By Nick Flaherty www.flaherty.co.uk
Renesas Electronics has launched a family of five 16bit single chip microcontrollers for the LED control, power supply control and communication functions required in LED lighting fixtures.
The RL78/I1A family addresses the need of a variety of lifestyles for lower cost, high-colour dimming and color temperature control and supports lighting communication standards for centralized control in buildings and offices. The new MCUs use the RL78 CPU core, which achieves both high computational performance and ultra low power consumption, and include from 32 to 64 kilobytes (KB) of flash memory in 20 to 38-pin package versions. These devices use 20% less power than the existing 78K0/Ix2 products.
Renesas is also launching evaluation boards, automatic software generation tools (Appilet EZ for HCD), a lighting fixture communication standard library, and other tools required for the development and evaluation of MCU software for lighting fixture applications in July.
LED lighting, which features low power consumption and long lifetimes, is the focus of attention as an effort to reduce CO2 emissions on a global scale. LED illumination is becoming increasingly widely used in industrial and commercial facilities, in streetlights, and in home lighting. The global market for LED lighting equipment is expected to grow rapidly from the roughly 20 million units sold in 2009 to over 400 million units in 2014.
Key features:
Data sheet
Samples are available now, priced at US$2.50 per unit for the 38-pin, 64 KB flash memory, 4 KB RAM version. Mass production is scheduled to begin in January 2012 and is expected to reach a combined volume of 1,000,000 units per month in 2012.
Key features:
- These new lighting MCUs provide six high-resolution PWM outputs that are capable of supporting an average resolution of 0.97 ns. This allows dimming and color temperature adjustments about 25 times more precise than RL78/Ix2 products. These new MCUs also include a new PWM output on/off control timer that allows them to support either current or PWM-based dimming adjustment. They also include a PGA (programmable gain amplifier) that can amplify the A/D converter input level by up to a factor of 32 to support high-precision LED current measurement. Not only does this make even finer-grained brightness adjustment possible, it also allows a smaller current measurement resistor to be used, thus contributing to reduced overall system power consumption.
- A new PFC control function supports interleaved operation for in high-power equipment requiring improved power factors. As the internal comparators and an interrupt pin are internally interlocked with the PWM timers, this enables efficient PFC control without CPU involvement and eliminates the need for an external PFC control IC.
- The new MCUs provide an overcurrent detection function that uses comparators (including window comparators that allow both upper and lower limits to be set) for overvoltage and overcurrent detection and stops PWM timer output automatically. This function can prevent breakdowns in lighting fixtures. The architecture allows different port output states when a forcible output stop occurs to be selected from three types: high-level output, low-level output, or high impedance, to support a wide range of protection circuits. The RL78/I1A MCUs support the IEC60730 European Home Appliance Safety Standard which is necessary for lighting fixtures by including; a FLASH memory CRC (cyclic redundancy check) calculation function, RAM parity error detection function, clock frequency detection function and illegal memory access prevention function.
- In addition to CSI, these devices also support the I²C bus and UART (DMX512) standards and even the DALI (Digital Addressable Lighting Interface) open standard for lighting communication which also supports extended DALI frames so they can flexibly support lighting communication protocols.
Data sheet
Samples are available now, priced at US$2.50 per unit for the 38-pin, 64 KB flash memory, 4 KB RAM version. Mass production is scheduled to begin in January 2012 and is expected to reach a combined volume of 1,000,000 units per month in 2012.
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