Can a 7805 be used in parallel to up the amperage?
I need a 5 volt power supply that can deliver 1.5 amps continuous. I know the 7805 can provide a good 1 amp if well heat sinked but I need a bit more.

Ideas?

Bob

 

The datasheet has example circuits for this.

 

Any decent 7805 datasheet should include a schematic in the "typical usage" section that shows how to increase the current capacity through the addition of a power transistor and a resistor. For example, the datasheet for Fairchild KA78XX has Figure 12 "High Current Voltage Regulator" and Figure 13 "High Output Current with Short Circuit Protection".

 

From TI, the same.

 

Thanks for the replays.
I have the same circuit on one of my data sheets.
But the question still remains, can you run 2 of them in parallel?

 

Thanks for the replays.
I have the same circuit on one of my data sheets.
But the question still remains, can you run 2 of them in parallel?

YES, if you do it right. If you have a bunch of them, select a pair that have close output voltage values. Then you have to put a series resistor from each output to the load such that there will be about a 0.2V drop across it at full current.

 

Why not just get a 5V regulator that will deliver 1.5A?

http://search.digikey.com/ca/en/products/LM1086IT-5.0/NOPB/LM1086IT-5.0-ND/363580

 

Being a cheap person, I found 10 of the 7805's in my junk drawer.
Have to order some other parts anyway just add a regulator to my list.
Just thought I could save a buck.
I may have a 6133 laying around somewhere, but I still need some caps, relays, couple switching transistors, Glcd, Pic, and a quadrature encoder.