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greenpowerZONE Products for the week of March 17, 2008
NEC Electronics Says…
Family of 16-Bit Flash Microcontrollers Ideal For Inverter Control In Low Power And Eco-Friendly Appliances
NEC Electronics has announced a new line of 16-bit All Flash microcontrollers (MCUs) for inverter control applications. Built around NEC Electronics’ fast and efficient 78K0R CPU core, the 19 MCUs in the 78K0R/Ix3 lineup are designed to enable a new generation of intelligent and eco-friendly appliances and motor drives. All devices in the lineup feature integrated inverter control circuits and deliver best-of-class power performance.
Inverter control systems are found in an ever-wider range of products, in response to consumer demand for more energy-efficient appliances. Fine-tuned control of motors and heating elements can deliver significant energy savings in products ranging from refrigerators and air conditioners to dishwashers and magnetic induction cooking appliances.
NEC Electronics’ 78K0R/Ix3 MCUs, with 16-bit performance and 8-bit power consumption levels, are ideal for such applications.
All devices in the lineup share the following features:
- CPU power consumption of only 1.8 mW per MIPS, the highest performance-to-power-consumption ratio in the industry;
- on-chip oscillators capable of driving timers at rates up to 40 megahertz (MHz) for fine-tuned inverter control;
- integrated hardware multiply and divide functionality for fast processing of mathematical algorithms;
- integration of all analog circuits required for inverter control, including comparators and an integrated operational amplifier (op amp).
This combination of features responds to strong demand from appliance manufacturers for flexible, low-cost, high-performance MCUs to help shorten time to market. Under pressure to differentiate their products from competitor offerings, manufacturers stress innovative features, stylish design and lower power consumption, but this results in mounting development costs and longer development schedules. NEC Electronics’ new MCUs allow fine-grained control of multiple types of 3-phase motors, making it easy to develop eco-friendly appliances. In addition, an all-flash memory configuration means that programs can be updated even after an MCU is mounted on a system board, allowing manufacturers to accelerate development schedules by developing software in parallel with hardware.
The principal features of NEC Electronics’ 78K0R/Ix3 MCUs are:
- Industry-leading performance to power consumption ratio - The new MCUs are built around NEC Electronics’ 78K0R CPU core that executes 13 MIPS at a clock speed of 20 MHz. Advances in process technology enable power consumption of only 1.8 mW per MIPS.
- Fine-tuned inverter control via integrated multifunction timers - Multifunction timers function as interval timers to generate periodic interrupts, as dividers to generate clock signals by dividing an input frequency, and as event counters to count external signals. The number of timer units has been increased from 8 channels to 12. This allows one channel of 6-phase pulse-width modulation (PWM) output for the 3-phase motors generally used in inverter control applications, as well as two channels of the half-bridge PWM output commonly used in magnetic induction cooking systems.
- First 16-bit MCUs with integrated inverter control circuits - In another industry first, the 78K0R/Ix3 MCUs integrate all of the basic analog circuits needed for inverter control, including an op amp, comparators, and high-speed A/D converters. By replacing discrete components with an integrated solution, manufacturers can dramatically reduce their bill of materials costs and save space on system boards.
- Wide selection of memory and packaging options - Available on-chip memory configurations include 16, 32, 48 or 64 kilobytes (KB) of internal flash memory and 1, 1.5, 2 or 3 KB of internal RAM. Packaging options include SSOP and LQFP packages in pin counts ranging from 30 to 64 pins. With a total of 19 MCUs in the lineup, designers can choose the optimum configuration for their applications.
- Full development tools support
NEC Electronics’ MCUs are supported by a comprehensive suite of development tools, including NEC Electronics’ MINICUBE2 on-chip debugger, IECUBE emulator for full tracing, starter kits and software tools. Compiler suites are also available from third-party source, IAR Systems.
Offering 16-bit performance at 8-bit power consumption levels, these new MCUs will enable appliance manufacturers to reduce bill of materials and development costs, and be faster to market with the eco-friendly products that consumers demand.
EN-Genius Says…
NEC has done a nice job of enhancing its popular 16-bit Flash MCU product line to serve the lucrative high-efficiency motor control market that’s driven by the growing demand for so-called green white goods. By integrating all the analog sense and drive elements and oscillators required to operate both BLDC and several kinds of ac motors, the controllers give designers considerable cost and PCB savings over more general-purpose solutions. With pricing in the $5 region for a nicely-provisioned controller, NEC will be giving competitors like STMicro, TI, and International Rectifier a real run for their money.
One of the other distinguishing features of this 16-bit controller is that it has enough processing power to support sinusoidal sensorless vector control (instead of the less efficient trapezoidal technique typically used on 8- and 16-bit processors) that usually requires a 32-bit processor to implement. This is in good part thanks to the hardware multiply/divide core that allows the CPU to perform a 16 x16 multiply operation in 1 clock and a 32 x 32 divide in 16 clocks. NEC says that the 13 MIPS available from the 16-bit K0R/Ix3 MCU running at 20 MHz is enough processing power to drive any 3-phase or BLDC motor in sensorless mode. They also say that this is enough processing power to even allow designers to implement high-efficiency vector control algorithms.
For most motor control applications, there should also be enough remaining processor cycles to support application software such as user interfaces or communications protocol stacks. NEC is still in the process of doing benchmark testing to find out just how much CPU power you can count but tests on the V850, an earlier low-end motor control device, showed that they could a run vector control algorithm and still have over 50% of CPU power left for other tasks and applications.
In some respects, NEC’s 16-bit controller family compares very favorably to STMicro’s very capable 32-bit STM32F103 flash-based motor controller (reviewed here in March 2008) which has a very similar feature set and targets roughly the same kinds of applications. In a head-on comparison, the NEC 78K0R/Ix3 MCU offers 12 channels of 16-bit timers against ST’s four channels, and a 12-channel, 10-bit ADC versus ST’s dual eight-channel 12-bit ADCs. For many low-to-mid-range applications, the board space and BOM savings realized by NEC’s integrated op amps and comparators will prove to be much more useful than the extra processing power offered by the STM32F103. The controller’s internal 20-MHz high-speed oscillator, power-on clear circuit and low-voltage indicator further reduce the need for external components, leading to a more compact and less expensive drive.
NEC says that the controller development kit will be released soon and will follow the same form factor and functionality offered in the kits for their other 8- and 32-bit motor control devices. They offer their own tools (NEC compiler, simulator, code generator, and IDE debugger) as a first option, but also offer IAR software as a second source.
The 78K0R/Ix3 is expected to sample in May 2008. Pricing varies according to memory; for example, the 78K0R/IE3 with 64 kbyte of Flash and 3 kbyte of RAM is priced at $5 per unit in sample quantities. Production is scheduled for December 2008.
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