c o p y r igh t @ w i n s em i microelectronics c o . , lt d . , a l l ri g h t r e s er v ed . WS3241 productdescription winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics 1201 features ? built-in 650v uhv power mos ? led constant current: 5% ? fixed primary peak current: 185ma ? without the secondary winding ? start up time less than 100ms ? high precision constant current regulation due to patented cc control ? built-in line compensation ? ultra low operation current ? maximum power 4w ? led open/short protection ? floating pin protection ? excellent emi performance with pfm control ? cycle-by-cycle current limit ? built-in leading edge blanking ? vdd under voltage lockout uvlo ? built-in over temperature protection applications ? led lighting description WS3241 is a high precision primary side feedback constant current led driver, suitable for flyback isolated led in sub 4w power range at universal ac input. it operates in discontinuous current mode. WS3241 integrates 650v power mos. it operates in primary side sensing and regulation, without a secondary feedback circuit, also need not the auxiliary transformer winding detection and power supply, only need few peripheral components can realize constant current, greatly saves the cost and size of the system. the start time of WS3241 is less than 100ms at universal ac input with the high voltage start technology, realizing instant bright of the led lamp. the current precision is less than 5% with high precision current sampling circuit and line compensation. with patented constant current controlling mode, excellent linear regulation is achieved. WS3241 provides a variety of comprehensive protection mode, including: cycle by cycle current limit protection(ocp), led open/short circuit protection, under voltage protection and clamping, over temperature protection, pin floating protection etc.. WS3241 is offered in to-92 package. high precision psr led constant current driver
WS3241 productdescription winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 2 / 8 typical application pin configuration and marking information WS3241 is offered in to-92 package, as bellows: pin definition pin name pin no. pin type function description drain 1 drain the drain terminal of power mosfet gnd 2 ground ground. vdd 3 power power supply. WS3241 n p a product code x internal code bcy internal code for qc y mx d/c
WS3241 productdescription winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 2 / 8 internal block diagram ordering information package marking part number 3 -pin to-92 , pb-free WS3241 np WS3241 np recommended operation conditions part number package input voltage maximum output power WS3241 np to-92 175vac-264vac 4 w 90vac-264vac 3 w absolute maximum ratings symbol paramete limites unit vdd power supply 7 v ivdd_max vdd clamping current 10 ma drain drain of internal power mos -0.3~650 v tj maximun junction temperature 150 tjo operating temperature range -40~150 tstg minimun/maximum storage temperature - 55 ~1 5 0 note : stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device.
WS3241 productdescription winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 2 / 8 electrical characteristics (unless otherwise specified, vcc=8v and ta =25 ) symbol parameter conditions min typ max units supply voltage section vdd_c lamp vdd clamping voltage 1 0 ma 6.3 v vdd_re g vdd power supply 5.8 6.1 v uvlo_ off vdd under voltage lockout 5.3 v i_vdd quiet current vdd=6.1v 1 50 250 ua current sense section vcs threshold voltage for peak current limit 490 500 510 m v tleb lead edge blanking 500 ns tdela y shutdown delay 1 00 ns d_max maximum duty cycle 50 % feedback input section toff_m ax maximum demagnetization time 255 us toff_mi n minimum demagnetization time 3.6 us tdem_ ovp open loop detection reference demagnetization time 4.5 us tcc/tde m cycle time/demagnetization time @constant current 2 power mosfet rds_on power on resistor idrain=50ma 30 bvdss breakdown voltage 650 v idss leakage current of power mos 10 ua over temperature protection t reg thermal regulation temperature 135
WS3241 productdescription winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 5 / 8 application information WS3241 is a constant current driver for led lighting, adopted advanced constant current control method.it integrates 650v power switch. only need a few peripheral components can achieve excellent constant current characteristic. with the primary side feedback technology, WS3241 do not need optocoupler and tl431, also need not the auxiliary winding for power supply and detection. thus achieve the low system cost. low operation current the operating current of WS3241 is very low. the typical value is 150ua. the low operating current improves the efficiency of the system, while reducing the vdd capacitor requirements. primary feedback psr technology assume that the system works in dcm flyback mode, the power transmission equations can be expressed o o s pk m i v f i l p ? ? ? ? ? ? 2 2 ? where, p is the output power, vo and io is the system output voltage and current, is the system power conversion efficiency, ipk is the primary side peak current, fixed 185ma. in dcm mode, demagnetization time tdem can be expressed as: pk p s dem m o i n n t l v ? ? ? where, np and ns is the transformer primary and secondary turns, respectively. combination of the above two formula, the average output current can be expressed as: dem s s p pk o t f n n i i ? ? ? ? ? 2 ? s dem s p pk o t t n n i i ? ? ? ? 2 ? where ts is the switch cycle. WS3241 adopts pfm mode to realize constant current, making the peak inductor current of primary side constant, also remains the ratio of the demagnetization time and the cycle time, which can realize constant output current, but also independent with the line input voltage and transformer inductance. the ratio of the demagnetization time and the cycle time is 0.5: 5 . 0 ? s dem t t single chip built-in 650v high voltage power supply, start time less than 100ms fig.1 shows the internal high voltage power supply module. when the system access ac power, vdd capacitor is charged by the internal 650v high voltage mos. it will not reset and start working until the vdd voltage reaches 5.8v. the start time is less than 100ms, which means that the light achieves instant bright. in normal operation, vdd is dynamically charged by drain, which can save the power supply auxiliary winding. demagnetization detection WS3241 detects the demagnetization time through the drainterminal waveform, which can save auxiliary winding. cycle by cycle current protection and lead edge blanking cycle-by-cycle current limiting is offered in WS3241 . an internal leading edge blanking circuit chops off the sense
www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 6 / 8 winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics WS3241 productdescription voltage spike on the current sense resistor at initial mosfet on state. the typical value of lead edge blanking is 500ns. the current limit comparator is disabled and thus cannot turn off the internal mosfet. pfm control improves the emi performance WS3241 uses the pfm control method, which can improve the system performance. because pfm belongs to frequency conversion control, built-in spread spectrum function . over voltage protection WS3241 has a built-in over voltage protection circuit. when the led open, the output voltage increased cycle by cycle, secondary demagnetization time induced. when the secondary demagnetization time is less than 5us, the over voltage protection will be triggered. minimum off time WS3241 integrates the minimum off time control, the typical value is 3.6us . it prevents the interference on the chip operation voltage caused by the burrs of the switch off, especially when larger leakage inductance of the transformer and lower output voltage. pin floating protection in WS3241 , pin floating phenomenon will not cause damage to the system. automatic restart protection in WS3241 , protection is locked when a certain protection is triggered, while the switching stops, intering restart delay mode. here the vdd voltage is oscillates between 5.3v and 5.8v, and entering into normal start mode after 64 cycles. after start up, it works and confirms whether the protection is removed. if the protection is not removed, the chip will enter into protection latch state, and repeat delay to restart, until the protection is released. soft driver of internal power mosfet WS3241 has a built-in soft driver, improving the emi performance, realizing a balance between the efficiency, the reliability and the emi.
www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 6 / 8 winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics WS3241 productdescription package information to-92 package outline dimensions e d b q1 l 1 e c 2 3 e a winsemi symbol dimensions in millimeters dimensions in inches min max min max a 3.30 3. 90 0.1 30 0.154 b 0.35 0.55 0.014 0.022 c 0.31 0.51 0.012 0.020 d 4.30 4.90 0.169 0. 193 e 4.30 4.90 0.169 0. 193 e 1.17 1.37 0. 046 0.054 l 12.5 15.5 0.492 0.610 q1 0.74 0.89 0 .029 0.035
www.winsemi.com tel : +86-755-8250 6288 fax : +86-755-8250 6299 6 / 8 winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics winsemi microelectronics WS3241 productdescription n ote: 1. we strongly recommend customers check carefully on the trademark when buying our product, if there is any question, please don't be hesitate to contact us. 2. please do not exceed the absolute maximum ratings of the device when circuit designing. 3. winsemi microelectronics co., ltd reserved the right to make changes in this specification sheet and is subject to change without prior notice. contact: winsemi microelectronics co., ltd. add:futian district, shenzhen tian an cyber tech plaza two east wing 1002 post code : 518040 tel : +86-755-8250 6288 fax : +86-755-8250 6299 web site : www.winsemi.com
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