>-----Original Message----- >From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] >Sent: 02 November 2005 09:06 >To: Microcontroller discussion list - Public. >Subject: Re: [EE] Help deciding on voltage regulation > > >On 11/2/05, Olin Lathrop wrote: >> Padu wrote: >> >> I might put a decent buck regulator on the main board >that produces >> >> about 5.5 volts, then distribute that to each daughter board. >> > >> > Do you have any suggestions on which one? >> > >> > I liked the idea, since there is a big step down from 12V >to 5V and >> > energy is very precious in my application. >> >> My knee jerk reaction is something like the 5.5V power supply of the >> QuickProto-01 (http://www.embedinc.com/products). You can see it on >> page two of the schematic at >> http://www.embedinc.com/products/qprot01/qprot2.pdf. > >Olin, >sheet2/7 from this design it's a very good prove about what is >happening if a good software PIC programmer is designing hardware... > >Take a critical look to the Q6, Q4 and Q2 and see the redudancy. > >cheers, >Vasile Vasile, I guess you have little experience of driving power MOSFETs in high frequency switching applications? The driver needs to have a high current capability in order to charge/discharge the (significant) gate capacitance of the MOSFET to minimise the time spent in the linear region. Failure to do this results in poor efficiency and high power dissipation. A single NPN with resistive collector load does not (usualy) satisfy these requirements unless the resistor has a very low value, which again increases power dissipation and reduces efficiency. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist