Ferroelectric RAM Provides Reliable, Flexible Memory for BEV Powertrains

With stark indicators like Ford and General Motors rushing to build battery plants from Michigan to Tennessee and the Tesla Model Y edging out the Toyota Corolla and RAV4 as the world’s best-selling car, there’s no disputing that the age of automotive electrification has fully arrived. This race forward – fueled by government incentives, consumer demand and climate concerns – continues to drive OEMs and their supply-chain partners to push the envelope for innovation and smart solutions.

One area of industry advancement that now has broad ramifications for the burgeoning battery-electric-vehicle sector is systems memory, with R&D departments around the globe searching for ways to upgrade the read/write capabilities of non-volatile memory (NVM), now the industry standard.

Critical for data-dependent applications requiring frequent updates in industries as diverse as telecom, factory automation and the medical field, NVM is crucial for automotive systems, because it allows a vehicle’s electronic components to remember important information, settings and software instructions. Unlike other types of memory such as random-access memory (RAM), which lose their stored information when the power is switched off, NVM is designed to keep the data intact.

But as extensively deployed as they are, today’s legacy NVM systems such as electrically erasable programmable read-only memory (EEPROM) and flash memory have diminished efficiencies for newer vehicles packed with data-hungry electronics. Issues include slower writes, a limited number of write/erase cycles and relatively high energy use because of the need for complex software overheads. Already in use in systems such as event data recorders, tire pressure monitoring, navigation and engine control, a more recent technology, F-RAM, is increasingly being positioned by companies such as Cypress and Infineon as the next-generation solution, particularly for EVs.

Under The Hood

Like previous NVM technologies, F-RAM retains data even when power is turned off. However, F-RAM’s ability to instantly update data without the need for time-consuming write cycles sets it apart. Changes made to F-RAM are immediately stored, ensuring data integrity and reducing latency, a mission-critical feature in automotive applications where real-time data updates are vital. The technology’s feature set also includes excellent durability in terms of data retention and endurance as well as low power consumption.

Getting under the hood, the properties that affirm F-RAM’s superiority to legacy data-logging solutions (and how it derives its name) is the technology’s reliance on the polarity of ferroelectric material. Data is stored by applying an electric field to the material, causing a state that remains intact even when power is removed.

This means that data stored in F-RAM persists across power cycles, eliminating the need for constant rewriting or backup operations. The process is non-destructive and can be performed repeatedly, allowing for frequent and efficient write operations.

Where the F-RAM Meets the Road

In EVs, F-RAM efficiencies become even more important with the extensive use of sensors and data-logging required to maintain the optimal performance of complex ECUs integrated into powertrain operations, including battery management systems (BMS) and inverters.

By their very nature, BMS are complex and make an excellent use case for F-RAM. Key functionalities include protecting each battery cell from damage, prolonging the life of each cell and providing real-time energy distribution to the vehicle. To achieve this, vital parameters are logged in split seconds including voltage, current and temperature to get inputs on cell capacity, state of charge, state of health, power consumption (charge/discharge), remaining operating time of cell and other critical data.

Equally mission-critical to the electric powertrain, EV inverters also have a strong use-case for F-RAM. Data loss prevention through instantaneous and continuous memory storage is essential to log motor position, current, voltage and temperature to ensure optimal operating conditions. With their zero-delay writes, low switching energy, virtually infinite endurance and long data retention (up to 100 years) it’s a safe bet that the low power, high speed attributes of F-RAM will be a major factor as the momentum of the EV category continues to surge ahead.