|Alguien dijo ...|
|Profundizar en el conocimiento científico es una de las mejores vías para lograr plenitud y libertad.|
Pilar Alvarez Pellicero(1944).
|Summit Hot-Swap Controller Minimizes Power Dissipation, System Cost
and Board Space|
San Jose, Calif. - Summit Microelectronics has expanded its programmable
power management family with the introduction of an innovative, dual-feed active OR'ing hot-swap controller. The
SMH4814 device can monitor and control two independent -48V feeds, allowing for redundant power supply control.
Furthermore, it eliminates the need for passive OR'ing diodes, which are bulky and significantly contribute to
system power dissipation. Using Summit's GUI-based, non-volatile programming technology, system designers can
customize the SMH4814 to address their specific power management and control requirements while using a single part
number for different platforms.
The SMH4814 provides precise current and voltage control during turn-on and
operation while an internal shunt regulator allows compatibility with a very wide input voltage range. Unlike
traditional implementations that utilize OR'ing diodes to connect redundant power supplies, the SMH4814 controls
external N-channel field effect transistors (FETs), thereby significantly reducing total system power dissipation.
This in turn minimizes costs and board space associated with cooling fans and heat-sinks. Lower power levels also
eliminate the need for through-hole components, so manufacturing complexity is reduced.
SMH4814 offers a variety of protection features that increase system performance and reliability. Included are
soft-start power-up, "over-current circuit-breaker" functions and integrated over-voltage and under-voltage
monitors, allowing for full protection from system failures. The over-current trip levels, forced shutdown mode, and
over-voltage/under-voltage monitor thresholds are fully programmable allowing for a high degree of design
flexibility. Additionally, a programmable glitch filter is provided on the monitor circuits to prevent false alarms
The SMH4814 continuously monitors the incoming feeds and switches to the most
negative feed as necessary. In addition, it hot-swaps and sequences up to four independent downstream DC-DC
converters with programmable sequence order and delay times. The SMH4814 ensures that a series of conditions are met
before the external power MOSFET is turned on and the supply voltage is ramped up in a controlled, well-behaved
manner. The device's integration, versatility and high-performance meet the most stringent requirements for
high-end systems requiring maximum up-time. Furthermore, all these features are offered in a space-saving 5x5mm QFN
package, providing an 85% footprint reduction over the traditional SOIC-28 package.
allows a variety of add-in cards to be removed from or inserted into a fully powered host platform without an
interruption in the system's operation and without damage to any of the devices on the board. Typical applications
are those with -48V power distribution, including high-availability servers, wireless base stations, central office
switches, and telecommunications line cards that demand both on-the-fly configurability and redundant power supply
to the system. Other applications include systems designed to support the Advanced Telecom Computing Architecture
(AdvancedTCA™) specifications, especially the ones with increasing power levels.
achieved via the convenient I2C bus and configuration data is safely stored in non-volatile EEPROM memory of which
256 bytes are available for user data storage. The devices can be programmed during development and then used in a
"fixed" configuration or they may be re-programmed in-system via the I2C interface.
Pricing, and Availability
The SMH4814 is offered in both the commercial and the industrial
operating temperature range and is packaged in the space-saving 5x5 28-pad QFN and 28-pin SOIC packages. Available
now in production quantities, the SMH4814 is priced at $4.18 each in the commercial temperature range, and at $6.43
in the industrial temperature range for the SOIC package in quantities of 1,000 devices. Unit pricing for the QFN
package is at $4.37 in the commercial temperature range and $6.75 in the industrial temperature range in quantities
of 1,000 units.
Jueves, 06 Octubre, 2005 - 08:35