prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 1 of 10 smart charge r with power path general description the lp 78090 is a monolithic linear battery charger whit smart power path switch for single - cell li - ion batteries in a wide range of tablet and other portable devices. i t integr ates a linear regulated voltage for power the system and charging the battery at the same time. t his device supports both usb and high power dc adapter input. its charger is a complete constant - current constant voltage linear charger with adjustable charge current up to 1000ma. no external sense resistor is needed, and no blocking diode is required due to the internal mosfet architecture. thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient t emperature. the charge voltage is fixed at 4.2v, and the charge current can be iset rammed externally with a single resistor. the charger automatically terminates the charge cycle when the charge current drops to 1/10th the iset rammed value after the fina l float voltage is reached. when the input supply (wall adapter or usb supply) is removed, the lp 78090 automatically enters a low current state, dropping the battery drain current to less than 15 a. w hen connecting a high power dc adapter, the smart power path management allows LP78090 power the system with vin voltage or bat voltage by switch ing the voltage level on sc pin and charge the battery simultaneously. t his allows immediate system operation even under moving away or deeply discharged battery. w he n the input current limit is reached, the voltage applied on the sys pin would pull down t o the battery voltage making the charge current decrease. i f the current out of sys pin is more than charge current plus 1200ma, LP78090 with turn power adapter and b attery support the system load together. t he LP78090 provides a n internal path from battery to system in the event the input is removed. other features include charge current monitor, under voltage lockout, automatic recharge and a status pin to indicate c harge termination and the presence of an input voltage. order information lp 78090 f: pb - free features ? programmable charge current up to 1 0 00ma ? smart power path management ? no mosfet, sense resistor or blocki ng diode required ? constant - current/constant - voltage op eration with thermal regulation to maximize charge rate without risk of overheating ? charges single cell li - ion batteries directly from usb port ? 15 a leakage current in shutdown ? c harging operation and ch arge c omplete indicator ? thermal limiting regulation on chip ? internal soft start function ? built - in short - circuit protection ? consumption available in tdfn - 10 package ? rohs compliant and 100% lead (pb) - free marking information applications ? mid/pad ? a utomobile data recorder or event data recorder ? power bank ? smart phone ? bluetooth applications device marking package shipp ing lp 78090 qvf qv:tdfn10 3k/reel package type qv:tdfn - 10
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 2 of 10 functional pin description p acka ge type p i n co n fi gur a ti ons tdfn - 10 pin description pin no. pin description 1 ,3 sys output of power supply for system . 2 ,5 vin p ower supply input for system and charge . 4, 6 bat bat is the connection to the battery. typically a 10f tantalum capacitor is needed for stability wh en there is no battery attached. when a battery is attached, only a 0.1f ceramic capacitor is required. 7 chrg 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 cyc le is completed, the pin is pulled high. 8 stdby open - drain complete 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 . 9 iset charge curren t program, charge current monitor and shutdown pin. the charge current is pro grammed by connecting a 1% resistor ( r prog )t o ground. when charging in constant - current mode, this pin servos to 2 v. in all modes, the voltage on this pin can be used to measure t he charge current using the following formula .lp 78090 : iset=1 2 00/r prog . 10 sc s mart controller . 11 gnd ground pin.
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 3 of 10 application circuit c1 10uf c2 10uf c3 10uf r3 2k zener 4.3v d1-red d2-green r1 1k r2 2k sy s vcc bat LP78090 vin vin stdby sc gnd iset bat sy s sy s bat chrg
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 4 of 10 function block diagram
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 5 of 10 absolute maximum ratings ? input voltage to gnd ( vin ) ---------------- --- ---------- -------------- ------------------------ -- -- ------------ ---- - 0.3 v to 6.5 v ? v sys ----------------------------------------------------- ---- --------- ------------- --------------------------- --- ------------ - - 0.3 v to 6 v ? bat, iset, stat ---------------- ----- ------------------- -------------- ------------------------------------- - 0.3v to v in +0.3v ? bat short - circuit duration ------------------------------- ---------------- ---------------------------------------- ----- continuous ? bat pin current -------------------------------------------- --------------- ---------- - --------------- -- --------------------- 12 00ma ? maximum junction temperature ---------------------- --------------- -- - ------------------------------------- --------------- 125c ? operating junction temperature range (t j ) -------------------- ------------- --------------------------------- - 40 to 85 c ? maximum sold ering temperature (at leads, 10 sec) ---------- ------------- -------------------------------------------- 260 c thermal information ? maximum power dissipation (pd ,ta<40 c) -------------------------- ---------------- --------------------- --------------- 1.5 w ? thermal resistance (ja) --------------------------------------------------------- --------------- -------------- -------------- 6 8 /w
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 6 of 10 electrical characteristics (t he specifications which apply over the full operating temperature range, otherwise specifications are at ta = 25 c. v in1/2= bvin = 5v, unless otherwise noted. ) symbol parameter conditions min typ. max units charge v in adapter /usb voltage range 3.9 5 5.5 v i q input supply current charge mod e , r iset = 10k 3 3 0 2000 ua standby mode (charge terminated) 2 3 0 50 0 shutdown mode (r iset not connected, vin < v bat , or vin < v uv and sc =0v ) 40 6 0 v float regulated output (float) voltage 0c t a 85c, i bat = 40ma 4.158 4.2 4.242 v i bat current input to battery r iset = 1 .2 k, current mode 800 1 0 0 0 1200 ma r iset = 2k, current mode 500 6 00 700 standby mode, v bat = 4.2v shutdown mode (r iset not connected) sleep mode, vin = 0v 0 - 2 .5 1 1 - 6 2 2 ua isys c urrent limit form bat or vin to sys 1100 12 5 0 1400 ma i trikl trickle charge current v bat < v trikl , r iset = 1. 2k 80 100 120 ma v trikl trickle charge threshold voltage r iset = 10k, v bat rising 2.8 2.9 3.0 v v trhys trickle charge hysteresis voltage r iset = 10k 120 mv v uv vin under voltage lockout threshold for charge vin from low to high 3. 9 v v uvhys vin under voltage lockout hysteresis for charge 150 200 300 mv v msd manual shutdown charge threshold voltage iset pin falling 2.2 v v asd vin C vbat lockout threshold voltage vin from low to high 70 100 140 mv vin from high to low 5 30 50 mv i term c/10 charge termination current threshold r iset = 10k , i term / i charge 0.085 0.10 0.115 ma/ma r iset = 2k , i t erm / i charge 0.085 0.10 0.115 ma/ma v set iset pin voltage r iset = 10k, current mode 2 v v stat chrg stdby pin output low voltage i stat = 5ma 0.35 0.6 v v restat recharge battery voltage 4.05 v v restat recharge battery threshold voltage v float - v restat 100 150 200 mv r on power fet on resistance (between vin and bat) 3 00 m r ds(on) path s witch nmos r ds(on) 130 m ? v sc l logic - low voltage 0. 4 v v sc h logic - high voltage 1 v i sc vin=v sc =5v - 1 1 ua v sys voltage on sys pin 4.3 v vin vin v vin =float vbat vin < 4.3 v vbat t lt t hermal limit temperature 120 t sd t hermal shut down 150 charge characteristics
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 7 of 10
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 8 of 10 application information the lp 78090 is a linear switching charger ic with smart power path management integrated for powering the system and charging a single cell lithium - ion battery simultaneously. i t can deliver up to 1 0 00ma of charge current (using a good thermal pcb layout) with a final float voltage accuracy of 1%. the lp 78090 includes an internal p - channel power mosfet and thermal regulation circuitry. no blocking diode or external current sense resistor is required; thus, the basic application circuit requires only four external com ponents. furthermore, the lp 78090 is capable of operat ing from a usb power source 500ma for usb 2.0 and 850ma for usb3.0 with resistor change on iset pin . i t has precious average input current limit and average current limit form battery to system, to make maximum use of the allowable input power. a nd LP78090 would give priority to en suring the system load approximately up to 2.4a, which contains 1.2a form vin and 1.2a form battery. LP78090 will reduce charging current or even power from battery to satisfy the system load when its demand is over the input current limit. i n low system l oad situation, t he remain ing current is supply for charger programmed by an external resistor connected from iset pin to gnd. t he device would reduce the charge current when the die temperature exceeds 120 . t wo 130m mosfet integrated work as an ideal diode to connecting the battery and vin to the system load, and one of this two mosfet will turn on allowing the battery to power up the system when the input is removed with circuit in page 3 . sys pin voltage switch t he voltage on the sys pin is set by the sc voltage, vin voltage and battery voltage. vin< 4.3 v condition , voltage power for system always keeps with battery voltage. 4.3 v < vin condition, voltage power for system always keeps with vin voltage current limit t he current limit regulate in two directions: from vin to sy stem and from battery to system , each one is limited to 1.2a. when the system load needs the current above 1.2a, LP78090 would divert part of charge current to system. a nd the device would power system from vin and battery when the system current is more than charge current plus 1.2a. normal charge cycle a charge cycle begins when the voltage at the vin pin ri ses above the uvlo threshold level and a 1% iset ram 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. in this mode, the lp 78090 supplies approximately 1/10 the iset rammed charge current to bring the battery volt age up to a safe level for full current charging. when the bat pin voltage rises above 2.9v, the charger enters constant - current mode, where the iset rammed charge curre nt is supplied to the battery. when the bat pin approaches the final float voltage (4.2v), the lp 78090 enters constant - voltage mode and the charge current begins to decrease. when the charg e current drops to 1/10 of the iset rammed value, the charge cycle ends. iset ramming charge current the charge current is iset rammed using a single resistor from the iset pin to ground. the battery charge current is 5 00 times the current out of the iset pin. the iset ram resistor and the charge current are calculated using the following equations: lp 78090 : rset= 1 2 00 v/ichg ichg= 1 2 00 v/rset 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= vset x 6 0 0/rset note: vset is 2v olts . charge termination when charging, transie nt loads on the bat pin can cause the iset pin to fall below 2 00mv for short periods of time before the dc charge current has dropped to 1/10th the iset rammed value. the 1ms filter time (t term ) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termi nation. once the average charge current drops below 1/10th the iset rammed value, the lp 78090 terminates the charge cycle and ceases to provide any current through the bat pin. in this state, all l oads on the bat pin must be supplied by the battery.
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 9 of 10 the lp 78090 constantly monitors the bat pin voltage in standby mode. if this voltage drops below the 4.05v recharge threshold (v re stat ), another charge cycle be gins and current is once again supplie d to the battery. to manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied, or the charger must be shut down and restarted using the iset pin. figure 2 shows the state diagram of a typical charge cycle. char ge status indicator the charge status output has two d ifferent st ates: strong pull - down (~10ma) and high impedance. the strong pull - down state indicates that the lp 78090 is in a charge cycle. once the charge cycle has terminated, the pin state is determin ed by under voltage lockout conditions. high impedance indicates that the lp 78090 is in under voltage lockout mode: either vin is less than 100mv above the bat pin voltage or insufficient voltage is applied to the vin pin. a microprocessor can be used to distin guish between these t wo states this method is dis cussed in the applications information section. function chrg (pin 8 ) stdby (pin7) charging low high charge completed high low thermal limiting an internal thermal feedback loop reduces the iset r ammed charge current if the die temperature attempts to rise above a preset value of approximately 120c. this feature protects the lp 78090 from excessive temperature and allows the user to push the limits of the power handling capability of a given circui t board without risk of damaging the lp 78090 . the charge current can be set according to typical (not worst - case) ambient temperature with the assurance that the charger will automatically reduce the current in worst - case conditions. tdfn power consid erat ions are discussed further in the applications informa tion section. automatic recharge once the charge cycle is terminated, the lp 78090 continu ously monitors the voltage on the bat pin using a com parator with a 2ms filter time (t recharge ). a charge cyc le restarts when the battery voltage falls below 4.05v (which corresponds to approximately 80% to 90% battery capac ity). this ensures that the battery is kept at or near a fully charged condition and eliminates the need for periodic charge cycle initiatio ns. stat output enters a strong pull - down state during recharge cycles.
prelimin ary datasheet lp 78090 lp 78090 C 0 0 version 1.0 feb . - 20 14 email : marketing@lowpowersemi.com www.lowpowersemi.com page 10 of 10 packag ing information tdfn - 10
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