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_______________general description the MAX1647/max1648 provide the power control neces- sary to charge batteries of any chemistry. in the MAX1647, all charging functions are controlled through the intel system management bus (smbus) interface. the smbus 2-wire serial interface sets the charge voltage and current, and provides thermal status information. the MAX1647 functions as a level 2 charger, compliant with the duracell/intel smart battery charger specification. the max1648 omits the smbus serial interface, and instead sets the charge voltage and current proportional to the voltage applied to external control pins. in addition to the feature set required for a level 2 charger, the MAX1647 generates interrupts to signal the host when power is applied to the charger or a battery is installed or removed. additional status bits allow the host to check whether the charger has enough input voltage, and whether the voltage on or current into the battery is being regulated. this allows the host to determine when lithium- ion batteries have completed charge without interrogating the battery. the MAX1647 is available in a 20-pin ssop with a 2mm profile height. the max1648 is available in a 16-pin so package. ________________________applications notebook computers personal digital assistants charger base stations phones ____________________________features charges any battery chemistry: li-ion, nicd, nimh, lead acid, etc. intel smbus 2-wire serial interface (MAX1647) intel/duracell level 2 smart battery compliant (MAX1647) 4a, 2a, or 1a maximum battery-charge current 11-bit control of charge current up to 18v battery voltage 10-bit control of voltage 0.75% voltage accuracy with external 0.1% reference up to 28v input voltage battery thermistor fail-safe protection MAX1647/max1648 chemistry-independent battery chargers ________________________________________________________________ maxim integrated products 1 20 19 18 17 16 15 14 13 1 2 3 4 5 6 7 8 bst lx dhi dlo ccv vl dcin iout top view pgnd dacv sda scl batt cs sel cci 12 11 9 10 thm int agnd ref MAX1647 ssop 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 bst lx dhi dlo pgnd setv seti thm dcin vl ccv cci cs batt ref agnd max1648 so __________________________________________________________pin configurations part MAX1647 eap max1648 ese -40? to +85? -40? to +85? temp range pin-package 20 ssop 16 narrow so ______________ordering information for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. smbus is a trademark of intel corp. 19-1158; rev 1; 12/02
MAX1647/max1648 chemistry-independent battery chargers 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v dcin = 18v, v ref = 4.096v, t a = 0? to +85? . typical values are at t a = +25?, unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. dcin to agnd..........................................................-0.3v to 30v dcin to iout...........................................................-0.3v to 7.5v bst to agnd ............................................................-0.3v to 36v bst, dhi to lx ............................................................-0.3v to 6v lx to agnd ..............................................................-0.3v to 30v thm, cci, ccv, dacv, ref, dlo to agnd ................................................-0.3v to (vl + 0.3v) vl, sel, int , sda, scl to agnd (MAX1647) ...........-0.3v to 6v setv, seti to agnd (max1648)................................-0.3v to 6v batt, cs+ to agnd.................................................-0.3v to 20v pgnd to agnd .....................................................-0.3v to +0.3v sda, int current ................................................................50ma vl current ...........................................................................50ma continuous power dissipation (t a = +70?) 16-pin so (derate 8.7mw/? above +70?).................696mw 20-pin ssop (derate 8mw/? above +70?) ...............640mw operating temperature range MAX1647eap, max1648ese ...........................-40? to +85? storage temperature.........................................-60? to +150? lead temperature (soldering, 10s) .................................+300? % -0.65 +0.65 MAX1647, chargingvoltage( ) = 0x1060, chargingvoltage( ) = 0x3130; max1648, v setv = 3.15v, v setv = 1.05v voltage accuracy mv 2.94 MAX1647, sel = open, chargingcurrent( ) = 0x0020 cs to batt single-count current-sense voltage v 019 batt, cs input voltage range ? 350 500 vl < 5.15v, v batt = 12v batt input current (note 1) 15 vl < 3.2v, v batt = 12v ? 614 high or low dlo on-resistance ? 47 high or low dhi on-resistance ma 46 7.5v < v dcin < 28v, logic inputs = vl dcin quiescent current v 7.5 28.0 dcin input voltage range % 89 93 dhi maximum duty cycle khz 200 250 300 oscillator frequency ? 700 ref overdrive input current v 5.15 5.4 5.65 7.5v < v dcin < 28v, no load vl output voltage mv 100 i load = 10ma vl load regulation v 3.20 4 5.15 MAX1647 vl ac_present trip point v 3.74 3.9 4.07 0? < i source < 500? ref output voltage units min typ max conditions parameter ? 170 400 vl < 5.15v, v cs = 12v cs input current (note 1) 15 vl < 3.2v, v cs = 12v mv 170 185 200 MAX1647, sel = open, chargingcurrent( ) = 0x07f0; max1648, v seti = 1.024v cs to batt full-scale current-sense voltage supply and reference switching regulator
MAX1647/max1648 chemistry-independent battery chargers _______________________________________________________________________________________ 3 electrical characteristics (continued) (v dcin = 18v, v ref = 4.096v, t a = 0? to +85? . typical values are at t a = +25?, unless otherwise noted.) note 1: when dcin is less than 4v, vl is less than 3.2v, causing the battery current to be typically 2? (cs plus batt input current). v 0 1.024 seti input voltage range v 0 4.2 setv input voltage range ? 5 seti input bias current ? 1 setv input bias current bits 10 guaranteed monotonic vdac voltage-setting dac resolution bits 6 guaranteed monotonic cdac current-setting dac resolution v -7.5 -1.0 with respect to dcin voltage iout operating voltage range ma 25 31 38 MAX1647, v dcin = 7.5v, v iout = 0v iout output current % of v ref 3 4.5 6 MAX1647 thm thermistor_ur under-range trip point % of v ref 22 23.5 25 thm thermistor_hot trip point % of v ref 74 75.5 77 thm thermistor_cold trip point ma/v 0.2 gmi amplifier transconductance ma/v 1.4 gmv amplifier transconductance % of v ref 89.5 91 92.5 MAX1647 thm thermistor_or over-range trip point % of v dcin 86.5 89 91.5 MAX1647 batt power_fail trip point ? ?0 gmv amplifier maximum output current ? ?00 gmi amplifier maximum output current mv 25 80 200 1.1v < v ccv < 3.5v cci clamp voltage with respect to ccv units min typ max conditions parameter ma 6 v sda = 0.6v sda output low sink current ? -1 +1 sda, scl input bias current v 2.8 sda, scl input high voltage v 0.8 sda, scl input low voltage mv 25 80 200 1.1v < v cci < 3.5v ccv clamp voltage with respect to cci error amplifiers trip points and linear current sources current- and voltage-setting dacs (MAX1647) setv, seti (max1648) logic levels (MAX1647) chargingcurrent( ) = 0x0000 10 ? chargingcurrent( ) = 0x001f
MAX1647/max1648 chemistry-independent battery chargers 4 _______________________________________________________________________________________ electrical characteristics (v dcin = 18v, v ref = 4.096v, t a = -40? to +85? . typical values are at t a = +25?, unless otherwise noted. limits over this temperature range are guaranteed by design.) ? cs input current 5 vl < 3.2v, v cs = 12v mv 160 185 200 MAX1647, sel = open, chargingcurrent( ) = 0x07f0; max1648, v seti = 1.024v cs to batt full-scale current-sense voltage % -0.65 +0.65 MAX1647, chargingvoltage( ) = 0x1060, chargingvoltage( ) = 0x3130; max1648, v setv = 3.15v, v setv = 1.05v voltage accuracy ? batt input current 5 vl < 3.2v, v batt = 12v ? 614 high or low dlo on-resistance ? 47 high or low dhi on-resistance ma 46 7.5v < v dcin < 28v, logic inputs = vl dcin quiescent current % 89 dhi maximum duty cycle khz 200 250 310 oscillator frequency v 5.15 5.4 5.65 7.5v < v dcin < 28v, no load vl output voltage v 3.74 3.9 4.07 0? < i source < 500? ref output voltage units min typ max conditions parameter ma/v 1.4 gmv amplifier transconductance ma/v 0.2 gmi amplifier transconductance ? ?30 gmv amplifier maximum output current ? ?20 gmi amplifier maximum output current % of v ref 89.5 91 92.5 MAX1647 thm thermistor_or over-range trip point % of v ref 74 75.5 77 thm thermistor_cold trip point ? 1 setv input bias current ? 5 seti input bias current v 0.8 sda, scl input low voltage v 2.8 sda, scl input high voltage ? -1 +1 sda, scl input bias current % of v ref 22 23.5 25 thm thermistor_hot trip point % of v ref 3 4.5 6 MAX1647 thm thermistor_ur under-range trip point ma 6 v sda = 0.6v sda output low sink current supply and reference switching regulator error amplifiers trip points and linear current sources setv, seti (max1648) logic levels (MAX1647)
MAX1647/max1648 chemistry-independent battery chargers _______________________________________________________________________________________ 5 timing characteristics?ax1647 ( t a = 0? to +85? , unless otherwise noted.) timing characteristics?ax1647 ( t a = -40? to +85? , unless otherwise noted. limits over this temperature range are guaranteed by design.) ? 1 t dv scl falling edge to sda valid, master clocking in data ns 0 t hd:dat scl falling edge to sda transition ? 4.7 t su:sta start-condition setup time ? 4.7 t low ? 4 t high scl serial-clock high period scl serial-clock low period ? 4 t hd:sta start-condition hold time ns 250 t su:dat sda valid to scl rising-edge setup time, slave clocking in data units min typ max symbol parameter conditions conditions ? 1 t dv scl falling edge to sda valid, master clocking in data ns 0 t hd:dat scl falling edge to sda transition ? 4.7 t su:sta start-condition setup time ? 4.7 t low ? 4 t high scl serial-clock high period scl serial-clock low period ? 4 t hd:sta start-condition hold time ns 250 t su:dat sda valid to scl rising-edge setup time, slave clocking in data units min typ max symbol parameter
MAX1647/max1648 chemistry-independent battery chargers 6 _______________________________________________________________________________________ __________________________________________typical operating characteristics (circuit of figure 3, t a = +25?, unless otherwise noted.) MAX1647 batt load transient MAX1647/48-01 chargingvoltage( ) = 0x2ee0 = 12000mv chargingcurrent( ) = 0xffff = max value acdcin = 18.0v, sel = open, r1 = 0.1 ? r2 = 10k ? , c1 = 68 f, c2 = 0.1 f, c3 = 47nf l1 = 22 h, v ref = 4.096v 1ms/div 2.4v 12v v cci v ccv 200mv/div v batt 1v/div cci cci 0.9a to 1.9a to 0.9a ccv ccv MAX1647 batt load transient MAX1647/48-02 chargingvoltage( ) = 0x2ee0 = 12000mv chargingcurrent( ) = 0x03e8 = 1000ma acdcin = 18.0v, sel = open, c1 = 68 f, c2 = 0.1 f, c3 = 47nf, r1 = 0.1 ? r2 = 10k ? , l1 = 22 h, v ref = 4.096v 2ms/div 2.3v 12v v ccv v cci 100mv/div v batt 5v/div ccv ccv ccv cci cci cci 1.1a to 0.9a to 1.1a 0 050 vl voltage vs. load current 3.5 5.5 MAX1647/48-03 load current (ma) vl (v) 30 4.5 4.0 10 20 40 5.0 circuit of figure 3 v dcin = 6.6v 3.70 02.0 internal reference voltage 3.74 3.72 3.86 MAX1647/48-04 load current (ma) v ref (v) 3.82 3.80 3.78 3.76 0.5 1.0 1.5 3.84 -0.4 16,500 output voltage error -0.2 0.8 MAX1647/48-07 programmed voltage code in decimal output voltage error (%) 0.4 0.2 0 4500 8500 12,500 0.6 3ma load 300ma load 0 0 2500 input and output power 10 5 40 MAX1647/48-05 current into batt (ma) power (w) 30 25 20 15 500 1000 1500 2000 35 power to batt power into circuit v dcin = 28v v batt = 12.6v chargingcurrent( ) = 0xffff chargingvoltage( ) = 0xffff 100 0 2500 MAX1647 output v-i characteristic 10 0.001 MAX1647/48-06 load current (ma) drop in batt output voltage (%) 1500 0.1 1 500 1000 2000 0.01 v dcin = 28v, v ref = 4.096v chargingvoltage( ) = 0xffff chargingcurrent( ) = 0xffff batt no-load output voltage = 16.384v
MAX1647/max1648 chemistry-independent battery chargers _______________________________________________________________________________________ 7 ______________________________________________________________pin description linear current-source output 1 iout input voltage for powering charger 1 2 dcin voltage-regulation-loop compensation point 3 4 ccv chip power supply. 5.4v linear regulator output from dcin. 2 3 vl current-range selector. tying sel to vl sets a 4a full-scale current. leaving sel open sets a 2a full-scale current. tying sel to agnd sets a 1a full-scale current. 6 sel battery voltage input and current-sense negative input 6 8 batt current-sense positive input 5 7 cs current-regulation-loop compensation point 4 5 cci 3.9v reference voltage output or external reference input 7 9 ref current-regulation-loop set point 10 seti voltage-regulation-loop set point 11 setv open-drain interrupt output 11 int analog ground 8 10 agnd thermistor sense voltage input 9 12 thm serial data 14 sda power ground 12 16 pgnd voltage dac output 15 dacv serial clock 13 scl high-side power mosfet driver output 14 18 dhi power connection for the high-side power mosfet driver 16 20 bst power connection for the high-side power mosfet driver 15 19 lx low-side power mosfet driver output 13 17 dlo function pin MAX1647 max1648 name
MAX1647/max1648 chemistry-independent battery chargers 8 _______________________________________________________________________________________ start condition most significant address bit (a6) clocked into slave a5 clocked into slave a4 clocked into slave a3 clocked into slave t high t low t hd:sta t su:sta t su:dat t hd:dat scl sda t su:dat t hd:dat figure 1. smbus serial interface timing?ddress t dv slave pulling sda low t dv most significant bit of data clocked into master acknowledge bit clocked into master rw bit clocked into slave scl sda figure 2. smbus serial interface timing?cknowledge
MAX1647/max1648 chemistry-independent battery chargers _______________________________________________________________________________________ 9 agnd 2 q1 d5 d2 r6 d6 r7 c9 r5 c6 m1 m2 d1 d4* dc source c1 r1b l1 d3 r1a c7 ref r3 c4 thm cci gnd vout iout c5 (note 2) 10 1 2 6 n.c. 3 20 18 19 17 16 7 8 13 14 11 4 6 9 12 5 4 15 = high-current traces (8a max) note 1: c6, m2, d1, and c1 grounds must connect to the same rectangular pad on the layout. note 2: c5 must be placed within 0.5cm of the MAX1647, with traces no longer than 1cm connecting vl and pgnd. *optional (see negative input voltage protection section). c8 c2 r2 c3 r4 vin dcin MAX1647 sel vl bst ccv dacv lx dlo pgnd cs dhi (note 1) smart battery standard connector -td c+ batt scl sda int host and load smbclock smbdata kint- gnd 7.5v?8v max874 figure 3. MAX1647 typical application circuit
MAX1647/max1648 chemistry-independent battery chargers 10 ______________________________________________________________________________________ units qty designation table 1a. component selection for figure 3 circuit (also use for figure 4) source/type notes sprague, 595d476x0020d7t, d case avx, tpse476m020r0150, e case 20v, esr at 250khz 0.4 ? ? 0.1 c2, c4, c7, c9 10v, ceramic or low esr ? 1 c5 nf 47 c3 ? 47 c1 35v 10v nf 22 c8 ? 22 c6 niec, nsq03a04, flat-pak (smc) niec, 30vq04f, to-252aa (smd) motorola, mbrs340t3, smc motorola, mbrd340t4, dpak diodes inc., sk33, smc ir, 30bq040, smc 3a i dc , 30v schottky diode, p d > 0.8w, 1n5821 equivalent 50ma i dc , 40v fast-recovery diode, 1n4150 equivalent d2, d5 motorola, mmsf5n03hd, so-8 motorola, mmdf3n03hd, so-8 motorola, mtd20n03hdl, dpak ir, irf7201, so-8 ir, irf7303, so-8 ir, irf7603, micro8 siliconix, si9410dy, so-8 siliconix, si9936dy, so-8 siliconix, si6954dq, tssop-8 r ds, on 0.1 ? , v dss 30v, p d > 0.5w, logic level, n-channel power mosfet motorola, 2n7002lt1, sot23 motorola, mmbf170lt1, sot23 diodes inc., 2n7002, sot23 diodes inc., bs870, sot23 zetex, zvn3306f, sot23 central semiconductor, 2n7002, sot23 r ds, on 10 ? , v dss 30v, logic level, n-channel power mosfet, 2n7002 equivalent m2 m1 d1, d3, d4 v ce, max -30v, 50ma i c, cont , 2n3906 equivalent q1 irc, chp1100r100f13, 2512 irc, lr251201r100f, 2512 dale, wsl-2512/0.1 ? /?%, 2512 ?%, 1w m ? 100 r1a sumida, rch-110/220m, 10mm x 10mm x 10mm coiltronics, up2-220, 0.541" x 0.345" x 0.231" coilcraft, do3340p-223, 0.510" x 0.370" x 0.450" coilcraft, do5022p-223, 0.730" x 0.600" x 0.280" ?0%, 3a i sat note: size in l x w x h ? 22 l1 ?%, 1/8w ? 1 r1b ?%, 1/16w k ? 10 r2, r4 ?%, 1/16w k ? 10 r3 ?%, 1/16w ? 10 r5, r7 ?%, 1/8w k ? 10 r6 4.3v zener diode, 1n4731 or equivalent d6
_______________detailed description output characteristics the MAX1647/max1648 contain both a voltage- regulation loop and a current-regulation loop. both loops operate independently of each other. the volt- age-regulation loop monitors batt to ensure that its voltage never exceeds the voltage set point (v0). the current-regulation loop monitors current delivered to batt to ensure that it never exceeds the current-limit set point (i0). the current-regulation loop is in control as long as batt voltage is below v0. when batt volt- age reaches v0, the current loop no longer regulates, and the voltage-regulation loop takes over. figure 5 shows the v-i characteristic at the batt pin. MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 11 table 1b. component suppliers d2 c5 r5 m1 m2 r1 battery l1 c7 d1 d3 d4 dc source r3 thm ref cci c6 c1 t c2 r2 c3 c4 r8 r9 r10 r11 r4 max1648 dcin vl ccv setv seti bst lx dlo pgnd dhi cs batt agnd 7.5v 28v figure 4. max1648 typical operating circuit 847-639-1469 847-639-6400 coilcraft 516-435-1824 516-435-1110 803-626-3123 803-946-0690 avx central semiconductor 561-241-9339 561-241-7876 coiltronics fax phone manufacturer 512-992-3377 512-992-7900 irc 310-322-3332 310-322-3331 605-665-1627 605-668-4131 dale ir 805-867-2698 805-867-2555 niec 603-224-1430 603-224-1961 408-970-3950 408-988-8000 siliconix sprague 847-956-0702 847-956-0666 sumida 516-864-7630 516-543-7100 zetex
MAX1647/max1648 setting v0 and i0 (MAX1647) set the MAX1647? voltage and current-limit set points through the intel system management bus (smbus) 2- wire serial interface. the MAX1647? logic interprets the serial-data stream from the smbus interface to set inter- nal digital-to-analog converters (dacs) appropriately. see the MAX1647 logic section for more information. setting v0 and i0 (max1648) set the max1648? voltage- and current-limit set points (v0 and i0, respectively) using external resistive dividers. figure 6b is the max1648 block diagram. v0 equals four times the voltage on the setv pin. i0 equals the voltage on seti divided by 5.5, divided by r1 (figure 4). _____________________analog section the MAX1647/max1648 analog section consists of a current-mode pwm controller and two transconduc- tance error amplifiers: one for regulating current and the other for regulating voltage. the MAX1647 uses dacs to set the current and voltage level, which are controlled through the smbus interface. the max1648 eliminates the dacs and controls the error amplifiers directly from seti (for current) and setv (for voltage). since separate amplifiers are used for voltage and cur- rent control, both control loops can be compensated separately for optimum stability and response in each state. the following discussion relates to the MAX1647; however, max1648 operation can easily be inferred from the MAX1647. whether the MAX1647 is controlling the voltage or cur- rent at any time depends on the battery? state. if the battery has been discharged, the MAX1647? output reaches the current-regulation limit before the voltage limit, causing the system to regulate current. as the bat- tery charges, the voltage rises until the voltage limit is reached, and the charger switches to regulating voltage. the transition from current to voltage regulation is done by the charger, and need not be controlled by the host. voltage control the internal gmv amplifier controls the MAX1647? out- put voltage. the voltage at the amplifier? noninverting input amplifier is set by a 10-bit dac, which is controlled by a chargingvoltage( ) command on the smbus (see the MAX1647 logic section for more information). the battery voltage is fed to the gmv amplifier through a 4:1 resistive voltage divider. with an external 4.096v refer- ence, the set voltage ranges between 0 and 16.38v with 16mv resolution. this poses a challenge for charging four lithium-ion cells in series: because the lithium-ion battery? typical per-cell voltage is 4.2v maximum, 16.8v is required. a larger reference voltage can be used to circumvent this. under this condition, the maximum battery voltage no longer matches the programmed voltage. the solu- tion is to use a 4.2v reference and host software. contact maxim? applications department for more information. the gmv amplifier? output is connected to the ccv pin, which compensates the voltage-regulation loop. typically, a series-resistor/capacitor combination can be used to form a pole-zero couplet. the pole intro- duced rolls off the gain starting at low frequencies. the zero of the couplet provides sufficient ac gain at mid- frequencies. the output capacitor then rolls off the mid- frequency gain to below 1, to guarantee stability before encountering the zero introduced by the output capaci- tor? equivalent series resistance (esr). the gmv amplifier? output is internally clamped to between one- fourth and three-fourths of the voltage at ref. current control the internal gmi amplifier and an internal current source control the battery current while the charger is regulating current. since the regulator current? accura- cy is not adequate to ensure full 11-bit accuracy, an internal linear current source is used in conjunction with the pwm regulator to set the battery current. the cur- rent-control dac? five least significant bits set the chemistry-independent battery chargers 12 ______________________________________________________________________________________ batt voltage average current through the resistor between cs and batt v0 v0 = voltage set point i0 = current-limit set point i0 figure 5. output v-i characteristic
MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 13 figure 6a. MAX1647 block diagram 10k ? 10k ? 10k ? 10k ? 8ma 4ma 2ma 1ma dcin iout ref 16ma 5 ref thm agnd cs batt from logic block thermistor_or logic block thermal shutdown thermistor_cold thermistor_hot therm_shut ac_present ccv ccv_low r 3r ref dhi note: ref/4 to 3/4 ref note: approx. ref/4 + v thresh to 3/4 ref + v thresh 3/8 ref = zero current lx pgnd from logic block agnd ccv cci gmi gmv vl bst dlo agnd vl agnd r min r r r r batt r r r to logic block from logic block from logic block voltage_inreg current_inreg to logic block to logic block power_fail 6-bit dac ref agnd agnd agnd ref dacv dcin/4.5 sel scl sda int thermistor_ur 100k ? 30k ? 3k ? 500 ? 5.4v linear regulator current-sense level shift and gain of 5.5 clamp 10-bit dac level shift driver summing comparator block clamp to ref (max) internal 3.9v reference dcin driver 6 10
MAX1647/max1648 chemistry-independent battery chargers 14 ______________________________________________________________________________________ figure 6b. max1648 block diagram 10k ? 10k ? ref thm agnd cs batt on thermistor_cold dhi lx pgnd ac_present and not (thermistor_hot or thermistor_cold) ccv cci on gmi gmv vl bst dlo min ref / 2 = zero current r r r seti batt r setv agnd thermistor_hot 30k ? 3k ? current-sense level shift and gain of 5.5 clamp level shift driver summing comparator block driver ref ac_present agnd vl 5.4v linear regulator internal 3.9v reference dcin
internal current sources?state, and the six most signifi- cant bits control the switching regulator? current. the internal current source supplies 1ma resolution to the battery to comply with the smart-battery specification. when the current is set to a number greater than 32, the internal current source remains at 31ma. this guar- antees that battery-current setting is monotonic regard- less of current-sense resistor choice and current-sense amplifier offset. the gmi amplifier? noninverting input is driven by a 4:1 resistive voltage divider, which is driven by the 6-bit dac. if an external 4.096v reference is used, this input is approximately 1.0v at full scale, and the resolution is 16mv. the current-sense amplifier drives the inverting input to the gmi amplifier. it measures the voltage across the current-sense resistor (r sen ) (which is between the cs and batt pins), amplifies it by approx- imately 5.45, and level shifts it to ground. the full-scale current is approximately 0.2v / r sen , and the resolution is 3.2mv / r sen . the current-regulation-loop is compensated by adding a capacitor to the cci pin. this capacitor sets the cur- rent-feedback loop? dominant pole. the gmi amplifier? output is clamped to between approximately one-fourth and three-fourths of the ref voltage. while the current is in regulation, the ccv voltage is clamped to within 80mv of the cci voltage. this prevents the battery volt- age from overshooting when the dac voltage setting is updated. the converse is true when the voltage is in regulation and the current is not at the current dac set- ting. since the linear range of cci or ccv is about 1.5v to 3.5v or about 2v, the 80mv clamp results in a rela- tively negligible overshoot when the loop switches from voltage to current regulation or vice versa. pwm controller the battery voltage or current is controlled by the cur- rent-mode, pulse-width-modulated (pwm), dc-dc con- verter controller. this controller drives two external n-channel mosfets, which switch the voltage from the input source. this switched voltage feeds an inductor, which filters the switched rectangular wave. the con- troller sets the pulse width of the switched voltage so that it supplies the desired voltage or current to the battery. the heart of the pwm controller is the multi-input com- parator. this comparator sums three input signals to determine the pulse width of the switched signal, set- ting the battery voltage or current. the three signals are the current-sense amplifier? output, the gmv or gmi error amplifier? output, and a slope-compensation sig- nal, which ensures that the controller? internal current- control loop is stable. the pwm comparator compares the current-sense amplifier? output to the higher output voltage of either the gmv or the gmi amplifier (the error voltage). this current-mode feedback corrects the duty ratio of the switched voltage, regulating the peak battery current and keeping it proportional to the error voltage. since the average battery current is nearly the same as the peak current, the controller acts as a transconductance amplifier, reducing the effect of the inductor on the out- put filter lc formed by the output inductor and the bat- tery? parasitic capacitance. this makes stabilizing the circuit easy, since the output filter changes from a com- plex second-order rlc to a first-order rc. to preserve the inner current-control loop? stability, slope compen- sation is also fed into the comparator. this damps out perturbations in the pulse width at duty ratios greater than 50%. at heavy loads, the pwm controller switches at a fixed frequency and modulates the duty cycle to control the battery voltage or current. at light loads, the dc current through the inductor is not sufficient to prevent the cur- rent from going negative through the synchronous recti- fier (figure 3, m2). the controller monitors the current through the sense resistor r sen ; when it drops to zero, the synchronous rectifier turns off to prevent negative current flow. mosfet drivers the MAX1647 drives external n-channel mosfets to regulate battery voltage or current. since the high-side n-channel mosfet? gate must be driven to a voltage higher than the input source voltage, a charge pump is used to generate such a voltage. the capacitor c7 (figure 3) charges to approximately 5v through d2 when the synchronous rectifier turns on. since one side of c7 is connected to the lx pin (the source of m1), the high-side driver (dhi) can drive the gate up to the volt- age at bst, which is greater than the input voltage, when the high-side mosfet turns on. the synchronous rectifier behaves like a diode, but with a smaller voltage drop to improve efficiency. a small dead time is added between the time that the high-side mosfet turns off and the synchronous rectifier turns on, and vice versa. this prevents crowbar currents (cur- rents that flow through both mosfets during the brief time that one is turning on and the other is turning off). connect a schottky rectifier from ground to lx (across the source and drain of m2) to prevent the synchronous rectifier? body diode from conducting. the body diode typically has slower switching-recovery times, so allow- ing it to conduct would degrade efficiency. MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 15
MAX1647/max1648 the synchronous rectifier may not be completely replaced by a diode because the bst capacitor charges while the synchronous rectifier is turned on. without the synchronous rectifier, the bst capacitor may not fully charge, leaving the high-side mosfet with insufficient gate drive to turn on. however, the synchronous rectifier can be replaced with a small mosfet, such as a 2n7002, to guarantee that the bst capacitor is allowed to charge. in this case, most of the current at high currents is carried by the diode and not by the synchronous rectifier. internal regulator and reference the MAX1647 uses an internal low-dropout linear regula- tor to create a 5.4v power supply (vl), which powers its internal circuitry. vl can supply up to 20ma. a portion of this current powers the internal circuitry, but the remain- ing current can power the external circuitry. the current used to drive the mosfets comes from this supply, which must be considered when calculating how much power can be drawn. to estimate the current required to drive the mosfets, multiply the total gate charge of each mosfet by the switching frequency (typically 250khz). the internal circuitry requires as much as 6ma from the vl supply. to ensure vl stability, bypass the vl pin with a 1? or greater capacitor. the MAX1647 has an internal ?% accurate 3.9v refer- ence voltage. an external reference can be used to increase the charger? accuracy. use a 4.096v reference, such as the max874, for compliance with the intel/ duracell smart-battery specification. voltage-setting accuracy is ?.65%, so the total voltage accuracy is the accuracy added to the reference accuracy. for 1% total voltage accuracy, use a reference with ?.35% or greater accuracy. if the internal reference is used, bypass it with a 0.1? or greater capacitor. MAX1647 logic the MAX1647 uses serial data to control its operation. the serial interface complies with the smbus specification (see system management bus specification , from intel architecture labs; http://www.intel.com/ial/power- mgm.html; intel architecture labs: 800-253-3696). charger functionality complies with the intel/duracell smart charger specification for a level 2 charger. the MAX1647 uses the smbus read-word and write- word protocols to communicate with the battery it is charging, as well as with any host system that monitors the battery to charger communications. the MAX1647 never initiates communication on the bus; it only receives commands and responds to queries for status information. figure 7 shows examples of the smbus write-word and read-word protocols. chemistry-independent battery chargers 16 ______________________________________________________________________________________ ack scl time sda sda write word: chargingmode( ), chargingvoltage( ), chargingcurrent( ), alarmwarning( ) read word: chargersstatus( ) d8 d9 d10 d11 d12 d13 d14 d15 ack d0 d1 d2 d3 d4 d5 d6 d7 ack cmd0 cmd1 cmd2 cmd3 cmd4 cmd5 cmd6 cmd7 ack w 1 0 0 1 0 0 0 start scl ack 1 1 0 0 1 0 0 0 ack w 1 0 0 1 0 0 0 start scl sda ack thermistor_or bold line indicates that the MAX1647 pulls sda low chargingmode( ) = 0 x 12 chargingvoltage( ) = 0 x 15 chargingcurrent( ) = 0 x 14 alarmwarning( ) = 0 x 16 chargerstatus( ) = 0 x 13 thermistor_cold thermistor_hot thermistor_ur alarm_inhibited power_fail battery_present ac_present ack charge_inhibited master_mode voltage_notreg current_notreg level_2 level_3 current_or voltage_or ack r 1 0 0 1 0 0 0 repeated start figure 7. write-word and read-word examples
each communication with the MAX1647 begins with a start condition that is defined as a falling edge on sda with scl high. the device address follows the start condition. the MAX1647 device address is 0b0001001 (0b indicates a binary number), which may also be denoted as 0x12 (0x indicates a hexadecimal number) for write-word commands, or 0x13 in hexadecimal for read-word commands (note that the address is only seven bits, and the hexadecimal representation uses r/ w as its least significant bit). chargermode( ) the chargermode( ) command uses write-word proto- col. the command code for chargermode( ) is 0x12; thus the cmd7?md0 bits in write-word protocol should be 0b00010010. table 2 describes the functions of the 16 different data bits (d0?15). bit 0 refers to the d0 bit in the write-word protocol (figure 7). whenever the battery_present status bit is clear, the hot_stop bit is set, regardless of any previous chargermode( ) command. to charge a battery that has a thermistor impedance in the hot range (i.e., thermistor_hot = 1 and thermistor_ur = 0), the host must use the chargermode( ) command to clear hot_stop after the battery is inserted. the hot_stop bit returns to its default power-up condition (?? whenever the battery is removed. chargingvoltage( ) the chargingvoltage( ) command uses write-word protocol. the command code for chargingvoltage( ) is 0x15; thus, the cmd7?md0 bits in write-word proto- col should be 0b00010101. the 16-bit binary number formed by d15?0 represents the voltage set point (v0) in millivolts; however, since the MAX1647 has only 16mv resolution in setting v0, the d0, d1, d2, and d3 bits are ignored. for d15 = d14 = 0: in equation 1, vdac is the decimal equivalent of the binary number represented by bits d13, d12, d11, d10, d9, d8, d7, d6, d5, and d4 programmed with the chargingvoltage( ) command. for example, if d4?13 are all set, vdac is the decimal equivalent of 0b1111111111 (1023). if either d15 or d14, or both d15 and d14, are set, all the bits in the voltage dac (figure 6a) are set, regardless of d13?0, and the status register? voltage_or bit is set. for d15 = 1 and/or d14 = 1: MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 17 table 2. chargermode( ) bit functions 1 6 power_fail_mask 0 5 4, 7, 8, 9, 11?5 n/a battery_present_mask 1 10 hot_stop 2 por_reset 1 0 0 inhibit_charge enable_polling 3 reset_to_zero por value** bit position* bit name 0 = interrupt on either edge of the power_fail status bit. 1 = do not interrupt because of a power_fail bit change. 0 = interrupt on either edge of the battery_present status bit. 1 = do not interrupt because of a battery_present bit change. not implemented. write 1 into this bit. 0 = the thermistor_hot status bit does not turn the charger off. 1 = thermistor_hot turns the charger off. 0 = no change in any non-chargermode( ) settings. 1 = change the voltage and current settings to 0xffff and 0x00c0 respectively; clear the thermistor_hot and alarm_inhibited bits. not implemented. write 0 into this bit. 0 = allow normal operation; clear the chg_inhibited status bit. 1 = turn the charger off; set the chg_inhibited status bit. not implemented. write 0 into this bit. function * bit position in the d15?0 data. ** power-on reset value. n/a = not available. voltage_or = 0 and v0 in volts = 4 x ref x vdac 2 10 () voltage_or = 1 and v0 in volts = 4 x ref x 2-1 2 10 10 ()
MAX1647/max1648 figure 8 shows the mapping between v0 (the voltage- regulation-loop set point) and the chargingvoltage( ) data. the power-on reset value for the chargingvoltage( ) register is 0xfff0; thus, the first time a MAX1647 is powered on, the batt voltage regulates to 16.368v with v ref = 4.096v. any time the battery_present status bit is clear, the chargingvoltage( ) register returns to its power-on reset state. chargingcurrent( ) the chargingcurrent( ) command uses write-word protocol. the command code for chargingcurrent( ) is 0x14; thus, the cmd7?md0 bits in write-word proto- col should be 0b00010100. the 16-bit binary number formed by d15?0 represents the current-limit set point (i0) in milliamps. tying sel to agnd selects a 1.023a maximum setting for i0. leaving sel open selects a 2.047a maximum setting for i0. tying sel to vl selects a 4.095a maximum setting for i0. chemistry-independent battery chargers 18 ______________________________________________________________________________________ 16.368 v ref = 4.096v 0 0b000000000000xxxx 0x000x 0x20dx 0x3ffx 0b001000001101xxxx 0b001111111111xxxx 0x313x 0b001100010011xxxx 0xfffx 0b111111111111xxxx 0x106x 0b000100000110xxxx 4.192 12.592 chargingvoltage( ) d15?0 data voltage set point (v0) 8.400 figure 8. chargingvoltage( ) data to voltage mapping
two sources of current in the MAX1647 charge the bat- tery: a binary-weighted linear current source sources from iout, and a switching regulator controls the current flowing through the current-sense resistor (r1). iout provides a small maintenance charge current to com- pensate for battery self-discharge, while the switching regulator provides large currents for fast charging. iout sources from 1ma to 31ma. table 3 shows the relationship between the value programmed with the chargingcurrent( ) command and iout source current. the ccv_low comparator checks to see if the output voltage is too high by comparing ccv to ref / 4. if ccv_low = 1 (when ccv < ref / 4), iout shuts off, preventing the output voltage from exceeding the voltage set point specified by the chargingvoltage( ) register. voltage_notreg = 1 whenever the internal clamp pulls down on ccv. (the internal clamp pulls down on ccv to keep its voltage close to cci? voltage.) MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 19 figure 9. average voltage between cs and batt vs. current dac code table 3. relationship between iout source current and chargingcurrent( ) value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 alarm_ inhibited (note 1) charge_ inhibited 0x0010?xffff 0x0010?xffff 0x0010?xffff 0x0010?xffff 0x0010?xffff 0x0010?xffff chargingvoltage( ) 0x0001?x001f 0x0020?xffff 0x0001?x001f 0x0020?xffff 0x0020?xffff 0x0001?x001f chargingcurrent( ) 1 0 1 1 1 0 ccv_low 0 x 1 1 0 x voltage_ notreg 0ma 31ma 1ma?1ma 31ma 0ma 1ma?1ma iout output current 0x0000?x000f x x x x x x x x 0 0 0 0x0000 x x x x x x x x x x 0ma 0ma 0ma 0ma 0ma x 1 0 1 x 0 x x 1 0 0 0 note 1: logical and of thermistor_hot, hot_stop, not(thermistor_ur). 185 sel = open or sel = vl 2.94 0b000001 0b100000 0b111111 current dac code, da5 da0 bits average cs - batt voltage in current regulation (mv) 94
MAX1647/max1648 with the switching regulator on, the current through r1 (figure 3) is regulated by sensing the average voltage between cs and batt. a 6-bit current dac controls the current-limit set point. da5?a0 denote the bits in the current dac code. figure 9 shows the relationship between the current dac code and the average volt- age between cs and batt. when the switching regulator is off, dhi is forced to lx and dlo is forced to ground. this prevents current from flowing through inductor l1. table 4 shows the relationship between the chargingcurrent( ) register value and the switching regulator current dac code. chemistry-independent battery chargers 20 ______________________________________________________________________________________ 0x0010?xffff chargingvoltage( ) 0x0001?x001f chargingcurrent( ) 0 current dac code no sw reg on? 0 (note 2) 0 0 0 alarm_ inhibited (note 1) charge_ inhibited table 4. relationship between current dac code and the chargingcurrent( ) value 0v sel 0v 0x0010?xffff 0x0020?x003f 2 yes 0 0 0 0 0v 0v 0x0010?xffff 0x03e0?x03ff 0x0010?xffff 62 yes 0 0 0 0 0x0040?x03df 4?0 yes 0 0 0 0 0v open 0x0010?xffff 0x0001?x001f 0x0010?xffff 0 no 0 0 0 0 open open 0x0400?xffff 0x0010?xffff 0x0040?x07df 0x0010?xffff 2?2 yes 62 0 0 0 0 0x0020?x003f yes 1 yes 0 0 0 1 0 0 0 0 open open 0x0010?xffff 0x0800?xffff 0x0010?xffff 63 yes 1 0 0 0 vl vl 0x07e0?x07ff 0x0010?xffff 0x0020?x003f 0x0010?xffff 1 yes 63 0 0 0 0 0x0001?x001f yes 0 no 0 0 0 0 0 vl vl 0x0010?xffff 0x0080?x0f9f 0x0010?xffff 2?2 yes 0 0 0 0 vl vl 0x0040?x007f 0x0010?xffff 0x0fc0?x0fff 0x0010?xffff 63 yes 1 0 0 0 0 0x0fa0?x0fbf yes 63 yes 0 0 0 0 0 0 0 0 0 0 0 vl x x 0x0000 0x0010?xffff 0 no 0 0 0 0 0x0001?xffff 63 yes 1 0 0 0 x x x x 0x0010?xffff n/c no n/c 1 x 0 x x x x x x n/c no n/c n/c x x 1 x no n/c no n/c x 1 n/c 0 0 0 0 note 1: logical and of thermistor_hot, hot_stop, not(thermistor_ur). note 2: value of current_or bit in the chargerstatus( ) register. n/c = no change. table 5. effect of sel pin-strapping on the chargingcurrent( ) data bits 45 vl 90 181 agnd open r1 (m ? ) sel 0 0 0 d15 0 0 0 d14 0 0 0 d13 0 0 0 d12 da5 0 0 d11 da4 da5 0 d10 da3 da4 da5 d9 da2 da3 da4 d8 da1 da2 da3 d7 da0 da1 da2 d6 * da0 da1 d5 i4 i4 i4 d4 i3 i3 i3 d3 i2 i2 i2 d2 i1 i1 i1 d1 i0 i0 i0 d0 * when sel = vl, d5 = 1 forces da0 to be 1 regardless of the d6 bit value.
MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 21 table 6. effect of the alarmwarning( ) command x x 1 x 1 x x x x 1 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x alarmwarning( ) write-word protocol data set alarm_inhibited set alarm_inhibited set alarm_inhibited d15 d14 d13 d12 d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 result with sel = agnd, r1 should be as close as possible to 0.185 / 1.023 = 181m ? to ensure that the actual output current matches the data value programmed with the chargingcurrent( ) command. with sel = open, r1 should be as close as possible to 90m ? . with sel = vl, r1 should be as close as possible to 45m ? . table 5 sum- marizes how sel affects the r1 value and the meaning of data bits d15?0 in the chargingcurrent( ) command. da5?a0 denote the current dac code bits, and i4?0 denote the iout linear-current source binary weighting bits. note that whenever any current dac bits are set, the linear-current source is set to full scale (31ma). the power-on reset value for the chargingcurrent( ) register is 0x000c. irrespective of the sel pin setting, the MAX1647 powers on with i0 set to 12ma (i.e., da5?a0, i1, and i0 all equal to zero, and only i3 and i2 set). anytime the battery_present status bit is clear (battery removed), the chargingcurrent( ) register returns to its power-on reset state. this ensures that upon insertion of a battery, the initial charging current is 12ma. alarmwarning( ) the alarmwarning( ) command uses write-word protocol. the command code for alarmwarning( ) is 0x16; thus the cmd7?md0 in write-word protocol should be 0b00010110. the alarmwarning( ) command sets the alarm_inhibited status bit in the MAX1647 if d15, d14, or d12 of the write-word protocol data equals 1. table 6 summarizes the alarmwarning( ) command? function. the alarm_inhibited status bit remains set until battery_present = 0 (battery removed) or a chargermode() command is written with the por_reset bit set. as long as alarm_inhibited = 1, the MAX1647 switching regulator and iout current source remain off. chargerstatus( ) the chargerstatus( ) command uses read-word proto- col. the command code for chargerstatus( ) is 0x13; thus, the cmd7?md0 bits in write-word protocol should be 0b00010011. the chargerstatus( ) com- mand returns information about thermistor impedance and the MAX1647? internal state. the read-word protocol returns d15?0 (figure 7). table 7 describes the meaning of the individual bits. the latched bits, thermistor_hot and alarm_inhibited, are cleared whenever battery_present = 0 or chargermode( ) is written with por_reset = 1. interrupts and the alert-response address an interrupt is triggered ( int goes low) whenever power is applied to dcin, the battery_present bit changes, or the power_fail bit changes. battery_present and power_fail have interrupt masks that can be set or cleared via the chargermode( ) command. int stays low until the interrupt is cleared. there are two methods for clearing the interrupt: issuing a chargerstatus( ) com- mand, and using the receive byte protocol with a 0x19 alert-response address. the MAX1647 responds to the alert-response address with the 0x89 byte. __________applications information using the MAX1647 with duracell smart batteries the following pseudo-code describes an interrupt rou- tine that is triggered by the MAX1647 int output going low. this interrupt routine keeps the host informed of any changes in battery-charger status, such as dcin power detection, or battery removal and insertion. doMAX1647: { this is the beginning of the routine that handles MAX1647 interrupts. } { check the status of the MAX1647. } tempword = readword( smbaddr = 0b00010011 = 0x13, command = 0x13 ) { check for the normal power-up case without a battery installed. thermistor_or = 1, battery_present = 0. use 0b1011111011111111 = 0xbeff as the mask. } if (tempword or 0xbeff) = 0xbfff then goto nobatt: { check to see if the battery is installed. battery_ present = 1. use 0b1011111111111111 = 0xbfff as the mask. }
MAX1647/max1648 if (tempword or 0xbeff) = 0xffff then goto havebatt: goto endint: havebatt: { a battery is installed. turn the battery? broadcast mode off to monitor the charging process. using the batterymode( ) command, make sure the charger_ mode bit is set. } writeword(smbaddr = 0b00010110 = 0x16, command = 0x03, data = 0x4000) goto endint: nobatt: { notify the system that ac power is present, but no bat- tery is present. } goto endint: endint: { this is the end of the interrupt routine. } the following pseudo-code describes a polling routine that queries the battery for its desired charge voltage and charge current, checks to make sure that the requested charge current and charge voltage are valid, and instructs the MAX1647 to comply with the request. dopolling: { this is the beginning of the polling routine. } { ask the battery what voltage it wants using the bat- tery? chargingvoltage( ) command. } tempvoltage = readword( smbaddr = 0b00010111 = 0x17, command = 0x15 ) { ask the battery what current it wants using the bat- tery? chargingcurrent( ) command. } tempcurrent = readword( smbaddr = 0b00010111 = 0x17, command = 0x14 ) { now the routine can check that the tempvoltage and tempcurrent values make sense and that the battery is not malfunctioning. } { with valid tempvoltage and tempcurrent val- ues, instruct the MAX1647 to comply with the request. } writeword( smbaddr = 0b00010010 = 0x12 , command = 0x15, data = tempvoltage ) writeword( smbaddr = 0b00010010 = 0x12 , command = 0x14, data = tempcurrent ) endpol: { this is the end of the polling routine. } negative input voltage protection in most portable equipment, the dc power to charge batteries enters via a two-conductor cylindrical power jack. it is easy for the end user to add an adapter to switch the dc power? polarity. polarized capacitor c6 would be destroyed if a negative voltage were applied. diode d4 in figure 3 prevents this from happening. if reverse-polarity protection for the dc input power is not necessary, diode d4 can be omitted. this eliminates the power lost due to the voltage drop on diode d4. selecting external components for the MAX1647 4a application the MAX1647 can be configured to charge at a maxi- mum current of 4a (instead of 2a, as shown in figure 3) by changing the external power components and tying sel to ref. the following paragraphs discuss the selec- tion requirements for each component in figure 3 that must be changed to accommodate the 4a application. diode d4 in figure 3 has to support both the charge current and the current required to operate the host load (i.e., what the batteries normally power when not charging). this means that the continuous current flow- ing through d4 exceeds 4a. one possible choice for d4 is the motorola mbrd835l 8a schottky barrier diode in a dpak surface-mount package. care must be taken in thermal management of the circuit board when using the 4a application circuit, by mounting d4 on a three-square-inch piece of copper. motorola? mbrd835l can also be used for d3. the siliconix si4410dy is a good choice for m1 and m2 in the 4a application. changing m2 from a 2n7002 (table 1) to a si4410dy increases the power dissipated by the MAX1647? 20-pin ssop. high-current inductors are difficult to find in surface-mount packages. low-cost solutions use toroidal powdered-iron cores with exposed windings of heavy-gauge wire. the coiltronics ctx20-5-52 20? 5a inductor provides a high- efficiency solution. r1a must also dissipate more power in the 4a applica- tion circuit than in the circuit of figure 3. r1a? value decreases to 50m ? in the 4a application. irc? lr2512-01-r050-f meets this requirement with a 1w maximum power-dissipation rating. chemistry-independent battery chargers 22 ______________________________________________________________________________________
MAX1647/max1648 chemistry-independent battery chargers ______________________________________________________________________________________ 23 table 7. chargerstatus( ) bit descriptions master_mode current_notreg charge_inhibited name level_2 voltage_notreg 3 4 2 no n/a no 0 = current through r1 is at its limit (i batt = i0). 1 = current through r1 is less than its limit (i batt < i0). always returns 1 0 = batt voltage is limited at the voltage set point (batt = v0). 1 = batt voltage is less than the voltage set point (batt < v0). voltage_or current_or level_3 thermistor_hot thermistor_cold thermistor_or 10 9 8 yes no no this bit reports the state of an internal sr flip-flop (denoted thermistor_hot flip-flop). the thermistor_hot flip-flop is set whenever thm is below 23% of ref. it is cleared whenever battery_present = 0 or chargermode( ) is written with por_reset = 1. 0 = thm voltage < 75% of ref voltage 1 = thm voltage > 75% of ref voltage 0 = thm voltage < 91% of ref voltage 1 = thm voltage > 91% of ref voltage 7 6 5 no no n/a 0 = chargingvoltage( ) value is valid for MAX1647. 1 = chargingvoltage( ) value exceeds what MAX1647 can actually deliver. 0 = chargingcurrent( ) value is valid for MAX1647. 1 = chargingcurrent( ) value exceeds what MAX1647 can actually deliver. always returns 0 thermistor_ur alarm_inhibited 12 yes 1 0 bit position n/a yes latched? this bit reports the state of an internal sr flip-flop (denoted alarm_inhibited flip-flop). the alarm_inhibited flip-flop is set whenever the alarmwarning( ) command is written with d15, d14, or d12 set. the alarm_inhibited flip-flop is cleared whenever battery_present = 0 or chargermode( ) is written with por_reset = 1. 11 no 0 = thm voltage > 5% of ref voltage 1 = thm voltage < 5% of ref voltage always returns ? 0 = ready to charge a smart battery 1 = charger is off; iout current = 0ma; dlo = pgnd; dhi = lx description power_fail 13 no 0 = batt voltage < 89% of dcin voltage 1 = batt voltage > 89% of dcin voltage battery_present 14 no 0 = no battery is present (thermistor_or = 1). 1 = a battery is present (thermistor_or = 0). ac_present 15 no 0 = vl voltage < 4v 1 = vl voltage > 4v * bit position in the d15-d0 data. n/a = not applicable. ___________________chip information transistor count: 3612 substrate connected to agnd
ssop.eps package outline, ssop, 5.3 mm 1 1 21-0056 c rev. document control no. approval proprietary information title: notes: 1. d&e do not include mold flash. 2. mold flash or protrusions not to exceed .15 mm (.006"). 3. controlling dimension: millimeters. 4. meets jedec mo150. 5. leads to be coplanar within 0.10 mm. 7.90 h l 0 0.301 0.025 8 0.311 0.037 0 7.65 0.63 8 0.95 max 5.38 millimeters b c d e e a1 dim a see variations 0.0256 bsc 0.010 0.004 0.205 0.002 0.015 0.008 0.212 0.008 inches min max 0.078 0.65 bsc 0.25 0.09 5.20 0.05 0.38 0.20 0.21 min 1.73 1.99 millimeters 6.07 6.07 10.07 8.07 7.07 inches d d d d d 0.239 0.239 0.397 0.317 0.278 min 0.249 0.249 0.407 0.328 0.289 max min 6.33 6.33 10.33 8.33 7.33 14l 16l 28l 24l 20l max n a d e a1 l c h e n 1 2 b 0.068 MAX1647/max1648 chemistry-independent battery chargers 24 ______________________________________________________________________________________ package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)
chemistry-independent battery chargers MAX1647/max1648 maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 25 ? 2002 maxim integrated products printed usa is a registered trademark of maxim integrated products. soicn .eps package outline, .150" soic 1 1 21-0041 b rev. document control no. approval proprietary information title: top view front view max 0.010 0.069 0.019 0.157 0.010 inches 0.150 0.007 e c dim 0.014 0.004 b a1 min 0.053 a 0.19 3.80 4.00 0.25 millimeters 0.10 0.35 1.35 min 0.49 0.25 max 1.75 0.050 0.016 l 0.40 1.27 0.394 0.386 d d min dim d inches max 9.80 10.00 millimeters min max 16 ac 0.337 0.344 ab 8.75 8.55 14 0.189 0.197 aa 5.00 4.80 8 n ms012 n side view h0.244 0.228 5.80 6.20 e 0.050 bsc 1.27 bsc c h e e b a1 a d 0-8 l 1 variations: package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)

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