Adding Intelligence to Lighting – LED Lighting



Adding Intelligence to Lighting – LED Lighting Solutions

LED Lighting Solutions Brochure

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LEDs are no longer used just for providing the pretty red and green indicator lights on electronic equipment. Advances in technology have allowed LEDs to be used as practical sources of illumination. The primary benefits of LEDs are lifetime, durability, and efficiency. When driven properly, a power LED can last tens of thousands of hours without a degradation of light output. The typical efficacy of a power LED, measured in lumens per watt, is 20 – 30. This greatly exceeds incandescent light sources and is only exceeded by fluorescent light sources. Since the LED is a solid-state device, it can withstand shock and vibration that would damage a filament bulb.

The benefits of LED lighting are helpful in many types of lighting applications:

• Automotive and aircraft cabin lighting

• Automotive and aircraft instrument panel lighting

• Architectural emergency exit lighting

• Architectural color effect lighting

• Industrial and outdoor lighting

• Traffic and railway signals

• Dot matrix signs and video displays

• LCD display backlighting

• Personal flashlights

• Medical instrument and tool lighting

• Digital camera flash and video light

Efficient LED Control

LEDs must be driven with a source of constant current. Most LEDs have a current level that will achieve the maximum brightness for that LED without premature failures. A LED could be driven with a linear voltage regulator configured as a constant current source. However, this approach is not practical for higher power LEDs due to power dissipation in the regulator circuit. A switch-mode power supply (SMPS) provides a much more efficient solution to drive the LED.

A LED will have a forward voltage drop across its terminals for a given current drive level. The power source voltage and the LED forward voltage drop characteristics will determine the SMPS topology that is required. Multiple LEDs can be connected in series to increase the forward voltage drop at the chosen drive current level.

Application Notes, Demos, and Source Code for LED Lighting

Charge Pump LED Demo Board Using the MCP1252

This demo uses the MCP1252 charge pump device to drive multiple LEDs.

Boost Mode Multiple LED Demo Board Using the MCP1650

This demo uses the MCP1650 device in a boost power supply configuration to drive a string of 9 white LEDs. The demo steps up the 4.5V supply voltage to approximately 30V to drive the LEDs. A 6-pin PIC10F206 MCU on the demo board provides a user interface to control the brightness of the LEDs.

3W White LED Demo Board Using the MCP1651

This demo uses the MCP1651 in a SEPIC power supply configuration to drive a single 3W power LED. The SEPIC power supply can step up or step down the 4.5V supply depending on the LED drive requirements. A 6-pin PIC10F206 MCU on the demo board provides the user interface. The LED can be dimmed and flashed.

AN1047 – Buck-Boost LED Driver Using the PIC16F785 MCU

This application note shows how to use the PIC16F785 MCU to implement a constant-current LED driver. The application circuit can be operated in buck-boost mode or boost mode to accommodate a variety of supply voltages.

AN874 - Buck Configuration High-Power LED Driver

This application note shows how to use a PIC MCU with an on-chip comparator for a high-power LED driver.

|AN1074 – Software PWM Generation for LED Dimming and RGB Color Applications |

|This application note describes a software solution that generates one or more pulse-width modulated (PWM) signals using a PIC MCU.|

|AN1076 – Using a PIC Microcontroller for DMX512 Communication |

|This application note presents a solution to transmit and receive the DMX512 communication protocol that can be implemented using |

|any PIC® microcontroller offering a Universal Asynchronous Receiver Transmitter (UART) module. |

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