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Power Management I Product News

Intersil announces industry’s first 30A fully-encapsulated power modules

As modern networking processors, FPGAs, memory and other complex digital circuits demand higher and higher currents at well regulated low voltages, power supply design challenges for system designers have been increasing dramatically. In response Intersil has launched the ISL8225M, the industry’s first 30A fully- encapsulated power module. It features the industry’s highest power density and dramatically simplifies the design of high-performance board-mounted power solutions. The ISL8225M and just a handful of resistors and capacitors are now able to provide a complete high power DC to DC converter solution for intermediate rail or POL application in a very small footprint. Available reference designs can be cut and pasted into a board designer’s layout, enabling a non power expert to quickly implement a dense, high performance converter solution. The module is designed to deliver up to 100W output power from a small 17mm square PCB footprint. The two 15A outputs may be used independently or combined to deliver a single 30A output. Current sharing and phase interleaving allow up to six modules to be paralleled for 180A output capability. Intersil’s encapsulated power modules are

able to provide improved power density by using thermally enhanced power packages for high power performance. The company’s custom QFN packages provide the power density and

are fully encapsulated, there is better electrical isolation, and fewer solder joints that can open or short over time. The ISL8225M provides a flexible converter solution operating over input voltage ranges from 4.5V to 20V and capable of providing output voltages of 0.6V to 6.0V. This enables direct POL conversion from standard 12V or 5V distributed power rails, or the generation of standard 3.3V and 5V distributed rails from 12V or higher Vin, even if that Vin is poorly regulated or varies significantly, such as a direct battery supply. The ISL8225 can also be used to provide two independent Vout supplies of 15A each, or a single Vout at 30A. Up to six of the modules can also be interleaved with a very simple applications circuit to provide up to a 180A supply.

thermal conductivity that allows a designer to implement a power solution without requiring either airflow or heat sinks, and a much denser solution than competitive modules that require system fans and heat sinks. These enhanced fully encapsulated QFN packages provide large thermal pads on the bottom of the package providing enhanced thermal conductivity, and exposed leads around the edge of the package offer easily accessible test points for monitoring and debug purposes.

In contrast to an open-framed module, these encapsulated modules are also very mechanically rugged; this ruggedness and the surface mountability of the QFN package allowa the ISL8225M to be handled by automatic pick and place equipment, eliminating manual mounting required by through hole open frame modules. Encapsulated module solutions also drive higher reliability and manufacturability due to their mechanical structure. Since all the components

PowerPath prioritiser from Linear looks to ease power system design

Linear Technology has introduced the LTC4417, a triple-supply prioritised PowerPath controller for 2.5V to 36V systems. The controller selects the highest priority valid supply among three inputs to power the load. Priority is defined by pin assignment, while a supply is considered valid after it has been inside a voltage window set by

1.5% accurate undervoltage and overvoltage thresholds for 256ms. The LTC4417 has been conceived to simplify designs, deriving power

from multiple, disparate voltage sources common in handheld and high availability electronics. In such systems, a prioritiser is a better solution than a simple diode-OR, especially when the preferred power source is not the highest voltage. The LTC4417 controller also protects the load from reversed inputs to -42V.

PowerPath switching is implemented by external back-to-back P-channel

MOSFETs protected by integrated 6V gate clamps. Carefully designed fast switch control blocks reverse and cross-conduction current while preventing output voltage droop. A low 28µA operating current, sub-1µA draw from the lower standby supplies, and a shutdown mode make the controller ideal for battery backup systems. The LTC4417’s wide operating range accommodates a wide range of power sources such as wall adapters, USB, Firewire, supercapacitors, and batteries such as lead-acid, Li-Ion and stacked NiCd. Built-in cascading support extends the LTC4417 prioritization beyond three supplies. To minimize start-up inrush current, the first connection is soft-started. Open- drain outputs indicate the supplies that are within their valid voltage window. Undervoltage and overvoltage hysteresis is adjustable with a single resistor.

Specified over the full commercial, industrial and automotive temperature ranges, the LTC4417 is offered in 24-pin QFN (4mm x 4mm) and 24-lead narrow SSOP packages. Evaluation circuit boards are available online or from your local Linear Technology sales office.

Linear Technology | 26 December 2012/January 2013

The efficiency of the ISL8225M’s power train and the thermal conductivity of the QFN package means the device generates less heat then competitive encapsulated modules, and is better able to move the heat that is generated out of the package. This means the ISL8225 can supply higher power levels than competitive devices at higher ambient temperatures. This means that in many applications the ISL8225M can operate without forced airflow and without external heatsinks. This is a significant advantage to the designer of sealed boxes or systems where board height limitations will not allow mounting of top side heat sinks. If heat sinks are an option, or if a system already includes airflow, the use of Intersil modules gives the designer more flexibility to locate the modules in areas that have restricted airflow, or to get significantly more power out of the same board area when operated in the same airflow environment of competitive solutions.

The ISL8225M allows a board designer with limited power design expertise to implement a dense, rugged, high performance converter with a minimum of design effort.

Intersil |

Vicor’s latest Picor Cool-Power ZVS buck regulators offer I2C telemetry and programmability

Vicor has introduced 14 new additions to its PI33XX Picor Cool-Power ZVS buck regulator product line for high efficiency point of load DC- DC regulation. This product line extension includes higher current devices and optional I2C fault telemetry and programmability. The PI33XX products are designed to convert 8V to 36V inputs to high current, low voltage

point of load system rails such as 3.3V, 2.5V, 1.8V and 1V, and deliver class-leading performance with advanced power management functions. The integration of a high performance Zero-Voltage Switching (ZVS) topology within the PI33XX series of Cool-Power ZVS buck regulators enhances point of load performance, providing best in class power efficiency for wide Vin operation. The ZVS topology enables high power density, and high-frequency operation that maximises efficiency by minimising the significant switching losses associated with conventional hard-switching buck regulators. The PI33XX series can support high performance conversions with large step down ratios up to the rated input voltage of 36V enabling system designers to deploy more efficient power distribution schemes that rely on a higher input voltage source. All products in the PI33XX series are highly integrated with control

circuitry, power semiconductors and support components in a high density 10mmx14mmx2.56mm LGA System in Package (SiP). Power delivery can be further increased by interleaving multiple Cool-Power ZVS buck regulators using single wire current sharing without the need for any additional components. Cool-Power ZVS buck regulators are the only buck regulators in their

class to offer an optional I2C extended fault telemetry capability allowing for six distinct types of fault reporting. Additional device-programmable I2C features include output margining, enable pin and synchronization pin logic polarity, and phase delay. Device programming can be performed via the Cool-Power Development Tool.

Vicor | Components in Electronics

New material promises fuel cell cost breakthrough

A new material for coating fuel cell bipolar plates, Ceramic MaxPhase developed by a Swedish company Impact Coatings, could change the economics for fuel cells by significantly reducing manufacturing costs. The cost for bipolar plates is currently one of the main obstacles to widespread commercialisation of fuel cell technology. Ceramic MaxPhase provides an alternative to coating the metal bipolar plates with gold, the current method used to prevent corrosion of the plates. “Cost-effective production of bipolar plates is one of the main elements needed for making fuel cells viable in the volume market. Using a material that is far less costly than

gold, but has similar physical properties, will help reduce the cost for fuel cell bipolar plates. We can today meet a coating cost of $5 per kW and expect to reach below the US Department of Energy 2017 target of $1 per kW, significantly ahead of time,” says Henrik Ljungcrantz, CEO at Impact Coatings. Bipolar plates are used as anodes and cathodes in fuel cells, connecting several cells into a stack for the desired voltage. Because of the highly aggressive environment inside the fuel cell, the plates are prone to corrosion. Graphite, which is a corrosion-resistant material, has been used, but produces bipolar plates that are bulky and heavy. Graphite plates are also difficult to manufacture at low cost and in high volume. They are now gradually replaced by stainless steel bipolar plates, with a thin protective coating to prevent corrosion. With less bulk than graphite and significantly lower cost than gold coated plates, metal plates with Ceramic MaxPhase is a solution that can meet the US Department of Energy’s targets for cost as well as technical performance.

Ceramic MaxPhase is a corrosion-resistant, electrically conductive ceramic coating that is applied by Physical Vapor Deposition. The material has been qualified for use in proton exchange membrane fuel cells (PEMFC) as well as direct-methanol fuel cells (DMFC) in tests exceeding 2500 hours. The bipolar plates of stainless steel coated with Ceramic MaxPhase showed equivalent stack performance to gold plated bipolar plates during the tests. The process and the material are now

commercially available. Impact Coatings |

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