Manuali utente per Texas Instruments LM3409 Demonstration Board LM3409EVAL/NOPB

Sommario

• Features

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• Applications

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• Description

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  • Typical Application

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  • Connection Diagram

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• Absolute Maximum RatingsLM3409/09N/09Q/09HV/09QHV

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• Operating Ratings (LM3409/09N/09Q/09HV/09QHV)

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• Electrical Characteristics LM3409/09N/09Q/09HV/09QHV

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• Typical Performance Characteristics

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• Block Diagram

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• Theory of Operation

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  • BUCK CURRENT REGULATORS

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  • CONTROLLED OFF-TIME (COFT) ARCHITECTURE

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    • Adjustable Peak Current Control

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    • Controlled Off-Time

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  • AVERAGE LED CURRENT

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  • INDUCTOR CURRENT RIPPLE

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  • SWITCHING FREQUENCY

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  • PWM DIMMING USING THE EN PIN

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  • HIGH VOLTAGE NEGATIVE BIAS REGULATOR

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  • INPUT UNDER-VOLTAGE LOCKOUT (UVLO)

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  • LOW POWER SHUTDOWN

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  • THERMAL SHUTDOWN

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• Design Considerations

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  • OPERATION NEAR DROPOUT

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  • LED RIPPLE CURRENT

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  • BUCK CONVERTERS W/O OUTPUT CAPACITORS

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  • BUCK CONVERTERS WITH OUTPUT CAPACITORS

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  • OUTPUT OVER-VOLTAGE PROTECTION

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  • INPUT CAPACITORS

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  • P-CHANNEL MosFET (PFET)

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  • RE-CIRCULATING DIODE

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  • EXTERNAL PARALLEL FET PWM DIMMING

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  • CIRCUIT LAYOUT

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• Design Guide

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  • TYPICAL APPLICATION

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  • SPECIFICATIONS

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  • 1. NOMINAL SWITCHING FREQUENCY

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  • 2. INDUCTOR RIPPLE CURRENT

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  • 3. AVERAGE LED CURRENT

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  • 4. OUTPUT CAPACITANCE

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  • 5. INPUT CAPACITANCE

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  • 6. PFET

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  • 7. DIODE

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  • 8. INPUT UVLO

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  • 9. IADJ CONNECTION METHOD

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  • 10. PWM DIMMING METHOD

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  • Design Example #1

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    • EN PIN PWM DIMMING APPLICATION FOR 10 LEDS

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    • SPECIFICATIONS

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    • 1. NOMINAL SWITCHING FREQUENCY

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    • 2. INDUCTOR RIPPLE CURRENT

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    • 3. AVERAGE LED CURRENT

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    • 4. OUTPUT CAPACITANCE

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    • 5. INPUT CAPACITANCE

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    • 6. PFET

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    • 7. DIODE

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    • 8. INPUT UVLO

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    • 9. IADJ CONNECTION METHOD

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    • 10. PWM DIMMING METHOD

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    • Design #1 Bill of Materials

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  • Design Example #2

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    • ANALOG DIMMING APPLICATION FOR 4 LEDS

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    • SPECIFICATIONS

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    • 1. NOMINAL SWITCHING FREQUENCY

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    • 2. INDUCTOR RIPPLE CURRENT

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    • 3. AVERAGE LED CURRENT

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    • 4. OUTPUT CAPACITANCE

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    • 5. INPUT CAPACITANCE

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    • 6. PFET

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    • 7. DIODE

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    • 8. INPUT UVLO

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    • 9. IADJ CONNECTION METHOD

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    • 10. PWM DIMMING METHOD

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    • Design #2 Bill of Materials

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• Applications Information

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  • DESIGN #3: EXTERNAL PARALLEL FET PWM DIMMING APPLICATION FOR 10 LEDS

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  • Design #3 Bill of Materials

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  • DESIGN #4: SINGLE POTENTIOMETER ANALOG DIMMING APPLICATION FOR 6 LEDS

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  • Design #4 Bill of Materials

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  • DESIGN #5: 75°C THERMAL FOLDBACK APPLICATION FOR 16 LEDS

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  • Design #5 Bill of Materials

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  • DESIGN #6: HIGH CURRENT APPLICATION FOR 4 LEDS

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  • Design #6 Bill of Materialslayout of National Data Sheet to TI format

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• Revision History

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