Renesas’ 500-watt onboard charger reference design uses gallium nitride transistors to enable electric two-wheelers to charge directly from standard AC outlets without specialised charging infrastructure.
Renesas has published a 500-watt (W) onboard battery charger reference design for electric two-wheelers, including scooters and motorcycles. The design allows the charger to be integrated into the vehicle, enabling the battery to be charged from a standard home AC socket instead of requiring a dedicated charging station. This can simplify charging for electric two-wheelers in applications where dedicated charging infrastructure is limited.
The reference design uses a two-stage architecture: a power factor correction (PFC) stage that converts incoming alternating current (AC) into a regulated direct current (DC) bus, followed by an LLC resonant converter that steps the DC voltage down to the battery-charging level. According to Renesas, the LLC stage achieves more than 95% peak efficiency during DC-to-DC conversion. The platform supports universal AC input, allowing the power-conversion architecture to accommodate common mains-voltage ranges across different markets. Engineers can configure and test the design remotely through Renesas’ Lab on the Cloud tool, a PC-based graphical interface that connects to the reference hardware for testing before building a physical prototype.
The TP65H070G4PS is a 650-volt (V), 72 mΩ gallium nitride (GaN) field-effect transistor (FET) in a TO-220 package. It is used as the switching device in both the PFC and LLC stages. Its low on-resistance, low gate charge and reduced switching and reverse-recovery losses help improve conversion efficiency and enable higher power density compared with conventional silicon devices, which can simplify thermal management in the limited space available inside a two-wheeler.
The RL78/F14 is a low-power, 8/16-bit microcontroller (MCU) designed for automotive applications. It includes an integrated CAN controller for automotive communication, with an external CAN transceiver providing the physical bus interface. The MCU enables the charger to report battery health, load connection and disconnection events, and other housekeeping information to the end device.
The RAA223181 is a 900-volt (V) off-line flyback regulator used for the platform’s low-voltage power supply, separate from the main high-voltage charging path. It controls an isolated auxiliary flyback supply, while the final isolation rating depends on the transformer, PCB creepage and clearance, insulation system and overall implementation.
According to Renesas, the reference design includes schematics, a bill of materials and PCB layout data. It can also be configured and tested remotely through Lab on the Cloud using a PC-based graphical interface, without requiring access to a physical board. The platform provides a reference architecture for developing onboard chargers for electric two-wheelers.
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