Hi,

I am using the L200 variable voltage regulator and would like to set the reference voltage to 0V. To do so, I supplied -2.77V instead of ground (on simulator). Why is the output not going to 0V when using this method?

Any help will be appreciated.

 

I think you have to lower the ground pin?

http://pdf.datasheetcatalog.com/datasheet/SGSThomsonMicroelectronics/mXxzqr.pdf

 

That technique will work with a 3-terminal regulator, such as the LM317, but not with the L200 which has a ground pin as well as a reference pin. If put both the reference pin and the ground pin at 2.77V below the circuit ground then it should adjust down to 0V (with respect to the circuit ground).

 

Thanks for the replies. Is there a way to set the reference voltage to -2.77V without using a center tap transformer please?

 

Can you get hold on the LT3080 regulator. That goes down to 0 volt. It was a project on EEVblog using that regulator in a power supply project