MH> Dear All, MH> I am trying to design a drive circuit for a brushless DC motor speed MH> controller. I plan to have a switching frequency of approximately 50kHz and MH> a PWM resolution of 8 bits. Motor is 32 Volt with 50 W power rating and MH> maximum allowable continuous current of 2.8A.
MH> Now for the questions: MH> 1. I have to select MOSFET transistors and their drive circuits for a 3 MH> phase drive circuit. Currently I plan to use IRFI540N. I know that they are MH> capable of much higher voltage and current but they seem to meet the timing MH> requirements. Any websites that I could use for searching for transistors MH> that are better suited for this application. MH> 2. I want to have some isolation between the microcontroller and the power MH> electronics. The problem is the high switching frequency. Most common MH> optocouplers are too slow for this. Can anyone suggest ways and components MH> to isolate the power electronics form the microcontroller? 50kHz shouldn't be a problem for opto couplers at all. If standard transistor-output really isn't fast enough for your purpose (with raise/fall times in the <10us range), then there are some specially fast ones available, e.g. http://www.vishay.com/optocouplers/opto-high/ Uwe. -- Author: Uwe Zimmermann INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
