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low power pwm controller for off-line battery charger AP3700E data sheet 1 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 general description the AP3700E is a green-mode pulse width modulation (pwm) controller. it is sp ecially designed for low power applications such as off-line battery chargers, where the needs for low standby power, space saving and low cost are all required. in a battery charger rated 5v/0.8a, the maximum standby power is only 0.18watt. in normal operation, the AP3700E switches on and off at a fixed switching frequency of 60 khz. with a cur- rent limit capability of 460ma, the AP3700E can directly drive the emitter of high voltage npn transis- tor. when output power falls below a given level, the ic enters skip cycle mode to reduce power consump- tion. the AP3700E also features under-voltage lockout, over-current and short circuit protections. the AP3700E is available in to-92 package. features current mode control with skip cycle capability lower operating current: 0.45ma fixed switching frequency: 60 khz frequency dithering for low emi: 2.5khz under-voltage lockout protection over-current protection internal short circuit protection higher output voltage at out terminal low total cost solution applications battery chargers off-line power supplies figure 1. package types of AP3700E to-92 to-92 (ammo packing) (buck packing)
low power pwm controller for off-line battery charger AP3700E data sheet 2 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 figure 2. pin configuration of AP3700E (top view) pin description pin number pin name function 1 vcc the power supply of the ic, and is gene rally connected to opt o-coupler's emitter 2 gnd supply ground 3 out the output pin, connected to the emitter of npn transistor or the source of mosfet pin configuration z package (to-92) out vcc gnd 1 2 3 low power pwm controller for off-line battery charger AP3700E data sheet 3 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 functional block diagram figure 3. functional block diagram of AP3700E vcc out gnd 1 pwm control regulator + _ + oscillator bandgap & bias vref vref vref pwm comparator clamp comparator uvlo comparator short circuit comparator driver slope compensation 2 3 + _ + _ + _ timer low power pwm controller for off-line battery charger AP3700E data sheet 4 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 parameter value unit supply voltage -0.3 to 6.0 v voltage at out (note 2) -0.3 to 40 v output current at out internally limited a power dissipation 0.6 w operating junction temperature 150 o c storage temperature -65 to 150 o c lead temperature (soldering, 10s) 300 o c esd (machine model) 200 v note 1: stresses greater than those li sted under "absolute maximum ratings" may cause perm anent damage to the device. these are stress ratings only, and functi onal operation of the device at these or any other condi tions beyond those indicated under "recommended operating c onditions" is not implied. exposure to "abs olute maximum ratings" for extended periods may affect device reliability. note 2: the breadown voltage. the actual operating vol tage can not be greater th an the value listed here. absolute maximum ratings (note 1) ordering information circuit type e1: lead free ap3700 - tr: ammo blank: tube e: AP3700E package z: to-92 package switching frequency temperature range part number marking id packing type lead free green lead free green to-92 60khz -40 to 85 o c AP3700Ez-e1 AP3700Ez-g1 3700ez-e1 3700ez-g1 bulk AP3700Eztr-e1 AP3700Eztr-g1 3700ez-e1 3700ez-g1 ammo bcd semiconductor's pb-free products, as designated with "e1" suffix in the part number, are rohs compliant. products with "g1" suffix are available in green packages. g1: green low power pwm controller for off-line battery charger AP3700E data sheet 5 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 parameter symbol conditions min typ max unit uvlo section start-up voltage v th (st) 5.5 5.75 5.95 v minimal operating voltage v opr (min) 3.6 3.8 4.0 v standby current section start-up current (note 3) i st v cc =4.5v 0.22 0.45 ma operating current i cc(opr) 0.45 0.7 v cc zener voltage v z i cc =10ma 6 6.3 v dynamic impedance r vcc v cc =3.8 to 4.8v 18 k internal oscillator switching frequency f sw 50 60 75 khz frequency dithering 2 2.5 3 khz temperature stability -40 to 85 o c 510% drive output section out turn-on voltage v out(on) 9.5 12 v out turn-off voltage v out(off) 55.56.5v rise time t r c l =1nf, 15 pull-up 60 ns fall time t f c l =1nf, 15 pull-up 30 maximum duty cycle d max v opr (min) + 0.2v 67 75 84 % minimum duty cycle 3 driver out on-resistance r out i out =0.06a 3 switch off current (out) driver off, v out =10v 20 40 a effective current limit i lim v cc = v opr +0.1v 460 ma out current coefficient g a -0.3 a/v (v cc =4.5v, t j =25 o c, unless otherwise specified.) electrical characteristics note 3: AP3700E is an emitter drive cont roller, the pwm controller will start up only when the voltage on the out pin rises up to its threshould value. low power pwm controller for off-line battery charger AP3700E data sheet 6 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 figure 6. switching frequency vs. ambient temperature typical performance characteristics figure 4. operating current vs. ambient temperature fi gure 5. start-up current vs. ambient temperature -40 -25 -10 5 20 35 50 65 80 95 110 125 200 220 240 260 280 300 start-up current ( a) ambient temperature ( o c) 12345 0 100 200 300 400 500 start-up current ( a) v cc voltage (v) figure 7. start-up current vs. v cc voltage -40-200 20406080100120 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 switching frequency (kh z ) ambient temperature ( o c) -40-20 0 20406080100120 0.46 0.48 0.50 0.52 0.54 0.56 0.58 0.60 operating current(ma) ambient temperature ( o c) low power pwm controller for off-line battery charger AP3700E data sheet 7 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 typical performance ch aracteristics (continued) -40-20 0 20406080100120 400 420 440 460 480 500 520 540 ambient temperature ( o c) current limit(ma) figure 8. current limit vs. ambient temperature low power pwm controller for off-line battery charger AP3700E data sheet 8 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 function description 1. startup circuit figure 3 is the functional block diagram of AP3700E, and there are 3 external pi ns: the vcc pin, the out pin and gnd pin. in typical application shown by figure 10, the vcc pin is used for both bias supply and feedback control. th e out pin directly drives external npn transistor or mosfet, and also provides initial bias power for uvlo comparator. when the ic works in pwm mode, the auxiliary winding will supply the v cc enough operating current. figure 9 shows the start-up sequence of the v cc and the v out . 2. v cc /feedback control an opto-coupler and secondary constant voltage/ current controller consists of voltage feedback network. when load is heavy, the voltage on vcc will be lower to enlarge duty cycle; on the contrary, if load drops, the voltage on vcc will rise to reduce duty cycle. 3. frequency dithering frequency dithering is performed by periodically spreading a single switchi ng frequency into adjacent frequency band, so the peak energy is spread. this technique can improve emi by reducing both quasi- peak and average emi emissions. AP3700E has reference switching frequency of 60 khz, and its frequency deviation is 2.5khz in period of 2ms. figure 10 shows the frequency dithering influ- ence to the waveform . 4. current limit control the AP3700E employs current mode control to improve transient response and voltage stability. in figure 11, the external inductor current through the out pin is converted to a voltage by an internal resistor, and this voltage will participate to control duty cycle and peak inductor current. ch1: v cc ch2: out figure 9. start-up sequence of v cc and v out figure 10. frequency dithering influences the swithcing cycle low power pwm controller for off-line battery charger AP3700E data sheet 9 bcd semiconductor manufacturing limited may 2008 rev. 1. 1 typical application figure 11. 5v/0.8a output for battery charger of mobile phone + 1 5 2 + j1 ac 85-264v bridge d1-d4 1n4007*4 c1 4.7 d8 1n4148 l2 5.5 c9 470 c11 470 5v/0.8a v cc 3 6 4 v out v ctrl v cc i ctrl gnd v sense u3 pc817 + + c2 4.7 + 1 out vcc gnd 2 3 u1 AP3700E u2 ap4313 q1 apt13003 d6 1n4148 r6 200 c4 10 c5 0.47 c6 q r7 200 d7 1n4148 r5 4 7 + c10 47 d9 $ 3 ' rs 0.25 r13 6.2k r15 2k r11 510 r10 22k & |