View STR-F6674_8238090.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

the series str-f6600 is specifically designed to satisfy the require- ments for increased integration and reliability in off-line quasi-resonant flyback converters. the series incorporates a primary control and drive circuit with discrete avalanche-rated power mosfets. covering the power range from below 25 watts up to 300 watts for 100/115/230 vac inputs, and up to 150 watts for 85 to 265 vac universal input, these devices can be used in a range of applications, from battery chargers and set top boxes, to televisions, monitors, and industrial power supply units. cycle-by-cycle current limiting, under-voltage lockout with hyster- esis, over-voltage protection, and thermal shutdown protects the power supply during the normal overload and fault conditions. over-voltage protection and thermal shutdown are latched after a short delay. the latch may be reset by cycling the input supply. low-current startup and a low-power standby mode selected from the secondary circuit completes a comprehensive suite of features. the series is provided in a five-pin overmolded to-3p style package, affording dielectric isolation without compromising thermal characteristics. features flyback operation with quasi-resonant soft switching for low power dissipation and emi rugged avalanche-rated mosfet choice of mosfet voltage and r ds(on) full over-current protection (no blanking) under-voltage lockout with hysteresis over-voltage protection direct voltage feedback low start-up current (<400 a) low-frequency, low-power standby operation overmolded 5-pin package off-line quasi-resonant flyback switching regulators always order by complete part number, e.g., str-f6652 . data sheet 28102.8 ? series str-f6600 absolute maximum ratings at t a = +25 c control supply voltage, v in . . . . . . . . 35 v drain-source voltage, v ds series str-f6620 . . . . . . . . . . . . 450 v series str-f6630 . . . . . . . . . . . . 500 v series str-f6650 . . . . . . . . . . . . 650 v series str-f6670 . . . . . . . . . . . . 900 v drain switching current, i d . . . see table peak drain current, i dm . . . . . . see table avalanche energy, e as . . . . . . . see table ocp/fb voltage range, v ocp . . . . . . . . . . . . . . . -0.3 v to +6 v package power dissipation, p d control (v in x i in(on) ) . . . . . . . . . 0.8 w total . . . . . . . . . . . . . . . . . . . see graph fet channel temperature, t j . . . +150 c internal frame temperature, t f . . +125 c operating temperature range, t a . . . . . . . . . . . . . . . -20 c to +125 c storage temperature range, t s . . . . . . . . . . . . . . . . -40 c to +125 c latch source drain over-current & feedback ground dwg. pk-011-1 v in 1 2 3 4 5 uvlo ovp tsd osc. ocp fdbk supply interim data sheet (subject to change without notice) february 22, 2000 tm
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 2 tm copyright ? 2000 allegro microsystems, inc. functional block diagram feedback & over-current protection ground v in source drain dwg. fk-002-6 0.73 v tsd over-volt. protect r sq ref. fault latch 4 3 2 1.45 v uvlo + 1 + drive reg. osc c ss r ss 1.0 0.6 0.2 50 100 starting channel temperature in c normalized allowable avalanche energy in mj dw g . 0.4 0.8 0 25 75 125 allowable package power dissipation curves are shown on page 10.
series str-f6600 off-line quasi-resonant flyback switching regulators 3 output maximum ratings at t a = +25 c part number v dss (v) r ds(on) ( ? )e as (mj)* i d (a)? i dm (a) p out (w) at v in (v rms) str-f6624 450 0.92 204 16 19 98 100 130 120 str-f6626 450 0.58 327 16 26 145 100 190 120 str-f6628 450 0.35 647 22 36 225 100 290 120 str-f6632 500 2.54 7.4 9.0 11.2 36 100 50 120 str-f6652 650 2.8 126 7.9 10 40 85-265 86 220 str-f6653 650 1.95 260 5.6 14 58 85-265 120 220 str-f6654 650 1.15 399 9.7 18 92 85-265 190 220 str-f6656 650 0.71 521 16 25 150 85-265 300 220 str-f6672 900 7.7 163 4.6 6.4 25 ( no heatsink ) 220 50 ( with heat sink ) 220 STR-F6674 900 4.49 242 6.0 9.2 28 85-265 76 220 str-f6676 900 2.81 275 7.8 12 44 85-265 115 220 * derate per graph, page 2 ? derate per graph, page 12
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 4 tm electrical characteristics at t a = +25 c, v in = 18 v (unless otherwise specified). limits characteristic symbol test conditions min. typ. max. units on-state voltage v int turn-on, increasing v in 14.4 16 17.6 v under-voltage lockout v inq turn-off, decreasing v in 9.0 10 11 v over-voltage threshold v ovp(th) turn-off, increasing v in 20.5 22.5 24.5 v drain-source breakdown voltage v br(dss) i d = 300 a v ds max CCv drain leakage current i dss at v ds max C C 300 a on-state resistance r ds(on) v s = 10 v, i d = 0.9 a, t j = +25 cC C see table ? maximum off time t off drain waveform high 45 C 55 s minimum pulse duration for input of quasi-resonant signals t w(th) drain waveform high 1 CC1.0 s minimum off time t off drain waveform high 1 CC1.5 s feedback threshold voltage v fdbk drain waveform low to high 1 0.68 0.73 0.78 v oscillation synchronized 2 1.3 1.45 1.6 v over-current protection/feedback sink current i ocp/fb v ocp/fb = 1.0 v 1.2 1.35 1.5 ma latch holding current i in(ovp) v in reduced from 24.5 v to 8.5 v C C 400 a latch release voltage v in i in 20 a, v in reduced from 24.5 v 6.6 C 8.4 v switching time t f v dd = 200 v, i d = 0.9 a C C 250 ns supply current i in(on) operating 3 CC30ma i in(off) increasing v in prior to oscillation C C 100 a insulation rms voltage v wm(rms) all terminals simultaneous refer- 2000 C C v ence to a metal plate against the backside thermal resistance r jm output channel to mounting frame C C 1.75 c/w thermal shutdown t j 140 C C c notes: typical data is for design information only. 1. feedback is square wave, v im = 2.2 v, t h = 1 s, t l = 35 s. 2. for quasi-resonant operation, the input signal must be longer than t w(th) and greater than v fdbk . 3. feedback is square wave, v im = 2.2 v, t h = 4 s, t l = 1 s.
series str-f6600 off-line quasi-resonant flyback switching regulators 5 the voltage on the v in terminal (pin 4) controls startup and shutdown of the series str-f6600 devices. figure 1 shows a typical start up circuit. the v in terminal voltage during startup is shown in figure 2. functional description and operation continued, next page... figure 1 C start-up circuit v in time drive winding voltage 16 v (typ.) operation start under-voltage lockout (v inq ) 11 v (max.) on-state voltage (v int ) startup delay figure 2 C waveform of v in terminal voltage at startup i in v in 11 v (max.) 30 ma (max.) 100 a (max.) 14.4 v (min.) i in(on) i in(off) v inq v int figure 3 C supply terminal current, i in at startup, c2 is charged through the startup resistor r s . when the v in terminal voltage reaches 16 v (typ.), the control circuit enables regulator operation. once the regulator starts, it draws up to 30 ma from c2 causing the voltage on c2 to fall momentarily. once the regulator output voltage is established, the drive winding d starts to charge c2 via d2. the voltage on c2 thus recovers to the nominal drive voltage (18 v). as shown in figure 3, the input current is below 100 a (at t m = 25 c) prior to control circuit turn on. the latch circuit holding current is 400 a (max.). to ensure latch operation, the current in r s at the lowest ac input voltage should be at least 500 a. the value of r s thus determines the charge time of c2 and thus the startup delay. r s is typicaly 68 k ? for wide operation (90 v ac to 265 v ac) and 100 k ? for 220 volt ac operation. the choice of c2 is a compromise between an accept- able startup delay (in conjunction with r s ) and a hold-up time sufficient to keep pin 4 above its under-voltage shutdown threshold of 11 v. typically c2 is in the range of 47 f to 100 f.
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 6 tm functional description and operation (contd) figure 4 C output current i out C terminal voltage v in figure 5 C soft-start operation the drive winding voltage is set such that in normal operation the c2 voltage is above the specified maximum shutdown voltage (11 v) and below the specified mini- mum over-voltage threshold (20.5 v). in applications where there is a significant variation in load current, the v in terminal voltage may vary, as shown in figure 4. this is due to peak charging of c2. in this case, adding a resistor in the range of a few ohms to tens of ohms in series with the rectifier diode d2 will bring the voltage variation within limits. soft start, quasi resonant and voltage regulation refer to the functional block diagram and the typical application diagram (figure 6). the internal oscillator uses the charge/discharge of an internal 4700 pf capacitor (c ss ) to generate the mosfet drive signals. the regulator has two modes of operation: 1. fixed 50 s off time (soft start) and 2. demagnetization sensing quasi-resonant mode normal operation. in both cases, voltage regulation is achieved by taking the composite optocoupled voltage error and superimposed drain current ramp (current-mode control) and comparing this to an internal 0.73 v reference. the fbk/ocp comparator output pre-terminates the oscillator, which turns off the mosfet drive signal. the mosfet is turned on again when either c ss discharges or a quasi-resonance signal is detected on pin 1. fixed 50 s off-time: soft-start mode this is the mode of operation in the absence of a quasi- resonance signal on pin 1 (see figure 5), and occurs at startup and in overload. it also can be commanded exter- nally to provide low-power standby operation. in the absence of a feedback signal (such as at startup, or a short circuit) the drain current ramp, sensed across r5 and noise filtered by r4/c5 appears on pin 1. when the ramp voltage on c5 exceeds the 0.73 v reference signal, the fbk/ocp comparator changes state, shutting down the oscillator and turning off the mosfet. thus the voltage on c ss is held high (6.5 v) by the comparator. when the comparator changes state, c ss discharges via r ss ; the voltage on c ss ramps down until it reaches 3.7 v. the oscillator turns on the mosfet. this ramp-down time is internally trimmed to 50 s. the comparator changes state again and the cycle repeats. thus in the absence of feedback, the current-sense resistor r5 accurately controls the mosfet maximum current. v in i out
series str-f6600 off-line quasi-resonant flyback switching regulators 7 functional description and operation (contd) figure 6 C series str-f6600 typical application full-bridge rectifier ac input + dwg. ek-003-5a 0.73 v tsd over-volt. protect r sq ref. fault latch 4 3 2 1.45 v uvlo + 1 + osc drive reg. + voltage sense + output ?output + warning these devices are designed to be operated at lethal voltages and energy levels. circuit designs that embody these components must conform with applicable safety requirements. precau- tions must be taken to prevent accidental contact with power-line potentials. do not connect grounded test equipment. the use of an isolation transformer is recommended during circuit development and breadboarding. soft start with voltage feedback (refer to figure 7) output voltage control is achieved by sensing the opto- coupled feedback current (proportional to the output voltage error signal) across resistor r4 and summing this with the drain current ramp on r5. the signal on pin 1 is therefore the opposite of the output voltage error signal and the drain current ramp. the dc bias signal across r4 is thus a function of the load. consequently at light load, the bias signal on r4 is closer to the threshold voltage of the comparator. to eliminate the possibility of false shutdown at mosfet turn on (when there is a current spike due to the discharge of primary capacitance), a constant-current sink of 1.35 ma is turned on, effectively lowering the input impedance on pin 1, and momentarily increasing the shutdown threshold.
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 8 tm functional description and operation (contd) figure 7 - voltage regulation waveforms normal operation (quasi-resonant) mode refer to the functional block diagram, typical appli- cation diagram (figure 6), and quasi-resonance wave- forms (figure 8). regulation is achieved as in fixed off-time mode but instead of having a fixed off-time, the demagnetization of the transformer is sensed by a second comparator. this comparator threshold, v th(2) is nominally 1.45 v. quasi- resonance sensing makes use of the natural magnetizing and leakage inductances and self-capacitances of the power circuit. figure 8 shows the drain voltage waveform, (v ds ), on pin 3 of the str-f66xx, as well as v p , the voltage on the primary of the transformer. once the current in the output diode stops flowing, the primary stored energy rings as shown by v p and v ds . the resonant frequency (f r ) is determined by the magne- tizing inductance of the transformer and the capacitor c4. the addition of this capacitor sets the ringing frequency and reduces the harmonic content in the v ds waveform, lowering emi. also since v ds falls to a minimum during the first half-cycle of the ring this point can be sensed and used to turn on the mosfet with minimum voltage across it. thus the mosfet is low voltage and zero current switched (lvs/zcs). figure 8 C quasi-resonance waveforms dwg. gk-021 v p v ds v d i d t = l p c 4 f r = 1/2 l p c 4 v ds (min) v p v in v ocp 2.8 v v th(2) 1.45 v v th(1) 0.73 v v fdbk
series str-f6600 off-line quasi-resonant flyback switching regulators 9 functional description and operation (contd) the voltage v ocp (pin 1) has the same form as the v ds waveform. the condition for quasi-resonant operation is given by: 2.0 v < v ocp > 5.5 v for >1 s transformer design is exactly as for any other discon- tinuous-mode type flyback. for optimum emi/efficiency performance, quasi- resonance turn off is achieved when the mosfet is at zero voltage and zero current; that is, at one half cycle of the quasi-resonance frequency, f r . over-current protection (ocp) functions refer to the functional block diagram and typical application diagram (figure 6). the regulator implements pulse-by-pulse over-current protection, which limits the maximum drain current in the mosfet on every pulse by switching off the internal drive to the mosfet, and the mosfet drain current is detected across r5. drive circuit refer to the functional block diagram. this circuit is driven from the oscillator and provides the current drive to charge and discharge the mosfet gate-source capacitance, thereby switching the device on and off. the basic circuit configuration is totem-pole type with an additional limiting resistor in the gate circuit at turn on. this limits the turn on speed of the mosfet, thereby reducing emi due to the discharge of primary capacitance. this is possible because of the low-voltage switching, zero-current switching nature of the turn on. the value of the turn-off resistance is lower, allowing the device turn-off current to be increased. this reduces the turn-off loss in the mosfet. the gate drive voltage (8.3 v) is such that even with 0.73 v across r5 (drain current sense resistor), the mosfet is fully enhanced, allowing full use to be made of its high current handling capacity. latch circuit the latch circuit keeps the oscillator output low to inhibit operation of the regulator when over-voltage protection (ovp) and thermal shutdown (tsd) circuits are in operation. as long as the latch hold-in current is 400 a (max., supplied via r s ) with v in at 8.5 v (pin 4), the regulator will stay in the off state. an internal noise filter provides 10 s of noise immu- nity to prevent spurious operation of the over-voltage protection or thermal shutdown. with the latch on, the voltage on pin 4 cycles between 16 v and 10 v as shown in figure 9. this is due to the higher current drawn when the pin 4 is at 16 v compared to that drawn close to shutdown (10 v). pulling v in (pin 4) below 6.5 v will reset the latch circuit, re-enabling the regulator. thermal shutdown this internal feature triggers the latch if the internal frame temperature exceeds 140 c (typ.). the temperature is sensed on the control ic, but also protects against overheating of the mosfet as the mosfet and the control ic are mounted on the same lead frame. additionally, protection is provided for other on- board components. v in time 16 v (typ.) 10 v (typ.) figure 9 C example of v in terminal voltage waveform at latch circuit on
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 10 tm functional description and operation (contd) over-voltage protection circuit this feature of the str-f66xx triggers the latch circuit when the v in voltage (pin 4) exceeds 22.5 v (typ.). because the voltage on pin 4 is proportional to the output voltage (they are linked by the transformer turns ratio), the regulator protects the output against over-voltage. this function is entirely independant of the output-voltage regulation loop and indeed will protect against output over-voltage should the voltage error signal be lost. the measure of over-voltage is given by: v out(ovp) = v out(nom) x v in(ovp) /v in(nom) where v in(ovp) is the drive voltage on pin 4. in an over-voltage sensitive application, the drive voltage can be set to close to 20 v and thus will protect the output, if it rises more than 10% above nominal. v out i out ac low ac high figure 10 C power supply output overload characteristics 60 40 20 20 60 100 140 limited by frame temp. = +125 c max. recommended max. frame temp. = +115 c 0 temperature in c allowable package power dissipation in watts dwg. gk- 0 controller 0.8 w max. mounting surface temperature str-f6676, 53 w max. str-f6672, 45 w max. free air all devices 2.8 w max. 60 40 20 20 60 100 140 limited by frame temp. = +125 c max. recommended max. frame temp. = +115 c 0 temperature in c allowable package power dissipation in watts dwg. gk- 0 controller 0.8 w max. mounting surface temperature str-f6656, 56 w max. str-f6654, 55 w max. str-f6653, 48 w max. str-f6652, 43 w max. free air all devices 2.8 w max. str-f665x str-f667x allowable package power dissipation
series str-f6600 off-line quasi-resonant flyback switching regulators 11 mosfet safe operating areas (single pulse at t a = +25 c) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 m s sin g le pu lse t w = 0.1 ms single pulse limited by v ds max limited by r ds(on) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 m s s in g le p u ls e t w = 0.1 m s sing le pulse limited by v ds max limited by r ds(on) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 ms single pulse t w = 0.1 ms single pulse limited by v ds max limited by r ds(on) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 ms single pulse t w = 0.1 ms single pulse limited by v ds max limited by r ds(on) str-f6652 str-f6653 str-f6654 str-f6656
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 12 tm mosfet safe operating areas (cont) (single pulse at t a = +25 c) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 ms single pulse t w = 0 .1 m s s in g l e p u l s e limited by limited by r ds(on) 50 5 0.5 0.05 drain-source voltage in volts drain current in amperes dwg. g k 0.15 1.5 15 3.0 10 30 100 300 t a = +25 c t w = 1 ms single pulse t w = 0.1 ms single puls e limited by v limited by r ds(on) str-f6672 str-f6676 1.0 0.6 0.2 50 100 frame temperature in c normalized safe operating area dw g . g 0.4 0.8 0 25 75 125 s.o.a. derating drain switching current (i d ) derating 20 12 4.0 1.0 source-to-ground voltage (v 2 -v 5 ) in volts maximum switching current (i d ) in amperes dw g 8.0 16 0 0.8 0.9 1.1 str-f6656 str-f6654 str-f6652 & str-f6672 str-f6653 str-f6672 t a = -20 c to +125 c
series str-f6600 off-line quasi-resonant flyback switching regulators 13 10 0.1 0.001 1 m power pulse duration in seconds thermal impedance (z jc ) in c/w 0.01 1.0 0.0001 10 n 10 10 m 100 m 100 100 n 1 str-f6654 str-f6656 str-f6652 str-f6653 10 0.1 0.001 1 m power pulse duration in seconds thermal impedance (z jc ) in c/w 0.01 1.0 0.0001 10 n 10 10 m 100 m str-f6672 100 100 n 1 str-f6676 str-f665x str-f667x transient thermal impedance
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 14 tm capacitors electrolytic capacitors carrying large switching fre- quency ripple currents (c1 and the output capacitors) should be capable of handling the high rms currents involved. capacitors with low esr are suitable. the quasi-resonance capacitor c4 should be a high-voltage ceramic type suitable for pulsed current operation. the safety critical nature of the off-line application must be considered when selecting both x and y capaci- tors for common- and differential-mode noise filtering. use of the low-noise quasi-resonant series str-f6600 will allow optimization of these capacitor values. c5, the 470 pf filtering capacitor should be a 50 v temperature-stable (cog) ceramic type. resistors resistor r5 carries high-frequency current, and so a low internal inductance type of 1 w rating should be used. resistor r9 (r s ) should be 2 w metal oxide. all other resistors can be 1/4 watt or 1/2 watt metal film. diodes diodes carrying the high-frequency flyback currents (such as the transformer rectifier diodes) should have a fast or ultrafast reverse-recovery characteristic, adequate current handing and peak reverse-voltage rating. allegro/ sanken supplies a range of suitable diodes, and these are described in the allegro/sanken short-form catalogue (ams-127) or latest issue of bulletin d01ec0. optocoupler both toshiba tlp 621 and siemens sfh 610a2 or 615a2 are suitable. a current-transfer ratio of 50% to 200% is acceptable. error amplifier a standard tl431 transconductance amplifier or an allegro/sanken series se error-amplifier ic can be used. the series se is particularly well-suited to high-voltage (70 v to 140 v) power outputs. if a series se error-amplifier ic is used, normally phase compensation is not required. should additional high- frequency attenuation be required, a capacitor (0.022 f or less) can be connected across the primary side (collector- emitter) of the optocoupler, a diode to maintain quasi- resonant operation should be added in series with the phototransistor emitter. applications information the products described here are manufactured in japan by sanken electric co., ltd. for sale by allegro microsystems, inc. sanken electric co., ltd. and allegro microsystems, inc. reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of their products. therefore, the user is cautioned to verify that the information in this publication is current before placing any order. these products are not authorized for use as critical components in life-support appliances, devices, or systems without express written approval. the information included herein is believed to be accurate and reliable. however, sanken electric co., ltd. and allegro microsystems, inc. assume no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
series str-f6600 off-line quasi-resonant flyback switching regulators 15 dimensions in inches (for reference only) 0.276 0.016 dwg. mk-003-50 in 0.614 0.008 0.126 0.008 0.906 0.012 0.100 0.004 at root 0.216 0.008 0.216 0.008 0.216 0.132 0.004 0.026 +0.008 0.004 0.177 0.028 1 5 0.033 +0.008 0.004 t ref. m 0.136 0.004 recommended mounting hardware torque: 4.34 5.79 lbf ft. recommended silicone grease: dow corning sc102, toshiba yg6260, shin-etsu g746., or equivalent
series str-f6600 off-line quasi-resonant flyback switching regulators 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 ? 16 tm dimensions in millimeters (controlling dimensions) 7.0 0.5 dwg. mk-003-50 mm 5.5 0.2 15.6 0.2 3.2 0.2 23.0 0.3 2.54 0.1 at root 5.5 0.2 5.5 3.35 0.1 0.65 +0.2 0.1 4.5 0.7 1 5 0.85 +0.2 0.1 t ref. m 3.45 0.1 recommended mounting hardware torque: 6 8 kg cm or 0.588 0.784 nm. recommended silicone grease: dow corning sc102, toshiba yg6260, shin-etsu g746., or equivalent

▲Up To Search▲

Price & Availability of STR-F6674

	To Download STR-F6674 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .