Low Power Digital Clock Multipliers for Battery-Operated Internet of Things (IoT) Devices

The recent advancements in system-on-chip (SoC) and network-on-chip (NoC) have enormously increased the number of on-chip frequency domains that are originating from multiple on-chip clock sources. In modern battery-operated internet of things (IoT) devices, limited power budget and requirement for complex clock distribution schemes increases the usage clock multipliers. These multiple clock signal requirements are usually catered for by using frequency multipliers with clock generators. However, most of these multipliers are based on analog components that require a customized layout, involve timing uncertainties, and are power hungry and highly prone to mismatches in the process variations and environmental changes. Moreover, in modern battery-operated smart devices for IoT have very limited power budget, which makes the design of clock multipliers even more challenging. To address these issues, we propose a delay-based digital frequency multiplier, which uses 2-input XNOR gates and a true single-phase clock (TSPC) flip-flop because of pulse generation and edge detection properties, respectively. The proposed multiplier is based on the digital components, therefore, it reduces the power consumption significantly, i.e., 1.6mW, which is almost 50% lesser than other low power state-of-the-art designs. Moreover, it can operate for a wide range of input frequencies, ~400MHz to 1GHz. The Monte-Carlo simulation results are very promising as they indicate the robustness of the design against process and environmental variations.