general description the max1645a evaluation system (ev system) consists of a max1645a evaluation kit (ev kit) and a companion maxim system management bus (smbus ) interface board. the ev kit simplifies evaluation of the max1645a chemistry-independent level 2 smart battery charger. the maxim smbus interface board (maxsmbus) allows an ibm-compatible personal computer to use its paral- lel port to emulate an intel smbus 2-wire interface. windows 95/98 software provides a user-friendly inter- face to exercise the max1645a? features. order the max1645aevsys for complete ibm pc- based evaluation of the max1645a. order the MAX1645AEVKIT if you already have an smbus inter- face. ev system features ? charges any battery chemistry: li+, nicd, nimh, lead acid, etc. ? smbus-compatible 2-wire serial interface ? 3a (max) battery charge current ? up to 18.4v battery voltage ? up to +28v input voltage ? easy-to-use software included ? proven pc board layout ? fully assembled and tested surface-mount board evaluate: max1645a max1645a evaluation kit/evaluation system ________________________________________________________________ maxim integrated products 1 19-1596; rev 1; 7/00 ev kit component list part MAX1645AEVKIT 0? to +70? temp range ic package 28 qsop ordering information schottky diodes (sot23) central semiconductor cmpsh-3 2 d3, d4 40v, 2a schottky diodes central semiconductor cmsh2-40 2 d1, d2 0.1?, 50v ceramic capacitors (0805) taiyo yuden umk212bj104mg 3 c18, c23, c24 1500pf ceramic capacitor (0603) 1 c13 0.01? ceramic capacitors (0603) 3 c9, c10, c11 designation 0.1?, 16v ceramic capacitors (0603) taiyo yuden emk107bj104ma 4 c8, c14, c15, c16 1?, 10v ceramic capacitors (0805) taiyo yuden lmk212bj105mg 3 c6, c7, c12 1?, 50v ceramic capacitors (1210) murata grm42-2x7r105k050 3 c5, c19, c20 22?, 25v low-esr tantalum caps avx tpsd226m025r0200 2 c3, c4 22?, 35v low-esr tantalum caps avx tpse226m035r0300 2 c1, c2 description qty smbus is a registered trademark of intel corp. windows 95/98 are registered trademarks of microsoft corp. 10k ? ?% resistors (0603) 5 r5, r7, r9, r10, r17 100k ? ?% resistors (0603) 2 r3, r4 0.050 ? ?%, 0.5w resistor dale wsl-2010/0.050 ? /1% 1 r2 0.040 ? ?%, 0.5w resistor dale wsl-2010/0.040 ? /1% 1 r1 30v, 11a p-channel mosfets fairchild fds6675 2 p1, p2 30v, 8.4a n-channel mosfet fairchild fds6612a 1 n2 30v, 11.5a n-channel mosfet fairchild fds6680 1 n1 red led 1 led1 22?, 3.6a inductor sumida cdrh127-220 1 l1 2-pin headers 3 ju1, ju2, ju3 5-element terminal block 1 h2 2x10 right-angle female header 1 h1 designation description qty 10k ? ?% resistor (0603) 1 r6 max1645aevsys 0? to +70? 28 qsop maxsmbus interface 1 none max1645a ev kit 1 none description qty designation 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.
quick start required equipment before you begin, you will need the following equip- ment: ibm pc-compatible computer capable of running windows 95/98 parallel printer port (this is a 25-pin socket on the back of the computer) standard 25-pin, straight-through, male-to-female cable to connect the computer? parallel port to the maxim smbus interface board dc power supply capable of supplying +20v to +28v at 3a procedure see figure 1 as you follow these steps: 1) carefully connect the boards by aligning the 20-pin connector of the max1645a ev kit with the 20-pin header of the maxsmbus interface board. gently press them together. the two boards should be flush against each other. 2) verify that jumpers ju1, ju2, and ju3 are all shunted. ju1 and ju2 pull up the smbus clock and data lines to the v dd supply. ju3 connects a 10k ? resistor between the ground and thermistor nodes, making it appear to the max1645a as if a smart bat- tery were connected. table 1 describes the jumper functions. caution: do not turn on the power until all connec- tions are made. 3) connect a +20vdc to +28vdc power supply between the vin pad and the adjacent gnd pad on the max1645a ev kit board. 4) connect a cable from the computer? parallel port to the smbus interface board. use a straight-through, 25-pin, female-to-male cable. to avoid damaging the ev kit or your computer, do not use a 25-pin scsi port or any other connector that is physically similar to the 25-pin parallel printer port. note: do not connect a power supply to the maxsmbus board. power is supplied through the max1645a ev kit board. evaluate: max1645a max1645a evaluation kit/evaluation system 2 _______________________________________________________________________________________ table 1. jumper functions jumper state function closed* scl pulled up to v dd through a 10k ? resistor. open scl not pulled up to v dd ; scl must be pulled up to external supply. ev kit component list (cont.) max1645a ev kit software disk 1 none max1645a ev kit data sheet 1 none max1645a data sheet 1 none max1645a pc board 1 none shunts (ju1, ju2, ju3) 3 none max1645aeei (28-pin qsop) 1 u1 4.7 ? ?% resistors (0603) 2 r14, r15 designation description qty 33 ? ?% resistor (0603) 1 r12 1 ? ?% resistors (0603) 2 r11, r16 1k ? ?% resistors (0603) 2 r8, r13 closed* sda pulled up to v dd through a 10k ? resistor. open sda not pulled up to v dd ; sda must be pulled up to external supply. closed* 10k ? resistor connected between thermistor and ground nodes, simulating the attach- ment of a smart battery. ju3 open 10k ? resistor disconnected; for use when an actual smart battery will be connected to the ev kit. ju1 ju2 *indicates default jumper setting supplier phone fax avx 803-946-0690 803-626-3123 central semiconductor 516-435-1110 516-435-1824 dale 402-564-3131 402-563-6418 fairchild 408-822-2000 408-822-2102 murata 814-237-1431 814-238-0490 sumida 847-956-0666 847-956-0702 taiyo yuden 408-573-4150 408-573-4159 component suppliers note: please indicate that you are using the max1645a when contacting the above component suppliers.
evaluate: max1645a max1645a evaluation kit/evaluation system _______________________________________________________________________________________ 3 vin gnd gnd batt max1645a evaluation kit maxsmbus smart battery dc power supply ju3 led1 vl ref load ju1 ju2 db-25m to pc parallel port (+) c d s (-) (+) c d t (-) + - figure 1. block diagram of max1645a ev system
evaluate: max1645a max1645a evaluation kit/evaluation system 4 _______________________________________________________________________________________ 5) install the max1645a ev kit software on your com- puter by running the install.exe program on the floppy disk. this program copies the max1645a program file and creates an icon for it. 6) turn on the power supply. verify that led1 turns on. 7) start the max1645a program by opening its icon in the start menu. the ev kit software automatically detects the correct port by testing for the pin 5 to pin 13 loopback. verify that led1 turns off, signifying that communication between the pc and the max1645a has been established. 8) the software should appear as shown in figure 2. verify that charging voltage = 65535mv, charging current = 128ma; hot_stop is checked; voltage polling, current polling, and status polling are checked; and the following checkboxes are checked in the charger status panel: voltage_notreg, voltage_or, battery_present, and ac_pre- sent. detailed description of software upon execution of the max1645a program, the soft- ware automatically resolves the smbus address of the device. the software enables the command panel (figure 2), after which the user may issue any of the allowed smbus commands to the max1645a. (refer to the max1645a data sheet for more information regard- ing the allowed smbus commands.) command panel chargingvoltage() to issue the chargingvoltage() command to the max1645a, enter the desired voltage, in millivolts, into the charging voltage text edit box and select the adja- cent [send] button. by default, the software issues the chargingvoltage() command three times a second. to enable/disable this feature, check/uncheck the voltage polling checkbox. if a smart battery is connected to the charger, the charging voltage value displayed will be identical to the value being broadcast by the smart bat- tery. chargingcurrent() to issue the chargingcurrent() command to the max1645a, enter the desired current, in milliamps, into the charging current text edit box and select the adja- cent [send] button. by default, the software issues the chargingcurrent() command three times a second. to figure 2. max1645a ev kit software command panel
evaluate: max1645a max1645a evaluation kit/evaluation system _______________________________________________________________________________________ 5 enable/disable this feature, check/uncheck the current polling checkbox. if a smart battery is connected to the charger, the charging current value displayed will be identical to the value being broadcast by the smart bat- tery. note that when either voltage polling or current polling are checked, the action of issuing the chargingvoltage() or chargingcurrent() commands automatically services the watchdog timer. if both of these checkboxes are unchecked, the watchdog timer will eventually time out and charging will stop. for more information about the watchdog timer, refer to the max1645a data sheet. if the watchdog timer period of 175s is exceeded, reset the watchdog timer by issuing both the chargingvoltage() and chargingcurrent() commands. chargermode() to issue the chargermode() command to the max1645a, select a combination of checkboxes in the charger mode panel of commands. check the check- boxes next to commands for which the software should write a 1, uncheck the checkboxes next to commands for which the software should write a 0, and then select the [send] button. chargerstatus() on the right-hand side of the command panel, locate the status polling checkbox and the charger status panel. if the status polling checkbox is checked (the default setting), the software automatically issues the chargerstatus() command three times a second, in which case the checkboxes in the charger status panel are automatically updated and always represent the charger? current status. unchecking the status polling checkbox disables automatic software polling. if polling is disabled, the user can issue the chargerstatus() command to the max1645a by select- ing the [charger status] button, which is adjacent to the status polling checkbox. alertresponse() the max1645a has an external interrupt pin that is polled by the software if the status polling checkbox is checked. when an interrupt occurs, led1 on the ev kit board illuminates. if polling is enabled, the software determines which event triggered the interrupt, clears the interrupt, and prints a diagnostic message in the interrupts box. if polling is disabled and an interrupt occurs, the user can manually service the interrupt by selecting the [alert response] button. the alert response operation works as follows: the smbus specification revision 1.0 describes an optional wired-or signal called smbalert that, in a typical sys- tem, is connected to all the devices and then pulled up to v dd . a slave device can use this signal to notify the bus master that it wants to communicate. it does this by pulling the smbalert line low. when the master sees the smbalert line go low, it knows that one of the slave devices wants attention, but not which one. to determine which slave pulled the smbalert line low, the master broadcasts the alert response address (0x18) to all of the slave devices on the bus using a modified receive byte operation. the slave device wanting to communicate with the master responds with its smbus address (0x13) during the second byte of the modified receive byte operation. alarmwarning() to issue the alarmwarning() command to the max1645a, select the [alarm warning] button. this operation sends the alarmwarning() command byte with a data word of 0x8000. chargerspecinfo() to issue the chargerspecinfo() command to the max1645a, select the [spec info] button. the response of the max1645a is displayed to the right of the [spec info] button. communication with a smart battery if a smart battery is connected to the max1645a ev kit, the user may observe the status of the smart battery by selecting the [battery] button. at this point, the smart battery window appears (figure 3). if software polling of the charger? status is enabled, the software also figure 3. max1645a ev kit smart battery window
evaluate: max1645a automatically polls the status of the smart battery, and the parameters displayed in the smart battery window always represent the current status of the smart battery. if polling is disabled, manually query the smart battery by selecting the [update] button. when finished, select the [done] button to return to the main max1645a user interface window. serial communications interface when the user issues a command, the max1645a soft- ware first determines the command byte, then, if the command is a write-word type, the data word corre- sponding to the selected function. the software and max1645a device communicate serially through the maxsmbus board. refer to the max1645a data sheet for more information regarding the serial communica- tions protocol. detailed description of hardware input current limiting the max1645a ev kit is configured to regulate the bat- tery current so that the total v in input current does not exceed 2.5a. if a load is connected across the load and gnd pads (another system power supply, for example) that would cause the total current from v in to exceed 2.5a, the max1645a will automatically decrease its charging current to regulate the input cur- rent to 2.5a. refer to the max1645a data sheet for more information regarding input current limiting. connecting a smart battery the max1645a ev kit includes a five-element terminal block to facilitate connecting the ev kit to a smart battery. refer to the smart battery specification to identify the type of smart battery connector suited to your application. make sure that the ev kit power is turned off, and connect the (+), c, d, t, and (-) terminals from the ev kit board to the smart battery connector using no more than 2 inches of wire. remove the ju3 shunt, attach a smart battery to the smart battery connector, and turn the ev kit power back on. see figure 1 if necessary. connecting an electronic load if a smart battery is unavailable, an electronic load can be connected across the batt and gnd pads on the max1645a ev kit board. make sure that the ev kit power is turned off before connecting a load. make sure that ju3 is shunted, making it appear to the max1645a as if a smart battery were connected. after the load is connected, program the load in voltage mode and set the electronic load to clamp at 5v. turn on the power to the ev kit, and program the max1645a with a charging voltage of 12v at the maximum charging current. verify that the max1645a is supplying the maximum current to the load. increase the electronic load clamp voltage in 1v increments, and verify that as the electronic load voltage crosses 12v, the max1645a transitions from current regulation to voltage regulation; as the electronic load voltage increases beyond 12v, the batt voltage should remain fixed at 12v. layout considerations the max1645a ev kit layout is optimized for fast switch- ing and high currents. the traces connecting the power components must be able to carry at least 3a. take care to ensure that c1 and c2 (the input capacitors), d2 and n2 (the synchronous rectifier), and c3 and c4 (the output capacitors) are all connected to gnd at a common point, and to isolate the power gnd from the quiet analog gnd. max1645a evaluation kit/evaluation system 6 _______________________________________________________________________________________
evaluate: max1645a max1645a evaluation kit/evaluation system _______________________________________________________________________________________ 7 2 8 4 3 10 7 6 5 11 12 15 13 14 27 26 25 24 23 22 21 20 19 18 17 16 9 28 1 bst cssn cssp dlov lx dhi pds csin csip pgnd dlo batt pdl cls ref gnd ldo ccs cci ccv dac thm scl sda dcin cvs v dd max1645a u1 int c6 1 f c5 1 f 50v c23 0.1 f 50v = 3a traces v in d1 p1 r14 4.7 ? r15 4.7 ? r1 0.040 ? 1% 1/2w c20 1 f 50v c19 1 f 50v c14 0.1 f c16 0.1 f n1 n2 d2 d3 c1 22 f 35v c2 22 f 35v l1 22 h r12 33 ? ldo load load p2 batt r2 0.050 ? 1% 1/2w r16 1 ? r11 1 ? c18 0.1 f 50v c24 0.1 f 50v c3 22 f 25v c4 22 f 25v h2 (+) cd t (-) gnd gnd r10 10k r9 10k r8 1k led1 ju2 ju1 ju3 r17 10k load h1-20 h1-7 h1-3 h1-6 h1-5 h1-4 h1-2 h1-1 c12 1 f c13 1500pf c11 0.01 f c10 0.01 f c8 0.1 f c15 0.1 f c7 1 f c9 0.01 f r6 10k 1% r7 10k r5 10k r4 100k 1% r3 100k 1% r13 1k ref ldo ldo d4 figure 4. max1645a ev kit schematic
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. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2000 maxim integrated products printed usa is a registered trademark of maxim integrated products. evaluate: max1645 max1645a evaluation kit/evaluation system figure 5. max1645a ev kit component placement guide component side 1.0" figure 6. max1645a ev kit component placement guide solder side 1.0" figure 7. max1645a ev kit pc board layout?omponent side 1.0" figure 8. max1645a ev kit pc board layout?older side 1.0"
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