ON Semiconductor introduced a GreenPoint open reference design for a 16 watt (W) ac-dc adapter for xDSL modems. This design exceeds ENERGY STAR requirements for single voltage ac-dc and ac-ac external power supplies revision 1.1, for high active-mode power efficiency and low standby-mode power consumption. The reference design can also be modified for use with 10-20 W, single output-voltage adapters for printers, routers, and hubs. This fully-implemented and tested solution achieves active-mode efficiency of 78 percent at 120 Vac and 79 percent at 230 Vac, exceeding ENERGY STAR guidelines of 74 percent for both input voltages. In standby-mode, the solution consumes 240 milliwatts (mW) at 120 Vac and 200 mW at 240 Vac, exceeding ENERGY STAR guidelines of 0.5 W for both input voltages.
In addition, the design complies with FCC Part 15 Level B EMI requirements. The reference design addresses all functional blocks of the adapter, utilizing several of ON Semiconductor’s power management devices and drawing from its leading discrete component portfolio to achieve superior efficiency performance.
Key Products in the Reference Design Include
NCP1027: This high voltage switcher includes a power MOSFET together with a startup current source, all directly connected to the bulk capacitor. To prevent lethal runaway in low input voltage conditions, an adjustable brown-out circuit blocks the activity until a sufficient input level is reached. Offered in a PDIP-7 package, the NCP1027 is priced at $0.97 per unit in 1,000-unit quantities.
MURS160: This 1 ampere (A), 600 volt (V) Ultrafast Rectifier is offered in an SMB package and priced at $0.20 per unit in 2,500-unit quantities.
MBRS360: This 3 A, 60 V Schottky Rectifier is offered in an SMC package and priced at $0.33 per unit in 2,500-unit quantities.
MMSD4148: This 100 V Switching Diode is offered in an SOD-123 package and priced at $0.04 per unit in 10,000-unit quantities.
MMSZ5241B: This 500 mW Zener Diode, offered in an SOD-123 package and priced at $0.04 per unit in 3,000-unit quantities. All of these devices are RoHS compliant and are delivered in Pb-free packages.
ON Semiconductor has a documentation package for the 16 W ac-dc adapter reference design, including description, schematics, bill-of-materials, Gerber files and evaluation guidelines.
