FRAM GX85RS2MC Compatible FM25V20A for Charging Pile DC Meter Solution

DC meter is an important part of DC charging pile, which is responsible for the metering of electric energy and has a huge market demand. Nowadays, many electric vehicle charging piles are billed by the actual power consumed. Therefore, it is very important to know how to accurately measure the DC electrical energy.

The hardware system solution of the DC meter of the charging pile mainly contains the design of analog-to-digital converter, processor, real-time clock, data storage, and display unit, and the software solution contains the main software framework of the system, the algorithm of voltage-current-power and the fast algorithm of power collection, the algorithm of improving the reliability of power data storage, and the algorithm of using the mass memory as the event logging memory, and in this paper, we recommend the use of FRAM GX85RS2MC instead of the traditional FLASH to store data, which can reduce the hardware cost.

FRAM technology combines many of the advantages of SRAM with the non-volatility of FLASH, and unlike FLASH, FRAM writing does not require pre-erasure cycles, which saves time and power.The GX85RS2MC has the advantages of fast read/write speeds (1,000,000 times), long write life, and low write power consumption.

The GX85RS2MC FRAM has a 2M capacity, provides an SPI interface, operates at 25 MHz, and supports 40MHz high-speed read commands. The chip is configured as 262,144 x 8 bits, which is formed by ferroelectric process and silicon gate CMOS process technology to form a non-volatile memory cell, which does not need a battery to keep data, and the industrial-grade temperature range of -40℃ to 85℃, which is in line with the application environment of the charging pile, and the key parameters are as follows:

- Power consumption: 4.8 mA, standby power consumption 9 microamps

- Operating voltage 2.7V to 3.6V

- High-speed read characteristics: support 40MHz high-speed read command

- 8-pin SOP wide-body 208 mil package, RoHS compliant

- Performance Compatible with MB85RS2MT (Fujitsu) and FM25V20A (Cypress).