EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 1 o f 8 4f06n - rev.f001 pin configuration pin description general description features the EC4304C is a continuous mode inductive step - down and buck - boost converter, designed for driving single or multiple series connected leds from a voltage source higher than or lower than the led voltage. it operates from input supply between 7v and 40v and provides and externally adjustable output current up to 1.5a with proper supply voltage and external components, the EC4304C can provide more than 50 watts of ou t p ut power . this EC4304C includes the output switch and high - side output current sensing circuit, which uses an external resistor to set the nominal average output current. the adj pin will accept either a wide range pulse dimming waveform or a dc voltage. this will provide either a continuous or gated output current depending upon the control frequency. the soft - start time can be increased by connecting an external capacitor from the adj pin to ground. the pwm filter components also serve as soft - start time setting . applying a 0.2v or lower to the adj pin turns the output off and switches the device into a low current standby state. ? operates from 7v t o 40v supply voltage ? single pin on/off and brightness control using dc voltage or pwm ? up to 95% efficiency ? internal 40v ndmos switch ? up to 1.5a output current ? typical +/ - 5% led current accuracy ? input under voltage lockout ? sop 8l(exposed pad) package ? rohs compliant and halogen - free applications ? automotive led lighting ? high power led lighting ? indicator and emer gency lighting ? architectural lighting ? low voltage industrial lighting ? signage and decorative led lighting pin no pin name pin function 1 vin power supply input pin. connect a nominal (7v~40v) power supply to t his pin. the power - on - reset (por) function monitors the input voltage by this pin. it is recommended that a decoupling capacitor (4.7f or higher x7r ceramic capacitor) be connected to the gnd for noise decoupling. 2/3/6/7 gnd ground for the ic. all volt ages levels are measured with respect to this pin. 4 isense current sense pin: sense led string current. 5 adj multi - function on/off and brightness control pin: - analog signal input for analog control of pwm dimming. - pwm signal input for digital pwm dim ming. 8 lx drain of ndmos switch. exposed pad ground and thermal pad
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 2 o f 8 4f06n - rev.f001 typical application ordering / marking information part number package marking marking information EC4304C nmhr sop 8l (exposed pad) 4304 c lllll dddddd lllll is lot no dddddd date code
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 3 o f 8 4f06n - rev.f001 functional block diagram functional description the EC4304C is a simple high - efficiency, continuous mode inductive step - down converter. the device operates with an input voltage range from 7v to 40v and delivers up to 1.5a of output current. a high - side current - sense resistor sets the output current and a dedicated pwm dimming input enables pulsed led dimming over a wide range of brig htness levels. a high side current - sensing scheme and an on - board current setting circuitry minimize the number of external components which is required while delivering led current with +5% accuracy, using a 1% sense resistor. adjusti ng output current the device contains a low pass filter between the adj pin and the threshold comparator and an internal current limiting resistor between adj and the internal reference voltage. this allows the adj pin to be overdriven with either dc or pu lse signals to change the v sense switching threshold and adjust the output current. details of the different modes of adjusting output current are given in the applications section by: the value of the output current is 1a at 0.1 (0.5a at 0.2) and this is a calculated output current when the adj terminal is 1.25v floating. shutdown mode taking the adj pin to a voltage below 0.2v for more than approximately 100s will turn off the out put, and supply current will fall to a low standby level of 20a nominal. soft - start the device has inbuilt soft - start action due to the delay through the pwm filter. an external capacitor from the adj pin to ground will provide additional soft - start del ay, by increasing the time taken for the voltage on this pin to rise to the turn - on threshold and by slowing down the rate of rise of the control voltage at the input of the comparator. with no external capacitor, the time taken for the output to reach 90% of its final value is approximately 500 s. adding capacitance increases this delay by approximately 0.5ms/ nf. inherent open - circuit led protection if the connection to the led(s) is open - circuited, the coil is isolated from the lx pin of the chip, so the chip will not be damaged. unlike in ma ny boost converters, where the back emf may damage the internal switch by forcing the drain above its breakdown voltage.
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 4 o f 8 4f06n - rev.f001 absolute maximum rating (note 1) supply input voltage, v in --------- ----------- ----------------------------- - -------- -- -- - -- - 0.3v to + 45v isense voltage, v isense ------------------------------------------------- -- --- -------- ---- +0.3v to - 5v(measured with respect to v in ) lx output voltage, v lx ---------------------------------------------------------- -- -- ----- - 0.3v to + 45v adjust pin input voltage, v adj ------------------------------------------------ ----- --- - --- - 0.3v to + 6v switch output current, i lx ---------------------------------------------- ------- - ---- ------- 1. 8 a operation temperature range ----------------------------------- ----------- - --- - ------- - 40 c to +1 50 c storage temperature range ------------------------------------------------ - ---- - -- - ---- - 55 c to +150 c junction temperature ---------------------------------------------------------- ------- ----- 150 c lead temperatu re (soldering, 10 sec) ----------------------------------- - ----- - ------- 260 c esd rating (note 2) hbm (human body mode) ----------------------------------------- - -- ------ - - ----- 4kv mm (machine mode) ---------------------------------------------------- --- ------ ---- 200v thermal information package thermal resistance (note 3) s op 8 l (exposed pad) ja --------------------------- ----------------------- ----------- - ---------- 47 c/w sop 8l(exposed pad) jc --------------------------------------- ----------------------------- - - -- 1 7.9 c/w power dissipation, p d @ t a = 25c sop 8l(exposed pad) ----------- --------------- ------------------------------------------ --------- 2.13 w recommended operation conditions operating junction temperature range (note 4 ) ---------------------------------- - 40c to +125c operating ambient temperature range ---------------- ------------------------------ - 40c to +85c note 1. stresses listed as the above absolute maximum ratings may cause permanent damage to the device. these are for stress ratings. functional operation of the device at these or any other con ditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. note 2. devices are esd sensitive. han dling precaution recommended. note 3. ja is measured in the natural convection at t a = 25c on a high effective thermal condu ctivity test board of jedec 51 - 7 thermal measurement standard. note 4 . the device is not guaranteed to function outside its operating conditions. electrical ch aracteristics (v in = 12v, t a = 25 , unless otherwise specified) parameter symbol test conditions min typ max units supply input supply voltage range v in 7 - 40 v vin por threshold v inrth v in rising - 4.95 - v vin por threshold v infth v in falling - 4 .8 - v quiescent current with output off i_ q off adj pin grounded - 20 40 a quiescent current with output switching i_ q on adj pin floating f = 250khz - 0.5 1.0 ma isense pin current sense threshold voltage v i sense isense pin with respect to vin, adj = 1.25v 95 100 105 mv isense input current i sense v sense = v in - 0,1 - - 1.0 a reference reference voltage v ref adj pin voltage - 1.25 - v reference voltage temperature coefficient - 50 - ppm/ o k
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 5 o f 8 4f06n - rev.f001 electrical characteristics (v in = 12v, t a = 25 , unle ss otherwise specified) parameter symbol test conditions min typ max units adj pin adj pin for dc control level v adj 0.3 - 2.5 v adj to switch device from on state to off state v adj_off v adj falling 0.15 0.2 0.25 v adj to switch device from off sta te to on state v adj_on v adj rising 0.2 0.25 0.3 v adj to vref resistance r adj 0 < v adj < v ref 135 - 250 k v adj > v ref +100mv 13.5 - 25 k adj pin low frequency duty cycle range d pwm (lf) pwm frequency < 500hz 10 - 100 % adj pin high frequency duty cycle range d pwm (hf) pwm frequency >10khz 16 - 100 % lx pin lx switch current i lxmean - - 1 .5 a lx r d s_on r lx @i lx = 1a - 0.3 0.6 lx leakage current - - 5 a minimum switch on time t on_min lx switch on - 240 - ns minimum switch off time t off_min lx switch off - 200 - ns recommended minimum switch on time t on_min_rec - 800 - ns frequency operati on frequency f lx adj pin floating, l=33h (0.093 ) i out = 1a @ v led =3.6v driving 1led - 280 - khz recommended maximum operation frequency f lxmax - - 1 mhz duty cycle range of output switch of operation frequency d lx 30 - 70 % internal comparator prop agation delay t pd - 50 - ns soft - start so f t - start time t ss time taken for output current to reach 90% of final value after voltage on adj pin has risen above 0.3v. - 500 - s
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 6 o f 8 4f06n - rev.f001 typical operation characteristics
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 7 o f 8 4f06n - rev.f001 typical operation characteristics
EC4304C 1 .5 a, hysteretic, high brightness led driver with internal switch e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 8 o f 8 4f06n - rev.f001 note 1.package outline unit description: bsc: basic. represents theoretical exact dimension or dimension target min: minimum dimension specified. max: maximum dimension specified. ref: reference. represents dimension for reference use only. this value is not a device specification. typ. typical. provided as a general value. this value is not a device specification. 2.dimensions in millimeters. 3.drawing not to s cale. 4.these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.15mm. package information so p 8l(exposed pad)
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