Post by thread:On/off control for LM7805 regulator

> I am powering a device using the LM7805 (5V regulator). I want to be > able to turn the LM7805 on and off. The LM7805, as you know, doesn't > have the on/off pin. Is there a way to do this? You could put a switching element in series with its input. A PNP transistor or P channel FET would work well. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

There are alot of LDO's that have a remote on/off capacity. Linear Tech, Micrel, National Semi, Vishay, ADI among others. Just check the websites for them. If this is a one time deal, National has a pretty good sample program. {Quote hidden}>From: Olin Lathrop <spam_OUTolin_piclistTakeThisOuTEMBEDINC.COM> >Reply-To: pic microcontroller discussion list <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> >To: PICLISTKILLspamMITVMA.MIT.EDU >Subject: Re: On/off control for LM7805 regulator >Date: Wed, 5 Mar 2003 07:45:12 -0500 > > > I am powering a device using the LM7805 (5V regulator). I want to be > > able to turn the LM7805 on and off. The LM7805, as you know, doesn't > > have the on/off pin. Is there a way to do this? > >You could put a switching element in series with its input. A PNP >transistor or P channel FET would work well. > > >***************************************************************** >Embed Inc, embedded system specialists in Littleton Massachusetts >(978) 742-9014, http://www.embedinc.com > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. _________________________________________________________________ Add photos to your messages with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Wouldn't you also need an NPN or N channel FET with pull up resistor tied to N drain/emitter with same tied to P gate/base with PIC output to N gate/base to fully turn off the PNP/P Fet? --- Olin Lathrop <.....olin_piclistKILLspam.....EMBEDINC.COM> wrote: {Quote hidden}> > I am powering a device using the LM7805 (5V > regulator). I want to be > > able to turn the LM7805 on and off. The LM7805, > as you know, doesn't > > have the on/off pin. Is there a way to do this? > > You could put a switching element in series with its > input. A PNP > transistor or P channel FET would work well. > > > ***************************************************************** > Embed Inc, embedded system specialists in Littleton > Massachusetts > (978) 742-9014, http://www.embedinc.com > > -- > http://www.piclist.com hint: The PICList is archived > three different > ways. See http://www.piclist.com/#archives for details. __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

About a year ago, I also needed to be able to use a PIC to turn off it's own power. I received an outstanding response to my question from Roman Black. (Thank you, Roman). Check out his page at: http://centauri.ezy.net.au/~fastvid/self_swi.htm Andrew ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.