Post by thread:[PIC]: LM7805

You might try the TL783: http://www-s.ti.com/sc/ds/tl783.pdf Rated up to 125VDC input, adjustable output. ------------------------------------------------------- On 14 Jan 2002, at 12:41, Shirollah Ghadirian wrote: {Quote hidden}> Hi all, > > Is there any +5V voltage regulator similar to LM7805 out there that could > withstand 40V DC in? > > -- > 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

part 0 44 bytes his is a multi-part message in MIME format. part 1 408 bytes content-type:text/plain; charset=koi8-r (decoded 7bit) Why dont try to put one 7824 in front of 7805?? See you.. Shirollah Ghadirian wrote: > Hi all, > > Is there any +5V voltage regulator similar to LM7805 out there that could > withstand 40V DC in? > > -- > 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 part 2 201 bytes content-type:text/x-vcard; charset=koi8-r; (decoded 7bit) begin:vcard n:Pavlica;Milan x-mozilla-html:FALSE org:SuperSonic Systems adr:;;;;;; version:2.1 email;internet:spam_OUTmpavlicaTakeThisOuTptt.yu title:Chief fn:Milan Pavlica end:vcard part 3 131 bytes -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Shirollah Ghadirian wrote: > > Hi all, > > Is there any +5V voltage regulator similar to LM7805 out there that could > withstand 40V DC in? Have you considered adding a series resistor, if the load current is relatively constant, or a 18v zener diode and a cap?? I have seen this in some TVs, quite common where the load from a 7812 is reasonably constant like a colour decoder chip. Seemed to work ok. :o) -Roman -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> Why dont try to put one 7824 in front of 7805?? > See you.. > > Is there any +5V voltage regulator similar to LM7805 out there that could > > withstand 40V DC in? In my datasheet the 7824 has 38 V as maximum input. Wouter van Ooijen Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler for PIC uC's: http://www.voti.nl/jal PICs kopen? http://www.voti.nl/shop -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I am not sure about the output current you need at 5V but, TL783 from TI can withstand upto 125V input and has an adjustable output with a max Iout of 700ma. But with 40VDC input , 5VDC output and a 22 degC package impedance to ambient (TO220 Case), you will be able to source only about 123ma to keep your junction temp at 120 degC (without heatsink). Now if you took your output up to 33V say (and used a 7805 in the next stage) then you can use the full 700ma from the TL783 and feed into the 7805. Madhu {Original Message removed}

part 0 44 bytes his is a multi-part message in MIME format. part 1 824 bytes content-type:text/plain; charset=koi8-r (decoded 7bit) hmmmm, i have builded it and it works :)) i havent no problems with it i think that max voltage input is about 45V DC See you... wouter van ooijen & floortje hanneman wrote: {Quote hidden}> > Why dont try to put one 7824 in front of 7805?? > > See you.. > > > Is there any +5V voltage regulator similar to LM7805 out there that > could > > > withstand 40V DC in? > > In my datasheet the 7824 has 38 V as maximum input. > > Wouter van Ooijen > > Van Ooijen Technische Informatica: http://www.voti.nl > Jal compiler for PIC uC's: http://www.voti.nl/jal > PICs kopen? http://www.voti.nl/shop > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. part 2 201 bytes content-type:text/x-vcard; charset=koi8-r; (decoded 7bit) begin:vcard n:Pavlica;Milan x-mozilla-html:FALSE org:SuperSonic Systems adr:;;;;;; version:2.1 email;internet:.....mpavlicaKILLspam@spam@ptt.yu title:Chief fn:Milan Pavlica end:vcard part 3 136 bytes -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

What about a cheap and simple LM317? Daniel... ----- Original Message ----- From: "Milan Pavlica (YU7AEC)" <.....mpavlicaKILLspam.....PTT.YU> To: <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> Sent: Tuesday, January 15, 2002 10:47 PM Subject: Re: [PIC]: LM7805 {Quote hidden}> hmmmm, i have builded it and it works :)) i havent no problems with it > i think that max voltage input is about 45V DC > See you... > > wouter van ooijen & floortje hanneman wrote: > > > > Why dont try to put one 7824 in front of 7805?? > > > See you.. > > > > Is there any +5V voltage regulator similar to LM7805 out there that > > could > > > > withstand 40V DC in? > > > > In my datasheet the 7824 has 38 V as maximum input. > > > > Wouter van Ooijen > > > > Van Ooijen Technische Informatica: http://www.voti.nl > > Jal compiler for PIC uC's: http://www.voti.nl/jal > > PICs kopen? http://www.voti.nl/shop > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestspam_OUTmitvma.mit.edu

Just put forward-biased diodes - say a 4001 but 400x will do - in series with the supply to the 7805. Each diode will drop about 0.6 volt so 4 in series should drop 40v down to 37.6 volts. Ted Mawson http://www.portfoliopm.com What about a cheap and simple LM317? Daniel... {Original Message removed}