at any time by monitoring the ISET pin voltage using the following equation: IBAT=VISET÷RISET×1000 Charge Status Indicator (CHRG) The charge status output has two different states: strong pull-down (~5mA) and high impedance. The strong pull -down state indicates that the LP4074 is in a charge cycle. High impedance indicates that the charge cycle complete or the LP4074 is in under voltage lockout mode: either V IN is less than 150mV above the BAT pin voltage or insufficient voltage is applied to the V IN pin. A microprocessor can b e used to distinguish between these two states. Charge Stage STAT1 Status STAT2 Status Charging Low High Charge Complete High Low Charge Termination A charge cycle is terminated when the charge current falls to 1.5/10th the programmed value after the final float voltage is reached. This condition is detected by using an internal, filtered comparator to monitor the ISET pin. When the ISET pin voltage falls below 100mV for longer than TTERM (typically 1ms), charging is terminated. The charge current is latched off and the LP4074 enters standby mode, where the input supply current drops to 50µA. When charging, transient loads on the BAT pin can cause the ISET pin to fall below 150mV for short periods of time before the DC charge current has dropped to 1.5/10th the programmed value. The 1ms filter time (TTERM) 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 below 1 .5/10th the programmed value, the LP4074 terminates the charge cycle and ceases to provide any current through the BAT pin. In this state, all loads on the BAT pin must be supplied by the battery. The LP4074 constantly monitors the BAT pin voltage in standby mode. If t his voltage drops below the 4.0 V recharge threshold (VRECHRG), another charge cycle begins and current is once again supplied to the battery. To manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied.

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 6 of 8 Preliminary Datasheet LP4074 Thermal Limit An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 125℃. This feature protects the LP4074 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the LP4074. The charge current can be set according to typical (not worst -case) ambient temperature with t he assurance that the charger will automatically reduce the current in worst-case conditions. Automatic Recharge Once the charge cycle is terminated, the LP4074 continuously monitors the voltage on the BAT pin using a comparator with a 2ms filter time (TRECHARGE). A charge cycle restarts when the battery voltage falls below 4.0 V (which corresponds to 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 c harge cycle initiations. CHRG output enters a strong pull-down state during recharge cycles. Power Dissipation The conditions that cause the LP4074 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the IC. Nearly all of this power dissipation is generated by the internal MOSFET —this is calculated to be approximately: PD=(VIN－VBAT) × IBAT VIN Bypass Capacitor Many types of capacitors can be used for input bypassing; however, caution must be exercised when using multilayer ceramic capacitors. Because of the self -resonant and high Q characteristics of some types of ceramic capacitors, high voltage transients can be generated under some start -up conditions, such as connecting the charger input to a live power source. Adding a 1.5Ω resistor in series with an X5R ceramic capacitor will minimize start-up voltage transients. Layout Considerations  For the main current paths as indicated in bold lines, keep their traces short and wide.  Put the input capacitor as close as possible to the device pins (VIN and GND).  Connect all analog grounds to a command node and then connect the command node to th e power ground behind the output capacitors.

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 7 of 8 Preliminary Datasheet LP4074 Packaging Information SOT23-5

LP4074-00 Aug.-2018 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 8 of 8 Preliminary Datasheet LP4074 SOT23-6