Description
The RD8 reference design board is an example of a low cost production worthy design for an AC wall adapter or similar applications requiring small size, high efficiency, and low cost. The RD8 utilizes the TNY254 member of the TinySwitch family of low cost Off-line Switchers from Power Integrations. It is intended to help TinySwitch users develop their products quickly by providing a production ready design which needs little or no modification to meet system requirements. The RD8 is designed to replace conventional linear AC wall adapters, offering universal input range, smaller size, and high efficiency, all at a competitive cost. The RD8 is cost-competitive with linear solutions (regulated 50/60 Hz transformers).
The unique ON/OFF control scheme of Tinyswitch virtually eliminates energy consumption at no load. Typical linear wall adapters consume 1-4 watts at no load, which costs $1-$4 per year ( based on $0.12/kWhr). In comparison, a typicalTinySwitch supply consumes 30-70 mW at no load, offering substantial energy savings.

Low Cost Production Worthy AC Adapter Reference Design
• Cost competitive with linear solutions (regulated 50/
   60 Hz transformers)
• Lowest component count switching solution
• Ultra low no-load power consumption (30/70 mW @115/
   230 VAC)
• Simple low cost two-winding transformer
• Greater than 72% efficiency
• Low average EMI, only one inductive component
   required for EMI filtering
• Small size

Designed for World Wide Operation
• Designed for IEC/UL safety requirements
• Meets FCC/VDE Class B EMI specifications
• Wide range input voltage