Hi guys
I was looking over DD311 chip which is a high constant current driver and I foun in its datasheet sayin that " the longer rise time and fall time of the EN dimming signal, adjustable by RC filter, produce the smooth transient response of output current "
how can I know if they mean RC low pass filter or high filter , also how would I know which value of R and C that would fit the best please

here is their datasheet
http://html.alldatasheet.com/html-pdf/307085/SITI/DD311/594/6/DD311.html

any help will be appreciated
Thanks

 

The diagram shows an RC low-pass filter at the input. From the scope diagrams of the output with the filter, I would estimate the filter has a time-constant of around 200ns. This can be achieved with a 1kΩ resistor and a 200pF capacitor.