High voltage (HV) bucks are widely used to power smart home IoT devices, home appliances, auxiliary power for industrial power, and E-meters. They are simple in design, low cost and require very little board space. Many electronic products use Bluetooth® Low Energy (BLE) to exchange data through PCs, smartphones, as well as dedicated BLE gateways. BLE has become one of the most popular standards for IoT applications. Renesas created a smart switching application by combining our HV buck and RX23W 32-bit microcontroller (MCU). This reference design shows a simple and effective design for a wall switch for smart appliances.