The standby power challenge: Wake-up receivers to the rescue

A large fraction of the average power dissipation of many modern multimedia components and mobile devices is spent in standby mode, scanning for potential input activity. Reducing the dissipation of the “always-on” components is essential to the realization of green devices. The common strategy is to duty-cycle the always-on components. While simple to implement, it comes at the expense of latency. A more effective approach that delivers both low standby-power and almost-zero latency is to exploit ultra low-power wake-up receivers. Combining innovative architectures with state-of-the-art CMOS and MEMS technologies, wake-up receivers have been built that consume less than 50 uW in on-mode. Their availability opens a whole new perspective on standby power management. On one end of the spectrum, they enable green devices to operate in a purely reactive mode, that is they are only turned on when input activity happens. On the other side, they allow for substantial improvements in existing communication protocols such as WiFi and Bluetooth. A number of examples will be presented in the talk. One important message that will emerge from the presentation however is that effective standby power management requires a system vision, and that the ad-hoc component-oriented approach of today will rarely be effective.