general description the max1645b evaluation kit (ev kit) is an efficient, multichemistry battery charger. it uses the intel system management bus (smbus ) to control the battery reg- ulation voltage, charger current output, and input cur- rent-limit set point. the max1645b ev kit can charge one, two, three, or four series li+ cells with a current up to 3a. the max1645b evaluation system (ev system) consists of a max1645b ev kit and the maxim smbusmon board. the max1645b ev kit includes windows 95-/98/ 2000-/xp-compatible software to provide a user-friendly interface. 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: max1645b max1645b evaluation kit/evaluation system ________________________________________________________________ maxim integrated products 1 19-1596; rev 2; 3/04 ev kit component list 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 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. ev system designation qty description none 1 max1645b ev kit none 1 smbusmon interface part temp range ic package max1645b evkit 0? to +70? 28 qsop max1645b evsys 0? to +70? 28 qsop
quick start recommended equipment ? dc source to supply the input current to the charger. this source must be capable of supplying a voltage greater than the battery-voltage set point and have sufficient current rating. ? voltmeter ? smart battery ? computer running windows 95, 98, 2000, or xp ? 9-pin serial extension cable ? smbusmon board procedure the max1645b ev kit is a fully assembled and tested board. follow the steps below to verify board operation. do not turn on the power supply until all connec- tions are completed. observe all precautions on the battery manufacturer? data sheet. 1) set the vpp jumper on the smbusmon board to vcc5. 2) carefully connect the boards by aligning the 20-pin connector of the max1645b ev kit with the 20-pin header of the smbusmon board. gently press them together. 3) connect a cable from the computer? serial port to the smbusmon interface board. use a straight-through 9-pin female-to-male cable. 4) install the software by running the install.exe program. the install program copies the files and creates icons for them in the windows 95/98/2000/xp start menu. an uninstall program is included with the software. click on the uninstall icon to remove the ev kit software from the hard drive. 5) connect power to the smbusmon board. 6) connect the input-current supply across the adapter_in and pgnd pads. 7) connect a smart battery to connector h2. 8) turn on the power supply. 9) start the max1645b ev kit software. 10) verify current is being delivered to the battery. evaluate: max1645b max1645b 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.) max1645b ev kit software cd 1 none shunts (ju1, ju2, ju3) 3 none max1645beei (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 max1645b when contacting the above component suppliers.
evaluate: max1645b max1645b evaluation kit/evaluation system _______________________________________________________________________________________ 3 vin gnd gnd vout max1645b evaluation kit smbusmon smart battery dc power supply ju3 led1 vl ref load ju1 ju2 db-25m to pc serial port (+) c d s (-) (+) c d t (-) + - vpp jumper vcc5 vcc3 db-9f figure 1. block diagram of max1645b ev system
evaluate: max1645b max1645b evaluation kit/evaluation system 4 _______________________________________________________________________________________ detailed description of software the max1645b program provides easy access to the max1645b registers. it is also capable of reading the registers of a smart battery and monitoring smbus traffic. upon execution of the program, the software enables the max1645b smart-charger command panel (figure 2), after which any of the allowed smbus commands can be sent to the max1645b. refer to the max1645b data sheet for more information regarding the allowed smbus commands. smart-charger command panel chargevoltage() to issue the chargevoltage() command to the max1645b, enter the desired voltage, in millivolts, into the charging voltage edit field and select the adjacent write button. chargecurrent() to issue the chargecurrent() command to the max1645b, enter the desired current, in milliamps, into the charging current edit field and select the adjacent write button. figure 2. max1645b smart-charger command panel
evaluate: max1645b max1645b evaluation kit/evaluation system _______________________________________________________________________________________ 5 auto rewrite checkboxes the max1645b needs to receive a chargevoltage() or chargecurrent() command every 175s (typ); otherwise, the max1645b times out and terminates charging. usually, a smart battery sends these necessary com- mands. however, when not using a smart battery with the max1645b ev k it, select either (or both) of the auto rewrite checkboxes located directly under the charging current and charging voltage edit fields. this generates a chargevoltage() or chargecurrent() command at the selected time interval located on the timer panel. chargermode() to issue the chargermode() command to the max1645b, select a combination of checkboxes in the charger mode panel of commands. each checkbox represents a bit in the chargermode() command word. select the checkboxes next to the bits for which the software should write a 1, unselect the checkboxes for a 0. send the command by selecting the write button. figure 3. max1645b smart-charger command panel showing the pulldown list for charger spec info and alarm warning
evaluate: max1645b chargerstatus() charger status is shown in the charger status panel. each of the bits in the chargerstatus() command word are shown individually with a short description of the bit. by default, the status is automatically read once every two seconds. disable this feature by unselecting the active read: charger checkbox located on the timer panel. change the refresh time by entering a new value into the timer interval edit box and select the set interval button. when auto refresh is disabled, issue a chargerstatus() command by selecting the read button on the charger status panel. chargerspecinfo() chargerspecinfo() returns the charger specification (0x0009) from the max1645b. this command is available through the ?ther bitmapped charger registers... panel. select charger spec info by picking it from the pulldown list located directly under the other bitmapped charger registers... label. issue a chargerspecinfo() command by selecting the read button. the returned hexadecimal value is shown at the bottom of the panel. alarmwarning() alarm warning is shown on the other bitmapped charger registers... panel (figure 3). select alarm warning by picking it from the pulldown list located directly under the other bitmapped charger registers... label. each of the bits in the alarmwarning() command word are shown individually with a short description of the bit and a checkbox. select the checkboxes next to the bits for which the software should write a 1; unselect the check- boxes for a 0. send the command to the max1645b by selecting the write button. smart-battery command panel the software is capable of reading the registers of a smart battery. the smart battery page of the software is shown in figure 4. the software only reads the registers selected with checkmarks. by default, the registers are automatically read once every two seconds. disable this feature by unselecting the active read: battery checkbox located on the timer panel. change the refresh time by entering a new value into the timer interval edit box and select the set interval button. when auto refresh is dis- abled, read the battery by selecting the refresh button. detailed description of hardware input current limiting the max1645b 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 max1645b will automatically decrease its charging current to regulate the input cur- rent to 2.5a. refer to the max1645b data sheet for more information regarding input current limiting. connecting a smart battery the max1645b 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 max1645b 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 max1645b 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 max1645b with a charging voltage of 12v at the maximum charging current. verify that the max1645b 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 max1645b 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 max1645b 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. max1645b evaluation kit/evaluation system 6 _______________________________________________________________________________________
evaluate: max1645b max1645b evaluation kit/evaluation system _______________________________________________________________________________________ 7 figure 4. max1645b smart-battery command panel
evaluate: max1645b max1645b evaluation kit/evaluation system 8 _______________________________________________________________________________________ 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 max1645b 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 5. max1645b 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. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ______________________ 9 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. figure 6. max1645b ev kit component placement guide component side figure 7. max1645b ev kit component placement guide solder side figure 8. max1645b ev kit pc board layout?omponent side figure 9. max1645b ev kit pc board layout?older side max1645b evaluation kit/evaluation system evaluate: max1645b
|
