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rev.a apr .201 1 WS2259 WS2259 WS2259 WS2259 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 . features features features features burst mode function low startup current (4ua) low operation current ( 1.7 ma) built in leading edge blanking (leb) built in synchronous slope compensation current mode operates external programmable switching frequency cycle by cycle over current protection over temperature protection ( otp soft-start vdd over voltage protection and clamp under voltage lockout with hysteresi s( uvlo driver output clamped ( 13v ) soft-driver function for lower emi frequency jitter constant output power limited over load protection(olp) free audio noise operation applications applications applications applications universal switch power supply and offline ac/dc flyback converter: battery charger power adaptor set-top box power supplies open-frame smps typical typical typical typical application application application application circuit circuit circuit circuit general general general general description description description description WS2259 which is optimized for high performance is a highly integrated current mode pwm control ic. it is applied for switch power of the small-sized and medium-sized for example the power adaptor. for lower the standby power and higher rohs compliant, the ic has the burst mode function and very low startup current and working current. at the condition of no load or light load, the ic operates in extended burst mode to minimize switching loss by lower the switching frequency. the low startup current and low operating current contribute to a reliable power on startup design with WS2259 . a large value resistor could thus be used in the startup circuit to minimize the power consumption and improve the efficiency of the power convert. the internal synchronous slope compensation circuit improves system large signal stability and reduces the possible subharmonic oscillation at high pwm duty cycle output. leading-edge blanking on current sense(sense) input removes the signal glitch due to snubber circuit diode reverse recovery and thus greatly reduces the external component count and system cost in the design. WS2259 offers complete protection coverage with automatic self-recovery feature including cycle by cycle over current protection (ocp), over load protection (olp), over temperature protection (otp), vdd over voltage protection, under voltage lockout (uvlo). the gate-driven output is clamped to maximum 13v to protect the external mosfet. excellent emi performance is achieved by using the frequency jitter and the soft-switching at the totem pole gate drive output. the tone energy at below 20khz is minimized in the design and audio noise is eliminated during operation. the ic can be used as the best alternative products of the linear power supply or the rcc-mode power to improve the whole performance of the switch power system and lower the cost. WS2259 is offered in sot23-6, sop-8 and dip-8 packages.
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 2 / 11 WS2259 WS2259 WS2259 WS2259 pin pin pin pin definition definition definition definition and and and and device device device device marking marking marking marking WS2259 is offered in sot23-6, sop-8 and dip-8 packages as shown below ordering ordering ordering ordering information information information information package package package package ic ic ic ic marking marking marking marking information information information information purchasing purchasing purchasing purchasing device device device device name name name name 8-pin dip8, pb-free WS2259dp WS2259dp 8-pin sop8, pb-free WS2259sp WS2259sp 6-pin sot23-6, pb-free 59xx x WS2259 y p sot23-6 59: WS2259 y: year code ( 1:2011; 2:2012 ) ww: week code (1-52) x: d = dip8 s = sop8 p: p = pb-free package d: ? v: ? ( ? 1-9) f: y: year code ( 1:2011; 2:2012 ) ww: week code (1-52) s e n s e s o t 2 3 - 6 1 2 3 6 5 4 g n d f b r i g a t e v d d 1 2 3 4 8 7 6 5 g n d g a t e v d d s e n s e f b r i n c n c d i p 8 s o p 8 w w w w s s s s 2259xp 2259xp 2259xp 2259xp dvf dvf dvf dvf yww yww yww yww
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 3 / 11 WS2259 WS2259 WS2259 WS2259 pin pin pin pin function function function function description description description description pin pin pin pin name name name name pin pin pin pin no. no. no. no. dip8 dip8 dip8 dip8 /sot2 /sot2 /sot2 /sot2 3 3 3 3 pin pin pin pin type type type type function function function function description description description description gate 1 / 6 output totem-pole gate drive output for the power mosfet vdd 2 / 5 power power supply nc 3 floating floating sense 4 / 4 current monitoring current sense input. ri 5 / 3 frequency setting internal oscillator frequency setting pin. a resistor which is connected between ri and gnd sets the pwm frequency nc 6 floating floating fb 7 / 2 feedback input feedback input pin. the pwm duty cycle is determined by voltage into this pin and the current-sense signal at pin 4 gnd 8 / 1 ground ground block block block block diagram diagram diagram diagram v d d c l a m p o s c l o g i c s o f t driver s o f t s t a r t o c p l e b s l o p e compensation voltage divider p w m o l p internal supply u v l o b u r s t m o d e
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 4 / 11 WS2259 WS2259 WS2259 WS2259 recommended recommended recommended recommended operating operating operating operating condition condition condition condition s s s s ymbol ymbol ymbol ymbol p p p p arameter arameter arameter arameter v v v v alue alue alue alue u u u u nit nit nit nit vdd vdd supply voltage 10~30 v ri ri resistor 100 kohm t a operating temperature -20~85 absolute absolute absolute absolute maximum maximum maximum maximum ratings ratings ratings ratings ( ( ( ( note note note note 1) 1) 1) 1) s s s s ymbol ymbol ymbol ymbol p p p p arameter arameter arameter arameter value value value value unit unit unit unit vdd dc power supply 30 v v fb fb input voltage -0.3~7 v v sense sense input voltage -0.3~7 v v ri ri input voltage -0.3~7 v t j operation junction temperature -20~150 t stg storage temperature -40~150 v cv vcc clamp voltage 3 1 v i cc vcc clamp continuous current 10 ma note note note note 1 1 1 1 : stresses above those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated in the recommended operating conditions section are not implied. exposure to absolute maximum-rated conditions for extended periods may affect device reliability. esd esd esd esd information information information information s s s s ymbol ymbol ymbol ymbol p p p p arameter arameter arameter arameter v v v v alue alue alue alue u u u u nit nit nit nit v esd-hbm human body model on all pins 3 kv v esd-mm machine model on all pins 300 v
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 5 / 11 WS2259 WS2259 WS2259 WS2259 electrical electrical electrical electrical characteristics characteristics characteristics characteristics (t a =25 vcc=16v, if not otherwise noted) supply supply supply supply voltage voltage voltage voltage (vdd) (vdd) (vdd) (vdd) p arameter s ymbol test condition min typ max unit operation voltage vdd_op 30 v turn on threshold voltage uvlo_on 6. 8 7 .5 8 v turn-off threshold voltage uvlo_off 1 3.5 1 4.5 1 5.5 v start up current i_vdd_st vdd=13v,ri=100k 4 10 ua operation current i_vdd_op vdd=16v,ri=100k,v fb =3v gate with 1nf to gnd 1.7 2.3 ma vdd_ovp 29 v vdd zener clamp voltage vdd_clamp ivdd=10ma 31 v feedback feedback feedback feedback input input input input section section section section v fb open loop voltage v fb _open vdd=16v,fb open, 5.4 5.9 6. 4 v fb pin short current i fb _short fb shorted to gnd 0. 3 0.45 0.6 ma power limiting fb threshold v th _pl vdd=16v, ri=100k 3.2 3.65 4.0 v power limiting debounce t d _pl vdd=16v,fb open,ri=100k ? 48 60 72 ms input impedance z fb _in vdd=16v,fb=2v/3v,cs open 11.5 14.5 18 k ? maximum duty cycle max_duty vdd=16v,fb open, cs=0,ri=100k ? 72 77 82 % current current current current sense sense sense sense section section section section leading edge blanking time tleb 330 ns ocp control delay t d _oc gate with 1nf to gnd 70 ns ocp threshold t th _oc fb 3.2v 0.6 8 0.7 8 0.7 8 v oscillator oscillator oscillator oscillator section section section section frequency fosc vdd=16v,ri=100k,,fb=3.2v 60 65 70 khz jitter period for 65k 4 ms jitter range 5 % burst mode frequency fosc_bm vdd=9.5v,ri=100k, fb=1v 22 khz frequency variation versus temp. deviation ? f_temp temp = -20 to 85 5 % frequency variation versus vdd ? f_vdd vdd = 12 to 25v 5 % ri ri ri ri section section section section ri voltage v ri vdd=16v,ri=1 00k ,cs=1v 1.94 2 2.06 v thermal thermal thermal thermal protection protection protection protection thermal shutdown temperature t_shutdown 150 gate gate gate gate output output output output section section section section output voltage low vol vdd = 16v, io = -20ma 0.8 v output voltage high voh vdd = 16v, io = 20ma 9 v output clamp voltage vclamp vdd = 20v 11 13 14.5 v rising time tr vdd = 16v, gate with 1nf to gnd 250 ns falling time tf vdd = 16v, gate with 1nf to gnd 75 ns
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 6 / 11 WS2259 WS2259 WS2259 WS2259 typical typical typical typical operating operating operating operating characteristics characteristics characteristics characteristics
rev.a apr .201 1 WS2259 WS2259 WS2259 WS2259 steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance function function function function description description description description WS2259 is a highly integrated current mode pwm control ic which is optimized for high performance. it is applied for switch power of the small-sized and medium-sized for example the power adaptor. the low startup current, operation current and burst mode function at the condition of no load and low load can decrease the standby power of the system, and improve the power convert efficiency. the internal synchronous slope compensation, the leading edge blanking function of the sense pin not only decrease the component number, but also improve the stability of the system and avoid the harmonics generation. WS2259 also have multiform general recovery protection mode. the main function is described as below. startup startup startup startup current current current current and and and and startup startup startup startup control control control control startup current of WS2259 is designed to be very low 4ua so that vdd could be charged up above uvlo threshold level and starts up quickly. a large value startup resistor can therefore be used to minimize the power loss, predigest the design of startup circuit and provides reliable startup in application. for the design of ac/dc adaptor with universal input range, a startup resistor of 2 m ? , 1/8 w could be used together with a vdd capacitor to provide a fast startup and low power dissipation solution. operating operating operating operating current current current current the operating current of WS2259 is very low .good efficiency is achieved with low operating current together with extended burst mode control circuit which can easy the design of vdd capacitor. soft-start soft-start soft-start soft-start as soon as vdd reaches uvlo(on), the soft-start function operates, the peak current is then gradually increased from zero. every restart attempt is followed by 4ms soft-start. burst burst burst burst mode mode mode mode at very light load or no load condition, the ic operates in burst mode. in this condition, the voltage at fb is below burst mode threshold level, thus system goes into burst mode. the gate dive output switches only when vcc voltage drops below a preset level or fb input is active to output an on state. otherwise the gate drive remains at off state to minimize the switching loss thus reduce the standby power consumption. the standby current of WS2259 is low as 800ua, thus the standby of WS2259 can be low than 100mw. the frequency control also eliminates the audio noise at any loading conditions . oscillator oscillator oscillator oscillator operation operation operation operation a resistor connected between ri and gnd sets the charge/discharge time of the constant current source to the internal cap and thus the pwm oscillator frequency is determined. the relationship between ri and switching frequency follows the below equation: ( ) ( ) khz kohm ri 6500 f osc = if ri floating, the frequency will be internal set at 50 khz current current current current sensing sensing sensing sensing and and and and leading leading leading leading edge edge edge edge blanking blanking blanking blanking cycle-by-cycle current limiting is offered in WS2259 . the switch current is detected by a sense resistor into the sense pin. the internal leading-edge blanking chops off the sense voltage spike at initial mosfet on state due to snubber diode circuit reverse recovery and thus reduce the external rc filter circuit. the current limit comparator is disabled and cannot turn off the external mosfet during the blanking period. pwm duty cycle is determined by voltage level into sense pin and fb pin. internal internal internal internal synchronized synchronized synchronized synchronized slope slope slope slope compensation compensation compensation compensation built-in slope compensation circuit adds slope voltage onto the current sense input voltage for pwm generation. this greatly improves the close loop stability at ccm and prevents the sub-harmonic oscillation and thus reduces the output ripple voltage. 7/11
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 8 / 11 WS2259 WS2259 WS2259 WS2259 gate gate gate gate driver driver driver driver gate pin of WS2259 is connected to the gate of an external power switch. the gate drive strength which is too weak leads to over switch loss of mosfet while too strong gate drive output compromises in the over emi. a good tradeoff between output strength and dead time control is achieved through the design of the built-in totem pole gate in WS2259 . the low standby dissipation and good emi system design is easier to achieve through this dedicated devise. for mosfet gate protection, an internal 13v clamp is added at higher than expected vcc input. protection protection protection protection controls controls controls controls good power supply system reliability is achieved with auto-recovery protection features including cycle-by-cycle current limiting (ocp), over load protection (olp), under voltage lockout on vdd (uvlo), over temperature protection (otp), and vdd over voltage protection & vdd clamp. internal line voltage compensation of ocp help to achieve constant output power limit over the universal input voltage range.
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 9 / 11 WS2259 WS2259 WS2259 WS2259 sot23-6 sot23-6 sot23-6 sot23-6 packa packa packa packa ge ge ge ge dimension dimension dimension dimension
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 10 / 11 WS2259 WS2259 WS2259 WS2259 dip-8 dip-8 dip-8 dip-8 pa pa pa pa ckage ckage ckage ckage dimension dimension dimension dimension
steady, steady, steady, steady, keep keep keep keep you you you you advance advance advance advance 11 / 11 WS2259 WS2259 WS2259 WS2259 sop-8 sop-8 sop-8 sop-8 package package package package dimension dimension dimension dimension unit: mm

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