Low power integrated audio processors sounding like an enabler for new generations of wearable products
The need to reduce the size and power requirements of the electronics in portable devices creates tough demands for component manufacturers. So the growing trend and increased popularity of even smaller wearable products is taking that challenge to an even higher level.
Voice recording and audio playback are two very common features in wearable and small form factor portable electronics – smartphones and Bluetooth headsets being two prime examples. In these applications the need for multiple high quality, advanced digital signal processing (DSP) algorithms implemented with minimal power and component counts, is highly desirable if ergonomic and aesthetic end products that do not compromise on performance are to be realized.
Wearable devices – a new market category that hardly existed a few years ago has been grabbing headlines recently. The category covers anything that can be worn – glasses, clothing, footwear, watches, wristbands and more. The sector is being driven by its ‘newness’ – there is no installed base so everyone who sees the benefit of these ‘constant companions’ needs to make a purchase – and the market is not just limited to humans, there are wearable devices for pets too.
Given that the market is so new it is not surprising to see rapid growth. According to research by International Data Corporation (www.idc.com) there were 80 million units shipped in 2015. IDC predict growth in excess of 40% for 2016, leading to 111.1 million shipments and looking further ahead, the wearable market is forecast to maintain a CAGR of 28% leading to around 215 million devices shipping in 2019.
Alongside this rapid growth, we are seeing rapid development. This is driven by a number of factors – new startups racing to bring new devices out to participate in the market and more established players seeking to hone their designs, adding more functionality or reducing size – or both. The fact that some devices are in their second or third iterations in a market space this new just underlines the rapid development we are witnessing.
As with any market, consumers are putting pressure on manufacturers and designers to constantly deliver better performance, smaller size and lower cost products to the market. Within the wearable market the key criteria for success include connectivity, functionality, size and time between battery charges.
One of the major challenges facing suppliers of wearable devices is ‘stickiness’. With the earlier devices, all too often once the novelty value had worn off, they were consigned to a drawer – a sure indication that they had not become compelling in the eyes of the user. To address this, manufacturers have to keep pushing on the key criteria to develop devices that, literally, cannot be put down.
Looking at the evolution of the smartphone market we can illustrate the point. Early mobile telephones were only suitable for mounting in a car, then they evolved to fit in a briefcase, then a pocket and now you can wear a fully-fledged smartphone on your wrist. All the time that the size was decreasing and battery life was being stretched, functionality was spiraling leading to the advanced devices we have today – that have now become our constant companions.
The wearable market is a long way down this path already, but it will continue to follow a similar trajectory with devices getting smaller, smarter and less power-hungry until we reach the point that wearable devices become fully integrated parts of our daily lives.
Not unsurprisingly, some of these key criteria start to lead us in opposing directions. Greater functionality moves us in the direction of more sophisticated software with greater memory requirements, more sensors – which require space and power to operate – and more intuitive user interfaces that need more buttons and more space. The challenges are similar across many areas of technology, but nowhere are they more sharply focused than in the wearable market.
Microphones with sizes around 1mm square are now available and the size remains constant no matter how large the instruction set becomes. When coupled with a low power, high functionality DSP the solution becomes very attractive.
A solution such as ON Semiconductor’s LC823450 low power, high-resolution audio processing system can act as an enabling technology for audio advanced recording and playback applications in miniature wearable devices. Based around a dual core ARM Cortex-M3 processor and a proprietary 32-bit DSP core the system-on-a-chip (SoC) incorporates 1656KB of SRAM and is capable of high-resolution (32-bit) / 192kHz audio processing.
Figure 1: Block Diagram of the LC823450 low power, high resolution audio processing system
The ultra-low power consumption offers audio playback times in excess of 120 hours when used with two AAA batteries – around 1.7x the playback time available from competitive products.
Figure 2: The LC823450 provides 70% longer playback time than that of other LSIs
The tiny footprint of the XA and XB versions (just 5.52mm x 5.33mm) is substantially smaller (c50%) than alternative solutions – especially when considering some other solutions do not offer on-board SDRAM.
Figure 3: The LC823450 offers features ideally suited to mobile devices, especially wearable
The advanced DSP algorithms include noise cancellation for the microphone and ‘S-Live’ (Low frequency Intelligence Virtual Excitation) that manages low frequencies to give the user the experience of listening to much larger speakers. The noise cancellation and ‘S-Live’ are just two examples of the large selection of royalty- and license-free DSP code libraries available to designers to accelerate software design and minimize development costs.
The wearable market is set to be ‘the next big thing’, but the solutions have to be sufficiently attractive in terms of performance and form factor to persuade consumers to buy. Some functions are new, many are not – but in all cases they are being fitted into smaller spaces and constrained by power requirements.
Without these innovative functions and features in the end products the wearable market will not reach its full potential and without innovative, groundbreaking solutions like this advanced DSP solution the necessary functions and features will not be sufficiently compelling. Breakthrough technology like this is truly enabling the wearable market.
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
