 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| FAN6754 -- Highly Integrated Green-Mode PWM Controller September 2009 FAN6754 Highly Integrated Green-Mode PWM Controller Brownout and Constant Power Limited by HV Pin Features High-Voltage Startup AC Input Brownout Protection with Hysteresis Low Operating Current: 1.7mA Linearly Decreasing PWM Frequency to 22KHz Frequency Hopping to Reduce EMI Emission Fixed PWM Frequency: 65KHz Peak-Current-Mode Control Cycle-by-Cycle Current Limiting Leading-Edge Blanking (LEB) Internal Open-Loop Protection GATE Output Maximum Voltage Clamp: 13V VDD Under-Voltage Lockout (UVLO) VDD Over-Voltage Protection (OVP) Programmable Over-Temperature Protection (OTP) Internal Latch Circuit (OVP, OTP) Open-Loop Protection (OLP); Restart for MR, Latch for ML Built-in 8ms Soft-Start Function Constant Power Limit (Full AC Input Range) Internal OTP Sensor with Hysteresis Description The highly integrated FAN6754 PWM controller provides several features to enhance the performance of flyback converters. To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to continuously decrease the switching frequency under light-load conditions. Under zero-load and very light-load conditions, FAN6754 saves PWM pulses by entering deep burst mode. This burst mode function enables the power supply to meet international power conservation requirements. FAN6754 integrates a frequency-hopping function internally to reduce EMI emission of a power supply with minimum line filters. Built-in synchronized slope compensation is accomplished by, proprietary internal compensation for constant output power limit over universal AC input range. Also, the gate output is clamped at 13V to protect the external MOSFET from over-voltage damage. Other protection functions include AC input brownout protection with hysteresis and VDD over-voltage protection. For over-temperature protection, an external NTC thermistor can be applied to sense the external switcher's temperature. When VDD OVP or OTP are activated, an internal latch circuit is used to latch-off the controller. The latch mode is reset when the VDD supply is removed. FAN6754 is available in an 8-pin SOP package. Applications General-purpose switch-mode power supplies and flyback power converters, including: Power Adapters Ordering Information Part Number FAN6754MRMY FAN6754MLMY Operating Temperature Range -40 to +105C -40 to +105C Eco Status RoHS RoHS Package 8-Pin, Small Outline Package (SOP) 8-Pin, Small Outline Package (SOP) Packing Method Tape & Reel Tape & Reel For Fairchild's definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com FAN6754 -- Highly Integrated Green-Mode PWM Controller Application Diagram Figure 1. Typical Application Internal Block Diagram HV 4 Line Voltage Sample Circuit OVP OTP OLP Latch Protection Soft Driver NC 3 I HV HV Startup Brownout Protection Current Limit Compensation 8 GATE OSC VDD 7 UVLO Internal BIAS S R Q Soft-Start Comparator 17.5V/10V Green Mode Current-Limit Comparator Soft-Start Circuit Blanking 6 SENSE VLimit Debounce OVP PWM Comparator 5.2V VDD-OVP IRT Slope Compensation 3R RT 5 1.05V tD-OTP1 Counter OTP OLP OLP Delay R 2 FB tD-OTP2 Counter 0.7V OLP Comparator 4.6V 1 GND Figure 2. Functional Block Diagram (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 2 FAN6754 -- Highly Integrated Green-Mode PWM Controller Marking Information F - Fairchild Logo Z - Plant Code X - 1-Digit Year Code Y - 1-Digit Week Code TT - 2-Digit Die Run Code T - Package Type (M=SOP) P - Y: Package (Green) M - Manufacture Flow Code ZXYTT 6754MR TPM ZXYTT 6754ML TPM Figure 3. Top Mark Pin Configuration SOP-8 GND FB NC HV 1 2 3 4 8 7 6 5 GATE VDD SENSE RT Figure 4. Pin Configuration (Top View) Pin Definitions Pin # 1 Name GND Description Ground. This pin is used for the ground potential of all the pins. A 0.1F decoupling capacitor placed between VDD and GND is recommended. Feedback. The output voltage feedback information from the external compensation circuit is fed into this pin. The PWM duty cycle is determined by this pin and the current-sense signal from Pin 6. FAN6754 performs an open-loop protection (OLP); if the FB voltage is higher than a threshold voltage (around 4.6V) for more than 55ms, the controller latches off the PWM. No Connection. High Voltage Startup. This pin is connected to the line input via a 1N4007 and 200k resistors to achieve brownout and high/low line compensation. Once the voltage on the HV pin is lower than the brownout voltage, PWM output turns off. High/low line compensation dominates the cycle-by-cycle current limiting to achieve constant output power limiting with universal input. Over-Temperature Protection. An external NTC thermistor is connected from this pin to GND. The impedance of the NTC decreases at high temperatures. Once the voltage on the RT pin drops below the threshold voltage, the controller latches off the PWM. Current Sense. This pin is used to sense the MOSFET current for the current-mode PWM and current limiting. Supply Voltage. IC operating current and MOSFET driving current are supplied using this pin. This pin is connected to an external bulk capacitor of typically 47F. The threshold voltage for turn-on and turn-off is 16.5V and 9V, respectively. The operating current is lower than 2mA. Gate Drive Output. The totem-pole output driver for the power MOSFET. It is internally clamped below 13V. 2 3 4 FB NC HV 5 6 7 8 RT SENSE VDD GATE (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 3 FAN6754 -- Highly Integrated Green-Mode PWM Controller Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol VVDD VFB VSENSE VRT VHV PD JA TJ TSTG TL ESD DC Supply Voltage (1, 2) Parameter FB Pin Input Voltage SENSE Pin Input Voltage RT Pin Input Voltage HV Pin Input Voltage Power Dissipation (TA50C) Thermal Resistance (Junction-to-Air) Operating Junction Temperature Storage Temperature Range Lead Temperature (Wave Soldering or IR, 10 Seconds) Human Body Model, JEDEC:JESD22-A114 Charged Device Model, JEDEC:JESD22-C101 Min. -0.3 -0.3 -0.3 Max. 30 7.0 7.0 7.0 500 400 141 Unit V V V V V mW C/W C C C kV V -40 -55 +125 +150 +260 4.5 1500 Notes: 1. All voltage values, except differential voltages, are given with respect to the network ground terminal. 2. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol TA RHV Parameter Operating Ambient Temperature HV Startup Resistor Conditions Min. -40 150 Typ. 200 Max. +105 Unit C k (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 4 FAN6754 -- Highly Integrated Green-Mode PWM Controller Electrical Characteristics VDD=15V and TA=25C unless otherwise noted. Symbol VDD Section VOP VDD-ON VDD-OFF VDD-OLP VDD-LH VDD-AC IDD-ST IDD-OP1 IDD-OP2 ILH IDD-OLP VDD-OVP tD-VDDOVP Parameter Continuously Operating Voltage Start Threshold Voltage Minimum Operating Voltage IDD-OLP Off Voltage Threshold Voltage on VDD Pin for Latch-Off Release Voltage Threshold Voltage on VDD Pin for Disable AC recovery to avoid Startup Failed Startup Current Operating Supply Current when PWM operation Operating Supply Current when Gate Stop Operating Current at PWM-Off Phase Under Latch-Off Conduction Conditions Min. Typ. Max. 24 Units V V V V V V A mA mA A A V s 15.5 8 5.5 3.5 VDD-OFF +2.5 VDD-ON - 0.16V VDD=20V, FB=3V Gate Open VDD=20V, FB=3V VDD=5V 30 180 24 75 16.5 9 6.5 4.0 VDD-OFF +3.0 17.5 10 7.5 4.5 VDD-OFF +3.5 30 1.7 1.2 60 210 25 165 2.0 1.5 90 240 26 255 Internal Sink Current under LatchVDD-OLP+0.1V Off Conduction VDD Over-Voltage Protection VDD Over-Voltage Protection Debounce Time HV Section IHV VAC-OFF Supply Current from HV Pin Brownout Threshold VAC=90V(VDC=120V), VDD=0V DC Source Series R=200k to HV Pin See Equation 1 DC Source Series R=200k to HV Pin See Equation 2 DC Source Series R=200k to HV Pin FB > VFB-N FB < VFB-G 1.50 92 2.75 102 4.00 112 mA V VAC-ON VAC tS-CYCLE tH-TIME tD-AC-OFF Brownin Threshold VAC-ON - VAC-OFF (Eq.2) 104 6 114 12 220 650 20 124 18 V V s s Line Voltage Sample Cycle Line Voltage Hold Period PWM Turn-off Debounce Time FB > VFB-N FB < VFB-G 65 180 75 235 85 290 ms ms Continued on the following page... (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 5 FAN6754 -- Highly Integrated Green-Mode PWM Controller Typical Performance Characteristics Figure 5. Brownout Circuit Figure 6. Brownout Behavior Figure 7. VDD-AC and AC Recovery (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 6 FAN6754 -- Highly Integrated Green-Mode PWM Controller Electrical Characteristics (Continued) VDD=15V and TA=25C unless otherwise noted. Symbol Oscillator Section fOSC tHOP fOSC-G fDV fDT Parameter Conditions Center Frequency Hopping Range FB > VFB-N FB=VFB-G VDD=11V to 22V TA=-40 to +105C Min. 61 3.7 3.9 10.2 19 Typ. 65 4.2 4.4 11.5 22 Max. Units 69 4.7 4.9 12.8 25 5 5 Frequency in Normal Mode Hopping Period Green-Mode Frequency Frequency Variation vs. VDD Deviation Frequency Variation vs. Temperature Deviation Input Voltage to Current-Sense Attenuation Input Impedance Output High Voltage FB Open-Loop Trigger Level Delay Time of FB Pin Open-Loop Protection Green-Mode Entry FB Voltage KHz ms ms KHz % % Feedback Input Section AV ZFB VFB-OPEN VFB-OLP tD-OLP VFB-N 1/4.5 13.5 FB Pin Open 4.8 4.3 50 Pin, FB Voltage (FB =VFB-N) Hopping Range VFB-G VFB-ZDCR VFB-ZDC Green-Mode Ending FB Voltage FB Threshold Voltage for Zero-Duty Recovery FB Threshold Voltage for Zero-Duty Pin, FB Voltage (FB =VFB-G) Hopping Range 2.6 3.7 2.1 1.27 1.9 1.8 1/4.0 15.5 5.0 4.6 55 2.8 4.2 2.3 1.45 2.1 2.0 1/3.5 17.5 5.2 4.9 60 3.0 4.7 2.5 1.62 2.3 2.2 V/V k V V ms V kHz V kHz V V Continued on the following page... PWM Frequency fOSC fOSC-G VFB-ZDC VFB-ZDCR VFB-G VFB-N VFB Figure 8. VFB vs. PWM Frequency (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 7 FAN6754 -- Highly Integrated Green-Mode PWM Controller Electrical Characteristics (Continued) VDD=15V and TA=25C unless otherwise noted. Symbol Feedback Input Section Current-Sense Section tPD tLEB Vlimit-L Vlimit-H tSS DCYMAX VGATE-L VGATE-H tr tf VGATECLAMP Parameter Conditions Min. Typ. Max. Units Delay to Output Leading Edge Blanking Time Current Limit at Low Line (VAC=86V) Current Limit tat High Line (VAC=259V) Period During Soft-Start Time Maximum Duty Cycle Gate Low Voltage Gate High Voltage Gate Rising Time Gate Falling Time Gate Output Clamping Voltage VDD=15V, IO=50mA VDD=12V, IO=50mA VDD=15V, CL=1nF VDD=15V, CL=1nF VDD=22V 9 8 VDC=122V, Series R=200k to HV VDC=366V, Series R=200k to HV Startup Time 230 0.43 0.36 7 86 100 280 0.46 0.39 8 89 250 330 0.49 0.42 9 92 1.5 ns ns V V ms % V V ns ns GATE Section 100 50 13 17 V RT Section RRT VRTTH1 VRTTH2 Internal Resistor from RT Pin Over-Temperature Protection Threshold Voltage 0.7V VRT 1.05V, after 12ms Latch Off VRT 0.7V, After 100s Latch Off VRTTH2 VRT VRTTH1 FB > VFB-N Over-Temperature Latch-Off Debounce tD-OTP2 VRTTH2 VRT VRTTH1 FB < VFB-G VRT< VRTTH2 FB > VFB-N VRT< VRTTH2 FB < VFB-G Protection Junction Temperature Restart Junction Temperature 9.50 1.000 0.65 14 40 110 320 10.55 1.035 0.70 16 51 185 605 11.60 1.070 0.75 18 ms 62 260 s 890 K V V tD-OTP1 Over-Temperature Protection Section (OTP) TOTP TRestart +135 TOTP-25 C C (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 8 FAN6754 -- Highly Integrated Green-Mode PWM Controller Typical Performance Characteristics (Continued) 45 40 35 4 3.5 3 IDD-ST (A) 30 25 20 15 10 5 -40 -25 -10 5 20 35 50 65 80 95 110 125 IDD-OP1 (mA) 2.5 2 1.5 1 0.5 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) Temperature ( ) Figure 9. Startup Current (IDD-ST) vs. Temperature 18 17.5 17 16.5 16 15.5 15 -40 -25 -10 5 20 35 50 65 80 95 110 125 Figure 10. Operation Supply Current (IDD-OP1) vs. Temperature 11 10.5 10 VDD-OFF (V) VDD-ON (V) 9.5 9 8.5 8 7.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) Temperature ( ) Figure 11. Start Threshold Voltage (VDD-ON) vs. Temperature 7 6 5 4 3 2 1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 Figure 12. Minimum Operating Voltage (VDD-OFF) vs. Temperature 3.5 3 2.5 2 1.5 1 0.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) IHV-LC (uA) IHV (mA) Temperature ( ) Figure 13. Supply Current Drawn from HV Pin (IHV) vs. Temperature 70 69 68 Figure 14. HV Pin Leakage Current After Startup (IHV-LC) vs. Temperature 100 66 65 64 63 62 61 60 -40 -25 -10 5 20 35 50 65 80 95 110 125 DCYMAX (%) 67 95 fOSC (KHz) 90 85 80 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) Temperature ( ) Figure 15. Frequency in Normal Mode (fOSC) vs. Temperature (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 Figure 16. Maximum Duty Cycle (DCYMAX) vs. Temperature www.fairchildsemi.com 9 FAN6754 -- Highly Integrated Green-Mode PWM Controller Typical Performance Characteristics (Continued) 6 5.5 5 4.5 4 3.5 3 -40 -25 -10 5 20 35 50 65 80 95 110 125 70 65 60 55 50 45 40 -40 -25 -10 5 20 35 50 65 80 95 110 125 VFB-OLP (V) Temperature ( ) tD-OLP (ms) Temperature ( ) Figure 17. FB Open-Loop Trigger Level (VFB-OLP) vs. Temperature 28 27 26 Figure 18. Delay Time of FB Pin Open-Loop Protection (tD-OLP) vs. Temperature 120 110 VDD-OVP (V) 24 23 22 21 20 -40 -25 -10 5 20 35 50 65 80 95 110 125 IRT (uA) 25 100 90 80 70 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) Temperature ( ) Figure 19. VDD Over-Voltage Protection (VDD-OVP) vs. Temperature 1.2 Figure 20. Output Current from RT Pin (IRT) vs. Temperature 0.9 1.1 0.8 VRTTH1 (V) 1 VRTTH2 (V) -30 -15 0 25 50 75 85 100 125 0.7 0.9 0.6 0.8 -40 0.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature () Temperature ( ) Figure 21. Over-Temperature Protection Threshold Voltage (VRTTH1) vs. Temperature 120 Figure 22. Over-Temperature Protection Threshold Voltage (VRTTH2) vs. Temperature 120 115 115 110 VAC-OFF (V) -40 -25 -10 5 20 35 50 65 80 95 110 125 VAC-ON (V) 110 105 100 95 105 100 90 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature ( ) Temperature ( ) Figure 23. Brownin (VAC-ON) vs. Temperature (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 10 Figure 24. Brownout (VAC-OFF) vs. Temperature www.fairchildsemi.com FAN6754 -- Highly Integrated Green-Mode PWM Controller Functional Description Startup Current For startup, the HV pin is connected to the line input through an external diode and resistor; RHV, (1N4007 / 150K recommended). Peak startup current drawn from the HV pin is (VAC x 2 ) / RHV and charges the hold-up capacitor through the diode and resistor. When the VDD capacitor level reaches VDD-ON, the startup current switches off. At this moment, the VDD capacitor only supplies the FAN6754 to keep the VDD until the auxiliary winding of the main transformer provides the operating current. Gate Output / Soft Driving The BiCMOS output stage is a fast totem-pole gate driver. Cross conduction has been avoided to minimize heat dissipation, increase efficiency, and enhance reliability. The output driver is clamped by an internal 13V Zener diode to protect power MOSFET transistors against undesirable gate over voltage. A soft driving waveform is implemented to minimize EMI. Soft-Start For many applications, it is necessary to minimize the inrush current at startup. The built-in 8ms soft-start circuit significantly reduces the startup current spike and output voltage overshoot. Operating Current Operating current is around 1.7mA. The low operating current enables better efficiency and reduces the requirement of VDD hold-up capacitance. Slope Compensation The sensed voltage across the current-sense resistor is used for peak-current-mode control and cycle-by-cycle current limiting. Built-in slope compensation improves stability and prevents sub-harmonic oscillation. FAN6754 inserts a synchronized, positive-going, ramp at every switching cycle. Green-Mode Operation The proprietary green-mode function provides off-time modulation to reduce the switching frequency in lightload and no-load conditions. VFB, which is derived from the voltage feedback loop, is taken as the reference. Once VFB is lower than the threshold voltage (VFB-N), switching frequency is continuously decreased to the minimum green-mode frequency of around 22KHz. Constant Output Power Limit When the SENSE voltage across sense resistor RSENSE reaches the threshold voltage, around 0.46V for low-line condition, the output GATE drive is turned off after a small delay, tPD. This delay introduces an additional current proportional to tPD * VIN / LP. Since the delay is nearly constant regardless of the input voltage VIN, higher input voltage results in a larger additional current and the output power limit is higher than under low input line voltage. To compensate this variation for a wide AC input range, a power-limiter is controlled by the HV pin to solve the unequal power-limit problem. The power limiter is fed to the inverting input of the current limiting comparator. This results in a lower current limit at highline inputs than at low-line inputs. Current Sensing / PWM Current Limiting Peak-current-mode control is utilized to regulate output voltage and provide pulse-by-pulse current limiting. The switch current is detected by a sense resistor into the SENSE pin. The PWM duty cycle is determined by this current-sense signal and VFB, the feedback voltage. When the voltage on the SENSE pin reaches around VCOMP = (VFB-0.6)/4, the switch cycle is terminated immediately. VCOMP is internally clamped to a variable voltage around 0.46V for low-line output power limit. Leading-Edge Blanking (LEB) Each time the power MOSFET is switched on, a turn-on spike occurs on the sense-resistor. To avoid premature termination of the switching pulse, a leading-edge blanking time is built in. During this blanking period, the current-limit comparator is disabled and cannot switch off the gate driver. Brownout and Constant Power Limited by HV Pin Unlike previous PWM controllers, FAN6754's HV pin can also detect the AC line voltage brownout function and set the current limit level. Using a fast diode and startup resistor to sample the AC line voltage, the peak value refreshes and is stored in a register at each sampling cycle. When internal update time is met, this peak value is used for brownout and current-limit level judgment. Equation 1 and 2 calculate the level of brownin or brownout converted to RMS value. For power saving, FAN6754 enlarges the sampling cycle to lower the power loss from HV sampling at light load condition. (RHV + 1.6) (1) )/ 2 1.6 (R + 1.6) VAC - OFF (RMS) = ( 0.81V x HV ) / 2 ; the unit of RHV is k (2) 1.6 VAC - ON (RMS) = ( 0.9V x Under-Voltage Lockout (UVLO) The turn-on and turn-off thresholds are fixed internally at 16.5V and 9V, respectively. During startup, the holdup capacitor must be charged to 16.5V through the startup resistor to enable the IC. The hold-up capacitor continues to supply VDD until the energy can be delivered from auxiliary winding of the main transformer. VDD must not drop below 9V during startup. This UVLO hysteresis window ensures that hold-up capacitor is adequate to supply VDD during startup. (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 11 FAN6754 -- Highly Integrated Green-Mode PWM Controller The HV pin can perform current limit to shrink the tolerance of OCP (Over-Current Protection) under full range of AC voltage, to linearly current limit curve as shown in Figure 25. FAN6754 also shrinks the Vlimit 2 level by half to lower the I RSENSE loss to increase the heavy-load efficiency. 0.47 0.46 0.45 0.44 Vlimit (V) 0.43 0.42 0.41 0.4 0.39 0.38 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 DC Voltage on HV Pin (V) Thermal Protection An NTC thermistor, RNTC, in series with resistor RA, can be connected from the RT pin to ground. A constant current IRT is output from the RT pin. The voltage on the RT pin can be expressed as VRT= IRT * (RNTC + RPTC), where IRT is 100A. At high ambient temperature, RNTC is smaller, such that VRT decreases. When VRT is less than 1.035V (VRTTH1), the PWM turns off after 16ms (tD-OTP1). If VRT is less than 0.7V (VRTTH2), PWM turns off after 185s (tD-OTP2). Limited Power Control The FB voltage increases every time the output of the power supply is shorted or overloaded. If the FB voltage remains higher than a built-in threshold for longer than tD-OLP, PWM output is turned off. As PWM output is turned off, VDD begins decreasing. When VDD goes below the turn-off threshold (9V) the controller is totally shut down and, VDD is continuously discharged to VDD-OLP (6.5V) by IDD-OLP to lower the average input power. This is called two-level UVLO. VDD is cycled again. This protection feature continues as long as the overloading condition persists. This prevents the power supply from overheating due to overloading conditions. Figure 25. Linearly Current Limit Curve VDD Over-Voltage Protection (OVP) VDD over-voltage protection prevents damage due to abnormal conditions. If the VDD voltage is over the overvoltage protection voltage (VDD-OVP) and lasts for tDVDDOVP, the PWM pulses are disabled until the VDD voltage drops below the UVLO, then starts again. Overvoltage conditions are usually caused by open feedback loops. Noise Immunity Noise on the current sense or control signal may cause significant pulse-width jitter, particularly in continuousconduction mode. Slope compensation helps alleviate this problem. Good placement and layout practices should be followed. Avoiding long PCB traces and component leads, locating compensation and filter components near the FAN6754, and increasing the power MOS gate resistance improve performance. (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 12 FAN6754 -- Highly Integrated Green-Mode PWM Controller Physical Dimensions 5.00 4.80 3.81 8 5 A 0.65 B 6.20 5.80 4.00 3.80 1 4 1.75 5.60 PIN ONE INDICATOR (0.33) 1.27 0.25 M CBA 1.27 LAND PATTERN RECOMMENDATION 0.25 0.10 1.75 MAX C 0.10 0.51 0.33 0.50 x 45 0.25 C SEE DETAIL A 0.25 0.19 OPTION A - BEVEL EDGE R0.10 R0.10 GAGE PLANE 0.36 OPTION B - NO BEVEL EDGE NOTES: UNLESS OTHERWISE SPECIFIED A) THIS PACKAGE CONFORMS TO JEDEC MS-012, VARIATION AA, ISSUE C, B) ALL DIMENSIONS ARE IN MILLIMETERS. C) DIMENSIONS DO NOT INCLUDE MOLD FLASH OR BURRS. D) LANDPATTERN STANDARD: SOIC127P600X175-8M. E) DRAWING FILENAME: M08AREV13 8 0 0.90 0.406 SEATING PLANE (1.04) DETAIL A SCALE: 2:1 Figure 26. 8-Pin SOP-8 Package Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild's worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor's online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 13 FAN6754 -- Highly Integrated Green-Mode PWM Controller (c) 2009 Fairchild Semiconductor Corporation FAN6754 * Rev. 1.0.0 www.fairchildsemi.com 14 |
Price & Availability of FAN6754MRMY
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |