*Article* **Idleness-Aware Dynamic Power Mode Selection on the i.MX 7ULP IoT Edge Processor**

#### **Alfio Di Mauro 1,\*, Hamed Fatemi 2, Jose Pineda de Gyvez 3 and Luca Benini 1**


Received: 15 April 2020; Accepted: 20 May 2020; Published: 5 June 2020

**Abstract:** Power managemen<sup>t</sup> is a crucial concern in micro-controller platforms for the Internet of Things (IoT) edge. Many applications present a variable and difficult to predict workload profile, usually driven by external inputs. The dynamic tuning of power consumption to the application requirements is indeed a viable approach to save energy. In this paper, we propose the implementation of a power managemen<sup>t</sup> strategy for a novel low-cost low-power heterogeneous dual-core SoC for IoT edge fabricated in 28 nm FD-SOI technology. Ss with more complex power managemen<sup>t</sup> policies implemented on high-end application processors, we propose a power managemen<sup>t</sup> strategy where the power mode is dynamically selected to ensure user-specified target idleness. We demonstrate that the dynamic power mode selection introduced by our power manager allows achieving more than 43% power consumption reduction with respect to static worst-case power mode selection, without any significant penalty in the performance of a running application.

**Keywords:** edge devices; power management; energy efficiency
