hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 1/6 H6842p, H6842s hsmc product specification H6842p / H6842s novel low cost green-power pwm controller description 8-lead plastic dip-8 package code: p the H6842 is a low startup current, low cost, curren. mode pwm controller with green-power & burst- mode power-saving operation. the integrated functions such as the leading-edge blanking of the curre nt sensing, internal slope compensation provide the users a high efficiency, low external component counts, and low cost solution for ac/dc power applications. the special green-power function provides off-time modulation to linearly decrea se the switching frequency under ight-load conditions. and under zero-load conditions, the power supply enters burst-mode to further reduce power consumption by shutting off pwm output. when the output of power supply is short or over loaded, the fb voltage will increase, and if the fb voltage is higher than 5.2v for longer th an 56msec the pwm output will be turned off. 8-lead plastic so-8 package code: s ? a external ntc resistor connected from pin rt to ground can be applied to over- temperature protection. pulse by pulse current limit ensures a constant output current even under short circuit. pwm output will be disabled as long as vdd exceeds a threshold. when internal latch circuit is us ed to latch-off the controller the latch wil be reset when the power supply vdd is disabled features ? low cost, green-power burst-mode pwm ? very low start-up current ( about 7.5ua) applications ? power adaptor ? open frame switching power supply ? battery charger adapter ? lcd monitor ordering information part number description H6842p dip-8, pb-free in tube H6842s sop-8, pb-free in tube H6842sa sop-8,pb-free in t/r ? low operating current ( about 3.0ma) ? current mode operation ? under voltage lockout (uvlo) ? vdd over voltage protection(ovp) ? programmable over-temperature protection ? internal latch circuit(otp,ovp) ? built-in soft start with 1ms ? soft clamped gate output voltage 16.5v ? vdd over voltage protect 25.5v ? cycle-by-cycle current limiting ? output scp (short circuit protection) ? built-in synchronized slope ompensation ? leading-edge blanking on sense input ? programmable pwm frequency ? high-voltage cmos process with esd ? dip-8 & sop-8 pb-free package ? compatible with sg6842j&ld7552& ob2269 & sg6841 & ob2268
hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 2/6 H6842p, H6842s hsmc product specification pin connection (top view) package function description pin1: gnd gnd pin pin2: fb voltage feedback pin. the pwm duty cycle is determined by fb and sense. pin3: vin this pin is pulled high to the rectified lin e input through a large resistor for start-up. this pin is also used to detect line voltage to compensate for constant output power limit for universal ac input. pin4: ri by connecting a resistor to ground to set the switching freq. increasing the resistor will reduce the switching freq. pin5: rt an ntc resistor is connected from this pin to ground for over-temperature protection. pin6: sense current sense pin, the sensed voltage is used for current-mode control and pulse-by-pulse current limiting. pin7: vdd power supply voltage pin. 1234 5678 dip-8 1234 5678 so-8 pin8: gate gate drive output to drive the external mosfet .a soft driving waveform isimplemented to improve emi. typical application circuit block diagram
hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 3/6 H6842p, H6842s hsmc product specification absolute maximum ratings symbol parameter value unit v dd supply voltage pin vo l t a g e 40 v v fb input voltage to fb pin -0.3 to 6v v v sens input voltage to sense pin -0.3 to 6v v p d power dissipation 1000 mw esd capability, hbm model 2000 v esd capability, machine model 200 v dip-8 10sec 260 t l lead temperature(soldering) sop-8 10sec 230 o c t j storage temperature range -55 to + 150 o c t stg lead temperature (soldering 10s) 300 o c electrical characteristics ( ta=25c unless otherwise noted, v dd = 15v. ) symbol parameter conditions min. typ. max. unit supply voltage (v dd pin) i st startup current vdd= 15v 7.5 30 a i ss operating current vfb=vsense= 0v vdd= 15v 3 5 ma v th(on) start threshold voltage -- 16 16.5 17 v v th(off) min. operating voltage -- 10.4 10.8 11.2 v vdd over voltage vdd-ovp protecti on(latch off) 23 24.5 25 v vdd low-threshold voltage vdd-th-g to exit green-off mode 11 12 13 v voltage feedback (fb pin) i fb short circuit current v fb =0v 1.42 ma v fb open loop voltage v fb =open 6 v current sensing (sen pin) v th threshold voltage for current limit i vin =0 0.76 0.9 v t pd delay to output 115 200 nsec z cs input impedance 13 k ? b nk leading edge blanking time 260 354 460 nsec oscillator (ri pin) f osc frequency in nominal mode ri=26k ? 63 67 70 khz f osc-green frequency in green mode ri=26 k ? 25 27 29 khz beginning of frequency v n reducing at fb voltage vdd=15v 1.95 2.05 2.15 v end of frequency reducing at v g fb voltage vdd=15v 1.5 1.54 1.6 v g
hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 4/6 H6842p, H6842s hsmc product specification frequency temp. stability -30-85 5 % gate drive output (gate pin) v ol output low level vdd=12v,i o =50ma 0.32 0.6 v v oh output high level vdd=12v,i o =50ma 7.2 8 v t r rising time vdd=15v,c l =1nf 200 240 280 ns t f falling time vdd=13v,c l =1nf 30 80 90 ns dc max maximum duty cycle 84 86 88 over-temperature protection section i rt output current of pin rt ri=26k ? 65 70 75 a v otp threshold voltage for over- temperature protection. 1 1.05 1.1 v ri section ri nor ri operating range 15.5 26 36 k ? ri max max ri value for protection 216 k ? ri min 6 k ? note 1: adjust v cc above the start threshold before setting at 15v. note 2: these parameters, although guaranteed are not 100% tested in production. note 3: parameter measured at trip point of latch with v pin2 =0. note 4: gain defined as: a=v pin1 /v pin3 , 0 dv pin3 d 0.8v operation description start-up current & operating current the typical start-up current is only 8 a. this allows a high resistance, low-wattage start-up resistor to be used to minimize power loss a 1.5mohms , 0.25w, start-up resistor and a 10 f/40v vdd hold-up capacitor would be sufficient for an ac/dc adapter with a universal input range the required operating current has been reduced to 3.4ma. this results in higher efficiency and reduces the vdd hold-up capacitance requirement green-power mode operation the proprietary green-power mode function provides off-time modulation to continuously decrease the pwm frequency under light-load conditions. to avoid acou stic-noise problem, the minimum pwm frequency set above 25khz. this green-power mode function dramatically r educes power consumption under light-load and zero-load conditions. power supplies using a H6842 controller can easily meet even the most restrictive international regulations regarding stan dby power consumption. oscillator operation a resistor connected from the ri pin to gnd pin generat es a constant current source for the H6842 controller this current is used to determine the center pw m frequency. increasing the resistance will reduce pwm frequency.using a 26k ? resistor r i results in a corresponding 67khz pwm frequency.the relationship between r i and the switching frequency is .the frequency variation ranges from around 63khz to 70khz for a center frequency 67khz.the emi enhancement function helps reduce emi emission of a power supply with minimum line filters leading edge blanking each time the power mosfet is switched on, a turn-on spike will inevitably oc cur at the sense-resistor. to avoid premature termination of the switching pulse, a lead ing-edge blanking time is built in. during this blanking period,the current-limit comparator is di sabled, and it cannot switch off the gate drive. under-voltage lockout (uvlo)
hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 5/6 H6842p, H6842s hsmc product specification the turn-on/turn-off thresholds are fixed internally at 12.4v/16.5v. to enable a H6842 controller during start-up, the hold-up capacitor must first be charged to 16.5v through the start-up resistor. the hold-up capacitor will continue to supply vdd before energy can be delivered from the auxiliary winding of the main transformer. vdd must not drop below 12.4v during this start-up process. this uvlo hysteresis window ensures that the hold-up capacitor can adequately supply vdd during start-up. gate output / soft driving the H6842 output stage is a fast totem pole gate driver . cross-conduction has been avoided to minimize heat dissipation, increase efficiency, and enhance reliability. the output driver is clamped by an internal 18v zener diode in order to protect the power mosfet transistors from any harmful over-voltage gate signals. a soft driving waveform is implemented to minimize emi. slope compensation the sensed voltage across the current sense resistor is used for peak-current-mode control and cycle-by-cycle current limiting. the built-in slope compensation function improves power supply stability and prevents peak-current- mode control from causing sub-harmonic oscillations. within every switching cycle, the H6842 controller produces a positively sloped, synchronized ramp signal constant output power limit when the sense voltage across the sense resistor r s reaches the threshold vo ltage, the output gate drive will be turned off following a small propagation delay t pd . this propagation delay will result in an additional current proportional to t pd *v in /l p . the propagation delay is nearly constant regardless of the input line voltage v in . higher input line voltages will result in larger addit ional currents. thus, under high input-line voltages the output power limit will be higher than under low input-line voltages. the output power limit variation can be significant ov er a wide range of ac input voltages. to compensate for this, the threshold voltage is adjusted by the current i in . since the pin vin is connected to the rectified input line voltage through the start- up resistor, a higher line voltage will result in a higher current i in through the pin vin. the threshold voltage decreases if the current i in increases. a small threshold voltage will force the output gate drive to terminate earlier, thus reducing total pwm turn-on time, and making the output power equal to to that of the low line input. this proprietary internal compensation feature ensures a constant output power limit over a wide range of ac input voltages (90vac to 264vac) vdd over-voltage protection vdd over-voltage protection has been built in to prevent damage due to over voltage conditions. when the voltage vdd exceeds the internal threshold due to abnormal conditions, pwm out put will be turned off. over-voltage conditions are usually caused by open feedback loops. limited power control the fb voltage will increase every time the output of the power supply is shorted or over-loaded. if the fb voltage remains higher than a built-in threshold for longer than t lps , pwm output will then be turned off. as pwm output is turned off, the supply voltage vdd will also begin decreasi ng. when vdd goes below the turn-off threshold (eg, 12.4v) the c ontroller will be totally shut down. vdd will be charged up to t he turn-on threshold voltage of 16.5v through the start-up re sistor until pwm output is restarted. this protection feature will continue to be activated as long as the over-loading condition persi sts. this will prevent the power supply from overheating due to over loading conditions thermal protection an external ntc thermistor can be connected from the rt pin to ground. a fixed current i rt is sourced from the rt pin. because the impedance of the ntc will decrease at high temperatures, when the voltage of the rt pin drops below 1.065v, pwm output will be disabled. the rt pin output current is related to the pwm frequency programming resistor r i. noise immunity noise from the current sense or the control signal may cause significant pulse width jitter, particularly in continuous-conduction mode. slope compensation helps alleviate this problem. good placement and layout practices should be followed. the designer should avoiding long pcb traces and component leads. compensation and filter components should be located near the H6842. finally, increasing the power -mos gate resistance is advised.
hi-sincerity microelectronics corp. spec. no. : ic200803 issued date : 2008.09.10 revised date : page no. : 6/6 H6842p, H6842s hsmc product specification dip-8 dimension a b 87 65 432 1 h i f g j k m l 1 e d c 8-lead dip-8 plastic package hsmc package code: p marking: date code control code hp 6842 pb free mark pb-free: " . " (note) normal: none note: green label is used for pb-free packing pin style: 1.gnd 2.fb 3.vin 4.ri 5.rt 6.sense 7.vdd i 8.gate material: ? lead solder plating: sn60/pb40 (normal), sn/3.0ag/0.5cu or pure-tin (pb-free) ? mold compound: epoxy resin family, flammabilit y solid burnin g class: ul94v-0 dim min. max. a 6.29 6.40 b 9.22 9.32 c - *1.52 d - *1.27 e - *0.99 f 3.25 3.35 g 3.17 3.55 h 0.38 0.53 i 2.28 2.79 j 7.49 7.74 k - *3.00 l 8.56 8.81 m 0.229 0.381 94 o 97 o 1 *: typical, unit: mm so-8 dimension a b f c d e g part a i h j k o m l n part a 234 5 6 7 8 pin1 index dim min. max. a 4.85 5.10 b marking: note: green label is used for pb-free packing 3.85 3.95 c 5.80 6.20 d 1.22 1.32 e 0.37 0.47 f 3.74 3.88 g 1.45 1.65 h 4.80 5.10 i 0.05 0.20 j 0.30 0.70 pin style: 1.gnd 2.fb 3.vin 4.ri 5.rt 6.sense 7.vdd i 8.gate k 0.19 0.25 l 0.37 0.52 material: ? lead solder plating: sn60/pb40 (normal), sn/3.0ag/0.5cu or pure-tin (pb-free) ? mold compound: epoxy resin family, flammabili ty solid b u rning c la ss: ul94 v 0 m 0.23 0.28 n 0.08 0.13 o 0.00 0.15 *: typical, unit: mm 8-lead so-8 plastic surface mounted package hsmc package code: s important notice: ? all rights are reserved. reproduction in whole or in part is prohibited without the prior written approval of hsmc. ? hsmc reserves the right to make changes to its products without notice. ? hsmc semiconductor products are not warranted to be suitable for use in life-support applications, or systems. ? hsmc assumes no liability for any consequence of customer prod uct design, infringement of paten ts, or application assistance. head office and factory: ? head office (hi-sincerity microelectronics co rp.): 10f.,no. 61, sec. 2, chung-shan n. rd. taipei taiwan r.o.c. tel: 886-2-25212056 fax: 886-2-25632712, 25368454
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