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ON Semiconductor Introduces a Highly Efficient GreenPoint™ Reference Design for 60 Watt Power Adapters

PHOENIX, Ariz. - ON Semiconductor (Nasdaq: ONNN), a leading global supplier of power management solutions, today unveiled it’s fifth GreenPoint™ reference design – this one for 60 watt (W) power adapters used to power LCD TVs and monitors, notebooks and other consumer products. This new reference design addresses the sometimes tedious design challenges inherent in meeting both standby and active mode energy efficiency regulations, and yet, it offers a cost effective solution.

Providing true energy efficiency, ON Semiconductor’s latest design blueprint addresses all functional blocks of the power adapter and achieves low standby power and compliance with CEC, Energy Star and European Code of Conduct (COC) requirements. It delivers 88 percent energy efficiency. It further conserves energy in standby mode – the mode in which power adapters typically spend the most time - by consuming less than 250 milliwatts (mW) of power. Today, most 60 W adapters in use are consuming 750 mW in standby mode.

“The new 60 watt power adapter reference design joins our previously announced 90 watt GreenPoint™ notebook adapter design, and helps strengthen our position as a leading silicon supplier for energy efficient power adapters”, said Andy Williams, senior vice president of ON Semiconductor’s Automotive and Power Supply Group. “This particular design addresses applications where high efficiency and adapter size are crucial at an optimal cost. By the end of the year, ON Semiconductor plans to introduce additional GreenPoint™ reference designs to cover a wide variety of power applications.”

The Reference Design
The enabling device for the reference design is the newly introduced NCP1337, an enhanced Pulse Width Modulation (PWM) current-mode controller. It combines a true current-mode modulator and a demagnetization detector – that ensures full borderline/critical conduction mode in any load/line. The device eliminates the need for an external signal, by providing internal transformer core reset detection. Frequency is internally limited to 130 kilohertz (kHz) to facilitate the compliance with EMI conducted emission standards, the lowest limit being 150 KHz.

By monitoring the feedback pin activity, the NCP1337 enters ripple mode as soon as the power demand falls below a pre-determined level. Because restart is softened by an internal soft-start and the frequency cannot fall below 25 kHz, no audible noise is emitted. The controller features an efficient protective circuitry that, in the presence of an overcurrent condition, disables the output pulses and enters a safe burst mode when trying to restart. Once the default has gone, the device auto-recovers and the power supply resume operation.

Additional features include a bulk voltage monitoring function known as brown-out protection, an adjustable overpower compensation that tackles the effect of the input voltage variation on the maximum power a quasi-resonance PSU can deliver , and an Over Voltage Protection on the Vcc. An internal 4.0 millisecond (ms) soft-start eliminates the traditional startup stress.

The NCP1337 is ideal for use in power adapters, offline battery chargers, CRT-TV power supplies, other consumer electronics such as DVD players and set-top boxes – primarily any power supply where efficiency and low EMI signature are needed.

The device is offered in both an SOIC-7 and a PDIP-7 package and priced at $1.04 per unit in 2,500 unit quantities.

Supporting Devices
TL431A – Programmable Precision Reference
NTP75N06 – 75 A, 60 V MOSFET
MBR160 – 1 A, 60 V Schottky Rectifier
1N4937 – 1 A, 600 V Fast-Recovery Rectifier
MMSZ13, MMSZ15 – 500 mW Zener Diodes
MMSD4148 – Switching Diode
MMBT3904L, MMBT3906L – General Purpose Transistors

A complete documentation package for the 60 W power adapter is available - including description, block diagram, schematic, bill-of-materials, Gerber images, and evaluation results.

Lunes, 12 Junio, 2006 - 11:38
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