Thank you... -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Rick C. Sent: 13 April 2002 11:26 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]:High power DC switching.. Try Microchip (believe it or not) http://www.telcom-semi.com/products/datasheets/tc426_8.pdf I believe Microchip bought Telcom to add to their line. Rick Kevin Howell wrote: > Thanks I found the datasheet on the IRF740, I didn't know that there are > inherent problems when driving a MOSFET (Cgs) . Now the search is on for a > mosfet driver. Can't the IRF740 b interfaced directly to a PIC? Surely it > was designed with a microcontroller in mind? > > Thanks > Kevin > > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of PY2NI > Sent: 13 April 2002 10:22 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE]:High power DC switching.. > > As a starting device try 2 or more IRF 740 (400V @ 10A each) you have > better options if you don't put more than 200V on the FET you can use only 2 > IRF 640 (200V @ 18A each). MOSFets are really friendly devices when you pay > attention on how to handle then, especial care with driver circuits, some of > then have quite a large input capacitive reatance. Cgs. There are especial > ICs (GATE DRIVERS) designed to deal with this problem if you don't want to > waste your time doing this. > Hope it helps a bit. > > P.S. the devices mentioned aren't expensive, I often buy then for a buck or > less. > > [ ] s > Horta > > ----- Original Message ----- > From: Kevin Howell > To: > Sent: Saturday, April 13, 2002 3:26 PM > Subject: Re: [EE]:High power DC switching.. > > > I can't find any Mosfets that can handle 200-300V. The problem is not to > > source them but to find a suitable part. (Keep in mind the 20A) > > > > Thanks > > Kevin > > > > > > -----Original Message----- > > From: pic microcontroller discussion list > > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Bob Blick > > Sent: 13 April 2002 06:44 PM > > To: PICLIST@MITVMA.MIT.EDU > > Subject: Re: [EE]:High power DC switching.. > > > > > > > I have some high power fast switching transistors, BUV48, which I want > to > > > use to control a 220V DC motor using PWM. The transistor can handle 10A > Ic > > > and 400 Vce (hfe =8!!). My problem is that the motor draws up to 20A and > > > thus I will > > > need more than one of these transistors in possibly a darlington > > > configuration. Please can someone help me with a circuit to control this > > > current hungry motor using a pic ... > > > > Hi Kevin, > > > > Do you really have to use this transistor? Do you already have some > > other transistors to use as drivers for them? If not, perhaps you > > should consider some other transistors, I would suggest MOSFETs. > > Your losses will generally be lower. Also if you do PWM you will > > need a freewheel diode across the motor. > > > > Others will likely also have suggestions. A transistor with hfe of 8 > > doesn't sound like a whole lot of fun. > > > > Cheers, > > > > Bob > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics