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THX203H switching power controller ic contents introduction, characteristics and applicati on fiel d 3 reference frame of interior circuit 4 description of pins ? functio n 4 ultimate pa rameters 5 recommended work ing condi tion 5 electric pa ramete rs 5 principal di scrip tion 7 definition of elect ric parame ters 8 application in forma tion 9 typical application circ uit 11 components listin g 12 making coils for transfor mer 13 test data 14 wave-form of main e xperimental units 15 parameters of thermal resistan ce and junction te mperatur e 19 dimensional chart of encapsul ation 20
pwm controller of high-pe rformance current mode THX203H introduction pwm controller of high-performance current mode is specially designed for ac/dc transformer with high performance and price ratio, which supplies continuous output power of 12w within the range of wide-voltage between 85v and 265v, the output power of peak value can be up to 18w. the combination of optimized reasonable circuit design and bipolar facture technology with high performance and price ratio economizes the whole cost ultimately. the power controller can be applied to the typical flyback circuit topology so as to form a simple ac/dc transformer. the startup circuit inside ic is designed as a pa rticular current inhalation way, so it can start up with the magnification function of the power switch tube itself, which lessens the power consumption for starting the resistance remarkably; when the output power is lower, ic will reduce the working frequency automatically, therefore, the standby power consumption becomes extremely low. when the power tube is closed, the interior ci rcuit will bias it reversely, utilize the characteristic of high pressure resistance cb of bipolar transistor directly, and improve its pressure resistance capacity to the high voltage of 700v, which ensures the security of the power tube. meanwhile, the perfect function of overload and saturation prevention is provided inside of ic, which can keep away some abnormal status, such as overload, saturation of transformer, and output short circuit, so as to improve the reliability of the power supply. the current limit and clock frequency can be set up by exterior components. now the standard encapsulation and the environmental protection leadless encapsulation that meets european standard of dip8 are supplied. - 2 -
pwm controller of high-pe rformance current mode THX203H characteristics z set-in high-voltage power switch tube of 700v and few peripheral components z with the modulation of lock pulse width, th e testing is according to the pulse limit current. z with the function of output frequency reduc tion, the non-output power consumption can be less than 0.3w. z inner-built ramp and anti-feedback compensation function z the independent upper-limit current testing controller deals with over-current and over-load of the controller real-timely. z the period emission pole is turned off a nd it outputs by deflected voltage, and the pressure resistance of the power tube is improved. z set-in current limit resistan ce with temperature compensation, which makes the current limit precise z set-in heat protection circuit z startup is accomplished with the magnificatio n function of the switch power tube, and the power consumption of startup resi stance is reduced more than10 times. z few peripheral components z low startup and operating current z vcc over-voltage automatic limit z continuous wide-voltage output power reaches 12w, and the output power of peak value arrives at 18w. applied field z adaptor (for example, travel charger, out power station) z open frame (for example, dvd, dvb) reference frame of interior circuit figure 1. frame of interior current 33 3 ?3 3
pwm controller of high-pe rformance current mode THX203H description of pins? function pins symbol pins description 1 ob base electrode of power tube, control terminal of start-up current, external startup resistance 2 vcc supply electric pins 3 gnd meet grounding pins 4 ct oscillate capacitance pins, external timing capacitance 5 fb feedback pins 6 is switching current sampling and limit enactment, sampling resistance of external current 7,8 oc output pins, meet switching transformer *: during pcb layout, the security distance should be kept more than 1mm between pin6 and pin7, so as to avoid discharging. limit parameter power supply volta ge vcc 16v startup inpu t volta ge 16v pins input vo ltage vcc+0.3v endurance voltage of oc co llect or 0.3-700v switching current of peak valu e 800ma total dissipati on power 1000mw operating temper ature ra nge 0---125 deposit temperat ure range 55---150 welding temp erature 260,10s recommended working condition item minimum typical maximum unit power supply voltage, vcc 4.8 5.5 9.0 v pins input voltage -0.3 - vcc v reverse voltage of peak value - - 520 v switching current of pea k value - - 600 ma timing capacitance 650 680 920 pf oscillating frequency 45 61 65 khz operating temperature 0 70 33 3 ?3 3
pwm controller of high-pe rformance current mode THX203H electric parameter ( ta=25 , vcc=5.5-7.5v, ct=680pf, rs=1 ? ) output item testing condition minimum typical maximum unit maximum pressure resistance o f switching tube ioc=10ma 700 - - v on-saturation pressure drop ioc=600ma - - 1 v output rise-time cl=1nf - - 75 ns output fall-time cl=1nf - - 75 ns output limit current tj=0-100 540 580 620 ma oe clamp voltage oe=0.001-0.60a - 1.5 - v reference item testing condition minimum typical maximum unit reference output voltage io=1.0ma 2.4 2.5 2.6 v p ower adjustment ratio vcc=5.5-9v - 2 20 mv load adjustment ratio io=0.1-1.2ma - - 3 % temperature stability - 0.2 - mv/ output noise voltage f=10hz-10khz - - 50 v long-term stability operate 1000h under the condition of t=85 - 5 - mv oscillator item testing condition minimum typical maximum unit oscillating frequency ct=680pf 55 61 67 khz frequency change ratio with voltage vcc=5.5-9v - - 1 % frequency change rate with temperature ta=0-85 - - 1 % vibration amplitude o f oscillator(vp-p) - 2.5 - v drop edge o f ct=330pf oscillator - 800 - ns feedback item testing condition minimum typical maximum unit pull-up current - 0.50 0.60 ma input impedance p ull-down resistance - 30 - k ? power supply rejection ratio vcc=5.5-9v - 60 70 db 33 3 3 3
pwm controller of high-pe rformance current mode THX203H current sampling item testing condition minimum typical maximum unit current sampling limit 0.54 0.58 0.62 v upper limit curren t p revention rs=1o 0.54 0.27 0.62 a power supply rejection ratio - 60 70 db transmission delay - 150 250 ns modulation of pulse width item testing condition minimum typical maximum unit maximum duty cycle 53 57 61 % minimum duty cycle - - 3.5 % power current item testing condition minimum typical maximum unit startup acceptance current 1.6 2.0 2.4 ma startup static current - 55 80 a static current vcc=8v - 2.8 - ma startup voltage 8.6 8.8 9.0 v close voltage o f oscillator 4.0 4.3 4.5 v restart voltage - 3.7 - v over-voltage limit margin 9.2 9.6 10.0 v description of the principle z during start-up phase, vr is closed when electrified; fb pull-up power source is closed, the start-up current is input from power tube to vcc thr ough oe; ob controls the base current of power tube and limits the current of power tube collector (namely, THX203H starts the acceptance current), accordingly, th e security of the power tube is ensured; when vcc voltage goes up to 8.8v, the start- up phase is ended, and it comes into the normal phase. z during normal phase, vcc voltage shall keep at 4.8~9.0v, vr outputs 2.5v benchmark; fb pull-up current source starts up; the os cillator output osc1 decides the maximum duty cycle, output osc2 tries to touch off th e power supply to enter open cycle to enter the open cycle, and shield flashing peak current of the power tube ; if fb is less than 1.8v (about between 1.2-1.8v), the cycle of th e oscillator will incr ease with it, the less fb is, the wider the cycle of the oscill ator is, until the oscillation stops (this characteristic reduces the st andby power consumption of th e switching power.) ; if the peripheral feedback trie s to make vcc more than 9.6v, the in-circuit is fed back to fb and makes vcc stabilize the voltage at 9.6v (a ccording to this characteristic, we can may not adopt peripheral feedback circuit, a nd stabilize the output voltage by in-circuit, but the precision of stabilizi ng voltage is low); during the op en cycle, ob supplies base 33 3 3 3
pwm controller of high-pe rformance current mode THX203H current for the power tube, oe pulls down the emitter of the power tube to is, and ob adopts the driving parameter of ramp current ( it refers to that ob on-current is the parameter of is, when is is 0v, ob on-cu rrent is about 40ma, then ob on-current increases linearly with is, when is increases to 0.6v, ob on-current is about 120ma, this characteristic makes effective use of the output current of ob, decreases the power consumption of THX203H), if is detects that the specified current fb, it will come into the close cycle; during the close cycle, ob pulls down, the power tube will not shut off immediately, but oe clamps 1.5v (after the pow er tube is shut off, the base will be biased reversely, which improves the voltage endurance); during open or close cycle, if the power tube is detected beyond the upper limit current, the trigger of the upper limit current will be placed prefer entially and forces fb to dr op, the duty cycle will become less so as to protect the power tube and transformer; at th e beginning of next close cycle or when fb is less than 1.8v, the trigger of the upper limit current will reset. in addition, THX203H is installed over heat protection in ternally, when the internal temperature is higher than 140 , it will broaden the cycle of the os cillator and makes the temperature of THX203H less than 150 ; the ramp compensation is al so placed internally, when THX203H is in a big duty cycle or in the mode of constant current, it can stabilize the open/close cycle. z if vcc declines to 4.3v or so, the oscillator will shut off, osc1 and osc2 are in the low level, and the power supply keeps at close cycle; when vcc goes on declining to 3.7v or so, THX203H will come into the start-up phase once again. fig.2 waveform graph of open a nd close cycle at normal phase 33 3 3 3
pwm controller of high-pe rformance current mode THX203H fig.3 overall waveform graph of THX203H definition of electric parameter z start-up acceptance current: the current on oc when ob inputs 0.5ma during the start-up phase z start-up quiescent current: the current of minimum current source that can make vcc oscillate (namely finish the start-up of t hx203h) when vcc meets filter capacitance and adjustable current source, ct meets 680pf, and other pins hang in the air. z start-up voltage: maximum vcc value of above vcc oscillation. z re-start voltage: minimum vcc value of above vcc oscillation. z close voltage of oscillator: vcc value that makes rc oscillator stop oscillating when the above vcc oscillates the falling edge. z quiescent current: vcc power current when fb is grounded with 1.0k of resistance at normal phase. z pull-up/pull-down current of the oscillator: at normal phase, fb is 2.5v, ct is 1.25v, and ct is in pull-up/pull-down current. z fb pull-up current: pull-up current on fb at normal phase when fb is 2.5v, is is 0v. z fb upper limit current prevention: the pull-do wn current on fb at normal phase when fb is 6v, is is 0.3v. z internal feedback power voltage: vcc valu e of THX203H power supply of the circuit without peripheral standby at normal phase z oc upper limit voltage: the minimum oc curre nt of pull-down current on fb when fb is 6v z ramp current drive: it refers to the power t ube base drive ob on-current is the function of is, when is is 0v, on-current ob is about 40ma, then on-current ob will increase linearly with is, when is is increased to 0.6v, on-current oe is about 120ma. - 8 -
pwm controller of high-pe rformance current mode THX203H application information: 1. relationship between ct timing capacitance and switching frequency ct capacitance is charged by 100ua constant current through internal current source to for the rise-up edge, when the voltage is charged to 2.5v, the internal circuit will discharge ct with 1.9ma of pull-down current to form the fall-down edge of the clock, and accomplish a clock cycle, which is about: t=ct*24000 (s) fs=1/t (hz) although the bipolar circuit can work under higher frequency, but for the switch of bipolar power, the influence caused by switch loss for the storage time is still be considered. generally, the appropriate switching frequency is about below 70khz. under common application situation, ct capacitance of THX203H can be configured by 680pf, when the relevant working frequency is around 61khz. 2. fb feedback and control in normal working state, the voltage of fb will decide the value of the maximum switching current, the higher the voltage is, the bi gger the switching current is (it is only limited at the peak value). fb pins pull up 600ua power source internally, the pull-down resistance is about 33k ? (it approximates the equi valent value). in addition, when fb voltage is less than 1.8v, the oscillating cycle will be enlarged, the switching frequency will declined, the more it is less than 1.8v, the lower the switchi ng frequency is. the external fb capacitance will influence the feedback bandwidth, so some external parameters will be affected, such as transient-state characteristic. as for the value of cfb capacitance, the typical application can be selected according to the frequency character of feedback circuit between 10nf and 100nf. 3. over temperature protection the interior of ic integrates the function of over temperature protection. when the internal temperature of the chip reaches 140 , the over-heat protection circuit will work, it will pull down the clock signal, the switching frequency will fall until the oscillator is turned off. as shown in the following figure, 4. driving characteristic and high voltage endurance bias technology of power tube 33 3 3 3
pwm controller of high-performance current mode THX203H the power tube adopts the ramp current drive, the driving current will increase with the output power, when fb is 0, the current of ob is about 40ma, when fb is 6v, the current of ob is about 120 ma, and the driving power consumption will decrease remarkably when the output is low. the interior of ic integrates the particular bias t echnology, when the power tube is shut, th e output of ob will be pulled down to the ground, meanwhile, it will bias the output of oe to 1.5v or so, bias the emitter junction, accelerate the decreasing speed of ic current, expand the effective safe working area, the switching tube affords the reverse voltage cb, therefore, the endurance characteristic of the switching tube can be up to 700v. for more detail information for the voltage endurance characteristic of the switching tube, please refer to the relevant technical data. the bias waveform is shown as follows: ob oe 1.5v 0.5v 5. over-voltage and under-voltage protection ic has the function of slow-moving under-voltage protection, when the voltage of vcc reaches 8.8v, ic will set out to start, the initial start-up voltage is provided by the driving resistance, the high voltage of input will be injected into the base of the switching tube through ic current, consequently, the driving voltage is formed. when ic works normally, the voltage of vcc shoul d be keep between 4.8v and 9v (including the situation of full load output), if the voltage of vcc falls to 4.4v, the oscillator will enter the state of shutoff, when it decreases to 3.8v further, ic will begin to reset. as shown in the following figure: 4.8-9v 4.4v 3.8v vcc ct vr vcc in side ic is provided with a comparator controlle r of the upper limit voltage, if vcc tries to be more than 9.6v, the comparator will work, fb will be pulled down, and it will lock vcc to 9.6v, and reach the limit function of over voltage, by which the voltage feedback function of the front terminal can be accomplished conveniently, the rising phenomenon of the output voltage in large extent can be avoided when the open-loop is output, so as to guarantee the security of the load. because of the existence of this characteristic, the design of vcc shall be kept at the proper range, so as to avoid vcc rising excessively high when the output is high, and make the output voltage escape from - 10 -
pwm controller of high-performance current mode THX203H decreasing when ic over-voltage limit works. 6. maximum switching current limit ic has the function of current limit cycle by cycle. it will test every switching current in every switching cycle, if the current fixed by fb or upper limit current prevention is reached, it will come into the close cycle, and the detection of the current has the function of real-time foreland hide, it can shield the switching peak, and avoid the wrong detection of the switching current. then the reasonable temperature compensation eliminates the influence of temperature, comparing with normal mosfet (the alteration of ron will be large when the temperature changes) switching chip, the switching current can always be very accurate in a larger range, thus not too much allowance is needed to match a larger working temperature range for the designer when he designs the scenario, and the security of th e circuit for use can be improved. the maximum limit value of switching current for THX203H is 0.80a. when designing a flyback power with 80v of emitter voltage and 0.65a of switching current, it can accomplish the output power of more than 12w easily, and meet the broad temperature range. 7. requirement of heat elimination as for a typical power switch, it must have necessary heat elimination measures, so as to avoid that the excessive heat leads to heat protection. the primary heat inside ic is produced by the on-off wasti ng of the switching tube, so appropriate heat elimination position is pin7-8 pin of ic, one wieldy way is to pave pcb copper foil of a certain area on pin7-8 pin, what?s more, plating tin on the copper foil will improve the heat elimination ability greatly. for an input of 85-265v, the typical application of 12w output and 200mm 2 copper foil are necessary. reference wiring is as the following figure: typical application circuit(input 85-265v, output 12v 1a): - 11 -
pwm controller of high-performance current mode THX203H fig. 4 typical application circuit components listing: - 12 -
pwm controller of high-performance current mode THX203H no. component n ame spec./model encapsulation amount sign 1 resistance 1k 0805 1 r6 2 2k 0805 1 r9 3 5.1k 0805 1 r5 4 10k,1% 0805 1 r7 5 38.3k,1% 0805 1 r8 6 1.5r 1206 1 r3 7 2.2r 1206 1 r4 8 75k,1/2w 1/2w 1 r2 9 2.2m,1/2w 1/2w 1 r1 10 capacitance 681j/50v 0805 1 c3 11 222/1kv ct5 1 c2 12 223/50v 0805 1 c4 13 104/50v 0805 1 c6 14 capacitance x 104/275v mkp,x1 1 cx1 15 capacitance y 222m/400v ct7,y1 1 cy1 16 electrolytic capacitance 33uf/400v ec23-13 1 c1 17 47uf/16v ec11-5 1 c5 18 470uf/25v ec13-8 2 c7 c8 19 diode 1n4007 do-41 5 d1-d4 d6 20 fr107 do-41 1 d5 21 sr3100 do-201ad 1 d7 22 luminous tube led2.5 d2.5 1 d8 23 filter inductance uu9.8, 25mh uu9.8 1 l1 24 power inductance dr6*8,10uh dr6*8 1 l2 25 transformer ef20 ef20-p10 1 t1 26 insurance tube f1.5a/250v d4*10mm 1 f1 27 voltage-depend ent resistance 7d471k ct7 1 tz1 28 ic THX203H dip8 1 ic1 29 tl431a sot23 1 ic2 - 13 -
pwm controller of high-performance current mode THX203H 30 pc817c dip4 1 ic3 31 circuitry panel pcb,33x65mm 1 coils of the transformer: 1. parameters of magnetic core core : ef20,tdk pc40 ae=33.5mm 2 aw=30.2mm 2 bobbin : ef20, 10pin, 5+5pin,velox 420-seo , 94v0 lp=1.4mh10% 2. bobbin diagram 3. bobbin data n o. n ame spec. direction coil/layer n ote 1 n p1, 1 st segment of main coil f0.24mm*1p,2uew 2-1 50ts thick coiling 2 insulated adhesive paper 3m,no.1350 -- 3 tiers -- 3 n s, output coil f0.50mm*1p,2uew 10-6 16ts thin coiling 4 insulated adhesive paper 3m,no.1350 -- 3 tiers -- 5 n p2, 2nd segment o f main coil f0.24mm*1p,2uew 3-2 50ts thick coiling 6 insulated adhesive paper 3m,no.1350 -- 2 tiers -- - 14 -
pwm controller of high-performance current mode THX203H 7 nvcc, icp powe r supply coil f0.15mm*1p,2uew 4-5 9ts thin coiling 8 insulated adhesive paper 3m,no.1350 -- 3 tiers -- note: the transformer is coiled with copper skin 1.1ts and welded to meet pin5. testing data: input voltage va c unit 85 110 135 180 220 265 input power (standby power) when io=0a w 0.09 0.10 0.11 0.14 0.17 0.24 output voltage when io=0a v 12.04 12.04 12.04 12.04 12.04 12.04 output ripple when io=0a mv 10.8 11.4 19.6 20.2 22.0 25.0 100% output load: output voltage when io=1a v 12.04 12.04 12.04 12.04 12.04 12.04 output ripple when io=1a mv 52.0 69.0 23.0 24.0 24.5 23.5 switch power when io=1a % 76.1 80.6 82.5 84.2 84.8 84.0 75% output load: output voltage when io=0.75a v 12.04 12.04 12.04 12.04 12.04 12.04 output ripple when io=0.75a mv 55.0 40.0 26.0 25.0 21.0 21.5 switch efficiency when io=0.75a % 77.7 81.2 83.3 84.2 84.5 83.1 50% output load: output voltage when io=0.5a v 12.04 12.04 12.04 12.04 12.04 12.04 output ripple when io=0.5a mv 50.0 19.0 20.0 17.0 19.0 20.5 switch efficiency when io=0.5a % 78.0 80.9 82.3 83.1 82.9 82.2 25% output load: output voltage when io=0.25a v 12.04 12.04 12.04 12.04 12.04 12.04 output ripple when io=0.25a mv 20.0 14.0 14.4 15.8 18.0 19.4 switch power when io=0.25a % 74.8 77.8 80.4 80.4 80.3 79.0 for cec, eff av =0.09*ln(12)+0.49=71.4% average efficiency of 25%-100% % 76.7 80.1 82.1 83.0 83.1 82.1 testing item testing data - 15 -
pwm controller of high-performance current mode THX203H of output input power when the outpu t suffers short circuit w 0.63 0.80 0.96 1.25 1.57 1.92 e lectric load: progigit 3310d, power meter: gw gpm-8212 , oscillograph: a gilentdso3102a primary waveform of testing point: 1. vce waveform diagram vin=85v, io=0.5a vin=85v, io=1a 50v/d i v 2 us/d i v 50v/d i v 2 us/d i v vin=110v, io=0.5a vin=110v, io=1a 50v/d i v 2 us/d i v 50v/d i v 2 us/d i v vin=220v, io=0.5a vin=220v, io=1a 1 00v/d i v 2 us/d i v 1 00v/d i v 2 us/d i v - 16 -
pwm controller of high-performance current mode THX203H vin=265v, io=0.5a vin=265v, io=1a 1 00v/d i v 5us/d i v 1 00v/d i v 5us/d i v 2. output noise waveform vin=85v, io=1a vin=265v, io=1a 50 m v/d i v 1 0 m s/d i v 2 0 m v/d i v 1 0 m s/d i v 3. output ripple waveform vin=85v, io=1a vin=265v, io=1a 2 0 m v/d i v 1 0us/d i v 2 0 m v/d i v 1 0us/d i v - 17 -
pwm controller of high-performance current mode THX203H 4. output waveform on start-up vin=85v, io=1a vin=265v, io=1a 2 .0v / d i v 1 0 m s/d i v 2 .0v / d i v 1 0 m s/d i v 5. vce and vo waveform on start-up vin=85v, io=1a vin=265v, io=1a 100v/div 200ms/div 5v/div 200v/div 200ms/div 5v/div 6. vce waveform when the output suffers short circuit vin=85v, io=short vin=265v, io=short - 18 -
pwm controller of high-performance current mode THX203H 50v/d i v 2 00 m s/d i v 1 00v/d i v 500us/d i v diagram of switch efficiency and input power consumption: - 19 -
pwm controller of high-performance current mode THX203H ic reference junction temperature and heat resistance data of dip8 encapsula tion junction temperature reference ( jc ) 1 ????...???...................................?15 /w ( ja ) 2 ????...???...................................?50 /w n ote:1. the testing point is where pin7,8 approaches the encapsulation cover 2. pin7, 8 is connected on two ounces of tinning copper, and the area of copper is not less than 200mm 2 . diagram of the dimension of encapsulation (dip8) 33 3 ??3 3
pwm controller of high-performance current mode THX203H 4 - 21 -

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