Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Can I parallel two 7805 for greater current?

Status
Not open for further replies.

neazoi

Advanced Member level 6
Joined
Jan 5, 2008
Messages
4,119
Helped
13
Reputation
26
Reaction score
15
Trophy points
1,318
Location
Greece
Activity points
36,918
Can I connect two 7805 regulators in parallel to increase the current?

Basically I need to supply 5v voltage (800mA) to a device and a 5v supply (800mA) to another device. It could be done with two regulators but the problem is that the two devices are connected to a common bus where there is only one VCC.

I have found this page High Current Voltage Regulation - Electric Circuit
but I would like to know if these circuits will work.

Also can I combine these?
 
Last edited:

Can I connect two 7805 regulators in parallel to increase the current?

Basically I need to supply 5v voltage (800mA) to a device and a 5v supply (800mA) to another device. It could be done with two regulators but the problem is that the two devices are connected to a common bus where there is only one VCC.

Preferably, it is better to use 7805 with a pnp power transistor that handles the large current and power dissipation.
As a first step, do you have an idea about the possible maximum and minimum voltages at the regulator input @1600mA?
 

Last edited:

Connecting two (or more) voltage regulators in parallel is not a good idea ..
As usual, you have several options: bigger regulator (2A or 3A rating), external PNP power transistor or –
just by cutting somewhere the Vcc track separating these two devices and supplying them from two separate (sharing only common) voltage regulators ..

:wink:
IanP
 

The reason that its a bad idea is commented on in the text of your link. Variations in voltage regulation between the different regulator chips will lead to one chip passing more current than the other one. That eventually, will most likely cause failure of that chip, that in turn will mean that the other chip will carry all the load and will promptly fail.

as the others have suggested use a current pass transistor, a higher current rated reg chip, or even better yet, use a DC-DC buck converter chip they are so so much more efficient and as a result dont run very hot like the LM78xx series.

Dave
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top