LM2678

Andi Zaganjori

Other Parts Discussed in Thread: LM2678

Hi,

I checked the output voltage of the LM2678 (no load connected) and it was 7.9V, when a load was added it lowered the Ouput voltage to 1.6V and the current output was also too weak, approx. 0.3A. Any suggestions?

Thanks and Regards
Andi

over 8 years ago

0 Nikhil Gupta (Product Folder Models) over 8 years ago

TI__Mastermind 39210 points

Andi,

We need some more information to debug your issue. Please attach your simulation files so that we can look into this issue for you.

Thanks,

0 Andi Zaganjori over 8 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 80 points

Hi,

I did not simulate the design, I only tested it.

It is impossible for me to attach the Layout in a public Forum, but in the table below you can find how the output changes depending on different inpunt parameters.

INPUT (Power Supply unit)	OUTPUT
12V	1,5V (0,3A)
10V	1,9V (0,4A)
8V	3V (0,9A)
6V	3.5V (1,5A)
5V	3,8V (2,1A)
4V	1,5V (0,7A)

Thank you and Regards
Andi

0 YangZhang over 8 years ago in reply to Andi Zaganjori

TI__Genius 11085 points

Please send your schematic and layout files to simpleswitcherapps@ti.com. We will review your deisgn. If you have scope shots on SW node, Vin, Vout before and after the Vout drops, it would be very helpful as well.
Please make sure the power supply of yours does not have current limitation. And the connection from supply to the board does not have too much voltage drop.
-Yang

Power management

Power management forum

LM2678