データシート (LM3448-EDSNEV/NOPB)目次FEATURES1APPLICATIONS1DESCRIPTION1Typical LM3448 LED Driver Application Circuit1Connection Diagram2ABSOLUTE MAXIMUM RATINGS3OPERATING CONDITIONS3ELECTRICAL CHARACTERISTICS4TYPICAL PERFORMANCE CHARACTERISTICS6SIMPLIFIED INTERNAL BLOCK DIAGRAM8THEORY OF OPERATION8OVERVIEW OF PHASE CONTROL DIMMING8SENSING THE RECTIFIED TRIAC WAVEFORM10ANGLE DETECT11BLEEDER12FLTR1 PIN12DIM DECODER12FLTR212COFF AND CONSTANT OFF-TIME CONTROL OVERVIEW12VCC BIAS SUPPLY14THERMAL SHUTDOWN14Design Considerations14VALLEY-FILL POWER FACTOR CORRECTION14FLTR2 LINE-INJECTION16DIRECT LINE-INJECTION FOR FLYBACK TOPOLOGY16TRIAC DIMMER HOLDING CURRENT17OPTIMIZING THE HOLDING CURRENT18Linear Hold Insertion Circuit19Valley-Fill Holding Current Circuit19TRIAC Edge Detect Circuit19Forward Phase Holding Current Circuit19Reverse Phase Holding Current Circuit19START-UP AND BIAS SUPPLY19COFF CURRENT SOURCE CIRCUITS21Design Guide23DETERMINING DUTY-CYCLE (D)23CALCULATING OFF-TIME24SETTING THE SWITCHING FREQUENCY24INDUCTOR SELECTION25SETTING THE LED CURRENT26CURRENT LIMIT27VALLEY FILL CAPACITORS27MAXIMUM NUMBER OF SERIES CONNECTED LEDS28OUTPUT CAPACITOR30RE-CIRCULATING DIODE30Design Calculation Example30SPECIFICATIONS30CHOSEN VALUES30CALCULATIONS30APPLICATIONS INFORMATION32DESIGN #1: 7W, 120VAC Non-isolated Buck LED Driver with Valley-Fill PFC32DESIGN #2: 6.5W, 120VAC Non-isolated “A19 Edison” Retrofit with AC-Coupled Line Injection35DESIGN #3: 6W, 120VAC Isolated Flyback LED Driver with Direct Line Injection36DESIGN #4: 6W, 230VAC Isolated Flyback LED Driver with Direct Line Injection38REVISION HISTORY40サイズ： 1.18MBページ数： 45Language: Englishマニュアルを開く
