This engineering report describes a non-dimmable, non-isolated buck-boost high side LED driver designed to drive a nominal LED voltage string of 75 V at 240 mA from a wide input voltage range of 90 VAC to 308 VAC. The LED driver utilizes the LYT5228D from the LYTSwitch-5 family of devices. The LYTSwitch-5 is a family of devices which are designed especially for non-dimmable wide range ac input LED drivers with a single stage PFC function and accurate LED current control. The DER-526 provides a single 18 W high density constant current output. The key design goals were high efficiency, low THD, high surge voltage immunity, low component count and low height profile. This design is ideal for LED tube applications. The document contains the power supply specification, schematic, bill of materials, transformer documentation, printed circuit layout, design spreadsheet and performance data. Figure 1 –Populated Circuit Board.