Design Article
Controlling multiple LED strings with C2000 MCUs
Daniel Chang; Brett Larimore, Patrick Carner, Texas Instruments
7/27/2012 10:29 AM EDT
Page 3
TI’s Piccolo MCU architecture is ideal for LED applications. In addition to offering flexible LED drive control, Piccolo MCUs have the capacity to implement advanced features that are becoming increasingly important in many lighting applications:
- Temperature sensing: Integrated ADCs allow the Piccolo MCU to easily monitor LED operating temperature. As temperature increases, LED efficiency drops. In addition, for color mixing applications, temperature also affects LED color. With temperature sensing, the digital controller can either dynamically compensate for changing temperature by adjusting the LED drive algorithm or by activating other system components such as a fan.
- Green operation: Systems can use a variety of sensing techniques to implement more complex control algorithms to optimize power utilization. For example, a system could dynamically adjust LED drive levels based on the available ambient light. Lower power consumption also reduces heat dissipation to result in lower operating costs and higher long-term reliability.
- System coordination and communications: Intelligent lighting control is essential for many LED-based systems ranging from flashing decorative lights to activating a vehicle’s cornering headlights to high-end stage lighting. Developers can implement a variety of generic and application-specific communications channels, including CAN, DMX, and power line communications (PLC). Combined with digital control of LEDs, a communications interface opens lighting systems to remote management and an extensive range of advanced usage models.
- Programmability: A programmable architecture enables developers to continue to introduce new features to existing architectures without requiring time-intensive and costly redesign of system hardware. Programmability also enables simple field upgradeability when a communications interface is available so that systems can be updated without requiring a physical visit from a technician.
- Color correction: The output of LEDs varies over temperature and time. To provide long-term accurate color mixing, Piccolo-based lighting systems can be programmed to compensate for temperature variation and to adjust the operating voltage to compensate for degradation from aging components.
- High reliability: Developers can introduce features such as fault detection and alarm notification to both improve reliability and reduce maintenance expenses.
- Integrated functionality: Piccolo digital LED controllers reduce system size and complexity by integrating a variety of on-chip peripherals required for a wide range of applications. For example, high-resolution ADCs support accurate current and voltage sensing for motor and power control applications.
- Adaptability: Piccolo digital LED controllers provide sufficient performance headroom to accommodate changing market conditions, shifting customer requirements, and evolving standards, thus future-proofing designs and protecting design investment. TI also offers an expanding range of microcontrollers to meet the needs of emerging applications so manufacturers can exploit new opportunities quickly and cost-effectively.
Next: Page 4
TI’s Piccolo MCU architecture is ideal for LED applications. In addition to offering flexible LED drive control, Piccolo MCUs have the capacity to implement advanced features that are becoming increasingly important in many lighting applications:
- Temperature sensing: Integrated ADCs allow the Piccolo MCU to easily monitor LED operating temperature. As temperature increases, LED efficiency drops. In addition, for color mixing applications, temperature also affects LED color. With temperature sensing, the digital controller can either dynamically compensate for changing temperature by adjusting the LED drive algorithm or by activating other system components such as a fan.
- Green operation: Systems can use a variety of sensing techniques to implement more complex control algorithms to optimize power utilization. For example, a system could dynamically adjust LED drive levels based on the available ambient light. Lower power consumption also reduces heat dissipation to result in lower operating costs and higher long-term reliability.
- System coordination and communications: Intelligent lighting control is essential for many LED-based systems ranging from flashing decorative lights to activating a vehicle’s cornering headlights to high-end stage lighting. Developers can implement a variety of generic and application-specific communications channels, including CAN, DMX, and power line communications (PLC). Combined with digital control of LEDs, a communications interface opens lighting systems to remote management and an extensive range of advanced usage models.
- Programmability: A programmable architecture enables developers to continue to introduce new features to existing architectures without requiring time-intensive and costly redesign of system hardware. Programmability also enables simple field upgradeability when a communications interface is available so that systems can be updated without requiring a physical visit from a technician.
- Color correction: The output of LEDs varies over temperature and time. To provide long-term accurate color mixing, Piccolo-based lighting systems can be programmed to compensate for temperature variation and to adjust the operating voltage to compensate for degradation from aging components.
- High reliability: Developers can introduce features such as fault detection and alarm notification to both improve reliability and reduce maintenance expenses.
- Integrated functionality: Piccolo digital LED controllers reduce system size and complexity by integrating a variety of on-chip peripherals required for a wide range of applications. For example, high-resolution ADCs support accurate current and voltage sensing for motor and power control applications.
- Adaptability: Piccolo digital LED controllers provide sufficient performance headroom to accommodate changing market conditions, shifting customer requirements, and evolving standards, thus future-proofing designs and protecting design investment. TI also offers an expanding range of microcontrollers to meet the needs of emerging applications so manufacturers can exploit new opportunities quickly and cost-effectively.
Next: Page 4
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anne-francoise.pele
7/30/2012 7:41 AM EDT
Click on the link below to check out the collection of Design Articles, Case Studies, Product How-To articles,... related to LEDs that have been published on Smart Energy Designline.
Check back frequently. The list will be updated as new articles arrive.
http://www.eetimes.com/design/smart-energy-design/4371743/LED-Focus
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Dr DSP
8/9/2012 12:43 PM EDT
Remember when driving an LED just used a GPIO pin and you picked a resistor value to control the brightness. No longer.
Luckily the controlSUITE software can help you climb the learning curve. If you can standardize on one or two simple architectures (like the two described here) it can make the design even easier. However, make sure you know the key application requirements so your implementation is the best fit..
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