New Industry Products

ON Semi's ATX Reference Design Exceeds New ENERGY STAR® Efficiency Standards for Desktop Computers

April 19, 2007 by Jeff Shepard

ON Semiconductor unveiled what it claims is the industry’s first open ATX reference design that meets the new ENERGY STAR® performance requirements for ATX power supplies used in desktop PCs scheduled to take effect this July. The new reference design is claimed to deliver efficiency that exceeds the ENERGY STAR® requirements under all specified load conditions, and provides a blueprint for power supply manufacturers to bring highly efficient power supplies to market with readily available, cost-effective technology.

ON Semiconductor’s reference design achieves full-load efficiency of 86.5% at high-line and 82.5 percent efficiency at 20% of load and low-line. This is said to reduce power losses by approximately 50%, compared to the typical power supplies on the market today that average 70% power efficiency. Additionally, ON Semiconductor’s ATX reference design meets IEC61000-3-2 power factor requirements.

The reference design addresses all functional blocks of the ATX power supply, including power factor correction, switch-mode power supply control and regulation, post regulation and standby power. The design utilizes several of ON Semiconductor’s newest power management devices and draws from its discrete component portfolio to achieve what is claimed to be superior efficiency performance.

Key products in the reference design include the NCP1653, a compact continuous conduction mode (CCM) power factor correction (PFC) controller makes the choice of incorporating a PFC front-end into an ATX design easy, by reducing part count and providing a robust, cost-effective front-end without range switches. Offered in Pb-free 8-lead SOIC and PDIP packages, the NCP1653 is priced at $0.80 USD in 2,500-unit quantities.

The NCP1562 is an active-clamp pulse width modulation (PWM) voltage-mode controller has a ±5% duty cycle limit with a soft-stop to prevent the typical oscillations in the forward active-clamp topology. The device has a dual-mode over-current protection circuit that handles momentary and continuous over-current conditions differently. Offered in Pb-free 16-lead TSSOP and SOIC packages, the NCP1562 is priced at US$1.60 per unit in 2,500-unit quantities.

The NCP1027 is a 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 circuitry blocks the activity until sufficient input level is reached. Offered in a Pb-free 8-pin PDIP package, the NCP1027 is priced at $0.97 per unit in 1,000-unit quantities.

The NCP4330 is a synchronous post-regulator replaces the mag-amp to provide higher efficiency in the output section of the ATX power supply. Offered in a Pb-free 8-pin SOIC package, the NCP4330 is priced at $0.60 per unit in 2,500-unit quantities. The MSR860 is an 8A, 600V power rectifier features SWITCHMODE™ soft recovery. Offered in a Pb-free TO-220 package, the MSR860 is priced at $1.07 per unit in 50-unit quantities.