How Timing Devices Improve Safety and Efficiency in EV Charging Systems

As EV charging power rises from 50 kW to 350 kW and beyond, charging times are shrinking from hours to minutes. Behind this progress are timing devices that provide stable, accurate clock signals i.e. the system’s “heartbeat.” In EV charging systems, these devices do more than establish operating frequencies: they support synchronized communication, precise power conversion, and reliable system control. This article examines the role of timing devices in charging applications and explains how Murata’s automotive-grade crystal units, CERALOCK® ceramic resonators, and Hybrid Crystal Resonators address requirements for precision, compact size, and reliability.

In electric vehicle fast-charging systems, the core task of timing devices is to generate stable and accurate clock signals (CLK) for each control unit and communication network throughout the system, ensuring that all operations work together at the correct points in time, playing a core role similar to a "system heartbeat." It is not only the cornerstone of error-free communication in in-vehicle networks (CAN, Ethernet), but also the important contributor for the battery management system (BMS) to accurately monitor battery status and the on-board charger (OBC) to achieve efficient power conversion. In harsh environments with high voltage, high current, and rapid temperature changes, the accuracy and reliability of timing devices can affect system safety of the charging process and the service life of the battery.
 
In the high-voltage, high-current environment of fast charging, the accuracy of timing devices is directly related to system safety, efficiency, and reliability. First, timing devices ensure communication synchronization and avoid errors, because fast charging involves real-time data exchange between the battery management system, on-board charger, and charging pile (via protocols such as CAN, FlexRay, and Ethernet). Timing devices provide accurate clock references for these communications, ensuring that high volumes of real-time data are sampled and interpreted at the correct times. Especially in modern smart cars, where various wireless communications (such as BLE, ZigBee™) and UWB (Ultra-Wideband) for vehicle positioning and secure entry are interwoven, high-precision clock sources are key to avoiding mutual interference and communication errors.
 
In addition, timing devices are key components for meeting strict safety and reliability standards, supporting high-frequency power conversion, ensuring precise control, and improving efficiency. The switching timing control of high-speed power switching devices such as SiC and GaN in OBCs and DC-DC converters directly depends on accurate clock signals. For example, the BMS needs to accurately monitor battery voltage, current, and temperature to calculate state of charge (SoC) and state of health (SoH). The accuracy of these operations is directly affected by the quality of the clock signal, which in turn determines charging efficiency and battery life.

As electric vehicles develop toward higher voltage, high-power fast charging, and advanced intelligence, the importance of timing devices is also becoming increasingly prominent. For example, they must cope with extreme environments, because fast charging generates enormous heat, and timing devices must remain stable at high temperatures to prevent frequency drift that may degrade performance or cause malfunction. Timing devices are also the foundation for supporting high-speed communications. As in-vehicle networks evolve toward higher-speed Ethernet, the accuracy requirements for clock sources have increased from the past level of hundreds of ppm (parts per million) to ±40 ppm or even tighter.
 
In addition, timing devices can simplify production and reduce costs. High-precision timing devices can eliminate the calibration processes necessary in the production of traditional crystal oscillators, significantly reducing manufacturing complexity and cost. Timing devices are also a factor in promoting system miniaturization. By integrating load capacitors and other design features, timing devices can significantly save PCB space (for example, saving about 48%), helping charging systems develop in a more compact, high-power-density direction. In summary, in electric vehicle fast-charging applications, timing devices have evolved from a basic frequency component to a key device that determines system performance, safety, and cost.
 
On the other hand, automotive electronic components must meet stringent automotive standards such as AEC-Q200, and timing devices need to operate stably over a wide temperature range from -40°C to +150°C, and withstand vibration and shock. Their accuracy and reliability are supporting the achievement of system-level functional safety requirements.

Murata's timing devices are the key cornerstone for ensuring precise control, stable communication, and system safety in electric vehicle charging systems. With the popularization of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), the demand for clock signals in core modules such as on-board chargers, battery management systems, and DC-DC converters is growing. Leveraging its extensive expertise in ceramic and crystal technologies, Murata provides a complete product matrix ranging from Crystal Units, CERALOCK® ceramic resonators, to Hybrid Crystal Resonators (HCR) to address various challenges faced by charging systems in harsh environments.
 
In electric vehicle fast-charging systems, the role of timing devices is to provide accurate and stable clock signals for each control unit (ECU) and communication network in the system. These clock signals are the foundation for all electronic control units to work properly and communicate with each other. Murata's Crystal Units, CERALOCK® ceramic oscillators, and Hybrid Crystal Resonator (HCR) series products can meet the stringent requirements of fast-charging applications for high precision, high reliability, and high temperature resistance. During the fast-charging process of electric vehicles, Murata's timing devices are mainly used in the following core areas.
 
First is the Battery Management System (BMS), which is the "brain" of fast charging, responsible for monitoring battery voltage, current, temperature, and other statuses. Timing devices provide accurate clocks for the BMS to ensure accurate calculation of the battery's state of charge (SoC) and state of health (SoH), thereby safely controlling the charging process.
 
In the On-Board Charger (OBC), which is responsible for converting AC power from the charging pile into DC power and charging the high-voltage battery, timing devices provide control signals for its internal high-frequency switching power supplies, directly affecting charging conversion efficiency.
 
The DC-DC converter module is responsible for converting high-voltage battery power into 12V or 48V low-voltage power to supply low-voltage systems such as interior lighting and infotainment. Timing devices ensure its stable and efficient operation.
 
In terms of in-vehicle local area network communication, fast charging involves real-time data exchange between the BMS, OBC, and charging pile, usually via in-vehicle networks such as CAN or FlexRay. High-speed, reliable communication depends on accurate and stable clock sources.

Murata provides three major categories of timing devices for automotive applications, including Crystal Units, CERALOCK® ceramic resonators, and high-precision Hybrid Crystal Resonators (HCR).
 
Crystal Units are suited to applications requiring high accuracy and long-term stability (such as Ethernet communication, ADAS, etc.), Murata offers a series of automotive-grade crystal units. Murata's automotive-grade crystal units can operate stably over a wide temperature range (-40°C to +125°C), and even up to extreme temperatures of +150°C.
 
Murata's crystal units offer a wide variety of frequencies and precision, covering a broad frequency range from 16MHz to 50MHz, with frequency tolerance options from ±15ppm to ±100ppm. For specific applications such as Ethernet, products meeting standards such as 50MHz ±50ppm are also available. In addition, Murata employs robust original packaging technology to achieve small-size, high-quality (low ESR, impact-resistant) crystal units. Some products further enhance reliability in vibration environments by strengthening solder crack resistance (dual-terminal electrode design).
 
Murata's automotive-grade CERALOCK® ceramic resonators are renowned for their high reliability, ease of use, and cost-effectiveness, holding a very high market share in the automotive market. The biggest feature of the CERALOCK® series is its built-in load capacitors, eliminating the need for two external load capacitors as required by traditional crystal units. This simplifies oscillator circuit design and saves about 48% of PCB board space, contributing to the miniaturization of charging system modules. In addition, the CERALOCK® series also offers excellent high-temperature resistance, complies with the AEC-Q200 standard, and some products can support operating temperatures up to 150°C, making them particularly suitable for installation near batteries or engines. They are also suitable as a clock source for CAN-based ECUs. The CERALOCK® series also features high reliability. Murata has over 30 years of global market performance in automotive ceramic oscillators and has provided support for matching more than 40,000 ICs, supporting compatibility with a broad range of ICs on the market, with proven reliability over time.
 
Another Murata timing device is the Hybrid Crystal Resonator (HCR). The HCR combines the packaging technology of ceramic resonators with the high-precision characteristics of quartz crystals, specifically designed to meet the needs of next-generation automotive electronics. The HCR offers ultra-high precision. Its XRCGE_M_F series is the world's first automotive-grade timing device to achieve a total frequency tolerance of ±40 ppm (including temperature characteristics and long-term aging) over a wide temperature range from -40°C to +125°C. It combines the technical essence of ceramic resonators and crystal resonators, setting a new standard for next-generation automotive electronics. In addition, the HCR requires no additional calibration or temperature compensation. Thanks to its extremely high full-temperature accuracy, systems do not require additional calibration or temperature compensation measures during design and production, reducing development complexity and cost.
 
On the other hand, the HCR features a compact and rugged package. Using Murata's proprietary resin-sealed packaging technology, the device is small in size (for example, 2.5 x 2.0mm), while offering impact resistance and solder crack resistance, ensuring long-term reliability. The HCR also supports high-speed communication. Its high precision makes it highly suitable as a clock source for high-speed in-vehicle networks (CAN, Ethernet, etc.) as well as wireless communications such as BLE and UWB, and it meets the stringent requirements of ADAS (cameras, LiDAR, radar) and wireless communications (BLE, UWB, etc.) for clock sources.

In the development blueprint for electric vehicle fast charging, "speed" and "safety" have always been the two equally important priorities. Timing devices are precisely the key link that maintains both. From ensuring that communication never "misses a beat" to guaranteeing accurate power conversion, their role has shifted from traditional peripheral components to core strategic components that determine system performance. Facing the stringent demands of fast-charging systems for high temperature, high precision, and high reliability, Murata, with its more than 30 years of deep experience in automotive timing, provides a complete product spectrum ranging from easy-to-use and efficient crystal units, CERALOCK® ceramic resonators, to the ultimate-precision HCR. These solutions not only simplify customers' design complexity but also help enable safer and more efficient electric vehicle charging experiences. As the industry continues to move toward ultra-high-voltage fast charging, a precise and reliable "system heartbeat" will be the key to determining future competitiveness.