Benutzerhandbuch für Texas Instruments LM3445 Evaluation Boards LM3445-EDSNEV/NOPB

Inhaltsverzeichnis

• FEATURES

  1
• APPLICATIONS

  1
• DESCRIPTION

  1
  • Typical LM3445 LED Driver Application Circuit

    1
  • Connection Diagram

    2
• ABSOLUTE MAXIMUM RATINGS

  3
• OPERATING CONDITIONS

  3
• ELECTRICAL CHARACTERISTICS

  3
• TYPICAL PERFORMANCE CHARACTERISTICS

  5
• SIMPLIFIED INTERNAL BLOCK DIAGRAM

  7
• APPLICATION INFORMATION

  7
  • FUNCTIONAL DESCRIPTION

    7
  • OVERVIEW OF PHASE CONTROL DIMMING

    7
• THEORY OF OPERATION

  9
  • SENSING THE RECTIFIED TRIAC WAVEFORM

    10
  • LM3445 LINE SENSING CIRCUITRY

    10
  • TRIAC HOLDING CURRENT RESISTOR

    11
  • ANGLE DETECT

    12
  • BLEEDER

    12
  • FLTR1 PIN

    12
  • DIM DECODER

    12
  • VALLEY-FILL CIRCUIT

    13
  • VALLEY-FILL OPERATION

    13
  • BUCK CONVERTER

    14
  • OVERVIEW OF CONSTANT OFF-TIME CONTROL

    15
  • MASTER/SLAVE OPERATION

    16
  • MASTER/SLAVE CONFIGURATION

    16
  • MASTER BOARD MODIFICATIONS

    16
  • SLAVE BOARD(S) MODIFICATIONS

    16
  • MASTER/SLAVE(S) INTERCONNECTION

    16
  • MASTER/SLAVE THEORY OF OPERATION

    16
  • MASTER/SLAVE CONNECTION DIAGRAM

    17
  • MASTER/SLAVE BLOCK DIAGRAMS

    18
  • THERMAL SHUTDOWN

    19
• DESIGN GUIDE

  20
  • DETERMINING DUTY-CYCLE (D)

    20
  • CALCULATING OFF-TIME

    20
  • SETTING THE SWITCHING FREQUENCY

    20
  • INDUCTOR SELECTION

    21
  • SETTING THE LED CURRENT

    23
  • VALLEY FILL CAPACITORS

    23
    • Determining the capacitance value of the valley-fill capacitors

      24
    • Determining Maximum Number of Series Connected LEDs Allowed

      24
  • OUTPUT CAPACITOR

    26
  • SWITCHING MOSFET

    26
  • RE-CIRCULATING DIODE

    27
• DESIGN EXAMPLE

  28
• LM3445 DESIGN EXAMPLE 1 INPUT = 90VAC TO 135VAC, VLED = 7 x HB LED STRING APPLICATION @ 400 MA

  30
• Revision History

  32