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his reference document describes a built – and – tested, GreenPoint t solution for an xDSL modem AC-DC adapter. This power supply reference design is intended for low power, offline applications where a regulated output voltage is required. Applications would also include modems, printers, routers, hubs and/or similar consumer audio and video products that require a single output voltage in the 10 to 20 W range.
The power supply design is based around ON Semiconductor’s NCP10xx family of monolithic controllers with an integrated 700 V MOSFET. In this particular design an NCP1027 is utilized in a 12 V, 1.3 A output supply with a surge capability of over 1.6 A.
This design can be tailored for any output voltage from several volts up to 28 V (or higher) with power outputs to approximately 20 W (depending on the AC input requirement) by merely reconfiguring the transformer turns ratio and the voltage reference zener. The power supply will meet typical safety agency isolation and leakage current standards and comply with FCC Part 15 Level B conducted EMI requirements and has an average efficiency of greater than 75%.