Today when electronics is becoming smart and connected μcontrollers have became an integral part every market segment. But apart from betterment of performance, power consumption is another important factor determines the entire system designing and execution.
Low energy MCUs are growing in importance for battery powered applications, which are ideal for power sensitive battery operated products. Today industry needs microcontrollers that are energy efficiency in all energy modes, enabling very long battery life coupled with optimal processing performance. Ultra-low-power (ULP) microcontrollers (MCUs) are the compute engines powering the edge of the Internet of Things (IoT), but ensuring ULP operation over periods of months, years, and decades presents application developers with a number of optimization challenges. Many experts from industry leaders further joined us on this survey. As per Mr. Guru Ganesan, President & Managing director, ARM India Operations, the significance of low power microcontrollers is due to the higher computation demands of today, more and more performance is expected out of microcontrollers. While performance improvement of a typical micro controller has multiplied many a time over, typical battery capacity however has mostly only doubled over the past five years. So a micro-controller’s ability to be power efficient while being able to do more tasks is indeed very critical. As stated by Mr. Mike Salas, Vice President of Marketing, Ambiq Micro, The microcontroller (MCU) market is currently going through a rapid growth phase due to the emergence of new applications such as wearable and Internet of Things (IoT). With Gartner predicting 26 billion connected devices by 2020, it is easy to see that the need for MCUs is only going to accelerate beyond its already wide base of applications. Therefore, Ambiq fully expect to see the MCU market grow at a very rapid pace for many years to come. Wearable electronics, Internet of Things (IoT) devices, and wireless sensor nodes – these and other battery-powered or power sensitive applications are expected to dramatically benefit from the use of upcoming, state-of-the art semiconductors that implement sub threshold technology. By using very low operating voltages that fall even below the transistor threshold voltage, sub threshold designs can achieve exceptionally low power operation compared to today’s traditional super-threshold designs; in particular low dynamic energy which is the dominant energy in most applications. For example, considering that dynamic energy varies as the square of the operating voltage, a sub threshold circuit operating at 0.3V could achieve an astounding 36X improvement in dynamic energy over a typical super-threshold circuit operating at 1.8V. The leakage energy is also tangibly reduced, although not as markedly as the dynamic energy. Both are important to optimize for the mentioned applications. Where low power consumption is a main objective, sub threshold may be the most appealing semiconductor design approach. Sub threshold design is also the most difficult, however. Therefore, standard super-threshold circuits may still make sense for parts of the design that don’t affect the power budget much, such as non-volatile memory that is only active during power-up and is then shut down. And for those applications that must trade off power consumption to achieve desired performance, there is also the option to use near –threshold techniques. Indeed, as demonstrated by Ambiq Micro’s Apollo’s MCU device, it isn’t so uncommon to have all three – sub threshold, near-threshold, and super-threshold coexisting on the same device. Mr. Chander Goel, Systems Applications Lead (MCU), Texas Instruments (TI) India shared his views with us as, a μcontroller(MCU) or a μprocessor is at the heart of almost every autonomous electronic application board. With more and more applications becoming portable, the low-power consuming characteristic of these MCUs becomes a significant factor in choosing the right fit MCU for these applications. Using an ultra-low power consuming μcontroller in portable applications helps reducing the size of the battery which in turn, helps in reducing the form-factor, weight, cost and maintenance of the application.
Massive Applications of Low Power μController
Let’s see what Microcontroller manufacturers themselves state about it. Mr. Guru Ganesan, ARM said, a microcontroller lets one do complex operations much more efficiently as compared to what can be accomplished otherwise. This efficiency is obtained not just in terms of power but also in terms of the area needed in system design. Devices can be re-programmed and system issues can be resolved where possible with a simple code update. Additionally, new features and functionalities can be added without the need for a hardware upgrade or system re-designs. So, designing a system from the ground up with a micro-controller in mind is contraty to popular belief, actually more cost effective and reduces overheads in multiple areas in long run. Mr. Mike Salas, Ambiq Micro said, traditionally, the answer to this question is yes – the cost and complexity of a system does go up when trying to design with existing low power microcontrollers. The reason for this is that most existing “low power” MCUs require elaborate schemes to find ways to reducing power – offering many different sleep modes, implementing complicated DMA engines to avoid the need to turn the processor on, etc. While these approaches do offer some incremental power consumption improvements, this comes at the cost of dramatically increased complexity for the system designer who must now spend time trying to determine how best to utilize these features. In addition, there is the cost and significant amount of time associated with converting floating point application code into fixed-point code in order to further improve energy consumption. This is a process that normally takes multiple software engineers working across several months which dramatically increases the implementation cost of the entire solution. The Ambiq Micro Apollo MCU is unique in the industry in that it overcomes these challenges and offers a solution that is just as easy and cost-effective as traditional MCU designs. By offering a solution that optimizes BOTH active power and sleep power simultaneously – and at DESIGN IDEA power consumption levels that are far below all competing MCUs – the system designer avoids the need to go to elaborate lengths to achieve incremental energy improvements. With the Apollo MCU, they get revolutionary improvements. Furthermore, the utilization of an ARM Cortex M4F core on the Apollo MCU enables designers to potentially skip the entire floating point-to-fixed point conversion process since the Apollo MCU supports a floating point engine at power levels that are far below even existing M0+ solutions. This dramatically simplifies the design and cuts a significant amount of development cost. Mr. Chander Goel, Texas Instruments said it takes a great deal of effort and expertise to design a low power μcontroller. The core and the peripherals have to be carefully specified by the systems engineers taking into account different application scenarios. The designers have to put a great deal of effort in designing the blocks with ultralow leakage. The testing, validation and application teams have to test each block with a greater detail to check that the specifications are exactly met. Finally the whole system has to be built over a state of art process technology. An ultra-low power μcontroller may be slightly more costly than its counterparts but the benefits that it provides in reducing the total system cost will definitely weigh more.
Solutions available from Industries
ARM Ltd.
Solutions available from Industries: ARM Ltd. ARM’s Cortex-M family of processors is optimized for cost and power sensitive MCU and mixed – signal devices for applications such as internet of Things, Connectivity, motor control, smart metering, human interface devices, automotive and industrial control systems, domestic household appliances, consumer products and medical instrumentation. These microcontrollers have a loss of power optimization features like architecture defined sleep modes, multiple power and clock domains, support for advanced low power technologies like state retention & power gating. Some of our partner’s ARM Cortex – M series based microcontrollers are small enough to fit within a dimple of a golf ball but computation wise have more performance capabilities than the guidance computer used in the Apollo Mission. ARM’s Cortex-M0+ based microcontroller can run for over 15 years on a single button cell battery. The ecosystem is very strong so a system developer can benefit from the widest third-party tools, RTOS and middleware support of any architecture. Using a standard processor within a system allows ARM partners & developers to create devices with a consistent base while enabling them to focus on creating superior device implementations.
Ambiq Micro
The Apollo MCU from Ambiq Micro is the industry’s first ever microcontroller that is based on sub threshold voltage technology. This results in a solution that goes well beyond the incremental improvements in power consumption that other microcontroller companies have offered. Ambiq have a fundamental belief that the low energy consumption has replaced performance as the foremost challenge in electronic design and we believe that by utilizing our patented sub threshold voltage technology Ambiq can make revolutionary advances in driving down power consumption. Unlike other MCU companies, Ambiq’s unique and patented sub threshold technology allows us to optimize BOTH active and sleep mode power simultaneously in our Apollo MCUs. Active mode power is an industry-leading 30uA/MHZ– this is up to 10 times better than other competing MCUs. Similarly, sleep mode in the Apollo MCUs can be as low as 100nA – this is also industry-leading and is up to 38 times better than competing solutions. Therefore, the key competitive advantage that Ambiq’s Apollo MCUs offer is power consumption numbers that are far less than all other competing solutions. Unlike other “low power” MCUs who have traditionally chosen to use an ARM Cortex- M0+ core; Ambiq purposely chose the M4F core for two key reasons. The first reason is that our sub threshold circuit level technology enables us to choose an M4F core instead of an M0+ core with absolutely no power penalty. This is demonstrated by the fact that our M4F-based Apollo MCU power consumption numbers are far lower than even the competing M0+ solutions from all other suppliers. The second reason is due to the fact that some of the major markets Ambiq is targeting – like wearables and IoT – are increasingly dependent on large numbers of sensors and complex algorithms. Having an M4F core is a great advantage for these applications since it is possible to execute instructions far faster than what is possible when using an M0+ solution. The end result is the best solution possible: power consumption levels that are below even competing M0+ solutions combined with the performance of an M4F processor. Therefore, the key competitive advantage that Ambiq’s Apollo MCUs offer are power consumption numbers that are dramatically lower than all other competing solutions.
Texas Instruments Inc.
Texas Instruments has been a forerunner in developing ultralow power μcontrollers for nearly two decades. The FRAM based MCUs known as the MSP430FR family features a 100μA/MHz of Active mode and 3μA sleep mode consumption. These are excellently fit for low power data logging applications as the FRAM in the MCU can be used to store the data at almost 100 times faster than flash/EEPROM and near to 250 times lower power consumption during the data write. Recently, TI has also introduced world’s lowest power ARM Cortex M4F based μcontroller family known as MSP432 MCUs. This family of M4F μcontrollers built over MSP430 DNA provides a unique advantage of 2X more processing power than M3 based μcontrollers at half the power. With an active mode consumption of 95μA/MHz and a standby consumption of 850nA, the customers will never have to compromise performance over power consumption.
Conclusion
Low power consumption in microcontrollers is becoming an essential demand of designers and applications in most of the areas, keeping circuit topologies & cost un-tacked. Many global companies are working in this line and coming us with breakthrough results.
