Adapter design creates greener power supplies

Reference design for 16W AC/DC adapter for xDSL modems exceeds Energy Star requirements and can be easily modified for use with 10-20W single-output adapters for printers, routers and hubs.

ON Semiconductor has created a GreenPoint open reference design for a 16W AC/DC adapter for xDSL modems.

The 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 easily modified for use with 10-20W single-output adapters for printers, routers and hubs.

This fully-implemented and tested solution achieves active-mode efficiency of 78% at 120V AC and 79% at 230V AC, exceeding Energy Star guidelines of 74% for both input voltages.

In standby mode, the solution consumes only 240mW at 120V AC and 200mW at 240V AC, exceeding Energy Star guidelines of 0.5W for both input voltages.

In addition, the design complies with FCC Part 15 Level B EMI requirements.

"ON Semiconductor's new 16W GreenPoint reference design expands the power range of ON Semiconductor's portfolio of efficient reference designs for AC/DC adapters", says Andy Williams, Senior Vice President and General Manager of ON Semiconductor's Automotive and Power Regulation Group.

"By utilising this proven solution, customers can quickly deploy consumer products that comply with evolving efficiency standards in a wide variety of geographic markets".

The reference design addresses all functional blocks of the adapter, using 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 the NCP1027, a high-voltage switcher that 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 brownout circuit blocks the activity until a sufficient input level is reached.

Offered in a PDIP-7 package, the NCP1027 is priced at US $0.97 per unit in 1000-unit quantities.

The MURS160 is a 1A.

600V ultrafast rectifier offered in an SMB package and priced at US $0.20 per unit in 2500-unit quantities.

The MBRS360 is a 3A, 60V Schottky rectifier in an SMC package and priced at US $0.33 per unit in 2500-unit quantities.

The SD4148 is a 100V switching diode in an SOD-123 package and priced at US $0.04 per unit in 10,000-unit quantities.

The MMSZ5241B is a 500mW Zener diode offered in an SOD-123 package and priced at US $0.04 per unit in 3000-unit quantities.

All devices are RoHS compliant and are delivered in Pb-free packages.

ON Semiconductor has a complete documentation package for the 16W AC/DC adapter reference design, including description, schematics, bill-of-materials, Gerber files and evaluation guidelines.

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