Mobile phone charger design keeps it green

Reference design exceeds Energy Star requirements for high active-mode power efficiency and low standby-mode power consumption.

ON Semiconductor has introduced a GreenPoint open reference design for a 5W AC/DC adapter for constant current, constant voltage (CCCV) mobile phone chargers.

This reference 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 could also be easily modified for use with low-power single-output-voltage adapters for cordless phone chargers.

This reference design solution achieves active-mode efficiency of 70% at 120V AC and 65% at 230V AC, exceeding Energy Star guidelines of 63.5% for both input voltages.

In standby-mode, the solution consumes only 75mW at 120V AC and 90mW 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 5W GreenPoint reference design expands the power range of our portfolio of power efficient solutions for AC/DC adapters", says Andy Williams, Senior Vice President and General Manager of ON Semiconductor's Automotive and Power Regulation Group.

"This open reference design is just one more example of ON Semiconductor's commitment to assisting customers to streamline their design cycles, meet a wide variety of global efficiency standards and deliver greener power technology solutions to consumers worldwide".

The 5W AC/DC adapter 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 NCP1014, a monolithic switcher that integrates a fixed-frequency current-mode controller and a 700V MOSFET.

The device includes soft-start, frequency jittering, short-circuit protection, skip-cycle and a maximum peak current setpoint.

The NCP1014 is priced at US $0.41-0.43 per unit in 1000-unit quantities for the PDIP-7 package, and at $0.43 per unit in 4000-unit quantities for the SOT-223 package.

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 design also uses the MBRS360, a 3A, 60V Schottky rectifier offered in an SMC package and priced at US $0.33 per unit in 2500-unit quantities.

The MMSD4148 is a 100V switching diode offered in an SOD-123 package and priced at US $0.04 per unit in 10,000-unit quantities.

The MMSZ5229B 500mW Zener diode is offered in an SOD-123 package and priced at US $0.04 per unit in 3000-unit quantities.

And the MMBT2907AW is a PNP transistor offered in a TO-92 package and priced at US $0.08 per unit in 5000-unit quantities.

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

ON Semiconductor has a complete documentation package for the 5W AC/DC adapter reference design, including description, schematics, bill of materials, Gerber files and evaluation guidelines.

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