Статья 1083. учет вины потерпевшего и имущественного положения лица, причинившего вред

Design Notes

• Powering 3.3V Digital Systems &mdash DN33

  PDF, 77 Кб, Файл опубликован: 1 апр 1990

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  Powering 3.3V Digital Systems – Design Note 33Dennis OвЂNeillThe new generation of high density digital devicesrequiring 3.3V power supplies impose some uniqueconstraints on power supply designers. In nearly allcases the computers using these devices already havea 5V system supply. Deriving the 3.3V supply from theexisting 5V rail permits system upgrades with a simpleon-card solution. In many cases the 5V rail is the onlysupply available, mandating this approach. The п¬Ѓrst decision to be made is whether to use a switching regulatoror a linear regulator? Switchers have a clear efп¬Ѓciencyadvantage when there is a large difference between theinput and output voltage, but that advantage diminishesas the input voltage approaches the output voltage.Simple calculations show that the efп¬Ѓciency of a switcheris marginally better in this application. Assuming anominal input voltage of 5.0V and an output voltage of3.3V, the efп¬Ѓciency of a linear regulator, (LTВ1083 typeFigure 1A), independent of output current, is simply3.3V/5.0V = 66%. For a switcher (Figure 1B) the efп¬Ѓciency is tougher to calculate. With only 5V availablea PNP switch must be used, a MOSFET is not practicaldue to its gate drive requirements. The average inductor 5V IN + 10ОјF LT1083 OUT100 ADJ 3.3V + 10ОјF 165 current will be equal to the load current. The duty cycle …

• Techniques for Deriving 3.3V from 5V Supplies &mdash DN74

  PDF, 73 Кб, Файл опубликован: 1 сен 1993

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  advertisement Techniques for Deriving 3.3V from 5V Supplies – Design Note 74Mitchell LeeMicroprocessor chip sets and logic families that operate from 3.3V supplies are gaining acceptance in bothdesktop and portable computers. Computing rates, andin most cases, energy consumed by these circuits showa strong improvement over 5V technology. The mainpower supply in most systems is still 5V, necessitatinga local 5V to 3.3V regulator.Linear regulators are viable solutions at lower (IO ≤ 1A)currents, but they must have a low dropout voltage inorder to maintain regulation with a worst-case input5 4.5V TO 5.5V IN OUT 1 + LT1129-3.34 SHUTDOWN SENSE 2 GND 3.3V OUT700mA3.3ОјFSOLID TANTALUM of only 4.5V. Figure 1 shows a circuit that converts a4.5V minimum input to 3.3V with an output toleranceof only 3% (100mV). The LTВ1129-3.3 can handle up to700mA in surface mount conп¬Ѓgurations, and includesboth 16ОјA shutdown and 50ОјA standby currents forsystem sleep modes. Unlike other linear regulators, theLT1129-3.3 combines both low dropout and low voltageoperation. Small input and output capacitors facilitate …

• 5V to 3.3V Regulator with Fail-Safe Switchover &mdash DN82

  PDF, 74 Кб, Файл опубликован: 1 май 1994

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  advertisement 5V to 3.3V Regulator with Fail-Safe Switchover – Design Note 82Mitchell LeeNewer microprocessors designed for replacing existing5V units operate from lower voltage supplies. In the pasta processor swap was simply a matter of removing oneIC and replacing it with an updated version. But nowthe upgrade path involves switching from a 5V chip toone that requires 3.xxV.One means of changing supply voltage from 5V to 3.xxVis to clip a jumper that bypasses a local 3.xxV regulator.This is not a good solution since it leaves too much tochance. Failure to remove the jumper can result in theinstant destruction of the new microprocessor uponapplication of power. A means of automatically sensingthe presence of a 3.xxV or 5V processor is necessary.Intel microprocessors include a special pin called“VOLDET” which can be used to determine whetheror not a particular chip needs 3.xxV or 5V. Figure 1shows a simple circuit that takes advantage of thispin to automatically “jumper out” a 3.xxV regulatorwhenever a 5V processor is inserted into the socket. VOLDET is pulled low on 3.xx processors; it is bufferedby transistor Q2 which grounds the gate of a bypassingswitch (Q1). Q1 is turned off leaving the LTВ1085 to …