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1 device operating temperature range package mixed frequency mode greenline pwm* controller: ordering information mc44603p t a = 25 to +85 c plastic dip16 p suffix plastic package case 648 16 1 16 15 14 13 12 11 10 9 2 3 4 5 6 7 8 (top view) v cc v c output r ref sync input pin connections order this document by mc44603/d gnd foldback input overvoltage protection (ovp) current sense input demag detection r frequency standby voltage feedback input error amp output r power standby softstart/d max / voltage mode c t variable frequency, fixed frequency, standby mode * pwm = pulse width modulation mc44603dw sop16l 16 1 dw suffix plastic package case 751g (sop16l) 1 motorola analog ic device data
? fixed frequency, variable frequency, standby mode the mc44603 is an enhanced high performance controller that is specifically designed for offline and dctodc converter applications. this device has the unique ability of automatically changing operating modes if the converter output is overloaded, unloaded, or shorted, offering the designer additional protection for increased system reliability. the mc44603 has several distinguishing features when compared to conventional smps controllers. these features consist of a foldback facility for overload protection, a standby mode when the converter output is slightly loaded, a demagnetization detection for reduced switching stresses on transistor and diodes, and a high current totem pole output ideally suited for driving a power mosfet. it can also be used for driving a bipolar transistor in low power converters (< 150 w). it is optimized to operate in discontinuous mode but can also operate in continuous mode. its advanced design allows use in current mode or voltage mode control applications. current or voltage mode controller ? operation up to 250 khz output switching frequency ? inherent feed forward compensation ? latching pwm for cyclebycycle current limiting ? oscillator with precise frequency control high flexibility ? externally programmable reference current ? secondary or primary sensing ? synchronization facility ? high current totem pole output ? undervoltage lockout with hysteresis safety/protection features ? overvoltage protection against open current and open voltage loop ? protection against short circuit on oscillator pin ? fully programmable foldback ? softstart feature ? accurate maximum duty cycle setting ? demagnetization (zero current detection) protection ? internally trimmed reference greenline controller: low power consumption in standby mode ? low startup and operating current ? fully programmable standby mode ? controlled frequency reduction in standby mode ? low dv/dt for low emi radiations greenline is a trademark of motorola, inc. ? motorola, inc. 1999 rev 1
mc44603 2 motorola analog ic device data maximum ratings rating symbol value unit total power supply and zener current (i cc + i z ) 30 ma supply voltage with respect to ground (pin 4) v c v cc 18 v output current (note 1) ma source i o(source) 750 sink i o(sink) 750 output energy (capacitive load per cycle) w 5.0 m j r f stby , c t , softstart, r ref , r p stby inputs v in 0.3 to 5.5 v foldback input, current sense input, e/a output, voltage feedback input, overvoltage protection, synchronization input v in 0.3 to v cc + 0.3 v synchronization input high state voltage v ih v cc + 0.3 v low state reverse current v il 20 ma demagnetization detection input current ma source i demagib (source) 4.0 sink i demagib (sink) 10 error amplifier output sink current i e/a (sink) 20 ma power dissipation and thermal characteristics p suffix, dualinline, case 648 maximum power dissipation at t a = 85 c p d 0.6 w thermal resistance, junctiontoair r q ja 100 c/w dw suffix, surface mount, case 751g maximum power dissipation at t a = 85 c p d 0.45 w thermal resistance, junctiontoair r q ja 145 c/w operating junction temperature t j 150 c operating ambient temperature t a 25 to +85 c notes: 1. maximum package power dissipation limits must be observed. 2. esd data available upon request. electrical characteristics (v cc and v c = 12 v, [note 3], r ref = 10 k w , c t = 820 pf, for typical values t a = 25 c, for min/max values t a = 25 to +85 c [note 4], unless otherwise noted.) characteristic symbol min typ max unit output section output voltage (note 5) v low state (i sink = 100 ma) low state (i sink = 500 ma) v ol 1.0 1.4 1.2 2.0 high state (i source = 200 ma) high state (i source = 500 ma) v oh 1.5 2.0 2.0 2.7 output voltage during initialization phase v ol v pgg v cc = 0 to 1.0 v, i sink = 10 m a v cc 10to50v i si k 100 m a ol 01 1.0 10 v cc = 1.0 to 5.0 v, i sink = 100 m a v cc =50to13v i sink =10ma 0.1 01 1.0 10 v cc = 5 . 0 to 13 v , i sink = 1 . 0 ma 0 . 1 1 . 0 output voltage rising edge slewrate (c l = 1.0 nf, t j = 25 c) dvo/dt 300 v/ m s output voltage falling edge slewrate (c l = 1.0 nf, t j = 25 c) dvo/dt 300 v/ m s error amplifier section voltage feedback input (v e/a out = 2.5 v) v fb 2.42 2.5 2.58 v input bias current (v fb = 2.5 v) i fbib 2.0 0.6 m a open loop voltage gain (v e/a out = 2.0 to 4.0 v) a vol 65 70 db notes: 3. adjust v cc above the startup threshold before setting to 12 v. 4. low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. 5. v c must be greater than 5.0 v.
mc44603 3 motorola analog ic device data electrical characteristics (continued) (v cc and v c = 12 v, [note 3], r ref = 10 k w , c t = 820 pf, for typical values t a = 25 c, for min/max values t a = 25 to +85 c [note 4], unless otherwise noted.) characteristic symbol min typ max unit error amplifier section (continued) unity gain bandwidth bw mhz t j = 25 c 4.0 t j = 25 to +85 c 5.5 voltage feedback input line regulation (v cc = 10 to 15 v) v fblinereg 10 10 mv output current ma sink (v e/a out = 1.5 v, v fb = 2.7 v) t a = 25 to +85 c i sink 2.0 12 source (v e/a out = 5.0 v, v fb = 2.3 v) t a = 25 to +85 c i source 2.0 0.2 output voltage swing v high state (i e/a out (source) = 0.5 ma, v fb = 2.3 v) v oh 5.5 6.5 7.5 low state (i e/a out (sink) = 0.33 ma, v fb = 2.7 v) v ol 1.0 1.1 reference section reference output voltage (v cc = 10 to 15 v) v ref 2.4 2.5 2.6 v reference current range (i ref = v ref /r ref , r = 5.0 k to 25 k w ) i ref 500 100 m a reference voltage over i ref range d v ref 40 40 mv oscillator and synchronization section frequency f osc khz t a = 0 to +70 c 44.5 48 51.5 t a = 25 to +85 c 44 52 frequency change with voltage (v cc = 10 to 15 v) d f osc / d v 0.05 %/v frequency change with temperature (t a = 25 to +85 c) d f osc / d t 0.05 %/ c oscillator voltage swing (peaktopeak) v osc(pp) 1.65 1.8 1.95 v ratio charge current/reference current i charge /i ref t a = 0 to +70 c (v ct = 2.0 v) 0.375 0.4 0.425 t a = 25 to +85 c 0.37 0.43 fixed maximum duty cycle = i discharge /(i discharge + i charge ) d 78 80 82 % ratio standby discharge current versus i r f stby (note 6) i dischstby / t a = 0 to +70 c i r f stby 0.46 0.53 0.6 t a = 25 to +85 c (note 8) 0.43 0.63 v r f stby (i r f stby = 100 m a) v r f stby 2.4 2.5 2.6 v frequency in standby mode (r f stby (pin 15) = 25 k w ) f stby 18 21 24 khz current range i r f stby 200 50 m a synchronization input threshold voltage (note 7) v inthh v inthl 3.2 0.45 3.7 0.7 4.3 0.9 v synchronization input current i syncin 5.0 0 m a minimum synchronization pulse width (note 8) t sync 0.5 m s undervoltage lockout section startup threshold v stupth 13.6 14.5 15.4 v output disable voltage after threshold turnon (uvlo 1) v disable1 v t a = 0 to +70 c 8.6 9.0 9.4 t a = 25 to +85 c 8.3 9.6 reference disable voltage after threshold turnon (uvlo 2) v disable2 7.0 7.5 8.0 v notes: 1 3. adjust v cc above the startup threshold before setting to 12 v. 1 4. low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. 1 6. standby is disabled for v r p stby < 25 mv typical. 1 7. if not used, synchronization input must be connected to ground. 1 8. synchronization pulse width must be shorter than t osc = 1/f osc .
mc44603 4 motorola analog ic device data electrical characteristics (continued) (v cc and v c = 12 v, [note 3], r ref = 10 k w , c t = 820 pf, for typical values t a = 25 c, for min/max values t a = 25 to +85 c [note 4], unless otherwise noted.) characteristic symbol min typ max unit demagnetization detection section (note 9) demagnetization detect input demagnetization comparator threshold (v pin 9 decreasing) v demagth 50 65 80 mv propagation delay (input to output, low to high) 0.25 m s input bias current (v demag = 65 mv) i demaglb 0.5 m a negative clamp level (i demag = 2.0 ma) c l(neg) 0.38 v positive clamp level (i demag = 2.0 ma) c l(pos) 0.72 v softstart section (note 11) ratio charge current/i ref i ss(ch) /i ref t a = 0 to +70 c 0.37 0.4 0.43 t a = 25 to +85 c 0.36 0.44 discharge current (v softstart = 1.0 v) i discharge 1.5 5.0 ma clamp level v ss(cl) 2.2 2.4 2.6 v duty cycle (r softstart = 12 k w ) duty cycle (v softstart (pin 11) = 0.1 v) d softstart 12k d softstart 36 42 49 0 % overvoltage section protection threshold level on v ovp v ovpth 2.42 2.5 2.58 v propagation delay (v ovp > 2.58 v to v out low) 1.0 3.0 m s protection level on v cc v cc prot v t a = 0 to +70 c 16.1 17 17.9 t a = 25 to +85 c 15.9 18.1 input resistance k w t a = 0 to +70 c 1.5 2.0 3.0 t a = 25 to +85 c 1.4 3.4 foldback section (note 10) current sense voltage threshold (v foldback (pin 5) = 0.9 v) v csth 0.86 0.89 0.9 v foldback input bias current (v foldback (pin 5) = 0 v) i foldbacklb 6.0 2.0 m a standby section ratio i r p stby /i ref i r p stby /i ref t a = 0 to +70 c 0.37 0.4 0.43 t a = 25 to +85 c 0.36 0.44 ratio hysteresis (v h required to return to normal operation from standby operation) v h /v r p stby t a = 0 to +70 c 1.42 1.5 1.58 t a = 25 to +85 c 1.4 1.6 current sense voltage threshold (v r p stby (pin 12) = 1.0 v) v csstby 0.28 0.31 0.34 v current sense section maximum current sense input threshold (v feedback (pin 14) = 2.3 v and v foldback (pin 6) = 1.2 v) v csth 0.96 1.0 1.04 v input bias current i csib 10 2.0 m a propagation delay (current sense input to output at v th of mos transistor = 3.0 v) 120 200 ns total device power supply current i cc ma startup (v cc = 13 v with v cc increasing) 0.3 0.45 operating t a = 25 to +85 c (note 3) 13 17 20 power supply zener voltage (i cc = 25 ma) v z 18.5 v thermal shutdown 155 c notes: 1 3. adjust v cc above the startup threshold before setting to 12 v. 1 4. low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. 1 9. this function can be inhibited by connecting pin 8 to gnd. this allows a continuous current mode operation. 10. this function can be inhibited by connecting pin 5 to v cc . 11. the mc44603 can be shut down by connecting the softstart pin (pin 11) to ground.
mc44603 5 motorola analog ic device data representative block diagram this device contains 243 active transistors. s r f stby r ref r f stby v ref 15 16 reference block v ref i ref + v cc v cc 1 14.5 v/7.5 v v aux 18.0 v to powe r transform e v c 2 output 3 gnd 4 ovp 6 current sense input 7 v cc v ref v ovp out 2.0 m s delay v ref 5.0 m s delay + 2.5 v r ovp 11.6 k 2.0 k v cc + 9.0 v ss/d max /vm 2.4 v r ss c ss 11 1.0 v demag detect 8 sync input 9 v ref + + + 65 mv 3.7 v 1.0 v 0.4 i ref c t 10 r pwr stby 12 feed back 14 compen sation 13 foldback input 5 1.6 v 3.6 v + c t 0.7 v v demag out synchro v osc prot 0.4 i ref v ref v ref v ref v ref v ref 0.4 i ref 0.6 i ref 0.8 i ref 0.25 i f stby 0.2 i ref i discharge i discharge/2 current mirror x2 0.4 i ref v ref 2r v cc 1.0 ma error amplifier r q s r q s r q s r q = sink only = positive true logic + 2.5 v thermal shutdown i f stby uvlo2 v osc + 1.6 v uvlo1 5.0 ma negative active clamp
mc44603 6 motorola analog ic device data figure 1. timing resistor versus oscillator frequency figure 2. standby mode timing capacitor versus oscillator frequency 10 k 10000 c t , timing capacitor (pf) f osc , oscillator frequency (hz) v cc = 16 v t a = 25 c r ref = 10 k 10 k 100 r ref , timing resistance (k ) w f osc , oscillator frequency (hz) v cc = 16 v t a = 25 c 1000 10 300 3.0 100 k 100 k 1.0 meg 1.0 meg c t = 100 pf c t = 500 pf c t = 2200 pf c t = 1000 pf r f stby = 2.0 k r f stby = 5.0 k r f stby = 27 k r f stby = 100 k t a , ambient temperature ( c) figure 3. oscillator frequency versus temperature t a , ambient temperature ( c) figure 4. ratio charge current/reference current versus temperature 52 51 48 47 46 45 44 50 25 0 25 50 75 100 v cc = 12 v r ref = 10 k c t = 820 pf 0.43 0.41 0.40 0.37 0.38 50 25 0 25 50 75 100 0.39 f osc , oscillator frequency (khz) = ratio charge current/ i charge /i ref reference current 49 50 0.42 v cc = 12 v r ref = 10 k c t = 820 pf figure 5. output waveform figure 6. output cross conduction v o i cc v cc = 12 v c l = 2200 pf t a = 25 c current voltage current voltage 1.0 m s/div 1.0 m s/div v cc = 12 v c l = 2200 pf t a = 25 c 600 400 200 400 600 800 1000 i o , output current (ma) 0 200 70 60 30 20 10 0 10 v o , output drive voltage (v) 40 50 70 60 30 20 10 0 10 40 50 300 200 10 0 20 0 30 0 40 0 50 0 0 100 v o , output drive voltage (v)
mc44603 7 motorola analog ic device data 500 425 400 375 350 325 300 50 25 0 25 50 75 100 i source , output source current (ma) t a , ambient temperature ( c) figure 7. oscillator discharge current versus temperature figure 8. source output saturation voltage versus load current 2.5 2.0 1.5 1.0 0 100 200 300 400 500 i disch , discharge current ( m a) v oh , source output saturation voltage (v) 450 475 v cc = 12 v r ref = 10 k c t = 820 pf v cc = 12 v r ref = 10 k c t = 820 pf t a = 25 c f, frequency (khz) figure 9. sink output saturation voltage versus sink current i sink , sink output current (ma) figure 10. error amplifier gain and phase versus frequency 1.6 0 0 100 80 2.0 1.2 0.8 0.4 200 300 400 500 v ol , sink output saturation voltage (v) gain (db) 60 40 20 0 20 100 1.0 10 1000 140 50 40 phase (degrees) v cc = 12 v g = 10 v in = 30 mv v o = 2.0 to 4.0 v r l = 100 k t a = 25 c t a = 25 c v cc = 12 v 80 m s pulsed load 120 hz rate sink saturation (load to v cc ) figure 11. voltage feedback input versus temperature figure 12. demag comparator threshold versus temperature 2.60 2.55 2.40 2.45 50 25 0 25 50 75 100 2.50 t a , ambient temperature ( c) v fb , voltage feedback input (v) 80 75 70 65 60 50 50 25 0 25 50 75 100 t a , ambient temperature ( c) v demagth , demag comparator threshold (mv) 55 v cc = 12 v g = 10 v o = 2.0 to 4.0 v r l = 100 k v cc = 12 v
mc44603 8 motorola analog ic device data 0 0 100 r ja , thermal resistance junctiontoair ( c/w) q 80 60 40 20 10 20 30 40 50 l, length of copper (mm) p d , maximum power dissipation (w) 5.0 4.0 3.0 2.0 1.0 0 graphs represent symmetrical layout 3.0 mm printed circuit board heatsink example l l 2.0 oz copper p d(max) for t a = 70 c r q ja 3.2 3.1 2.8 2.9 3.0 50 25 0 25 50 75 100 t a , ambient temperature ( c) figure 13. current sense gain versus temperature figure 14. thermal resistance and maximum power dissipation versus p.c.b. copper length a vcs , current sense gain v cc = 12 v r ref = 10 k c t = 820 pf v cc , supply voltage (v) figure 15. propagation delay current sense input to output versus temperature t a , ambient temperature ( c) figure 16. startup current versus v cc propagation delay (ns) startup current (ma) 0 4.0 0 2.0 6.0 140 120 100 80 50 25 0 25 50 75 100 0.35 0.30 0.25 0.20 0.15 0.10 0.05 8.0 10 12 14 v cc = 12 v r ref = 10 k c t = 820 pf r ref = 10 k c t = 820 pf figure 17. supply current versus supply voltage figure 18. power supply zener voltage versus temperature 16 0 v cc , supply voltage (v) 21.0 20.5 20.0 19.5 19.0 50 25 0 25 50 75 100 t a , ambient temperature ( c) i cc , supply current (ma) v z , zener voltage (v) 14 12 10 8.0 6.0 4.0 2.0 2.0 4.0 6.0 8.0 10 12 14 16 21.5 t a = 25 c r ref = 10 k c t = 820 pf v fb = 0 v v cs = 0 v i cc = 25 ma
mc44603 9 motorola analog ic device data 50 25 0 25 50 75 100 t a , ambient temperature ( c) figure 19. startup threshold voltage versus temperature figure 20. disable voltage after threshold turnon (uvlo1) versus temperature 50 25 0 25 50 75 100 t a , ambient temperature ( c) v stupth , startup threshold voltage (v) v disable1 , uvlo1 (v) 15.5 15.0 14.5 14.0 13.5 9.50 9.00 8.55 8.50 9.25 v cc increasing v cc decreasing t a , ambient temperature ( c) figure 21. disable voltage after threshold turnon (uvlo2) versus temperature t a , ambient temperature ( c) figure 22. protection threshold level on v ovp versus temperature 2.60 8.0 2.30 v disable2 , uvlo2 (v) 50 25 0 25 50 75 100 7.8 7.6 7.4 7.2 7.0 6.8 2.55 2.50 2.45 2.40 2.35 50 25 0 25 50 75 100 v ovpth , protection threshold level (v) v cc decreasing v cc = 12 v figure 23. protection level on v cc versus temperature figure 24. propagation delay (v ovp > 2.58 v to v out low) versus temperature 18 t a , ambient temperature ( c) 3.0 2.0 1.5 1.0 50 25 0 25 50 75 100 t a , ambient temperature ( c) 2.5 17.5 17 16.5 16 50 25 0 25 50 75 100 v cc prot , protection level (v) m propagation delay ( s) r ref = 10 k c t = 820 pf pin 6 open v cc = 12 v r ref = 10 k c t = 820 pf
mc44603 10 motorola analog ic device data 50 25 0 25 50 75 100 t a , ambient temperature ( c) figure 25. standby reference current versus temperature figure 26. current sense voltage threshold standby mode versus temperature 50 25 0 25 50 75 100 t a , ambient temperature ( c) 270 260 250 240 230 0.33 0.32 0.31 0.30 m ia) v csstby , current sense threshold 265 255 245 235 standby mode (v) v r p stdby (pin 12) voltage increasing v cc = 12 v r ref = 10 k c t = 820 pf pin 12 clamped at 1.0 v r p stby , standby reference current ( pin function description pin name description 1 v cc this pin is the positive supply of the ic. the operating voltage range after startup is 9.0 to 14.5 v. 2 v c the output high state (v oh ) is set by the voltage applied to this pin. with a separate connection to the power source, it can reduce the effects of switching noise on the control circuitry. 3 output peak currents up to 750 ma can be sourced or sunk, suitable for driving either mosfet or bipolar transistors. this output pin must be shunted by a schottky diode, 1n5819 or equivalent. 4 gnd the ground pin is a single return, typically connected back to the power source; it is used as control and power ground. 5 foldback input the foldback function provides overload protection. feeding the foldback input with a portion of the v cc voltage (1.0 v max) establishes on the system control loop a foldback characteristic allowing a smoother startup and sharper overload protection. above 1.0 v the foldback input is inactive. 6 overvoltage protection when the overvoltage protection pin receives a voltage greater than 17 v, the device is disabled and requires a complete restart sequence. the overvoltage level is programmable. 7 current sense input a voltage proportional to the current flowing into the power switch is connected to this input. the pwm latch uses this information to terminate the conduction of the output buffer when working in a current mode of operation. a maximum level of 1.0 v allows either current or voltage mode operation. 8 demagnetization detection a voltage delivered by an auxiliary transformer winding provides to the demagnetization pin an indication of the magnetization state of the flyback transformer. a zero voltage detection corresponds to complete core saturation. the demagnetization detection ensures a discontinuous mode of operation. this function can be inhibited by connecting pin 8 to gnd. 9 synchronization input the synchronization input pin can be activated with either a negative pulse going from a level between 0.7 v and 3.7 v to gnd or a positive pulse going from a level between 0.7 v and 3.7 v up to a level higher than 3.7 v. the oscillator runs free when pin 9 is connected to gnd. 10 c t the normal mode oscillator frequency is programmed by the capacitor c t choice together with the r ref resistance value. c t , connected between pin 10 and gnd, generates the oscillator sawtooth. 11 softstart/d max / voltagemode a capacitor, resistor or a voltage source connected to this pin limits the switching dutycycle. this pin can be used as a voltage mode control input. by connecting pin 11 to ground, the mc44603 can be shut down. 12 r p standby a voltage level applied to the r p standby pin determines the output power level at which the oscillator will turn into the reduced frequency mode of operation (i.e. standby mode). an internal hysteresis comparator allows to return in the normal mode at a higher output power level. 13 e/a out the error amplifier output is made available for loop compensation. 14 voltage feedback this is the inverting input of the error amplifier. it can be connected to the switching power supply output through an optical (or other) feedback loop. 15 r f standby the reduced frequency or standby frequency programming is made by the r f standby resistance choice. 16 r ref r ref sets the internal reference current. the internal reference current ranges from 100 m a to 500 m a. this requires that 5.0 k w r ref 25 k w .
mc44603 11 motorola analog ic device data figure 27. starting behavior and overvoltage management figure 28. demagnetization ???????? ???????? ???????? ?? ?? ?? ??? ??? ??? v cc prot v stupth v disable1 v disable2 v ref v cc uvlo1 v pin 11 (softstart) v ovp out output i cc 17 ma 0.3 ma startup restart >2.0 m s notake over loop failure normal mode v demag in output (pin 3) v demag out v demag in v demag out demagnetization management oscillator buffer output
mc44603 12 motorola analog ic device data figure 29. switching off behavior figure 30. oscillator ??? ??? v cc v stupth v disable1 v disable2 v ref uvlo1 v pin 11 (softstart) output (pin 3) i cc 17 ma 0.3 ma v ct 1.0 v v stby v demag out v osc v osc prot v demag out synchronization input v osc prot v osc v stby c t 1.6 v 3.6 v oscillator
mc44603 13 motorola analog ic device data figure 31. softstart & d max 3.6 v 1.6 v v ct v ct low v ref output (pin 3) v css + 1.6 v softstart internal clamp external clamp v osc operating description error amplifier a fully compensated error amplifier with access to the inverting input and output is provided. it features a typical dc voltage gain of 70 db. the noninverting input is internally biased at 2.5 v and is not pinned out. the converter output voltage is typically divided down and monitored by the inverting input. the maximum input bias current with the inverting input at 2.5 v is 2.0 m a. this can cause an output voltage error that is equal to the product of the input bias current and the equivalent input divider source resistance. the error amp output (pin 13) is provided for external loop compensation. the output voltage is offset by two diode drops ( 1.4 v) and divided by three before it connects to the inverting input of the current sense comparator. this guarantees that no drive pulses appear at the output (pin 3) when pin 13 is at its lowest state (v ol ). the error amp minimum feedback resistance is limited by the amplifier's minimum source current (0.2 ma) and the required output voltage (v oh ) to reach the current sense comparator's 1.0 v clamp level: r f(min) 3.0 (1.0 v) 1.4 v 0.2 ma 22 k + 1.0 ma 2.5 v compensation r fb c f r1 r2 from power supply output r f 13 voltage feedback input error amplifier 2r r current sense comparator gnd 4 foldback input 5 14 figure 32. error amplifier compensation current sense comparator and pwm latch the mc44603 can operate as a current mode controller or as a voltage mode controller. in current mode operation, the mc44603 uses the current sense comparator. the output switch conduction is initiated by the oscillator and terminated when the peak inductor current reaches the threshold level
mc44603 14 motorola analog ic device data established by the error amplifier output (pin 13). thus, the error signal controls the peak inductor current on a cyclebycycle basis. the current sense comparator pwm latch ensures that only a single pulse appears at the source output during the appropriate oscillator cycle. the inductor current is converted to a voltage by inserting the ground referenced sense resistor r s in series with the power switch q1. this voltage is monitored by the current sense input (pin 7) and compared to a level derived from the error amp output. the peak inductor current under normal operating conditions is controlled by the voltage at pin 13 where: i pk v (pin 13) 1.4 v 3r s the current sense comparator threshold is internally clamped to 1.0 v. therefore, the maximum peak switch current is: i pk(max) 1.0 v r s figure 33. output totem pole r r s q uvlo v osc prot v demag out thermal protection pwm latch current sense comparator substrate current sense 14 3 7 c r s r r3 q1 v in v c r2 1n5819 oscillator the oscillator is a very accurate sawtooth generator that can work either in free mode or in synchronization mode. in this second mode, the oscillator stops in the low state and waits for a demagnetization or a synchronization pulse to start a new charging cycle. ? the sawtooth generation: in the steady state, the oscillator voltage varies between about 1.6 v and 3.6 v. the sawtooth is obtained by charging and discharging an external capacitor c t (pin 10), using two distinct current sources = i charge and i discharge . in fact, c t is permanently connected to the charging current source (0.4 i ref ) and so, the discharge current source has to be higher than the charge current to be able to decrease the c t voltage (refer to figure 35). this condition is performed, its value being (2.0 i ref ) in normal working and (0.4 i ref + 0.5 i f stby in standby mode). figure 34. oscillator 10 c t 1.0 v 1.6 v 3.6 v v ref 0.4 i ref c vos prot c osc low c osc high c osc regul synchro 10 i regul r s disch q c t < 1.6 v v osc prot r s l osc q v osc v demag out 01 i discharge discharge figure 35. simplified block oscillator v ref c t 10 i charge 0.4 i ref 01 0: discharge phase 1: charge phase c osc regul i regul 1.6 v i discharge two comparators are used to generate the sawtooth. they compare the c t voltage to the oscillator valley (1.6 v) and peak reference (3.6 v) values. a latch (l disch ) memorizes the oscillator state. in addition to the charge and discharge cycles, a third state can exist. this phase can be produced when, at the end of the discharge phase, the oscillator has to wait for a synchronization or demagnetization pulse before restarting. during this delay, the c t voltage must remain equal to the oscillator valley value ( 1.6 v). so, a third regulated current source i regul controlled by c osc regul , is connected to c t in order to perfectly compensate the (0.4 i ref ) current source that permanently supplies c t . the maximum duty cycle is 80%. indeed, the ontime is allowed only during the oscillator capacitor charge. consequently: t charge = c t x d v/i charge t discharge = c t x d v/i discharge where: t charge is the oscillator charge time d v is the oscillator peaktopeak value i charge is the oscillator charge current and t discharge is the oscillator discharge time i discharge is the oscillator discharge current
mc44603 15 motorola analog ic device data so, as f s = 1 /(t charge + t discharge ) when the regul arrangement is not activated, the operating frequency can be obtained from the graph in figure 1. note: the output is disabled by the signal v osc prot when v ct is lower than 1.0 v (refer to figure 30). synchronization and demagnetization blocks to enable the output, the l osc latch complementary output must be low. reset is activated by the l disch output during the discharge phase. to restart, the l osc has to be set (refer to figure 34). to perform this, the demagnetization signal and the synchronization must be low. ? synchronization: the synchronization block consists of two comparators that compare the synchronization signal (external) to 0.7 and 3.7 v (typical values). the comparators' outputs are connected to the input of an and gate so that the final output of the block should be : high when 0.7 < sync < 3.7 v low in the other cases. as a low level is necessary to enable the output, synchronized low level pulses have to be generated on the output of the synchronization block. if synchronization is not required, the pin 9 must be connected to the ground. figure 36. synchronization oscillator output buffer 3.7 v 0.7 v 9 sync ? demagnetization: in flyback applications, a good means to detect magnetic saturation of the transformer core, or demagnetization, consists in using the auxiliary winding voltage. this voltage is: negative during the ontime, positive during the offtime, equal to zero for the deadtime with generally some ringing (refer to figure 37). that is why, the mc44603 demagnetization detection consists of a comparator that can compare the auxiliary winding voltage to a reference that is typically equal to 65 mv. figure 37. demagnetization detection v pin 8 0.75 v 65 mv 0.33 v zero current detection ontime offtime deadtime a diode d has been incorporated to clamp the positive applied voltages while an active clamping system limits the negative voltages to typically 0.33 v. this negative clamp level is sufficient to avoid the substrate diode switching on. in addition to the comparator, a latch system has been incorporated in order to keep the demagnetization block output level low as soon as a voltage lower than 65 mv is detected and as long as a new restart is produced (high level on the output) (refer to figure 38). this process prevents ringing on the signal at pin 8 from disrupting the demagnetization detection. this results in a very accurate demagnetization detection. the demagnetization block output is also directly connected to the output, disabling it during the demagnetization phase (refer to figure 33). note: the demagnetization detection can be inhibited by connecting pin 8 to the ground. figure 38. demagnetization block c dem oscillator output buffer r s q demag v cc negative active clamping system 8 d 65 mv v demag out standby ? power losses in a classical flyback structure figure 39. power losses in a classical flyback structure v in r icl ac line + r startup v cc clamping network snubber mc44603 r s + in a classical flyback (as depicted in figure 39), the standby losses mainly consist of the energy waste due to: the startup resistor r startup p startup the consumption of the ic and the power switch control p control the inrush current limitation resistor r icl p icl the switching losses in the power switch p sw the snubber and clamping network p sncln p startup is nearly constant and is equal to: (v in v cc ) 2 r startup
mc44603 16 motorola analog ic device data p icl only depends on the current drawn from the mains. losses can be considered constant. this waste of energy decreases when the standby losses are reduced. p control increases when the oscillator frequency is increased (each switching requires some energy to turn on the power switch). p sw and p sncln are proportional to the switching frequency. consequently, standby losses can be minimized by decreasing the switching frequency as much as possible. the mc44603 was designed to operate at a standby frequency lower than the normal working one. ? standby power calculations with mc44603 during a switching period, the energy drawn by the transformer during the ontime to be transferred to the output during the offtime, is equal to: e 1 2 xlxi pk 2 where: l is the transformer primary inductor, l pk is the inductor peak current. input power is labelled p in : p in 0.5xlxi pk 2 xf s where f s is the normal working switching frequency. also, i pk v cs r s where r s is the resistor used to measure the power switch current. thus, the input power is proportional to v cs 2 ( v cs being the internal current sense comparator input). that is why the standby detection is performed by creating a v cs threshold. an internal current source (0.4 x i ref ) sets the threshold level by connecting a resistor to pin 12. as depicted in figure 40, the st andby comparator noninverting i nput voltage is typically equal to (3.0 x v cs + v f ) while the inverter input value is (v r p stby + v f ). figure 40. standby c stby current mirror x2 r p stby er ampout 0.4 i ref 0.6 i ref 0 1 2r 1r c. s. comparator 0.8 i ref 0.25 i f stby v ref v ref v ref v ref v ref 0.2 i ref oscillator discharge current 10 i discharge/2 i discharge 12 13 the v cs threshold level is typically equal to [(v r p stby )/3] and if the corresponding power threshold is labelled p thl : p thl 0.5xlx v rpstby 3.0 r s 2 xf s and as: v rpstby r pstby x0.4xi ref r rpstby x0.4x v ref r ref r pstby 10.6 x r s xr ref v ref x p thl lxf s thus, when the power drawn by the converter decreases, v cs decreases and when v cs becomes lower than [v csth x (v r p stby )/3], the standby mode is activated. this results in an oscillator discharge current reduction in order to increase the oscillator period and to diminish the switching frequency. as it is represented in figure 40, the (0.8 x i ref ) current source is disconnected and is replaced by a lower value one (0.25 x i f stby ). where: i f stby = v ref /r f stby in order to prevent undesired mode switching when power is close to the threshold value, a hysteresis that is proportional to v r p stby is incorporated creating a second v cs threshold level that is equal to [2.5 x (v r p stby )/3]. when the standby comparator output is high, a second current source (0.6 x i ref ) is connected to pin 12. finally, the standby mode function can be shown graphically in figure 41. figure 41. dynamic mode change p thl p thh p in [(v r p stby )/3] 2.5 x [(v r p stby )/3] 1 v cs f stby f s normal working standby this curve shows that there are two power threshold levels: the low one: p thl fixed by v r p stby p thh (2.5) 2 xp thl x f stby f s the high one: p thh 6.25 x p thl x f stby f s
mc44603 17 motorola analog ic device data maximum duty cycle and softstart control maximum duty cycle can be limited to values less than 80% by utilizing the d max and softstart control. as depicted in figure 42, the pin 11 voltage is compared to the oscillator sawtooth. figure 42. d max and softstart c dmax 11 softstart capacitor v osc oscillator d max output drive output control 0.4 i ref v ref 2.4 v d z figure 43. maximum duty cycle control voltage d max pin 11 v ct (pin 10) using the internal current source (0.4 i ref ), the pin 11 voltage can easily be set by connecting a resistor to this pin. if a capacitor is connected to pin 11, the voltage increases from 0 to its maximum value progressively (refer to figure 44), thereby, implementing a softstart. the softstart capacitor is discharged internally when the v cc (pin 1) voltage drops below 9.0 v. figure 44. different possible uses of pin 11 pin 11 ri ri r connected to pin 11 i = 0.4 i ref v z v z c c // r t = rc if no external component is connected to pin 11, an internal zener diode clamps the pin 11 voltage to a value v z that is higher than the oscillator peak value, disabling softstart and maximum duty cycle limitation. foldback as depicted in fgure 32, the foldback input (pin 5) can be used to reduce the maximum v cs value, providing foldback protection. the foldback arrangement is a programmable peak current limitation. if the output load is increased, the required converter peak current becomes higher and v cs increases until it reaches its maximum value (normally, v cs max = 1.0 v). then, if the output load keeps on increasing, the system is unable to supply enough energy to maintain the output voltages in regulation. consequently, the decreasing output can be applied to pin 5, in order to limit the maximum peak current. in this way, the well known foldback characteristic can be obtained (refer to figure 45). figure 45. foldback characteristic v out v o nominal v cc v disable2 i pk max new startup sequence initiated i out overload note: foldback is disabled by connecting pin 5 to v cc . overvoltage protection the overvoltage arrangement consists of a comparator that compares the pin 6 voltage to v ref (2.5 v) (refer to figure 46). if no external component is connected to pin 6, the comparator noninverting input voltage is nearly equal to: 2.0 k 11.6 k 2.0 k xv cc 2.0 k 11.6 k 2.0 k xv cc 2.5 v the comparator output is high when: v cc 17 v a delay latch (2.0 m s) is incorporated in order to sense overvoltages that last at least 2.0 m s. if this condition is achieved, v ovp out , the delay latch output, becomes high. as this level is brought back to the input through an or gate, v ovp out remains high (disabling the ic output) until v ref is disabled. consequently, when an overvoltage longer than 2.0 m s is detected, the output is disabled until v cc is removed and then reapplied. the v cc is connected after v ref has reached steady state in order to limit the circuit startup consumption. the overvoltage section is enabled 5.0 m s after the regulator has started to allow the reference v ref to stabilize. by connecting an external resistor to pin 6, the threshold v cc level can be changed. figure 46. overvoltage protection v cc v ref 0 t v ovp external resistor 2.5 v (v ref ) 2.0 k 11.6 k 2.5 v 5.0 m s v ovp out 2.0 m s (if v ovp out = 1.0, the output is disabled) in out delay t enable c ovlo 6 delay in out t
mc44603 18 motorola analog ic device data undervoltage lockout section figure 47. v cc management reference block: voltage and current sources generator (v ref , i ref , ...) v cc v ref enable c startup 10 1 0 v disable2 7.5 v startup 14.5 v uvlo1 (to softstart) v disable1 9.0 v c uvlo1 r f stby r ref pin 15 pin 16 1 as depicted in figure 47, an undervoltage lockout has been incorporated to garantee that the ic is fully functional before allowing system operation. this block particularly, produces v ref (pin 16 voltage) and i ref that is determined by the resistor r ref connected between pin 16 and the ground: i ref v ref r ref where v ref 2.5 v (typically) another resistor is connected to the reference block: r f stby that is used to fix the standby frequency. in addition to this, v cc is compared to a second threshold level that is nearly equal to 9.0 v (v disable1 ). uvlo1 is generated to reset the maximum duty cycle and softstart block disabling the output stage as soon as v cc becomes lower than v disable1 . in this way, the circuit is reset and made ready for the next startup, before the reference block is disabled (refer to figure 29). finally, the upper limit for the minimum normal operating voltage is 9.4 v (maximum value of v disable1 ) and so the minimum hysteresis is 4.2 v. ((v stupth ) min = 13.6 v). the large hysteresis and the low startup current of the mc44603 make it ideally suited for offline converter applications where efficient bootstrap startup techniques are required.
mc44603 19 motorola analog ic device data figure 48. 250 w input power offline flyback converter with mosfet switch 185 vac to 270 vac rfi filter r1 1.0/5.0 w c4 ... c7 1.0 nf/1000 v d1 ... d4 1n4007 c1 220 m f r2 68 k/2.0 w c2 220 m f d5 1n4934 c17 47 nf d7 m856 l1 1.0 m h sync c8 2.2 nf c9 1.0 nf c10 1.0 m f r15 5.6 k r15 22 k c11 1.0 nf r17 22 k r25 1.0 k c12 6.8 nf r18 27 k r19 10 k c13 100 nf r12 22 r11 39 r10 10 r7 180 k r8 15 k r9 1.0 k r12 27 k c16 100 pf c15 1.0 nf 9 10 11 12 13 14 15 16 8 7 6 5 4 3 2 1 d6 1n4148 r5 1.2 k r6 150 r26 1.0 k r14 0.2 r13 1.0 k d12 mr856 mtp6n60e c14 4.7 nf c18 2.2 nf l aux l p d8 mr856 d9 mr852 d10 mr852 d11 mr852 c32 220 pf c29 220 pf c26 220 pf c23 220 pf c27 1000 m f c28 0.1 m f c25 1000 m f c24 0.1 m f c21 1000 m f c22 0.1 m f c30 100 m f c33 100 m f c31 0.1 m f r20 22 k 5.0 w r24 270 r23 147.5 k r22 2.5 k l2 22.5 m h 150 v/0.6 a 30 v/2.0 a 14 v/2.0 a 7.0 v/2.0 a c20 33 nf c19 100 nf r21 10 k tl431 moc8101 c3 1.0 nf/1.0 kv r3 4.7 m d14 1n4733 mc44603p d15 1n5819
mc44603 20 motorola analog ic device data 250 w input power flyback converter 185 v 270 v mains range mc44603p & mtp6n60e tests conditions results line regulation 150 v 1 30 v 1 14 v 7.0 v v in = 185 vac to 270 vac f mains = 50 hz i out = 0.6 a i out = 2.0 a i out = 2.0 a i out = 2.0 a 10 mv 10 mv 10 mv 20 mv load regulation 150 v v in = 220 vac i out = 0.3 a to 0.6 a 50 mv cross regulation 150 v v in = 220 vac i out (150 v) = 0.6 a i out (30 v) = 0 a to 2.0 a i out (14 v) = 2.0 a i out (7.0 v) = 2.0 a < 1.0 mv efficiency v in = 220 vac, p in = 250 w 81% standby mode p input switching frequency v in = 220 vac, p out = 0 w 3.3 w 20 khz fully stable output short circuit p out (max) = 270 w safe on all outputs startup p in = 250 w vac = 160 v
mc44603 21 motorola analog ic device data figure 49. 125 w input power offline flyback converter with bipolar switch 185 vac to 270 vac rfi filter r1 1.0/5 w c4 ... c7 1.0 nf/1000 v d1 ... d4 1n4007 c1 100 m f r2 68 k/2 w c2 220 m f d5 1n4934 l1 1.0 m h c9 1.0 nf c10 1.0 m f r15 5.6 k r16 22 k c11 1.0 nf r17 22 k r25 1.0 k c12 6.8 nf r18 27 k r19 10 k c13 100 nf r7 180 k r8 15 k r9 1.0 k r4 27 k c16 100 pf c15 1.0 nf d6 1n4148 r5 1.2 k r6 150 r14 0.33 r13 1.0 k d12 mr856 mjf18006 c14 4.7 nf c18 2.2 nf l aux l p d8 mr856 d9 mr852 d10 mr852 d11 mr852 c32 220 pf c29 220 pf c26 220 pf c23 220 pf c27 1000 m f c28 0.1 m f c25 1000 m f c24 0.1 m f c21 1000 m f c22 0.1 m f c30 100 m f c31 0.1 m f r24 270 r23 117.5 k r22 2.5 k 120 v/0.5 a 28 v/1.0 a 15 v/1.0 a 8.0 v/1.0 a c20 33 nf c19 100 nf r21 10 k tl431 moc8101 c3 1.0 nf/1.0 kv r3 4.7 m v cc 9 10 11 12 13 14 15 16 8 7 6 5 4 3 2 1 d13 1n4728 c34 1.0 m f d14 1n4733 mc44603p r11 39 r10 10 d15 1n5819
mc44603 22 motorola analog ic device data 125 w input power flyback converter 185 v 270 v mains range mc44603p & mjf18006 tests conditions results line regulation 120 v 1 28 v 1 15 v 8.0 v v in = 185 vac to 270 vac f mains = 60 hz i out = 0.5 a i out = 1.0 a i out = 1.0 a i out = 1.0 a 10 mv 10 mv 10 mv 20 mv load regulation 120 v v in = 220 vac i out = 0.2 a to 0.5 a = 0.05 v cross regulation 120 v v in = 220 vac i out (120 v) = 0.5 a i out (28 v) = 0 a to 1.0 a i out (15 v) = 1.0 a i out (8.0 v) = 1.0 a < 1.0 mv efficiency v in = 220 vac, p in = 125 w 85% standby mode p input switching frequency v in = 220 vac, p out = 0 w 2.46 w 20 khz fully stable output short circuit p out (max) = 140 w safe on all outputs startup p in = 125 w vac = 150 v
mc44603 23 motorola analog ic device data p suffix plastic package case 64808 issue r outline dimensions notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: inch. 3. dimension l to center of leads when formed parallel. 4. dimension b does not include mold flash. 5. rounded corners optional. a b f c s h g d j l m 16 pl seating 18 9 16 k plane t m a m 0.25 (0.010) t dim min max min max millimeters inches a 0.740 0.770 18.80 19.55 b 0.250 0.270 6.35 6.85 c 0.145 0.175 3.69 4.44 d 0.015 0.021 0.39 0.53 f 0.040 0.70 1.02 1.77 g 0.100 bsc 2.54 bsc h 0.050 bsc 1.27 bsc j 0.008 0.015 0.21 0.38 k 0.110 0.130 2.80 3.30 l 0.295 0.305 7.50 7.74 m 0 10 0 10 s 0.020 0.040 0.51 1.01 dim min max min max inches millimeters a 10.15 10.45 0.400 0.411 b 7.40 7.60 0.292 0.299 c 2.35 2.65 0.093 0.104 d 0.35 0.49 0.014 0.019 f 0.50 0.90 0.020 0.035 g 1.27 bsc 0.050 bsc j 0.25 0.32 0.010 0.012 k 0.10 0.25 0.004 0.009 m 0 7 0 7 p 10.05 10.55 0.395 0.415 r 0.25 0.75 0.010 0.029 m b m 0.010 (0.25) notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: millimeter. 3. dimensions a and b do not include mold protrusion. 4. maximum mold protrusion 0.15 (0.006) per side. 5. dimension d does not include dambar protrusion. allowable dambar protrusion shall be 0.13 (0.005) total in excess of d dimension at maximum material condition. a b p 8x g 14x d 16x seating plane t s a m 0.010 (0.25) b s t 16 9 8 1 f j r x 45 m c k dw suffix plastic package case 751g02 (sop16l) issue a
mc44603 24 motorola analog ic device data motorola reserves the right to make changes without further notice to any products herein. motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. atypicalo parameters which may be provided in motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including atypicalso must be validated for each customer application by customer's technical experts. motorola does not convey any license under its patent rights nor the rights of others. motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the motorola product could create a situation where personal injury or death may occur. should buyer purchase or use motorola products for any such unintended or unauthorized application, buyer shall indemnify and hold motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that motorola was negligent regarding the design or manufacture of the part. motorola and are registered trademarks of motorola, inc. motorola, inc. is an equal opportunity/affirmative action employer. mfax is a trademark of motorola, inc. how to reach us: usa / europe / locations not listed : motorola literature distribution; japan : motorola japan ltd.; spd, strategic planning office, 141, p.o. box 5405, denver, colorado 80217. 13036752140 or 18004412447 4321 nishigotanda, shinagawaku, tokyo, japan. 81354878488 customer focus center: 18005216274 mfax ? : rmfax0@email.sps.mot.com touchtone 1 6022446609 asia / pacific : motorola semiconductors h.k. ltd.; silicon harbour centre, motorola fax back system us & canada only 18007741848 2, dai king street, tai po industrial estate, tai po, n.t., hong kong. http://sps.motorola.com/mfax/ 85226629298 home page : http://motorola.com/sps/ mc44603/d ?

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