About UsFreescale single-chip solution enables energy-efficient lighting systems
8-bit HC908LB8 microcontroller designed to improve effectiveness and reduce system complexity and cost
Lamp ballast designers can now meet demands for energy efficiency by using an advanced 8-bit microcontroller from Freescale Semiconductor. The HC908LB8 helps create more energy-efficient and cost-effective lamp ballast systems compared to traditional technologies on the market today.
The high level of integration on the HC908LB8 helps simplify overall system design. This makes 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 (PWM).
The drive for energy efficiency
Industrialized countries throughout the world are committing to improve energy efficiency and cut greenhouse gas emissions over the next decade. In some cases, this commitment includes legal mandates that the efficiency of traditional systems be improved, forcing a migration to new, innovative solutions.
One area impacted by the drive for energy efficiency is the lamp ballast market.
“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.”
Meeting the needs of the lighting market
Power factor correction (PFC), 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 (HRP) — 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.
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.
Features of the Freescale Semiconductor HC908LB8 Lighting 8-bit Microcontroller include:
- 8KB Flash Memory, 128 Byte random access memory (RAM)
- High-resolution PWM (HRP)
- Two PWM outputs with dead-time insertion
- Shutdown input
- Output resolution of 3.9ns using frequency dithering
- Variable frequency and variable duty cycle modes
- Power factor correction
- Two-channel PWM module, featuring fault input detection and shutdown
- Integrated operational amplifier/analog comparator module
- 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 (RC), internal and external crystal options
- Up to 18 input/output (I/O) (multiplexed with peripherals)
- Keyboard interrupts on seven I/O pins
- High current sink/source on I/O, Typical 10mA
The NXP website address is www.nxp.com
[Freescale Semiconductor is now part of NXP]