14 new 8-bit MCUs from NEC for energy-efficient lighting applications
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Designed specifically for fluorescent and LED lighting devices requiring low cost, high efficiency and intelligent control, NEC’s extremely low-power-consuming 78K0/Ix2 devices stand apart from the competition by having two unique 16-bit timers with high-speed pulse-width modulation (PWM) output, three channels of internal comparators, a one-channel operational amplifier with programmable gains and an extended operating temperature range of –40 to +105 degrees Celsius. The 14-device lineup includes 78K0/IY2 MCUs in 16-pin packages, 78K0/IA2 MCUs in 20-pin packages and 78K0/IB2 MCUs in 30-pin packages.
As energy costs for lighting equipment rise, and consumers become more eco-conscious about global warming, lighting has become an area of focus for energy conservation. By switching from incandescent to fluorescent bulbs, and by using an MCU rather than a dedicated integrated circuit (IC) to provide inverter control and dimming functions, lighting manufacturers can control illumination at a fine-grained level and provide communication functions that enable illumination and ambient conditions to be adjusted via remote control, delivering further energy savings and added value.
LED-based lighting systems, which consume less power than other lighting systems, are becoming more popular as major advances in brightness levels are made. However, providing high-brightness illumination in LEDs requires functions to control dimming and manage color, thermal conditions and communication, and this need has increased the popularity of MCUs for system control.
Features
- Inverter and LED dimming control function
Two 16-bit PWM timers and a built-in high-speed oscillator that drives the timers at a maximum clock speed of 40 megahertz (MHz) enable fine-grained inverter control. These timers, each capable of two outputs, make it possible for the MCUs to drive four-channel LEDs with precise dimming and color control. - Instantaneous control of PWM timer output
Built-in comparators with outputs linked to the PWM timer automatically detect abnormal conditions, such as over-current and over-voltage conditions, and immediately shut down PWM output—without CPU intervention—providing much faster protection against damage than an interrupt-based mechanism. - Internal power factor correction (PFC) control
An external interrupt and built-in comparators linked to the 16-bit timers fulfill hardware requirements for power factor correction (PFC), while NEC Electronics’ high-performance 78K0 core—along with the on-board hardware multiplier—tackle the software computation, eliminating the need for a dedicated PFC control IC and thereby reducing system cost and space. - Best-in-class low power consumption
With the same low-power technologies used in NEC Electronics’ low-power 16-bit MCUs, the new 8-bit devices consume only 0.3 micro-amps (µA) during standby operation and 260 µA during operation at 1 MHz, which helps reduce system standby power consumption to meet energy efficient regulations. - Extended operating temperature range
The new devices are qualified for an extended temperature range from –40 to +105oC, exceeding the extreme ambient temperatures demanded by lighting devices. - Built-in inter-lighting communications peripheral
A dedicated circuit, including a Manchester encoder/decoder in the digital addressable lighting interface (DALI)-compliant UART, enables lighting control for multiple networked lighting devices.