ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 1/8 general description the ELP6230A is a current mode boost dc-dc converte r .its pwm circuitry with built in 30v,1a current power mosfet makes this converter highly power efficientl y. select able high switching frequency allows fast er loop response and easy filtering with a low noise output . the non-inverting input and its error amplifier is connected to an internal 1.25v precision reference voltage .soft -start time can be programmed with an external capa citor, which sets the input current ramp rate. current mode cont rol and external compensation network make it easy and flexible to stabilize the system. features ? up to 92% efficiency ? shut-down current : <1ua ? output voltage up to 30v ? internal compensation ? 1.2mhz fixed frequency switching ? high switch on current : 1a ? available in msop-8 package applications battery products . host products . panel. pin assignments
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 2/8 pin description pin pin name description 1,7,8 nc no connection . 2 fb regulation feedback input . connect to an external resistive voltage divider from the output to fb to set the output voltage . 3 en regulator on/off control input . a logic high input (ven>1.4v) turns on the regulator . a logic low input (ven<0.4v) puts the ELP6230A into l ow current shut down mode . 4 gnd ground. 5 sw output switching node . sw is the drain of the inte rnal low-side n-channel mosfe . connect the inductor to sw to complete the step-up converter. 6 vdd power supply pin . ordering information elp6230 an xx x function block diagram part number package marking marking information ELP6230Anr1r msop-8l r1 msop 8 r tape & reel
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 3/8 typical application circuit application circuit ELP6230A application circuit of lcd bias ELP6230A ELP6230A
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 4/8 absolute maximum ratings supply input voltage----------------------------- --------------------------------------------------- -------------------------- 6v power dissipation , pd@ta=25c msop8-------------------------------------------- --------------------------------------------------- ---------------------------900mw package thermal resistance msop 8, ja------------------------------------------------- --------------------------------------------------- -------------165c/w lead temperature (soldering,10sec.)-------------- --------------------------------------------------- -----------------260c recommended operating conditions supply input voltage----------------------------- --------------------------------------------------- ---------------------2.2vto5.5v en input voltage--------------------------------- --------------------------------------------------- ---------------------0vto5.5v operation junction temperature range------------- --------------------------------------------------- ----?40cto125c operation ambient temperature range-------------- --------------------------------------------------- ------?40cto85c electrical characteristics (vin=2.4v,vout=5v,cin=10uf,cout=22uf,l1=4.7uh) parameter conditions min typ max units supply voltage 2.7 6 v output voltage range 2.5 30 v supply current (shut down) v en =v out =0v,v sw =5v 0.1 1 ua supply current 430 550 ua feedback voltage 1.22 1.25 1.28 v feedback input current v fb =1.25v 50 na switching frequency 1200 khz maximum duty cycle 93 % en input low voltage 0.3 v en input high voltage 1.0 v low-side current limit 1 a high-side on resistance vout =3.3v 0.4 mosfet voltage 30 v
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 5/8 typical operation characteristics
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 6/8
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 7/8 operation information the ELP6230A uses a 1200khz fixed frequency, curr ent-mode regulation architecture to regulate the ou tput voltage. the ELP6230A measures the output voltage t hrough an external resistive voltage divider and co mpares that to the internal 1.25v reference to generate th e error voltage to the inductor current to regulate the output voltage . the use of current-mode regulation improv es transient response and control loop stability . when the ELP6230A is disable (en=low), both power switches are off. ther e is no current path from sw to out. therefore, the output voltage discharges to ground. when the e lp6230a is enabled (en=high), a limited start-curre nt charges the output voltage rising to sw ,then the p art operates in force pwm mode for regulating the o utput voltage to the target value. at the beginning of ea ch cycle, the n-channel mosfet switch is turned on, forcing the inductor current to rise, the current at the sourc e of the switch is internally measured and converte d to a voltage by the current sense amplifier . that voltage is co mpared to the error voltage. when the inductor curr ent rises sufficiently, the pwm comparator turns off the swit ch, forcing the inductor current to the output capa citor through the internal p-channel mosfet rectifier, which forc es the inductor current to decrease. the peak induc tor current is controlled by the error voltage. thus th e output voltage controls the inductor current to s atisfy the lode . setting the output voltage set the output voltage by selecting the resistive v oltage divider ratio. the voltage divider drops the output voltage to the 1.24v feedback voltage. use a 100k resistor for r2 of the voltage divider. determine the high-s ide resistor r1 by the equation: vout=(r1/r2+1) vfb vout=(r1/r2+1) 1.25v
ELP6230A e-cmos corp. (www.ecmos.com.tw) 5 k0 6 n - rev. f00 1 high efficiency 1a/30v boost dc/dc convertor 8/8 package information
|
