View LTC4062EDD_7263598.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

ltc4062 1 4062fb charge current programmable up to 1a charges single-cell li-ion batteries directly from usb port preset float voltage with 0.35% accuracy micropower comparator for battery monitoring thermal regulation maximizes charge rate without risk of overheating programmable charge current detection/ termination programmable charge termination timer smart pulsing error feature smartstart tm prolongs battery life 20 a charger quiescent current in shutdown available in a low profile (0.75mm) 10-lead (3mm 3mm) dfn package typical applicatio u features descriptio u standalone linear li-ion battery charger with micropower comparator applicatio s u handheld computers portable mp3 players digital cameras complete charge cycle (1100mah battery) the ltc 4062 is a full-featured, flexible, standalone linear charger for single-cell lithium-ion batteries. it is capable of operating within usb power specifications. both programmable time and programmable current based termination schemes are available. furthermore, the chrg open-drain status pin can be programmed to indicate the battery charge state according to the needs of the applica- tion. a precise low power comparator is available even with no power applied as long as battery voltage is higher than 2.5v. additional safety features designed to maxi- mize battery lifetime and reliability include the smartstart charging algorithm. no external sense resistor or external blocking diode is required for charging due to the internal mosfet architec- ture. internal thermal feedback regulates the charge cur- rent to maintain a constant die temperature during high power operation or high ambient temperature conditions. the charge current is programmed with an external resis- tor. with power applied, the ltc4062 can be put into shutdown mode to reduce the supply current to 20 a and the battery drain current to less than 5 a. without power applied, the internal low power comparator can work sinking only 10 a from the battery. other features include smart recharge, usb c/5 current programming input and undervoltage lockout. time (hours) 0 0.5 1.5 2.5 3.0 charge current (ma) battery voltage (v) 2.0 900 800 700 600 500 400 300 200 100 0 4.3 4.2 4.1 4.0 3.9 3.8 3.7 3.6 3.5 3.4 4062 ta01b 1.0 battery current battery voltage v cc = 5v t a = 25 c 800ma single-cell li-ion battery charger (c/10 termination) + timer prog en c/5 i out bat v in 4.3v to 8v in + det ltc4062 gnd 619 ? 100k 715k 347k 800ma 1 f 4062 ta01 single-cell li-ion battery v cc bat > 3v bat < 3v , lt, ltc and ltm are registered trademarks of linear technology corporation. smartstart is a trademark of linear technology corporation. all other trademarks are the property of their respective owners. protected by u.s. patents, including 6522118.
ltc4062 2 4062fb absolute axi u rati gs w ww u package/order i for atio uu w (note 1) electrical characteristics the denotes specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v cc = 5v, unless otherwise noted. input supply voltage (v cc ) ........................ ?.3v to 10v en, out, chrg, in + , prog, c/5, bat ....... ?.3v to 10v timer, i det ..................................... ?.3v to v cc +0.3v bat short-circuit duration ........................... continuous v cc pin current ......................................................... 1a bat pin current ......................................................... 1a maximum junction temperature .......................... 125 c operating temperature range (note 2) ... ?0 c to 85 c storage temperature range .................. ?5 c to 125 c symbol parameter conditions min typ max units v cc input supply voltage 4.3 8 v i cc input supply current charge mode (note 4), r prog = 10k 240 500 a standby mode, charge terminated 130 300 a shutdown (en = 5v, v cc < v bat or v cc < v uv ) 20 50 a v float v bat regulated output voltage 4.185 4.2 4.215 v 0 < t a < 85 c 4.175 4.2 4.225 v i bat bat pin current r prog = 10k, constant current mode 93 100 107 ma r prog = 1.25k, constant current mode 760 800 840 ma standby mode, charge terminated, v bat = 4.2v ?.5 7 a shutdown mode, v bat = 4.2v 1 5 a v prog prog pin voltage r prog = 10k, constant current mode 0.97 1 1.03 v r prog = 1.25k, constant current mode 0.97 1 1.03 v v out out output low voltage i out = 5ma 0.10 0.25 v i out = 5ma, v cc = 0v, v bat = 2.55v 0.16 0.26 v v chrg chrg output low voltage i chrg = 5ma 0.1 0.25 v i trikl trickle charge current v bat < v trikl , r prog = 10k 6 10 14 ma v bat < v trikl , r prog = 1.25k 60 80 100 ma v trikl trickle charge threshold voltage v bat rising 2.8 2.9 3 v hysteresis 100 mv v uv v cc undervoltage lockout from low to high 3.7 3.8 3.9 v voltage hysteresis 200 v v asd v cc ?v bat lockout threshold v cc from low to high, v bat = 4.3v 145 190 230 mv voltage v cc from high to low, v bat = 4.3v 10 45 75 mv r en en pin pull-down resistor 2 3.4 5 m ? top view 10 9 6 7 8 11 4 5 3 2 1 v cc prog i det en c/5 bat in + timer out chrg dd package 10-lead (3mm 3mm) plastic dfn t jmax = 125 c, ja = 40 c/w (note 3) exposed pad is ground (pin 11) must be soldered to pcb order options tape and reel: add #tr lead free: add #pbf lead free tape and reel: add #trpbf lead free part marking: http://www.linear.com/leadfree/ consult ltc marketing for parts specified with wider operating temperature ranges. order part number dd part marking LTC4062EDD lbjt
ltc4062 3 4062fb electrical characteristics the denotes specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v cc = 5v, unless otherwise noted. note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: the ltc4062 is guaranteed to meet performance specifications from 0 c to 70 c. specifications over the ?0 c to 85 c operating temperature range are assured by design, characterization and correlation with statistical process controls. note 3: failure to correctly solder the exposed pad of the package to the pc board will result in a thermal resistance much higher than 40 c/w. note 4: supply current includes prog pin current and i det pin current (approximately 100 a each) but does not include any current delivered to the battery through the bat pin (approximately 100ma). note 5: this ic includes overtemperature protection that is intended to protect the device during momentary overload conditions. overtemperature protection will become active at a junction temperature greater than the maximum operating temperature. continuous operation above the specified maximum operating junction temperature may impair device reliability. symbol parameter conditions min typ max units v en en input threshold voltage en rising, 4.3v < v cc < 8v 0.4 0.7 1 v hysteresis 70 mv v ct charge termination mode threshold v timer from high to low 0.4 0.7 1 v voltage hysteresis 50 mv v ut user termination mode threshold v timer from low to high 3.9 4.2 v voltage hysteresis 50 mv i detect charge current detection threshold r det = 1k, 0 t a 85 c 90 100 110 ma r det = 2k, 0 t a 85 c455055ma r det = 10k, 0 t a 85 c81012ma r det = 20k, 0 t a 85 c 3.8 5 6.2 ma ? v rechrg recharge threshold voltage v float v rechrg , 0 t a 85 c 65 100 135 mv t ss soft-start time i bat from 0 to i chg 100 s t term termination comparator filter time current termination mode 0.8 1.5 2.5 ms t rechrg recharge comparator filter time 3 7 14 ms t timer charge cycle time c timer = 0.1 f 2.55 3 3.45 hr r c/5 c/5 pin pull-down resistor 2 3.4 5 m ? v c/5 c/5 input threshold voltage c/5 rising, 4.3v < v cc < 8v 0.4 0.7 1 v hysteresis 70 mv t lim junction temperature in constant 105 c temperature mode r on power fet ?n?resistance v bat = 3.85v, i cc = 175ma, r prog = 2k 375 m ? (between v cc and bat) comparator v in + in + pin threshold voltage v in + falling 0.988 1 1.012 v hysteresis 50 mv v bat-min minimum v bat supply voltage for the v cc = 0v, v bat falling 2.4 2.5 2.6 v low power comparator hysteresis 100 mv i bat supply current for the low power v cc = 0v, v bat = 2.5v 7 9 13 a comparator
ltc4062 4 4062fb typical perfor a ce characteristics uw battery regulated output (float) voltage vs charge current prog pin voltage vs temperature (constant-current mode) charge current vs prog pin voltage prog pin voltage vs v cc (constant-current mode) trickle charge current vs temperature charge current vs battery voltage trickle charge threshold voltage vs temperature battery regulated output (float) voltage vs temperature battery regulated output (float) voltage vs supply voltage charge current (ma) 0 600 1000 4062 g01 200 400 800 4.26 4.24 4.22 4.20 4.18 v float (v) 4.16 4.14 4.12 4.10 temperature ( c) ?0 v float (v) 4.215 4.210 4.205 4.200 4.195 4.190 4.185 ?5 02550 4062 g02 75 100 ?0 ?5 0 25 50 75 100 ?0 ?5 0 25 50 75 100 temperature ( c) v prog (v) 4062 g05 1.006 1.004 1.002 1.000 0.998 0.996 0.994 v prog (v) 0 i bat (ma) 1200 1000 800 600 400 200 0 0.2 0.4 0.6 0.8 4062 g04 1.0 1.2 temperature ( c) i trickle (ma) 84 82 80 78 76 4062 g07 ?0 ?5 0 25 50 75 100 temperature ( c) v trickle (v) 2.96 2.94 2.92 2.90 2.88 2.86 2.84 4062 g08 v bat (v) 3.0 i bat (ma) 550 450 350 250 150 50 3.8 4062 g09 3.2 3.4 3.6 4.0 v cc = 5v r prog = 1k v cc = 5v r prog = 10k r prog = 10k c/5 = v cc v cc = 5v v bat = 2.5v r prog = 1.25k v cc = 5v r prog = 1.25k v cc = 5v r prog = 1k c/5 = 5v v timer = 5v v cc = 5v r prog = 2k v cc = 4.3v v cc = 8v c/5 = 5v c/5 = 0v 4062 g03 v cc (v) 4.0 v float (v) 8.0 5.0 6.0 7.0 4.5 5.5 6.5 7.5 4.26 4.24 4.22 4.20 4.18 4.16 4.14 4.12 4.10 r prog = 1k t a = 25 c i bat = 10ma 4062 g06 v cc (v) 4.0 v prog (v) 8.0 5.0 6.0 7.0 1.006 1.004 1.002 1.000 0.998 0.996 0.994 4.5 5.5 6.5 7.5 v cc = 5v v bat = 4v r prog = 10k c/5 = 5v t a = 25 c unless otherwise noted.
ltc4062 5 4062fb internal charge timer vs temperature charge current vs supply voltage charge current vs ambient temperature with thermal regulation recharge threshold voltage vs temperature power fet ?n?resistance vs temperature charge current vs battery voltage undervoltage lockout voltage vs temperature en pin pulldown resistance vs temperature c/5 pin pulldown resistance vs temperature temperature ( c) ?0 ?5 0 i bat (ma) 400 1000 0 50 75 4062 g13 4062 g14 200 800 600 25 100 125 r prog = 1.25k onset of thermal regulation r prog = 2k v cc (v) 4.0 i bat (ma) 8.0 5.0 6.0 7.0 104 102 100 98 96 4.5 5.5 6.5 7.5 temperature ( c) ?0 v recharge (v) 4.16 4.14 4.12 4.10 4.08 4.06 4.04 ?5 02550 4062 g15 75 100 temperature ( c) ?0 500 r ds(on) (m ? ) 450 400 350 300 250 ?5 02550 4062 g16 75 100 v cc = 4v i bat = 200ma v cc = 8v v cc = 4.3v v cc = 5v v bat = 4v c/5 = 5v r prog = 10k ?0 ?5 0 25 50 75 100 temperature ( c) t timer (minutes) 195 190 185 180 175 170 165 4062 g10 c timer = 0.1 f v cc = 4.3v v cc = 8v 4062 g17 4062 g18 temperature ( c) ?0 25 75 ?5 0 50 100 v uv (v) 3.900 3.875 3.850 3.825 3.800 3.775 3.750 3.725 3.700 v bat (v) 0 i bat (ma) 3.0 900 800 700 600 500 400 300 200 100 0 0.5 4.5 1.0 1.5 2.0 2.5 3.5 4.0 v cc = 5v c/5 = 5v r prog = 1.25k ja = 40 c/w v cc = 5v v bat = 4v ja = 40 c/w 4062 g19 temperature ( c) ?0 25 75 ?5 0 50 100 5.0 4.5 4.0 3.5 3.0 2.5 2.0 r en (m ? ) 4062 g20 temperature ( c) ?0 25 75 ?5 0 50 100 5.0 4.5 4.0 3.5 3.0 2.5 2.0 r c/5 (m ? ) typical perfor a ce characteristics uw t a = 25 c unless otherwise noted.
ltc4062 6 4062fb en pin threshold voltage (on-to-off) vs temperature shutdown supply current vs temperature and v cc c/5 pin threshold voltage (high-to-low) vs temperature chrg pin output low voltage vs temperature out pin output low voltage vs temperature chrg pin i-v curve out pin i-v curve 4062 g22 4062 g25 4062 g26 temperature ( c) ?0 25 75 ?5 0 50 100 v c/5 (mv) 900 850 800 750 700 650 600 temperature ( c) ?0 v chrg (v) 0.6 0.5 0.4 0.3 0.2 0.1 0 25 75 ?5 0 50 100 temperature ( c) ?0 v out (v) 0.6 0.5 0.4 0.3 0.2 0.1 0 25 75 ?5 0 50 100 v cc = 5v v cc = 5v i out = 5ma v cc = 5v i chrg = 5ma temperature ( c) ?0 v en (mv) 900 850 800 750 700 650 600 ?5 02550 4062 g21 75 100 temperature ( c) ?0 i cc ( a) 70 60 50 40 30 20 10 ?5 02550 4062 g23 75 100 v cc = 5v en = v cc v cc = 4.3v v cc = 8v v cc = 5v i out (ma) 4062 g24 v out (v) 04 1 2 3 160 140 120 100 80 60 40 20 0 v cc = 5v v bat = 4v t a = 40 c t a = 25 c t a = 90 c v chrg (v) 0 i chrg (ma) 160 140 120 100 80 60 40 20 0 1 23 4 4062 g27 v cc = 5v v bat = 4v t a = 25 c t a = 40 c t a = 90 c in + 1.05v typical perfor a ce characteristics uw t a = 25 c unless otherwise noted.
ltc4062 7 4062fb uu u pi fu ctio s bat (pin 1): charge current output. this pin provides charge current to the battery and regulates the final float voltage to 4.2v. in + (pin 2): positive input of the micropower comparator. the negative input is tied internally to a precise bandgap voltage reference of 1v. there is approximately 50mv of hysteresis associated with the input comparator threshold (rising edge). timer (pin 3): timer program and termination select pin. this pin selects which method is used to terminate the charge cycle. connecting a capacitor, c timer , to ground selects charge time termination. the charge time is set by the following formula: time hours hours c f or cf time hours hours timer timer ()() . . () () = = 3 01 01 3 connecting the timer pin to ground selects charge cur- rent termination, while connecting the pin to v cc selects user termination. see applications information for more information on current and user termination. out (pin 4): low power comparator open-drain output. this comparator output pin has two states; pull-down and high impedance. this output can be used as a logic interface or as an led driver. in the pull-down state, an nmos transistor capable of sinking 10ma pulls down on the out pin. the state of this pin is dependent on the value of in + . when in + is greater than 1v the output pin is in pull- down state, if in + is less than 1v the output pin is in high impedance state. see applications information. chrg (pin 5): open-drain charge status output. the charge status indicator pin has three states: pull-down, pulse at 6hz and high impedance. this output can be used as a logic interface or as a led driver. in the pull-down state, an nmos transistor capable of sinking 10ma pulls down on the chrg pin. the state of this pin depends on the value of i detect as well as the termination method being used. see applications information. c/5 (pin 6): c/5 enable input. used to control the amount of current drawn by the charger when powered from a usb port. a logic high on the c/5 pin sets the current limit to 100% of the current programmed by the prog pin. a logic low on the c/5 pin sets the current limit to 20% of the current programmed by the prog pin. an internal 3m ? pull-down resistor defaults the c/5 pin to its low current state. en (pin 7): charger enable input. a logic high on the en pin places the charger into shutdown mode, where the input quiescent current is less than 50 a. a logic low on this pin enables charging. an internal 3m ? pull-down resistor to ground defaults the charger to its enabled state. i det (pin 8): current detection threshold program pin. the current detection threshold, i detect , is set by con- necting a resistor, r detect , to ground. i detect is set by the following formula: i r r i v r or r v i detect prog det chg det det detect == = 10 100 100 the chrg pin becomes high impedance when the charge current drops below i detect . i detect can be set to 1/10th the programmed charge current by connecting i det di- rectly to prog. if the i det pin is not connected, the chrg output remains in its pull-down state until the charge time elapses and terminates the charge cycle. see applications information. this pin is clamped to approximately 2.4v. driving this pin to voltages beyond the clamp voltage should be avoided. prog (pin 9): charge current program and charge cur- rent monitor. the charge current is set by connecting a resistor, r prog , to ground. when charging in constant current mode, this pin servos to 1v. the voltage on this pin can be used to measure the charge current using the following formula: i v r bat prog prog =? 1000
ltc4062 8 4062fb uu u pi fu ctio s + + + 11 9 8 3 ca ma 1 1 1000 1.2v 2.9v prog i det r det c timer r prog 0.1v to bat 0.2v 1v 0.1v + + c3 c2 logic t a t die 105 c shdn 4062 bd gnd + va bat v cc 1 10 term rechrg 4.1v 1v to bat en sel timer counter oscillator in + out chrg c/5 en logic c/5 c/5 stop 3m 3m 5 6 7 + + c1 4 2 c4 block diagra w v cc (pin 10): positive input supply voltage. provides power to the battery charger. this pin should be bypassed with a 1 f capacitor. gnd (exposed pad) (pin 11): ground. this pin is the back of the exposed metal pad package and must be soldered to the pcb copper for minimal thermal resistance.
ltc4062 9 4062fb operatio u the ltc4062 is designed to charge single-cell lithium-ion batteries. using the constant current/constant voltage algorithm, the charger can deliver up to 1a of charge current with a final float voltage accuracy of 0.35%. the ltc4062 includes an internal p-channel power mosfet and thermal regulation circuitry. no blocking diode or external sense resistor is required; thus, the basic charger circuit requires only two external components. normal operation the charge cycle begins when the voltage at the v cc pin rises above the uvlo level and a discharged battery is connected to bat. if the bat pin voltage is below 2.9v, the charger enters trickle charge mode. in this mode, the ltc4062 supplies 1/10th of the programmed charge current in order to bring the battery voltage up to a safe level for full current charging. once 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 ltc4062 enters constant voltage mode and the charge current decreases as the battery becomes fully charged. the ltc4062 offers several methods with which to termi- nate a charge cycle. connecting an external capacitor to the timer pin activates an internal timer that stops the charge cycle after the programmed time period has elapsed. grounding the timer pin and connecting a resistor to the i det pin causes the charge cycle to terminate once the charge current falls below a set threshold when the charger is in constant voltage mode. connecting the timer pin to v cc disables internal termination, allowing external charge user termination through the en input. see applications information for more information on charge termination methods. programming charge current the charge current is programmed using a single resistor from the prog pin to ground. when the charger is in the constant current mode, the voltage on the prog pin is 1v. the battery charge current is 1000 times the current out of the prog pin. the program resistor and the charge current are calculated by the following equations: r v i i v r prog chg chg prog == 1000 1000 , the charge current out of the bat pin can be determined at any time by monitoring the prog pin voltage and applying the following equation: i v r bat prog prog =? 1000 smartstart when the ltc4062 is initially powered on or brought out of shutdown mode, the charger checks the battery voltage. if the bat pin is below the recharge threshold of 4.1v (which corresponds to approximately 80-90% battery capacity), the ltc4062 enters charge mode and begins a full charge cycle. if the bat pin is above 4.1v, the ltc4062 enters standby mode and does not begin charging. this feature reduces the number of unnecessary charge cycles, prolonging battery life. automatic recharge when the charger is in standby mode, the ltc4062 continuously monitors the voltage on the bat pin. when the bat pin voltage drops below 4.1v, the charge cycle is automatically restarted and the internal timer is reset to 50% of the programmed charge time (if time termination
ltc4062 10 4062fb operatio u is being used). this feature eliminates the need for peri- odic charge cycle initiations and ensures that the battery is always fully charged. automatic recharge is disabled in user termination mode. thermal regulation an internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 105 c. this feature protects the ltc4062 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 ltc4062. the charge current can be set according to typical (not worst-case) ambient temperatures with the assurance that the charger will automatically reduce the current in worst-case conditions. undervoltage lockout (uvlo) an internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until v cc rises above the undervoltage lockout threshold (3.8v). the uvlo circuit has a built-in hysteresis of 200mv. furthermore, to protect against reverse current in the power mosfet, the uvlo circuit keeps the charger in shutdown mode if v cc falls to less than 45mv above the battery voltage. hysteresis of 145mv prevents the charger from cycling in and out of shutdown. manual shutdown at any point in the charge cycle, the charger can be put into shutdown mode by pulling the en pin high. this reduces the supply current to less than 50 a and the battery drain current of the charger to less than 2 a. a new charge cycle can be initiated by floating the en pin or pulling it low. if shutdown is not required, leaving the pin disconnected continuously enables the circuit. trickle-charge and defective battery detection when the bat pin voltage is below the 2.9v trickle charge threshold (v trikl ), the charger reduces the charge current to 10% of the programmed value. if the battery remains in trickle charge for more than 25% of the total programmed charge time, the charger stops charging and enters a fault state, indicating that the battery is defective 1 . the ltc4062 indicates the fault state by driving the chrg open-drain output with a square wave. the duty cycle of this oscillation is 50% and the frequency is set by c timer : f f c hz chrg timer =? 01 6 . a led driven by the chrg output exhibits a pulsing pattern, indicating to the user that the battery needs replacing. to exit the fault state, the charger must be restarted either by toggling the en input or removing and reapplying power to v cc . charge status output (chrg) the charge status indicator pin has three states: pull- down, pulse at 6hz and high impedance. in the pull-down state, an nmos transistor pulls down on the chrg pin capable of sinking up to 10ma. a pull-down state indicates that the ltc4062 is charging a battery and the charge current is greater than i detect (which is set by the external component r det ). a high impedance state indicates that the charge current has dropped below i detect . in the case where the i det pin is left unconnected (r det = , i detect = 0), a high impedance state on chrg indicates that the ltc4062 is not charging. 1 the defective battery detection feature is only available when time termination is being used.
ltc4062 11 4062fb smart pulsing error feature ltc4062 has a pulsing state at the chrg pull-down pin of 6hz (50% duty cycle) due to defective battery detection (see trickle-charge and defective battery detection sec- tion). low power comparator (in + ; out) the low power, low offset comparator is designed with an internal 1v reference connected to the negative input. this reference is generated by a precise bandgap circuit. the + 1v 2 ltc4062 4062 f01 in + 4 out figure 1. low power comparator circuit comparator output drives a pull down nmos transistor able to sink up to 10ma. voltages lower than 1v at the in + pin set the out pin to a high impedance state. voltages higher than 1v plus a built-in 50mv hysteresis at the in + pin set the out pin to a low impedance state. the comparator is operational even when v cc is not applied provided the bat pin voltage is greater than 2.5v. when the voltage at the bat pin drops below 2.5v, the compara- tor shuts down and the current at the bat pin is reduced to <1 a. operatio u
ltc4062 12 4062fb method charge time termination mode charge current termination timer 0.1? to gnd i det r det to gnd charger description charges for 3 hours. after 3 hours, the charger stops charging and enters standby mode. recharge cycles last for 1.5 hours. charges for 3 hours. after 3 hours, the charger stops charging and enters standby mode. recharge cycles last for 1.5 hours. charges until charge current drops below i det , then enters standby mode. pull-down state when charging. high impedance state when charging is stopped. pulsing state available when ntc is used and is still charging. pull-down state when charging. high impedance state when charging is stopped. pulsing state available when ntc is used and is still charging. chrg output description pull-down state while i bat > i det . high impedance state while i bat < i detect or when charging is stopped. pulsing state available when ntc is used and is still charging. pull-down state while i bat > i detect . high impedance state while i bat < i detect or when charging is stopped. pulsing state available when ntc is used and is still charging. 0.1? to gnd gnd r det to gnd user selectable charge termination v cc r det to gnd charges indefinitely. charges indefinitely. smartstart is disabled. v cc nc charges indefinitely. smartstart is disabled. pull-down state when charging. high impedance state when charging is stopped. pulsing state available when ntc is used and is still charging. pull-down state when charging. high impedance state when charging is stopped. pulsing state available when ntc is used and is still charging. gnd nc nc applicatio s i for atio wu uu table 1 programming charge termination the ltc4062 can terminate a charge cycle using one of several methods, allowing the designer considerable flex- ibility in choosing an ideal charge termination algorithm. table 1 shows a brief description of the different termina- tion methods and their behaviors. charge time termination connecting a capacitor (c timer ) to the timer pin enables the timer and selects charge time termination. the total charge time is set by: time hours c f hours timer () . = 01 3 when the programmed time has elapsed, the charge cycle terminates and the charger enters standby mode. subse- quent recharge cycles terminate when 50% of the pro- grammed time has elapsed. the i det pin determines the behavior of the chrg output. connecting a resistor (r det ) from the i det pin to ground sets the charge current detection threshold, i detect : i r r i v r or r v i detect prog det chg det det detect == = 10 100 100 when the charge current (i bat ) is greater than i detect , the chrg output is in its pull-down state. when the charger enters constant voltage mode operation and the charge current falls below i detect , the chrg output becomes high impedance, indicating that the battery is almost fully charged. the chrg output will also become high impedance once the charge time elapses. if the i det pin is not connected, the chrg output remains in its pull- down state until the charge time elapses and terminates the charge cycle. figure 2 shows a charger circuit using charge time termi- nation that is programmed to charge at 500ma. once the charge current drops below 100ma in constant voltage mode (as set by r det ), the chrg output turns off the led. this indicates to the user that the battery is almost fully charged and ready to use. the ltc4062 continues to
ltc4062 13 4062fb applicatio s i for atio wu uu charge the battery until the internal timer reaches 3 hours (as set by c timer ). during recharge cycles, the ltc4062 charges the battery until the internal timer reaches 1.5 hours. figure 3 describes the operation of the ltc4062 charger when charge time termination is used. charge current termination connecting the timer pin to ground selects charge cur- rent termination. with this method, the timer is disabled and a resistor (r det ) must be connected from the i det pin to ground. i detect is programmed using the same equa- tion stated in the previous section. the charge cycle terminates when the charge current falls below i detect . this condition is detected using an internal filtered com- parator to monitor the i det pin. when the i det pin falls below 100mv for longer than t term (typically 1.5ms), charging is terminated. when charging, transient loads on the bat pin can cause the i det pin to fall below 100mv for short periods of time before the dc current has dropped below the i detect + v cc chrg prog i det c timer 0.1 f v in 4062 f02 bat 500ma timer r det 1k r prog 2k ltc4062 gnd c/5 figure 2. time termination mode. the charge cycle ends after 3 hours figure 3. state diagram of a charge cycle using charge time termination charge mode full current chrg state: pull-down if i bat > i detect hi-z if i bat < i detect charge time elapses 1/4 charge time elapses bat < 4.1v 4062 f03 trickle charge mode 1/10th full current bat > 2.9v bat < 2.9v 2.9v < bat < 4.1v bat > 4.1v en = 5v or uvlo condition standby mode no charge current chrg state: hi-z shutdown mode i cc drops to 20 a chrg state: hi-z chrg state: pull-down defective battery fault mode no charge current chrg state: pulsing recharge mode full current chrg state: pull-down if i bat > i detect hi-z if i bat < i detect 1/2 charge time elapses power on en = 0v or uvlo condition stops
ltc4062 14 4062fb applicatio s i for atio wu uu threshold. the 1.5ms filter time (t term ) on the internal comparator ensures that transient loads of this nature do not result in premature charge cycle termination. once the average charge current drops below i detect , the charger terminates the charge cycle. the chrg output is in a pull-down state while charging and in a high impedance state once charging has stopped. figure 4 describes the operation of the ltc4062 charger when charge current termination is used. when the charger is set for charge current termination and the battery is removed from the charger, a sawtooth waveform of several hundred mv will appear at the charger output. this is caused by the repeated cycling between termination and recharge events. this cycling results in pulsing at the chrg output. if an led is connected to this pin, it will exhibit a pulsing pattern, indicating to the user that a battery is not present. the frequency of the sawtooth is dependent on the amount of output capacitance. figure 4. state diagram of a charge cycle using charge current termination charge mode full current i bat < i detect in voltage mode 4062 f04 trickle charge mode 1/10th full current bat > 2.9v bat < 2.9v 2.9v < bat < 4.1v bat > 4.1v bat < 4.1v en = 5v or uvlo condition standby mode no charge current chrg state: hi-z shutdown mode i cc drops to 20 a chrg state: hi-z chrg state: pull-down chrg state: pull-down power on en = 0v or uvlo condition stops charge mode full current 4062 f05 trickle charge mode 1/10th full current bat > 2.9v bat < 2.9v 2.9v < bat en = 5v or uvlo condition shutdown mode i cc drops to 20 a chrg state: hi-z chrg state: pull-down power on en = 0v or uvlo condition stops chrg state: pull-down if i bat > i detect hi-z if i bat < i detect figure 5. state diagram of a charge cycle using user-selectable termination
ltc4062 15 4062fb applicatio s i for atio wu uu user-selectable charge termination connecting the timer pin to v cc selects user-selectable charge termination, in which all of the internal termination features are disabled. the charge cycle continues indefi- nitely until the charger is shut down through the en pin. the i det pin programs the behavior of the chrg output in the same manner as when using charge time termination. if the i det pin is not connected, the chrg output remains in its pull-down state until the charger is shut down. with user-selectable charge termination, the smartstart feature is disabled; when the charger is powered on or enabled, the ltc4062 automatically begins charging, re- gardless of the battery voltage. figure 5 describes charger operation when user-selectable charge termination is used. programming c/10 current detection/termination in most cases, an external resistor, r det , is needed to set the charge current detection threshold, i detect . however, when setting i detect to be 1/10th of i chg , the i det pin can be connected directly to the prog pin. this reduces the component count, as shown in figure 6. when prog and i det are connected in this way, the full- scale charge current, i chg , is programmed with a different equation: r v i i v r prog chg chg prog == 500 500 , stability considerations the battery charger constant voltage mode feedback loop is stable without any compensation provided a battery is connected. however, a 1 f capacitor with a 1 ? series resistor to gnd is recommended at the bat pin to reduce noise when no battery is present. when the charger is in constant current mode, the prog pin is in the feedback loop, not the battery. the constant current stability is affected by the impedance at the prog pin. with no additional capacitance on the prog pin, the charger is stable with program resistor values as high as 10k ? ; however, additional capacitance on this node re- duces the maximum allowed program resistor value. power dissipation when designing the battery charger circuit, it is not necessary to design for worst-case power dissipation scenarios because the ltc4062 automatically reduces the charge current during high power conditions. the conditions that cause the ltc4062 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the ic. most of the power dissipation is generated from the internal charger mosfet. thus, the power dissipation is calculated to be approximately: p d = (v cc ?v bat ) ?i bat p d is the power dissipated, v cc is the input supply voltage, v bat is the battery voltage and i bat is the charge current. the approximate ambient temperature at which the ther- mal feedback begins to protect the ic is: t a = 105 c ?p d ? ja t a = 105 c ?(v cc ?v bat ) ?i bat ? ja + v cc prog i det v in bat 500ma timer r det 2k r prog 2k ltc4062 gnd + v cc prog i det v in 4062 f06 bat 500ma timer r prog 1k ltc4062 gnd c/5 c/5 figure 6. two circuits that charge at 500ma full-scale current and terminate at 50ma
ltc4062 16 4062fb applicatio s i for atio wu uu example: an ltc4062 operating from a 5v wall adapter is programmed to supply 800ma full-scale current to a discharged li-ion battery with a voltage of 3.3v. assuming ja is 40 c/w (see thermal considerations), the ambient temperature at which the ltc4062 will begin to reduce the charge current is approximately: t a = 105 c ?(5v ?3.3v) ?(800ma) ?40 c/w t a = 105 c ?1.36w ?40 c/w = 105 c ?54.4 c t a = 50.6 c the ltc4062 can be used above 50.6 c ambient, but the charge current will be reduced from 800ma. the approxi- mate current at a given ambient temperature can be approximated by: i ct vv bat a cc bat ja = 105 ( ) using the previous example with an ambient temperature of 60 c, the charge current will be reduced to approximately: i cc vvcw c ca ima bat bat = = = 105 60 53340 45 68 662 (.) / / it is important to remember that ltc4062 applications do not need to be designed for worst-case thermal condi- tions, since the ic will automatically reduce power dissi- pation if the junction temperature reaches approximately 105 c. thermal considerations in order to deliver maximum charge current under all conditions, it is critical that the exposed metal pad on the backside of the ltc4062 package is properly soldered to the pc board ground. correctly soldered to a 2500mm 2 double sided 1oz copper board, the ltc4062 has a ther- mal resistance of approximately 40 c/w. failure to make thermal contact between the exposed pad on the backside of the package and the copper board will result in thermal resistances far greater than 40 c/w. as an example, a correctly soldered ltc4062 can deliver over 800ma to a battery from a 5v supply at room temperature. without a good backside thermal connection, this number could drop to less than 500ma. v cc bypass capacitor many types of capacitors can be used for input bypassing; however, caution must be exercised when using multi- layer ceramic capacitors. because of the self-resonant and high q characteristics of some types of ceramic capaci- tors, high voltage transients can be generated under some start-up conditions such as connecting the charger input to a live power source. adding a 1.5 ? resistor in series with an x5r ceramic capacitor will minimize start-up voltage transients. for more information, see application note 88. charge current soft-start and soft-stop the ltc4062 includes a soft-start circuit to minimize the inrush current at the start of a charge cycle. when a charge cycle is initiated, the charge current ramps from zero to the full-scale current over a period of approximately 100 s. likewise, internal circuitry slowly ramps the charge cur- rent from full-scale to zero when the charger is shut off or self terminates. this has the effect of minimizing the transient current load on the power supply during start-up and charge termination. reverse polarity input voltage protection in some applications, protection from reverse polarity on v cc is desired. if the supply voltage is high enough, a series blocking diode can be used. in other cases, where the diode voltage drop must be kept low, a p-channel mosfet can be used (as shown in figure 7). figure 7. low loss input reverse polarity protection v cc v in 4062 f07 ltc4062 drain-bulk diode of fet
ltc4062 17 4062fb applicatio s i for atio wu uu figure 8. combining wall adapter and usb power + v cc d1 prog i det 3.3k 2k mn1 5v wall adapter i chg = 800ma usb power i chg = 500ma mp1 4062 f08 bat ltc4062 1.24k li-ion battery system load 1k c/5 usb and wall adapter power the ltc4062 allows charging from both a wall adapter and a usb port. figure 8 shows an example of how to combine wall adapter and usb power inputs. a p-channel mosfet, mp1, is used to prevent back conducting into the usb port when a wall adapter is present and a schottky diode, d1, is used to prevent usb power loss through the 1k ? pull-down resistor. typically a wall adapter can supply more current than the 500ma limited usb port. therefore, an n-channel mosfet, mn1, and an extra 3.3k ? program resistor are used to increase the charge current to 800ma when the wall adapter is present.
ltc4062 18 4062fb typical applicatio s u + v cc timer bat prog i det ltc4062 gnd 2k 2.5k 5v wall adapter usb power 4062 ta04 li-ion cell 1 f c/5 400ma full-featured li-ion charger with low-battery comparator (using time termination) usb/wall adapter power li-ion charger (using charge current termination) + timer prog en c/5 i out bat v in 4.3v to 8v in + det ltc4062 gnd 1.24k 619 ? 100k 715k 347k 800ma 1 f 0.1 f 4062 ta03 single-cell li-ion battery v cc bat > 3v bat < 3v
ltc4062 19 4062fb dd package 10-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1669) package descriptio u 3.00 0.10 (4 sides) note: 1. drawing to be made a jedec package outline m0-229 variation of (weed-2). check the ltc website data sheet for current status of variation assignment 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package 0.38 0.10 bottom view?xposed pad 1.65 0.10 (2 sides) 0.75 0.05 r = 0.115 typ 2.38 0.10 (2 sides) 1 5 10 6 pin 1 top mark (see note 6) 0.200 ref 0.00 ?0.05 (dd10) dfn 1103 0.25 0.05 2.38 0.05 (2 sides) recommended solder pad pitch and dimensions 1.65 0.05 (2 sides) 2.15 0.05 0.50 bsc 0.675 0.05 3.50 0.05 package outline 0.25 0.05 0.50 bsc information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
ltc4062 20 4062fb linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2005 related parts lt/lwi 0906 rev b ?printed in usa part number description comments battery chargers ltc1734 lithium-ion linear battery charger in thinsot tm simple thinsot charger, no blocking diode, no sense resistor needed ltc1734l lithium-ion linear battery charger in thinsot low current version of ltc1734, 50ma i chrg 180ma ltc4002 switch mode lithium-ion battery charger standalone, 4.7v v in 24v, 500khz frequency, 3 hour charge termination ltc4050 lithium-ion linear battery charger controller features preset voltages, c/10charger detection and programmable timer, input power good indication, thermistor interface ltc4052 monolithic lithium-ion battery pulse charger no blocking diode or external power fet required, 1.5a charge current ltc4053 usb compatible monolithic li-ion battery charger standalone charger with programmable timer, up to 1.25a charge current ltc4054 standalone linear li-ion battery charger thermal regulation prevents overheating, c/10 termination, with integrated pass transistor in thinsot c/10 indicator, up to 800ma charge current ltc4057 lithium-ion linear battery charger up to 800ma charge current, thermal regulation, thinsot package ltc4058 standalone 950ma lithium-ion charger in dfn c/10 charge termination, battery kelvin sensing, 7% charge accuracy ltc4059 900ma linear lithium-ion battery charger 2mm 2mm dfn package, thermal regulation, charge current monitor output ltc4061/ standalone li-ion chargers with thermistor 4.2v/4.4v, 0.35%/ 0.4% float voltage, up to 1a charge current, ltc4061-4.4 thermistor input, 3mm 3mm dfn package ltc4063 li-ion charger with linear regulator up to 1a charge current, 100ma, 125mv ldo, 3mm 3mm dfn ltc4411/ltc4412 low loss powerpath tm controller in thinsot automatic switching between dc sources, load sharing, replaces oring diodes power management ltc3405/ltc3405a 300ma (i out ), 1.5mhz, synchronous step-down 95% efficiency, v in : 2.7v to 6v, v out = 0.8v, i q = 20 a, i sd < 1 a, dc/dc converter thinsot package ltc3406/ltc3406a 600ma (i out ), 1.5mhz, synchronous step-down 95% efficiency, v in : 2.5v to 5.5v, v out = 0.6v, i q = 20 a, i sd < 1 a, dc/dc converter thinsot package ltc3411 1.25a (i out ), 4mhz, synchronous step-down 95% efficiency, v in : 2.5v to 5.5v, v out = 0.8v, i q = 60 a, i sd < 1 a, dc/dc converter ms package ltc3440 600ma (i out ), 2mhz, synchronous buck-boost 95% efficiency, v in : 2.5v to 5.5v, v out = 2.5v, i q = 25 a, i sd < 1 a, dc/dc converter ms package ltc4413 dual ideal diode in dfn 2-channel ideal diode oring, low forward on-resistance, low regulated forward voltage, 2.5v v in 5.5v thinsot and powerpath are trademarks of linear technology corporation.

▲Up To Search▲

Price & Availability of LTC4062EDD

	To Download LTC4062EDD Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .