The advantages of RTC module in automotive battery management system

. 1 Engine Type Automotive Market Forecast

Lithium ion batteries have become the mainstream rechargeable batteries used in electric vehicles. Although these batteries are highly energy-efficient, they also carry a fire risk if not properly managed. Therefore, a BMS is needed to safely manage the health status of lithium-ion batteries. BMS is a system that monitors and manages the input/output current, voltage, and temperature of lithium-ion batteries. Overcharging or discharging of batteries, or voltage differences between battery cells, can lead to battery failure and reduced lifespan. Even after the engine is shut down, the BMS must be shut down in this way

Continue to monitor the battery regularly, which is enabled by the RTC function within the BMS.

Figure 2 BMS Outline Drawing

[RTC Function Configuration]

There are three system configurations to implement RTC functionality: (1) Use RTC modules

(2) Using the built-in RTC function of a microcontroller (3) Using RTC IC

Table 1 Configuration and Function of RTC Function

The selected configuration is based on the specifications required by the application and

The customer's design philosophy.

The RTC module in configuration (1) refers to a crystal oscillator and RTC product

Combined into one software package. Its advantages are high accuracy and low current consumption,

Compared to other configurations, there is no need to save board space, making it easier to design as a circuit evaluation. Epson has a wide product lineup of RTC modules.

[Advantages of Epson's RTC module]

As mentioned above, BMS is an application that regularly monitors batteries to ensure safety. Therefore, BMS manufacturers require equipment components to be highly reliable and designed

Used by vehicles with AEC-Q qualifications.

By designing, developing, and manufacturing built-in crystal units and internal RTC integrated circuits,

Epson can provide stable, highly reliable, and traceable RTC modules. Other

The following will discuss the advantages of using the Epson RTC module.

1. High operating temperature

BMS equipment components typically require an operating temperature range of -40 ° C to+125 ° C

Because the BMS may need to be placed near the battery pack or in the environment in front of the car

The maximum temperature can reach 125 degrees Celsius. For autonomous driving and ADAS, their quantity

The processing and information processing in MCU have increased, which also drives the surrounding environment of the car

The temperature rises. Observing the operating temperature range

The automotive application has also increased by+125 ° C.

To meet these needs, Epson has a series of RTC modules designed to operate at temperatures ranging from -40 ° C to+125 ° C.

2. Automotive quality support

Automotive semiconductors require stricter environmental and quality conditions than consumers

In addition, reliability testing is conducted under stricter testing conditions

Prove that the number of components installed in applications has increased in recent years

With the increasing popularity of electric vehicles and the advancement of autonomous driving technology

The safety standards for automotive electronic components are developed by automotive electronic product companies

The Council (AEC) is a standardized development organization. The AEC standard is a reliability testing standard

Targeted electronic components used in cars around the world and classified their standards

Based on components such as semiconductors and passive components. Because the RTC module

Semiconductor, Epson's RTC module is AEC-Q100 compatible and currently used in various applications

Automotive applications.

3. Low current consumption

The maximum limit requirement for the dark current value (parasitic battery consumption) of each car module has been reduced to maximize the battery life during each charge. If the vehicle generates higher dark current, the battery will discharge at a faster rate and provide the driver with shorter driving time

A series of

Due to the BMS regularly checking the battery status after the engine is shut down, the distributed dark current value needs to be very small. Therefore, the low current consumption RTC module can serve as an independent timer, reducing the running time of the microcontroller and reducing dark current.

The Epson RTC module has the following advantages in reducing dark current consumption.

A combination design for low current consumption operation optimization

Clock RTC IC.

RTCIC design adopts Epson's low leakage process

Using these unique technologies, the current consumption in backup mode is only 300nA typ.

(Epson Automotive RTC Module), which helps to reduce the overall power of the BMS.

Epson utilizes its advantages in the design, development, and manufacturing of internal crystals and integrated circuits

Provide products that help solve customer problems.

The BMS application of Epson's automotive RTC module.