Electronics News
Archive : 30 November 2007 год
All four modules offer active single-wire current sharing which operates from 10 to 100% of full load, enabling multiple modules to be easily paralleled for very high current applications. The modules are all hot pluggable, and incorporate low-loss internal ORing FETs (Field Effect Transistors) on their main 12 V output, for fault-tolerant and N+1 redundancy applications. They have no minimum load requirement, and maintain main output regulation to within ±5%. Each power module contains a serial EEPROM (electrically erasable programmable read-only memory) that is pre-programmed with data about the unit - including its type, serial number and date of manufacture - to facilitate replacement in the field. A built-in I2C interface, which uses the PMBus protocol, enables the data to be read back to the system under power; the interface also allows the system to interrogate the power module to ascertain various operational parameters, including input and output status, fan blocked or running under-speed, and overcurrent and overtemperature flags. The dc-input DS series power modules are compact, high efficiency units with a 1U x 2U form factor. They incorporate fan cooling and have an ambient operating temperature range of +10 to +45 degrees Celsius, with 50% derating at +70 degrees Celcius.
The modules comply with all applicable EMC immunity standards, including EN61000-4-2, -3, -4, -5, -6 and -11. The power supplies carry UL/cUL60950-1 and EN60950-1 VDE safety approvals. Sample quantities of all four dc-input DS series power modules are available for immediate delivery. Standard lead-time is stock to 8 weeks. Pricing starts at US $418 for the DS450DC and US $498 for the DS850DC, in quantities of 250.
STMicroelectronics announced a software library for the STM32 Flash microcontroller family - which is based on the ARM CortexT-M3 core. The software was designed specifically to simplify the testing and securing end-product approval and compliance with the demands of the IEC 60335-1 standard, when the MCU is used in household appliances. Since October 2007, IEC 60335-1 requires the software of MCU-based appliances to be evaluated according to its impact on overall consumer and application safety. When some of the fault detection relies on the microcontroller, the embedded code must contain self-test routines, and must be evaluated under the so-called Class B requirements for its ability to detect safety critical failures.
The self-diagnostic software modules developed by ST for the STM32 family have been approved by the VDE (German Association for Electrical, Electronic & Information Technologies) testing and certification institute, which is recognized globally for its efforts. Now, when a manufacturer uses these modules in an application - unchanged and in accordance with ST's integration guidelines - the application will not need to be completely re-evaluated by VDE as part of the final product certification, thereby saving significant time for the appliance manufacturer. The software library, with associated documentation, is available free of charge. It includes a complete safe-boot sequence, plus self-diagnostic modules for the CPU, non-volatile memory, RAM, and the clock frequency. Transparent RAM tests are also carried out during run-time. In addition, the STM32 embeds safety-related hardware, including dual internal watchdogs and fail-safe clock circuitry, which simplifies certification by reducing the number of self-test routines actually required and decreasing the software overhead.