Austin, Tex. The high level of integration on Freescale Semiconductor Corp.'s new 8-bit HC908LB8 microcontroller will simplify overall system design making the device an attractive solution for smart fluorescent lighting, motor control, high-intensity discharge lighting and applications that require power factor correction and/or high-resolution pulse width modulation, according to the company.
The MCU is based on Freescale's HC08 central processing unit, with an 8 MHz internal bus frequency and software within +/- 2% accuracy. Embedded into the MCU are 8Kbytes flash memory and 128B of RAM. The high-resolution PWM offers two PWM outputs with dead-time insertion, shutdown input, 3.9ns output resolution using frequency dithering, variable frequency and variable duty cycle modes.
Also built into the MCU is a seven-channel, 8-bit analog-to-digital converter, 1 x 16-bit timer with interrupt, low voltage inhibit and computer operating properly for noise immunity and software safety, clock generation module with resistor-capacitor internal and external crystal options. There are up to 18 input/output (I/O) (multiplexed with peripherals, keyboard interrupts on seven I/O pins and high current sink/source on I/O (typical 10mA).
Power factor correction, a key requirement in efficient main-powered applications, converts input current to a sine wave in phase with input voltage. The result is increased efficiency, lower signal distortion, reduced running costs and lower noise emissions. The HC908LB8 performs cost-effective PFC, providing an ideal integrated solution for main-powered applications.
Controlling the brightness of individual tubes has consistently provided a challenge for designers of fluorescent lighting systems " the tube is either fully on or off. Freescale helps address this challenge with a new module " the high-resolution PWM " which is integrated on the HC908LB8 to continuously control the brightness and allow dimming in a fluorescent lighting system.
The HC908LB8 is also capable of supporting the digitally addressed lighting interface (DALI) protocol to provide intelligence in large lighting systems. A DALI-based system, for example, can be programmed to turn off (or dim) lights near windows, where adequate natural light is available.
"One of the most prevalent forms of indoor lighting used today is the ubiquitous fluorescent tube," said Mike McCourt, vice president and general manager of Freescale's Microcontroller Division. "The ever-growing international concern about energy efficiency has prompted new legislation and programs like the Kyoto Protocol and Energy Star, which have exerted renewed pressure on ballast designers to improve the efficiency of their systems."
In typical lamp ballast applications, the HC908LB8 could help reduce the total number of discreet digital system parts by up to 50 percent. This helps deliver the additional benefits of space conservation " reduced board and manufacturing costs and decreased administration overhead.
To demonstrate the device's capabilities, Freescale has developed a fully functional reference design (dimmable light ballast control with PFC). Associated software, schematics and BOM are available for download on the Freescale Web site.
The DEMO908LB8 demonstration board is available for a suggested resale price of $49.95 (USD), which includes a complimentary Metrowerks Code Warrior IDE, Special Edition.
Freescale says it is committed to helping reduce developers' time-to-market by offering affordable development hardware (evaluation board and demonstration board), reference designs, application notes and online tutorials. The Metrowerks Code Warrior integrated development environment (IDE), Special Edition is also available.
The HC908LB8 is currently available in production quantities. Suggested resale pricing in 100,000-piece quantities is $1.60 (USD) in either 20-pin small outline integrated circuit (SOIC) package or plastic dual-inline package (PDIP).
Data sheet: Freescale MCU.
Freescale Semiconductor Corp. +1 (512) 895-2044
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