Efficient energy consumption in technology is critical, especially since the characteristics of a semiconductor can change during its operation when the temperature or voltage varies. Our i.MX RT500 Crossover MCU is ideal for many low-power applications, thanks to having a process, voltage and temperature (PVT) sensor that can be used for dynamic voltage scaling (DVS).
This PVT sensor measures the immediate performance, giving users the ability to adjust the voltage of a system in order to bring the ideal balance. The DVS PVT sensor application software pack innovates how users can adjust and customize their application’s power. This software pack helps users reduce power and lower the voltage below the minimum specifications in the data sheet.
The PVT sensor is designed to help reduce voltage and power in active modes, including the i.MX RT500 Crossover MCU sleep mode. It is a peripheral on the i.MX RT500 that monitors the timing margin of the main_clk in the VDDCORE power domain at runtime. It triggers an interrupt when this timing margin is not met, which indicates VDDCORE must be increased to meet the required timing. This can be used to create a closed-loop system using an external PMIC to adjust the voltage to VDDCORE. When conditions change and the PVT sensor indicates VDDCORE must be increased, the application requests the PMIC to increase this voltage through I2C. Using the PVT sensor can reduce power by up to 30% and additional details on the power savingscan be found in the DVS using the PVT sensor on i.MX RT500 application note.
In the graph below, you can see when the temperature changes over time and how the VDDCORE voltage is optimized. The application tests lower VDDCORE voltage levels and if there are no detected timing issues, the PVT sensor will allow the VDDCORE to remain at the new voltage. The VDDCORE can also be adjusted based on the current temperature.
Simplification is a key goal of the DVS PVT sensor application software pack. That's why, with minimal steps, the PVT sensor library can be added to your project. Additionally, the application software pack example code provides a reference to leverage the same power saving techniques in your application. In Section 8 of the lab guide, it shows users how to add the library to your code and optimize the power consumption. The PVT sensor library included in the application software pack features easy to use functions to quickly integrate in your application and start saving power. In the image of the i.MX RT595EVK (Part number: MIMXRT595-EVK) below, the red boxes indicate all the locations to follow the lab guide, to measure the voltage and power, and evaluate the PVT sensor.
The PVT sensor integrated on the i.MX RT500 is a great option to increase the battery life of applications. Using this DVS PVT sensor application software pack will optimize the voltage leveraging the PVT sensor resulting in power savings.
Derek Snell has been focused on supporting NXP micro-controllers since 2008. He has spent that time supporting customers, writing examples and application notes, creating trainings, improving software and enablement, and optimizing MCU power and performance. A graduate of Rose-Hulman Institute of Technology, he currently resides in Indianapolis, Indiana.
