N2Power, a Qualstar Company, has announced the initial models of the XL275 Series, a family of very compact, 275-watt ac-dc power supplies that feature digital power management capabilities including optional I²C-capability.
The XL275 Series delivers 275W of output power from 15 square inches of system real estate. Very low profile packaging yields 12.22 watts per cubic inch power density. The XL275 family is expressly designed for OEM applications such as industrial automation, telecommunications, gaming systems, security and surveillance systems, and network servers.
“The XL275 Series packs more power in a smaller package than any other product on the market. That gives our OEM customers a distinct edge, while simultaneously reducing overall power consumption and cooling requirements,” said Randy Johnson, N2Power Business Unit Manager. “Our very compact, high-efficiency technology gives OEM engineers and designers new flexibility in their power systems designs that pays real competitive dividends in their final products.”
“Power supplies have traditionally been controlled and protected by analog circuitry that does well under one set of conditions (such as cold startup), but suffers from stored charges in components that do not discharge quickly enough to respond to power line dropouts and load glitches, Johnson continued. “The XL275 breaks that mold by using a dedicated digital microcontroller to supervise the unit’s operation.”
The microcontroller monitors the following power supply parameters: dc voltage on the bulk capacitor (supplied by the ac mains), output voltage, output current, auxiliary 12V output voltage, transformer temperature, ambient temperature, and fan tachometer
Unlike the conventional analog circuitry that can provide timing accuracies in the range of +/- 10%-20%, the microcontroller can provide timing accuracies in the 1% range and does not suffer from stored charge memory. It responds to changing conditions 500 times each second with knowledge of the past but without being slowed by its knowledge.
The microcontroller is responsible for enabling the main output whenever all of the required startup conditions are met and shutting it down upon command, loss of input power or whenever the power supply’s longevity is threatened by excessive loads or temperatures. It always provides the host system with advanced warning of an impending shutdown to that it may perform its housecleaning before power is lost.
To minimize acoustic noise, the microcontroller can turn a 12V fan on or off based upon the present load conditions and the amount of cooling air available. Because it’s programmable, the microcontroller code can be customized to fit the OEM’s requirements.
An optional I2C digital communications interface is also available to allow up to four XL275 to communicate over the same bus. This communications interface allows routine remote control of the main outputs and the 12V fans. It can also notify the host if a fan fails (lost tachometer pulses). The host can also query the microcontroller for its output voltage and current plus the ambient and transformer temperatures.
The XL275 Series incorporates the same industry leading features as its widely regarded XL125, XL160 and XL250 power supply families, such as active power factor correction for reduced input power, built in or’ing diodes, active inrush current protection, remote on-off, and high efficiency: up to 90% in some models. All N2Power supplies meet a full range of international agency approvals, including UL, DEMKO, CE Mark and FCC Class B.
