rev. 1.00 1 december 24, 2014 rev. 1.00 pb december 24, 2014 HT7A6312 low power primary switcher for off line smps features ? fixed 60 khz switching frequency ? 9v to 38 v wide range v cc voltage ? wide ac input range from 85 v ac to 265 v ac ? pwm with current mode control ? auxiliary under v oltage lock o ut with hysteresis ? high voltage start-up current source ? excellent standby low power consumption ? over-temperature, o ver-current a nd o ver-voltage protection with auto-restart ? integrated 7 30v mosfet ? b urst mode under low load condition s applications ? off line power supply for battery charger adapters ? standby power supply for tv or monitors ? auxiliary supply for motor control ? air conditioner power supply ? electromagnetic oven power supply general description the HT7A6312 is highly functionally integrated device which combines an integrated pwm controller with current mode control and a high voltage power mosfet on the same silicon chip. typical power capability type 8sop 8dip european (195~265v ac ) 8w 13w us (85~265v ac ) 5w 8w typical performance characteristics application circuit isolation flyback topology v out + v out - pc817 tl 431 HT7A6312 vss sw fb vcc vac snubber circuit
rev. 1.00 2 december 24, 2014 HT7A6312 block diagram 60khz oscillator otp detector leb regulator uvlo 8v/14.5v 38v 0.23v r1 r2 r3 s r4 q r s q on/off r fb1 internal supply over voltage latch pwm latch vcc fb sw vss r fb2 pin assignment vss sw fb vss sw sw sw vcc HT7A6312 8 sop-a vss sw fb vss sw sw sw vcc 1 2 3 4 8 7 6 5 1 2 3 4 8 7 6 5 HT7A6312 8 dip-a pin description pin no. pin name description 8sop 8dip 1, 2 1, 2 vss power mosfet source and circuit ground reference. 3 3 fb feedback input. the useful voltage range extends from 0v to 1v, and defines the peak drain mosfet current. the current limitation, which corresponds to the maximum drain current, is obtained for when the fb pin is shorted to the source pin. 4 4 vcc control circuits power supply. also provides a charging current during start up thanks to a high voltage current source connected to sw. for this purpose, a hysteresis comparator monitors the v cc voltage and provides two thresholds: v ccon : voltage value (typically 14.5v) at which the device starts switching and turns off the start up current source. v ccoff : voltage value (typically 8v) at which the device stops switching and turns on the start up current source. 5, 6, 7, 8 5, 6, 7, 8 sw power mosfet drain. also used by the internal high voltage current source during the start up phase to charge the external v cc capacitor.
rev. 1.00 3 december 24, 2014 HT7A6312 absolute maximum ratings symbol parameter value unit v ds(sw) switching drain source voltage (t j =25 to 125c) (1) -0.3 to 730 v v ds(st) start-up drain source voltage (t j =25 to 125c) (2) -0.3 to 400 v i d continuous drain current internally limited a v cc supply voltage 0 to 41 v i fb feedback current 3 ma v esd electrostatic discharge: machine mode 400 v electrostatic discharge: human body mode 3 kv t c operating temperature range -40 to 150 c t stg storage temperature range -55 to 150 c t j junction operating temperature internally limited c note: 1.this parameter applies when the start-up current source is off . this is the case when the v cc voltage has reached v ccon and remains above v ccoff . 2. this parameter applies when the start up current source is on. this is the case when the v cc voltage has not yet reached v ccon or has fallen below v ccoff . thermal data symbol parameter 8sop 8dip unit r thjc thermal resistance junction-case 25 15 c/w r thja thermal resistance ambient-case (1) 55 45 c/w note: when mounted on a standard single-sided fr4 board with 200mm 2 of cu (at least 35m thick) connected to all sw pins.
rev. 1.00 4 december 24, 2014 HT7A6312 electrical characteristics t a=25c, v cc =18v, unless otherwise specifed symbol parameter test conditions min. typ. max. unit power section bv dss drain-source voltage i d =1ma; v fb =2v 730 v i dss off state drain current v ds =500v; v fb =2v; t j =125c 0.1 ma r ds(on) static drain-source on state resistance i d =0.2a 19 22 t f fall time i d =0.1a; v in =300v (1) 100 ns t r rise time i d =0.2a; v in =300v (1) 50 ns c oss drain capacitance v ds =25v 20 pf supply section i ccch start-up charging current v ds =100v; v cc =0v to v ccon -1 ma i ccoff start-up charging current in thermal shutdown v cc =5v; v ds =100v t j > t sd - t hyst 0 ma i cc operating supply current not switching i fb =2ma 0.55 0.65 0.8 ma operating supply current switching i fb =0.5ma; i d =50ma (2) 0.5 0.7 0.9 ma d rst restart duty-cycle 16 % v ccoff v cc under- voltage shutdown threshold 7 8 9 v v ccon v cc start-up threshold 13 14.5 16 v v cchyst v cc threshold hysteresis 5.8 6.5 7.2 v v ccovp v cc over-voltage threshold 35 38 41 v oscillation section f osc oscillator frequency total variation v cc =v ccoff to 35v; t j =0 to 100c 54 60 66 khz pwm comparator section g id i fb to i d current gain 320 i dlim peak current limitation v fb =0v 0.32 0.4 0.48 a i fbsd i fb shutdown current 0.9 ma r fb fb pin input impedance i d =0ma 1.2 k t d current sense delay to turn-off i d =0.2a 200 ns t b blanking time 350 ns t onmin minimum turn-on time 550 ns over-temperature section t sd thermal shutdown temperature 140 170 c t hyst thermal shutdown hysteresis 40 c 1rwh evrowh pdlpp udwlqjv lqglfdwh olplwv ehrqg klfk gdpdjh wr wkh ghylfh pd rffu 2shudwlqj 5dwlqjv lqglfdwh frqglwlrqv iru klfk wkh ghylfh lv lqwhqghg wr eh iqfwlrqdo ew gr qrw jdudqwhh vshflf shuiru pdqfh olplwv 7kh jdudqwhhg vshflfdwlrqv dsso rqo iru wkh whvw frqglwlrqv olvwhg )ru fodpshg lqgfwlyh ordg 7khvh whvw frqglwlrqv duh rewdlqhg lwk d uhvlvwlyh ordg klfk shuplw wkh pdlpp frqgfwlrq wlph ri wkh ghylfh
rev. 1.00 5 december 24, 2014 HT7A6312 functional description the HT7A6312 is highly functionally integrated device which combines an integrated pwm controller with current mode control and a high voltage power mosfet on the same silicon chip. the secondary side feedback signal passes through a photo-coupler on the primary side while the output voltage is regulated by the device according to the feedback signal. t he de vice ha s a sm all qui escent c urrent and low power consumption when operating in the standby mode. it also has a range of protection features to protect the controller from fault conditions. high voltage start up the sw pi n i n t he de vice i s a hi gh vol tage st art up current source. this current source will generate a current which is regulated from a high voltage and which wi ll c harge t he vc c p in u ntil t he uvl o is t riggered wh en a n ac vol tage i s a pplied on t he converter i nput. w hen t he v cc vol tage i s l arger t han the uvl o t rigger vol tage, t he hi gh vol tage sta rt up current source will be cut off by uvlo and the device will start operatio n by switching the power mosfet on and off. feedback the fb pin determ ines the devic e operation. the power mosfet current will be sensed by the current sensing resistor which is connected between the source terminal of the power mosfet and the ground terminal. in addition, this sensing resistor also senses the current coming from the fb pin. the voltage across the resistor will be compared to a fxed reference voltage (0.23v). the power mosfet is turned of f when the sensing resistor voltage is lar ger than 0.23v. leading edge blanking C leb when the power mosfet is turned on, there is usually a high current spike which is generated by the primary side capa citor and the secondary side rectifer diode r everse r ecovery. t his sp ike wi ll b e se nsed b y the sensing resistor to indicate an excessive voltage which will in turn lead to false feedback operation in the current mode pwm control circuit. in order to avoid this problem, the device inclu des a leading edge blanking circuit which inhibits the comparator for a short time after the power mosfet is turned on. under voltage lock out C uvlo when the fault condition happens, the device will shut d own t he p ower mosfe t a nd c ause t he v cc voltage to fall. when the v cc voltage is lower than the uvlo lower voltage (8v), the protection circuits will be reset and the internal high voltage start up current source will char ge the v cc capacitor . not until the v cc voltage reaches the uvlo higher voltage (14.5v), the device will resume normal operation. in this way , the auto-res tart function can enable and dis able the power mosfet switching alternately until the fault condition is eliminated. thermal shutdown C tsd because the device integrates the controller and the power mosfet on the same chip, the temperature of the device including the power mosfet can be easily detected. when the temperat ure is over 170c, the t hermal sh utdown p rotection f unction wi ll b e active to turn off the power mosfet. the device will resume normal operation when the device temperature is lower than the recovery temperature of about 130c and when the v cc voltage is lower than 2v. over voltage protection C ovp when a m alfunction oc curs i n t he se condary si de feedback circuit, or if a wiring defect allows the feedback l oop t o b e o pen, t he c urrent t hrough t he opto-coupler will be near to zero. at this time, as the excess ener gy will be supplied to the output, the output voltage may be higher than the regulated voltage and may damage the components in the secondary si de. t he de vice i ncludes a n ove r vol tage protection functio n to avoid this condition happening. if t he v cc v oltage i s h igher t han 3 8v, t he d evice will be shut down by the ovp protection function to prevent the malfunctions from damaging components.
rev. 1.00 6 december 24, 2014 HT7A6312 application circuits buck topology vss sw vcc fb emi solution HT7A6312 v out - vac v out + buck ? boost topology emi solution vss sw vcc fb HT7A6312 v out + v out - vac non-isolation flyback topology HT7A6312 fb vss sw vcc snubber circuit v out1 v out2 vac
rev. 1.00 7 december 24, 2014 HT7A6312 package information note that the package information provided here is for consultation purposes only . as this information may be updated at regular intervals users are reminded to consult the holtek website for the latest version of the package information. additional supplementary information with regard to packaging is liste d below . click on the relevant section to be transferred to the relevant website page. ? further package information (include outline dimensions, product t ape and reel specifcations) ? packing meterials information ? carton information
rev. 1.00 8 december 24, 2014 HT7A6312 8-pin dip (300mil) outline dimensions symbol dimensions in inch min. nom. max. a 0.355 0.365 0.400 b 0.240 0.250 0.280 c 0.115 0.130 0.195 d 0.115 0.130 0.150 e 0.014 0.018 0.022 f 0.045 0.060 0.070 g 0.100 bsc h 0.300 0.310 0.325 i 0.430 symbol dimensions in mm min. nom. max. a 9.02 9.27 10.16 b 6.10 6.35 7.11 c 2.92 3.30 4.95 d 2.92 3.30 3.81 e 0.36 0.46 0.56 f 1.14 1.52 1.78 g 2.54 bsc h 7.26 7.87 8.26 i 10.92
rev. 1.00 9 december 24, 2014 HT7A6312 8-pin sop (150mil) outline dimensions symbol dimensions in inch min. nom. max. a 0.236 bsc b 0.154 bsc c 0.012 0.020 c 0.193 bsc d 0.069 e 0.050 bsc f 0.004 0.010 g 0.016 0.050 h 0.004 0.010 0 8 symbol dimensions in mm min. nom. max. a 6.00 bsc b 3.90 bsc c 0.31 0.51 c 4.90 bsc d 1.75 e 1.27 bsc f 0.10 0.25 g 0.40 1.27 h 0.10 0.25 0 8
rev. 1.00 10 december 24, 2014 HT7A6312 copyright ? 2014 by holtek semiconductor inc. the information appearing in this data sheet is believed to be accurate at the time of publication. however, holtek assumes no responsibility arising from the use of the specifcations described. the applications mentioned herein are used solely for the purpose of illustration and holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. holtek's products are not authorized for use as critical components in life support devices or systems. holtek reserves the right to alter its products without prior notifcation. for the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
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