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general description HT2263 is a highly integrated current mode pwm control ic optimized for high p erformance, low stan dby power and cost effective offline flyback converter applications in sub 30w range. pwm switching frequency at normal operation is externally programmable and trimmed to tight range. at no load or light load condition, the ic operates in extended ?burst mode? to minimize switching loss. lower standby power and higher conversion efficiency is thus achieved. vdd low startup current and low operating current contribute to a reliable power on startup design with HT2263 . a large value resistor could thus be used in the startup circuit to minimize the standby power. the internal slope compensation improves system large signal stability and reduces the possible sub - harmonic oscillation at high pwm duty cycle output. leading - edge blanking on current sense(cs) 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. HT2263 offers complete protection coverage with automatic self - recovery feature including cy cle - by - cycle current limiting (ocp), over load protection (olp), vdd over voltage clamp and under voltage lockout (uvlo). the gate - drive output is clamped to maximum 18v to protect the power mosfet. excellent emi performance is achieved with frequency sh uffling technique together with soft switching control at the totem pole gate drive output. tone energy at below 20khz is minimized in the design and audio noise is eliminated during operation. HT2263 is offered in sot23 - 6, sop - 8 and dip - 8 packages. fea tures ? extended burst mode control for improved efficiency and minimum standby power design . ? audio noise free operation ? external programmable pwm switching frequency ? internal synchronized slope compensation ? low vdd startup current and low operating curre nt (1.4ma) ? leading edge blanking on current sense input ? good protection coverage with auto self - recovery ? vdd over voltage clamp and under voltage lockout with hysteresis (uvlo) ? gate output maximum voltage clamp (1 3 v) ? line input compensated cycle - by - cyc le over - current threshold setting for constant output power limiting over universal input voltage range. ? overload protection (olp) 1 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
applications offline ac/dc flyback converter for ? battery charger ? power adap tor ? set - top box power supplies ? open - frame smps block diagram 2 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
typical application general information pin configuration the HT2263 is offered in sot23 - 6, dip8 and sop8 packages, shown as below. ordering inform ation part number de scription HT2263 mp sot23 - 6, pb - free HT2263 ap dip8, pb - free HT2263 cp sop8, pb - free package dissipation rating package rja (c/w) dip8 90 sop8 150 sot23 - 6 200 absolute maximum ratings parameter value vdd dc supply voltage 30 v vdd zener clamp voltage note vdd_clamp+0.1v vdd dc clamp current 10 ma v fb input voltage - 0.3 to 7v v sense input voltage to sense pin - 0.3 to 7v 3 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
min/max operating junction temperature t j - 20 to 150 o c min/max storage temperature t stg - 55 to 160 o c note : vdd_clamp has a nominal value of 34v. stresses beyond 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 under recommended operating conditions is not implied. exposure to absolute maximum - rated conditions for extended peri ods may affect device reliability. terminal assignments pin name i/o description gnd p ground fb i feedback input pin. the pwm duty cycle is determined by voltage level into this pin and sense pin input. nc sense i current sense input pin. conne cted to mosfet current sensing resistor node. vdd p chip dc power supply pin. gate o totem - pole gate drive output for the power mosfet. recommended operating condition symbol parameter min max unit vdd vdd supply voltage 10 to 30 v t a operating ambient temperature - 20 to 85 o c electrical characteristics (ta = 25oc if not otherwise noted) symbol parameter test conditions min typ max unit supply voltage (vdd) i_vdd_startup vdd start up current vdd =12.5v, measure leakage current into vdd 3 20 ua i_vdd_ops operation current vdd=16v, v fb =3v 1.4 ma uvlo(on) vdd under voltage lockout enter 7. 5 8. 5 9. 5 v 4 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
uvlo(off) vdd under voltage lockout exit (recovery) 13 .5 14 .5 15 .5 v vdd _clamp vdd zener clamp voltage i vdd = 5 ma 34 v feedback input section(fb pin) a vcs pwm input gain v fb /v cs 2.0 v/v v fb _open v fb open loop voltage 4.8 v i fb _short fb pin short circuit current short fb pin to gnd and measure current 0.4 ma v th _0d zero duty cycle fb threshold voltage vdd = 16v, 0.75 v v th _pl power limiting fb threshold vo ltage 3.7 v t d _pl power limiting debounce time 47 msec z fb _in input impedance 6 kohm dc_max maximum duty cycle vdd=18v, fb=3v, cs=0 75 % current sense input(sense pin) t_blanking leading edge blanking time 3 3 0 ns z sense _in input impeda nce 40 kohm t d _oc ocp control delay gate with 1 n f to gnd 120 nsec v th _oc over current threshold voltage at zero duty cycle fb=3.3v 0. 75 0. 8 0.8 5 v oscillator f osc normal oscillation frequency 60 65 70 khz ? f_temp frequency temperature stability vdd = 16v, t a - 20 o c to 85 o c 5 % ? f_vdd frequency voltage stability vdd = 12 - 25v, 5 % fosc_bm burst mode base frequency vdd = 16v, 22 khz gate drive output vol output lo w level vdd = 16v, io = - 20 ma 0.8 v 5 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
voh output high level vdd = 16v, io = 20 ma 10 v v_clamp output clamp voltage level 1 3 v t_r output rising time vdd = 16v, cl = 1nf 2 0 0 nsec t_f output falling time vdd = 16v, cl = 1nf 70 nsec frequenc y shuffling ? f_osc frequency modulation range /base frequency - 3 3 % f_shuffling shuffling frequency 6 5 hz characterization plots vdd = 16v, ta = 25 o c condition applies if not otherwise noted. 6 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
operation description the HT2263 is a highly integrated pwm controller ic optimized for offline flyback converter applications in sub 30w power range. the extended burst mode control greatly reduces the standby power consumption and helps the design easily meet the internationa l power conservation requirements. ? startup current and start up control startup current of HT2263 is designed to be very low so that vdd could be charged up above uvlo threshold level and device starts up quickly. a large value startup resistor can th erefore be used to minimize the power loss yet provides reliable startup in application. for ac/dc adaptor with universal input range design, a 2 m?, 1/8 w startup resistor could be used together with a vdd capacitor to provide a fast startup and low powe r dissipation solution. ? operating current the operating current of HT2263 is low at 1.4ma. good efficiency is achieved with HT2263 low operating current together with extended burst mode control features. ? frequency shuffling for emi improvement t he frequency shuffling/jittering (switching frequency modulation) is implemented in HT2263 . the oscillation frequency is modulated with a random source so that the tone energy is spread out. the spread spectrum minimizes the conduction band emi and there fore reduces system design challenge. ? extended burst mode operation at zero load or light load condition, majority of the power dissipation in a switching mode power supply is from switching loss on the mosfet transistor, the core loss of the transfo rmer and the loss on the snubber circuit. the magnitude of power loss is in proportion to the number of switching events within a fixed period of time. reducing switching events leads to the reduction on the power loss and thus conserves the energy. ht226 3 self adjusts the switching mode according to the loading condition. at from no load to light/medium load condition, the fb input drops below burst mode threshold level. device enters burst mode control. the gate drive output switches only when vdd volta ge drops below a preset level and fb input is active to output an on state. otherwise the gate drive remains at off 7 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
state tominimize the switching loss and reduces the standby power consumption to the greatest extend. the frequency control also eliminates the audio noise at any loading conditions. ? oscillator operation the pwm oscillator frequency is internally set to 65khz ? current sensing and leading edge blanking cycle - by - cycle current limiting is offered in HT2263 current mode pwm control. the switch current is detected by a sense resistor into the sense pin. an internal leading edge blanking circuit chops off the sense voltage spike at initial mosfet on state due to snubber diode reverse recovery so that the external rc filtering on sense inp ut is no longer required. the current limit comparator is disabled and thus cannot turn off the external mosfet during the blanking period. pwm duty cycle is determined by the current sense input voltage and the fb input voltage. ? internal synchronized sl ope c ompensation built - in slope compensation circuit adds voltage ramp 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 rip ple voltage. ? gate drive HT2263 gate is connected to an external mosfet gate for power switch control. too weak the gate drive strength results in higher c onduction and switch loss of mosfet while too strong gate drive output compromises the emi. a g ood tradeoff is achieved through the built - in totem pole gate design with right output strength and dead time control. the low idle loss and good emi system design is easier to achieve with this dedicated control scheme. an internal 1 3 v clamp is added for mosfet gate protection at higher than expected vdd input. ? protection controls good power supply system reliability is achieved with its rich protection features including cycle - by - cycle current limiting (ocp), over load protection (olp) and over voltage clamp, under voltage lockout on vdd (uvlo). t he ocp threshold tracks pwm duty cycles and is line voltage compensated to achieve constant output power limit over the universal input voltage range with recommended reference design. at overload cond ition when fb input voltage exceeds power limit threshold value for more than td_pl, control circuit reacts to shut down the output power mosfet. device restarts when vdd voltage drops below uvlo limit. vdd is supplied by transformer auxiliary winding out put. it is clamped when vdd is higher than threshold value. the power mosfet is shut down when vdd drops below uvlo limit and device enters power on start - up sequence thereafter. 8 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
package mechanical data sot - 23 - 6 package outline dimensions symbol dimensions in millimeters dimensions in inches m in max min max a 1.050 1.250 0.041 0.049 a1 0.000 0.100 0.000 0.004 a2 1.050 1.150 0.041 0.045 b 0.300 0.400 0.012 0.016 c 0.100 0.200 0.004 0.008 d 2.820 3.020 0.111 0.119 e 1.500 1.700 0.059 0.067 e1 2.650 2.950 0.104 0.116 e 0.950typ 0.037typ e1 1.800 2.000 0.071 0.079 l 0.700ref 0.028ref l1 0.300 0.600 0.012 0.024 0 0 8 0 0 0 8 0 9 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
sop 8 package outline dimensions 10 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263
dip8 package outline dimensions 11 of 11 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification HT2263

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