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LED Lighting Technology

At the forefront of the most efficient incandescent alternatives are LED and Fluorescent technologies. Both have advantages and technical challenges and provide significantly improved efficacy (lumens/watt) over incandescent lighting. Additionally both technologies provide opportunities to add intelligence beyond simple incandescent light bulb replacement.

Advantages

  • Best overall efficiency
    • ~75% less energy than incandescent
    • ~25% input energy = light
    • more than 100 lumens/watt (efficacy)
  • Long life: >50,000 hours
  • No “warm-up”
  • No radiated heat
  • Good in indoor and outdoor applications

Disadvantages

  • Near term expense
  • Requires electronic drive
  • Requires thermal solution to remove conducted heat

Unlike an incandescent or fluorescent light source, a LED does not radiate heat. Rather, the heat is conducted via the backside of the LED semiconductor material. This creates a technical obstacle as excessive heat can deteriorate LED performance, function, and overall lifetime. In order to properly remove the heat in a high power LED application, it may be necessary to utilize a thermal heat sink, active fan, or actively reduce lumen output based on temperature.

A Microchip based solution can provide these capabilities and more….

Controlling a LED

LED light output is a direct function of the current flow – too little current and the light will dim, too much current and lifetimes will be shortened. A typical LED driver is DC power supply providing converted AC or DC power directly controlling the LED via constant current, Pulse Width Modulation (PWM), or other variations. The LED driver must also provide high efficiencies and power factor correction (PFC) while protecting from AC line voltage fluctuations.

Constant Current Method

  • Light output maintained by constant current level
  • Dimming control via varying current level
  • Requires high resolution current control
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Modulated Current Method

  • Fixed current drive chopped by PWM
  • Dimming control via varying PWM duty cycle
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LED drivers can be designed to offer dimming and RGBW color mixing capabilities by either providing a high resolution PWM (or variants such VFM – Variable Frequency Modulation) signal or varying the constant current.

To learn more about PWM variants – visit Focus Peripherals

Efficient Power Conversion

Microchip based solutions can support any LED drive methodology as well as add additional capabilities beyond that of traditional lighting solutions. The flexibility of these solutions allows for simplified attachment to existing designs or the development of full Switch Mode Power Supply (SMPS) based intelligent solutions.

SMPS with PIC® MCU & Microchip Analog

  • Increased MCU integration
  • Fully Customizable
  • Increased Efficiency
  • Power Factor Correction (PFC)
  • Flexible Topologies
  • Simplified modifications via firmware updates
  • Closed loop control feedback
  • High performance PWM and current control variation
  • Intelligent Control Capabilities

PIC® MCU attach to basic power supply

  • Simplified design-in
  • Customizable features
  • Simplified modifications via firmware updates
  • Intelligent Control Capabilities

Energy Harvesting & Battery Charging

  • PIC MCU controlled power conversion & battery storage
  • Peak power tracking control, charging, & power delivery
  • Customizable MPPT* & battery charging algorithms
  • Support for various power supply topologies
  • Intelligent Control Capabilities

The input supply voltage and the LED forward voltage characteristics determine the SMPS topology that is required. The SMPS topologies utilized to regulate the power within LED lighting applications are the same used within a power supply application. Each SMPS topology has its advantages and determining the proper topology is dependent upon the specific application requirements. Reference the table for topology guidelines…

Common Power Conversion Topologies

General SMPS Guidelines

TopologyVin vs. Vout RelationshipPower Range (max)Peak Efficiency
BuckVin > Vout1000W>90%
BoostVin < Vout150W>90%
Buck/BoostVout < Vin < Vout150W>80%
SEPIC, Cuk, ZetaVout < Vin < Vout150W>90%
FlybackVout < Vin < Vout150W>80%
ResonantVout < Vin < Vout500W>90%
Push-PullVout < Vin < Vout1KW>90%

Intelligent Control Capabilities

In addition to efficient power conversion and LED control, a Microchip based lighting solution provides opportunities to further enhance your lighting application through product differentiation and increased user experience.

  • Custom User Interface & Control
  • Communication & Networking
  • Environmental Sensing
    • Motion, External Light Source, etc.
  • Day Light Harvesting & Auto-Dimming
  • Thermal Management
    • Active & Passive
  • Smooth Dimming Control
  • Color Mixing
  • Closed Loop Lighting Control
  • Color & Lumen Compensation
  • System Health Monitoring
  • Predictive Failure Monitoring
  • Remote Fault Detection
  • Energy Monitoring & Control
  • Energy Harvesting
  • Solar, Radio, etc.
  • Battery Management & Charging
  • Fully Customizable Options