FA5640

FA5640/41/42 Fuji Switching Power Supply Control IC Green mode Quasi-resonant IC FA5640/41/42 Application Note April 2011 Fuji Electric Co., Ltd. Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 1 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 Caution 1. The contents of this note (Product Specification, Characteristics, Data, Materials, and Structure etc.) were prepared in April 2011. The contents will subject to change without notice due to product specification change or some other reasons. In case of using the products stated in this document, the latest product specification shall be provided and the data shall be checked. 2. The application examples in this note show the typical examples of using Fuji products and this note shall neither assure to enforce the industrial property including some other rights nor grant the license. 3. Fuji Electric Co.,Ltd. is always enhancing the product quality and reliability. However, semiconductor products may get out of order in a certain probability. Measures for ensuring safety, such as redundant design, spreading fire protection design, malfunction protection design shall be taken, so that Fuji Electric semiconductor product may not cause physical injury, property damage by fire and social damage as a result. 4. Products described in this note are manufactured and intended to be used in the following electronic devices and electric devices in which ordinary reliability is required: - Computer - OA equipment - Communication equipment (Pin) - Measuring equipment - Machine tool - Audio Visual equipment - Home appliance - Personal equipment - Industrial robot etc. 5. Customers who are going to use our products in the following high reliable equipments shall contact us surely and obtain our consent in advance. In case when our products are used in the following equipment, suitable measures for keeping safety such as a back-up-system for malfunction of the equipment shall be taken even if Fuji Electric semiconductor products break down: - Transportation equipment (in-vehicle, in-ship etc.) - Communication equipment for trunk line - Traffic signal equipment - Gas leak detector and gas shutoff equipment - Disaster prevention/Security equipment - Various equipment for the safety. 6. Products described in this note shall not be used in the following equipments that require extremely high reliability: - Space equipment - Aircraft equipment - Atomic energy control equipment - Undersea communication equipment - Medical equipment. 7. When reprinting or copying all or a part of this note, our company’s acceptance in writing shall be obtained. 8. If obscure parts are found in the contents of this note, contact Fuji Electric Co.,Ltd. or a sales agent before using our products. Fuji Electric Co.,Ltd. and its sales agents shall not be liable for any damage that is caused by a customer who does not follow the instructions in this cautionary statement. Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 2 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 Contents 1. Overview ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 2. Features ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 3. Outline drawings ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 4. Block diagram ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 5. Functional description of pins ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 6. Rating and Characteristics ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 7. Characteristic curve ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 8. Basic operation ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 9. Description of the function ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 10. How to use pin and advice designing ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ 11. Precautions for pattern design ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 12. Example of application circuit ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・・ ・ ・ ・ ・ ・ 4 4 4 5-6 7 7-12 13-17 18 19-24 25-33 34 35 Caution) ・ The contents of this note will subject to change without notice due to improvement. ・ The application examples or the components constants in this note are shown to help your design, and variation of components and service conditions are not taken into account. In using these components, a design with due consideration for these conditions shall be conducted. Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 3 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 1. Overview FA5640 series are a quasi-resonant type switching power supply control IC with excellent stand-by characteristics. Though it is a small package with 8 pins, it has a lot of functions and enables to decrease external parts. Therefore it is possible to realize a small size and a high cost-performance power supply. 2. Features • A quasi-resonant type switching power supply • A power supply with excellent standby characteristics • Low power consumption achieved by integrated startup circuit • Low current consumption, During operation: 0.85 mA • Control of number of bottom skips by on-off width detection • Burst operation function under light load • Built-in drive circuit directly connectable to a power MOSFET, Output current: 0.5 A (sink)/0.25 A (source) • Built-in overload protection function • Built-in latch protection function based on overvoltage detection on the secondary side • Maximum input threshold voltage of IS pin and threshold voltage of stopping on-pulse are compensated by detecting high-line voltage. • Built-in under voltage lock out function, ON threshold voltage: 14 V and 10 V • Package: SOP-8 Function list by types (Lineup is under review.) Type Overload protection FA5640 FA5641 FA5642 Auto recovery Auto recovery Auto recovery ON threshold voltage 14V 14V 10V Operation compensation Yes Yes No Minimum switching frequency No 25kHz No 25us 7.6us 25us Delay time of restart * See 10. (9) “Other advice on designing” for details of the lineup without the minimum oscillating frequency function. 3. Outline drawings SOP-8 0° ～ 10 ° 3.9±0.2 6.0±0.3 1 PIN MARK 5.0±0.25 1.8 MAX 0. 2± 0 .1 1.27 0.4±0.1 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 4 http://www.fujielectric.co.jp/products/semiconductor/ 0.2 0.65±0.25 FA5640/41/42 4. Block diagram FA5640 ZCD ZCD Bottom detection 7.5V Bottom Skip control Pulse width detection Restart Timer 25μs Off timer (2μs) MP1 Resistance ratio MP1 on/off 91.3%/100% 84.1%/100% 1 shot (290ns) set VH enb Input voltage detection mode select signal VinH Startup management 11V/9V Startup Current 30k UVLO VCC 14V/8V 4.8V 4.8V Reg. Internal supply 24k VinH Reset Max. Ton (24μs) VinH - Disable 4.8V 10μA IS Current comparator FB 1/6 Soft start (1ms) Overload VthFB0 0.45V 0.35V S R2 R1 Q enb Driver OUT + Off timer (4.5μs) Standby Standby detection 0.55V OVP detection OVP1 ZCD VthIS VinH 0.5V 0.45V VthIS at Standby 0.15V VinH 0.10V Timer 200ms 1600ms 6V Latch protection Latch timer 60μs enb 3.5/3.3V OLP protection Reset GND FA5641 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 5 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 FA5642 ZCD ZCD Bottom detection 7.5V Bottom Skip control Pulse width detection Restart Timer 25μs Off timer (2μs) MP1 1 shot (290ns) set VH enb Startup management 11V/9V Startup Current 30k UVLO VCC 10V/8V 4.8V 4.8V Reg. Internal supply Reset 24k Resistance ratio MP1 on/off 91.3%/100% - Disable 4.8V 10μA IS Current comparator FB 1/6 Soft start (1ms) Overload enb 3.5/3.3V S R2 R1 Q enb Driver OUT + VthFB0 0.45V Max. Ton (24μs) Off timer (4.5μs) Standby Standby detection 0.55V OVP detection OVP1 ZCD VthIS VthIS at Standby 0.5V 0.15V 6V Latch protection Timer 200ms 1600ms Latch timer 60μs OLP protection Reset GND Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 6 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 5. Functional description of pins Pin number 1 2 3 4 5 6 7 8 Pin name ZCD FB IS GND OUT VCC (N.C.) VH Pin function Zero current detection, OVP detection Feedback input, OLP detection, Burst operation control Current sense input, Over-current limiter, Standby signal detection Ground Output Power supply, UVLO, VH pin current control （No connection） High voltage input 6. Rating and characteristics * “+” shows sink and “–“ shows source in current prescription. (1) Absolute maximum ratings Item Supply voltage Peak current at OUT pin The voltage at OUT pin Input voltage at FB and IS pin The current at FB and IS pin The current at ZCD pin The voltage at ZCD pin Input voltage at VH pin Power dissipation（Ta=25℃） Operating junction temperature Storage temperature (Note 1) Symbol Vcc IoH IoL Vout Vfb, Vis Ifb, Iis IsoZCD IsiZCD Vzcd VVH Pd Tj Tstg Rating 28 -0.25 +0.5 -0.3 to Vcc+0.3 -0.3 to 5.0 -0.3 to +0.3 -2.0 +3.0 -2 to +8 -0.3 to 500 400 -40 to +125 -40 to +150 Unit V A A V V mA mA mA V V mW ℃ ℃ Note 1) Please consider power supply voltage and load current well and use this IC within maximum power dissipation, operating junction temperature and recommended ambient temperature in operation. The IC may cross over maximum power dissipation at normal operating condition by power supply voltage or load current within peak current absolute maximum rating. * Allowable loss reduction characteristics Pd [mW] 400 Package thermal resistor θj-a= 250℃／W Maximum dissipation 許容損失 0 -40 25 85 125 周囲温度 Ambiance temperature Ta [ ℃] Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 7 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 (2) Recommended operating conditions Item Supply voltage Input voltage at VH pin Capacitance at VCC pin Turn-off resonant period Ambient temperature in operation Symbol Vcc Vvh Cvcc Trs Ta MIN. 11 50 10 － -40 TYP. 15 － 47 2 － MAX. 26 450 220 4 85 Unit V V uF us ℃ (3) DC Electric characteristics (Unless otherwise specified : VCC=15V, VH=141V, ZCD=0V, FB=3V, IS=open, Tj=25℃) Current sense part (IS pin) Item Input bias current Symbol IIS VthIS1 Maximum threshold voltage VthIS2 Voltage gain Minimum ON pulse width Delay to output AvIS Tonmin TpdIS Conditions Vis=0V Vfb=3.2V, Vvh=141V FA5640,FA5641 Vfb=3.2V, Vvh=324V ΔVfb/ΔVis Vfb=3.2V,Vis=1.5V IS input: 0V to 1.5V (Pulse signal) MIN. -15 0.47 0.42 5 .4 205 30 TYP. -10 0.5 0.45 6 .0 290 70 MAX. -5 0.53 0.48 6 .6 375 150 Unit uA V V V/V ns ns Feedback part (FB pin) Item Symbol VthFB01 Input threshold voltage of stopping on-pulse VthFB02 Conditions DUTY=0% Vvh=141V FA5640,FA5641 DUTY=0% Vvh=324V Rfb11 Rfb12 FB pin input resistance Rfb21 Rfb22 FB pin source current Ifb0 ⊿Rfb1 FB pin input resistance ratio ⊿Rfb2 Vfb=1V to 2V Vvh=141V Vfb=1V to 2V Vvh=324V Vfb=0V to 0.3V Vvh=141V Vfb=0V to 0.3V Vvh=324V Vfb=0V ⊿Rfb1=Rfb11/Rfb21 Vvh=141V FA5640,FA5641 ⊿Rfb2=Rfb12/Rfb22 Vvh=324V 82.1 84.1 86.1 % 1 4 .2 1 3 .0 1 5 .5 1 5 .5 -260 89.3 1 8 .9 1 7 .4 2 0 .7 2 0 .7 -200 91.3 2 3 .6 2 1 .7 2 5 .9 2 5 .9 -160 93.3 kΩ kΩ kΩ kΩ uA % 315 350 385 mV MIN. 405 TYP. 450 MAX. 495 Unit mV Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 8 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 Zero current detection part (ZCD pin) Item Input threshold voltage Vthzcd2 Hysteresis Minimum detectable pulse width Vhyzcd Tzcdmin Vih Input clamp voltage Vil ZCD pin internal ｒesistance ZCD pin propagation delay time Rzcd Tzcd Tb12 Tb21 The ON/OFF pulse width of changed number of bottom at turn-on Tb32 Tb34 Tb43 Tb23 Vzcd increasing Vthzcd2-Vthzcd1 ZCD input pulse Vpulse=1V to 0V f=100kHz Izcd=+3mA （high state） Izcd=-2mA （low state） Vzcd=1V to 5V ZCD pulse:1V to 0V, OUT: turn-on Changed 1st bottom to 2nd bottom Changed 2nd bottom to 1st bottom Changed 2nd bottom to 3rd bottom Changed 3rd bottom to 2nd bottom Changed 3rd bottom to 4th bottom Changed 4th bottom to 3rd bottom FA5640,FA5642 OUT=low, Vzcd=0V FA5641 OUT=low, Vzcd=0V 100 30 300 6.5 -1.0 2 2 .5 50 8.1 12.6 7.2 10.5 6.3 9.0 20 6.7 150 90 － 7.5 -0.8 30 150 9.0 14.0 8.0 11.67 7.0 10.0 25 7.6 220 150 － 9.5 -0.4 3 7 .5 300 9.9 15.4 8.8 12.84 7.7 11.0 30 8.5 mV mV ns V V kΩ ns us us us us us us us us Symbol Vthzcd1 Conditions Vzcd decreasing MIN. 40 TYP. 60 MAX. 80 Unit mV Timeout after last ZCD trigger Trestart Over-voltage protection part (ZCD pin) Item Over-voltage threshold voltage Over-voltage detection timing Delay time to latch-off Symbol Vovp Tlat1 Tlaｔ2 Conditions Vzcd is increased, and timer latch function is operated Delay from turn-off Delay from upper the Vovp voltage 3.5 40 4.5 60 5.5 80 us us 5.7 6.0 6.3 V MIN. TYP. MAX. Unit Overload protection part (FB pin) Item Symbol Volp1 OLP threshold voltage Volp2 Hysteresis Fault time duration Auto recovery mode latch-off time duration Hysolp Tolp Toff Vfb decreasing Volp1-Volp2 Delay from Vfb>Volp1 The OFF time only by internal signal 3.0 0.1 140 980 3.3 0.2 200 1400 3.6 0.3 260 1820 V V ms ms Conditions Vfb increasing MIN. 3.3 TYP. 3.5 MAX. 3.8 Unit V Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 9 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 Soft start part Item Soft-start time Symbol Tsoft Conditions at start-up only MIN. 0.7 TYP. 1.0 MAX. 1.3 Unit ms Standby-mode function (IS pin) Item Stand-by detection threshold voltage at IS pin Stand-by detection timing Symbol VISstb Conditions Read timing is turn-off after Tstb. Delay from turn-off MIN. 0.5 TYP. 0.55 MAX. 0.6 Unit V Tstb 1.5 2.0 2.5 us VthISsｔ1 Maximum threshold voltage at stand-by VthISsｔ2 Vfb=3.2V Vvh=141V FA5640,FA5641 Vfb=3.2V Vvh=324V 0.12 0.15 0.18 V 0.07 0.10 0.13 V Other protection part Item Maximum on pulse width Symbol Tonmax Conditions Vis=0V, Vis=2V Vzcd=0V FA5641 Vis=0V,Vfb=3.2V MIN. 20 TYP. 24 MAX. 28 Unit us Minimum switching frequency Fmin 20.8 25 30.3 kHz Drive Output part (OUT pin) Item OUT Low voltage OUT High voltage Rise time Fall time Symbol VOL VOH tr tf Condition IOL=100mA Vcc=15V IOH=-100mA, Vcc=15V Vcc=15V, CL=1nF Tj=25℃ Vcc=15V, CL=1nF Tj=25℃ MIN. 0.5 12 20 12.5 TYP. 1.0 13.2 40 25 MAX. 2.0 14.5 80 60 Unit V V ns ns Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 10 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 High voltage input part (VH pin) Item Symbol IVHrun Supply Current of VH pin IVH1 IVH0 Ipre1 Charge current for VCC pin Ipre2 Condition Vvh=400V, Vcc > Vstoff Vvh=100V, VCC=6.5V Vvh=100V, VCC=0V Vcc=8V, Vvh=100V Vcc=13V, Vvh=100V At UVLO mode FA5640,FA5641 Vcc>Vstoff VHdcH The threshold voltage to change input voltage mode setting at DC input VHdcL VH pin input voltage is increasing voltage. FA5640,FA5641 Vcc>Vstoff VH pin input voltage is decreasing voltage. Hysteresis voltage width at DC input only The threshold voltage to change input voltage mode setting at AC input (AC RMS conversion voltage) Delay time of changing input voltage mode setting VHac FA5640,FA5641 VHdcHys VH: DC voltage input VHdcH-VHdcL FA5640,FA5641 Vcc>Vstoff VH pin input Voltage is half-wave rectified AC waveform. FA5640,FA5641 TpdVH Vcc>Vstoff (VCC charge off) 11 30 70 ms 141 160 177 Vrms 8 14 18 V by DC 190 212 235 V by DC 200 226 250 V MIN. 10 4.0 0.49 -10 -9 TYP. 30 8.0 0.7 -7.4 -5.7 MAX. 60 10.5 1.4 -3.7 -3 Unit uA mA mA mA mA Low voltage malfunction protection circuit (UVLO) part (VCC pin) Item Symbol Condition FA5640,FA5641 Start-up threshold voltage VCCon Vcc Increasing FA5642 Vcc Increasing Shutdown threshold voltage Hysteresis (UVLO) Istart-up off voltage Istart-up restart voltage Hysteresis width at Istart-up Vstoff Vstrst VCCoff Vhys1 Vcc decreasing FA5640,FA5641 VCCon-VCCoff FA5642 VCCon-VCCoff Vcc Increasing Vcc decreasing MIN. 12.5 9 7 5 1.5 9.5 8 TYP. 14 10 8 6 2 11 9 MAX. 15.5 11 9 7 2.5 12.5 10 Unit V V V V V V V Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 11 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 Current consumption (VCC pin) Item Symbol ICCop1 Operating-state supply current ICCop2 Condition Vfb=2V, IS=open Vzcd=0V OUT= no load Duty cycle=0%, Vfb=0V, IS=open Vzcd=0V FB=open Latch mode supply current ICClat Vcc=11V At latch-mode *1 : Regarding to these items, guaranteed by design. The column showing ‘-‘ has no specified value. 100 200 350 uA 0.6 0.8 1.1 mA 0.7 0.85 1.5 mA MIN. TYP. MAX. Unit Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 12 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 7. Characteristic curve ・Unless otherwise specified : Tj=25℃, VCC=15V ・“+” shows sink and “–“ shows source in current prescription. ・Data listed here shows the typical characteristics of an IC and does not guarantee the characteristics. 0.6 IS pin maximum threshold voltage (VthIS1) vs. FB pin voltage (VFB) 0.5 0.4 VthIS1 [V] 0.3 0.2 0.1 0 0 1 2 VFB [V] 3 4 0.53 IS pin maximum threshold voltage (VthIS1) vs. Junction temperature (Tj) 0.48 IS pin maximum threshold voltage (VthIS2) vs. Junction temperature (Tj) 0.52 0.47 0.51 VthIS1 [V] VthIS2 [V] -25 0 25 50 Tj [℃] FB pin input threshold voltage switching off (VthFB01) vs. Junction temperature(Tj) 0.46 0.5 0.45 0.49 0.44 0.48 0.43 0.47 -50 75 100 125 150 0.42 -50 -25 0 25 50 Tj [℃] 75 100 125 150 500 490 FB pin input threshold voltage switching off (VthFB02) vs. Junction temperature (Tj) 385 375 480 470 VthFB01 [mV] 460 450 440 430 420 410 400 -50 -25 0 25 50 Tj [℃] 75 100 125 150 325 315 -50 -25 0 25 50 Tj [℃] 75 100 125 150 VthFB02 [mV] 365 355 345 335 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 13 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 ZCD pin input threshold voltage (Vthzcd1) vs. Junction temperature (Tj) 80 220 ZCD pin input threshold voltage (Vthzcd2) vs. Junction temperature (Tj) 70 200 Vthzcd1 [mV] Vthzcd2 [mV] -25 0 25 50 Tj [℃] 75 100 125 150 60 180 50 160 40 140 30 120 20 -50 100 -50 -25 0 25 50 Tj [℃] 75 100 125 150 37.5 ZCD pin internal resistance (Rzcd) vs. Junction temperature (Tj) 6.3 ZCD pin OVP threshold voltage (Vovp) vs. Junction temperature (Tj) 35 6.2 32.5 Rzcd [kΩ] Vovp [V] -50 -25 0 25 50 Tj [℃] 75 100 125 150 6.1 30 6 27.5 5.9 25 5.8 22.5 5.7 -50 -25 0 25 50 Tj [℃] 75 100 125 150 260 Delay time to OLP (Tolp) vs. Junction temperature (Tj) 1800 1700 1600 OLP off time (Toff) vs. Junction temperature (Tj) 240 220 Tolp [ms] Toff [ms] 1500 1400 1300 1200 1100 200 180 160 1000 140 -50 -25 0 25 50 Tj [℃] 75 100 125 150 900 -50 -25 0 25 50 Tj [℃] 75 100 125 150 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 14 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 IS pin maximum threshold voltage at standby (VthISst1) vs. Junction temperature (Tj) IS pin maximum threshold voltage at standby (VthISst2) vs. Junction temperature (Tj) 0.2 0.18 0.16 0.14 VthISst2 [V] 0.12 0.1 0.08 0.06 0.04 0.02 0 0.2 0.18 0.16 0.14 VthISst1 [V] 0.12 0.1 0.08 0.06 0.04 0.02 0 -50 -25 0 25 50 Tj [℃] 75 100 125 150 -50 -25 0 25 50 Tj [℃] 75 100 125 150 60 55 50 45 IVHrun [uA] Input current of VH pin (IVHrun) vs. Junction temperature (Tj) 10 9 8 7 IVH [mA] 6 5 4 3 2 1 0 Input current of VH pin (IVH) VH pin voltage (VVH) 40 35 30 25 20 15 10 -50 -25 0 25 50 Tj [℃] 75 100 125 150 0 100 200 300 VVH [V] 400 500 11 10 Input current of VH pin (IVH1) vs. Junction temperature (Tj) 1.4 1.3 1.2 Input current of VH pin (IVH0) vs. Junction temperature (Tj) 9 IVH1 [mA] 8 7 6 5 4 -50 IVH0 [mA] -25 0 25 50 Tj [℃] 75 100 125 150 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 -50 -25 0 25 50 Tj [℃] 75 100 125 150 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 15 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 -3 -4 Charge current for VCC pin (Ipre1) vs. Junction temperature (Tj) Startup threshold voltage (VCCon) vs. Junction temperature (Tj) 15.5 15 -5 14.5 Ipre1 [mA] -6 -7 -8 -9 -10 -50 -25 0 25 50 Tj [℃] 75 100 125 150 VCCon [V] 14 13.5 13 12.5 -50 -25 0 25 50 Tj [℃] 75 100 125 150 9 8.8 8.6 8.4 VCCoff [V] Shutdown threshold voltage (VCCoff) vs. Junction temperature (Tj) 10 9.8 9.6 9.4 Vstrst [V] 9.2 9 8.8 8.6 8.4 8.2 Startup device ON voltage (Vstrst) vs. Junction temperature (Tj) 8.2 8 7.8 7.6 7.4 7.2 7 -50 -25 0 25 50 Tj [℃] 75 100 125 150 8 -50 -25 0 25 50 Tj [℃] 75 100 125 150 12.5 Startup device OFF voltage (Vstoff) vs. Junction temperature (Tj) 1.6 1.4 1.2 Operating-state supply current (ICCop1) vs. VCC pin voltage (VCC) 12 11.5 ICCop1 [mA] -50 -25 0 25 50 Tj [℃] 75 100 125 150 Vstoff [V] 1 0.8 0.6 0.4 11 10.5 10 0.2 0 0 5 10 15 VCC [V] 20 25 30 9.5 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 16 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 1.5 1.4 1.3 1.2 1.1 1 ICCop1 [mA] Operating-state supply current (ICCop1) vs. Junction temperature (Tj) 350 Latch mode supply current (ICClat) vs. Junction temperature (Tj) 300 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -50 ICClat [uA] -25 0 25 50 Tj [℃] 75 100 125 150 0.9 0.8 250 200 150 100 -50 -25 0 25 50 Tj [℃] 75 100 125 150 Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 17 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 8. Basic operation(The values in the following description are typical values unless otherwise specified.) The basic operation of the power supply using IC is not switching operation with fixed frequency using an oscillator but switching with self-excited oscillation. This is shown in Fig.1 Schematic circuit diagram and Fig.2 Waveform in the basic operation. t1 to t2 Q1 turns ON and then Q1 drain current Id (current of primary windings of T1) begins to rise from zero. Q1 current is converted into the voltage by Rs and is input into IS pin. t2 When the current of Q1 get to the reference voltage of the current comparator that is fixed by the voltage of FB pin, a reset signal is input into RS flip-flop and Q1 turns OFF. t2 to t3 When Q1 turns OFF, then the windings voltage of the transformer turns over and the current IF is provided from the transformer into the secondary side through D1. t3 to t4 When the current from the transformer into the secondary side stops and the current of D1 gets to zero, the voltage of Q1 turns down rapidly due to the resonance of the transformer inductance and the capacitor Cd. At the same time the transformer auxiliary windings voltage Vsub also drops rapidly. ZCD pin receives this auxiliary windings voltage but then it has a little delay time because of CR circuit composed with RZCD and CZCD on the way. t4 If ZCD pin voltage turns down lower than the threshold voltage 50mV of Bottom detection, a set signal is input into R-S flip-flop and Q1 turns ON again. If the delay time of CR circuit placed between the auxiliary windings and ZCD pin is adjusted properly, Q1 voltage can be turned on at the bottom. This operation makes the switching loss of TURN ON to the minimum. (Return to t1) Subsequently repeat from t1 to t4 and continue switching. IF D1 t1 t2 t3 t4 Current comparator out put (reset) 1 shot out put (Valley signal、set) ZCD Pin 60mV Vsub D1 IF Q1 Id Q1 Vds OUT (Q1 gate) Fig.2 Waveform in basic operation OUT 5 1 shot (290ns) Q1 R1 Cd Rs C1 Vds Bottom Skip control Set Q S R Rset Bottom detection ZCD 1 Driver Current Comparator 3 Level shift 2 Vsub IS FB Fig.1 Schematic circuit diagram in basic operation Fuji Electric Co., Ltd. AN-064E Rev.1.1 April 2011 18 http://www.fujielectric.co.jp/products/semiconductor/ FA5640/41/42 9. Description of the function (The values in the following description are typical values unless otherwise specified.) (1) Steady-state operation, bottom-skip operation, and burst operation • Steady-state operation, bottom-skip operation The ON/OFF cycle, which is from turn-on of the driver signal to the end of fly-back voltage, is detected, and bottom-skip operations are performed at the time detected. Since the relation between the ON/OFF width and the number of times of bottom skip operations is exhibited in the hysteresis as shown in Fig. 4, waveform fluctuations can be prevented and transformer audible noise can be decreased. Fig. 5 shows the change image of the switching frequency to the output electric power. Fig. 6 shows the change image of the ON/OFF width. Load decrease Vds 1st 2nd 3rd 4th ON-OFF width On/Off pulse width T>9us 9us>T>8us 8us>T>7us T