On/Off control for 5V regulator 1

[thomasn101]

Hi all,

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? What's about using the LM317?

Is there any 5V, 800mA regulator out there that has the on/off control? Thank you in advance!

Regards,
Thomas

 

[a31ford]

what method of "on-off" eg: relay drive, simple toggle switch ? remote control ? , is it from within the circuit that is being driven by the 7805 ?

G

 

[thomasn101]

Hi,

Thank for helping me! I want to control the on/off pin directly by a microcontroller running on 5V. The maximum source/sink current of the microcontroller is 20mA.

Regards,
Thomas

 

[melone]

Why don't you put a transistor in the source leg?

 

[buzzp]

Melones idea is painless and likely the most economical.

 

[Heydave]

National Semiconductor has several. You should learn to use their selector trees. Other vendors such as TI, and Linear Technology have similar offerings. Keep in mind that many of the newer regulators are low drop out and need substantial capacitors on them to keep from oscillating. You may even find one that supplies regulation and reset for your microcontroller at the same time.

http://www.national.com/parametric/0,1850,663-c8-1,00.html

Many of these are available from Digikey etc.

 

[jbartos]

Suggestion: What about using a regulator which has the on/off pin?