Today, virtually every aspect of the IoT device’s design is focused on making sure it is as energy efficient as possible (Figure 1). For a smartphone, for example, that might mean making it an order of magnitude better, but this won’t happen overnight. On the contrary, it will happen in steps over multiple generations of products. IoT devices must be created with energy efficiency as a prime concern at all levels.
Most IoT applications are required to be “Always-On”. In the most minimalistic example, the IoT terminal is in a standby mode, waiting for some human interaction to wake it up. Yet if an active processor is used to monitor the device for user interaction, the device will consume significant power. The main processor, the processor core in the wireless module, and the display are the biggest consumers of power. In IoT terminals, unique approaches must therefore be employed to minimize the power profile.
One aproach provides “always-on” solutions using a small, low-power FPGA to monitor sensors, buttons, or even voice commands. The processors, wireless modules, and displays can be left in a standby mode until the FPGA determines the user’s need to “wake-up” the terminal and provide service.
In addition to low power, this architecture enables modal state power management with some granularity on what mode the device is actually in — is it on or off, is it sleeping or partially awake — allowing it to dynamically go from one phase to another. This approach offers significant power savings, resulting in longer battery life, longer display lifetime, and lower thermal radiation.