How do I create a 5 second soft-start with an LM334Z current regulator?
A bit of a newbie to creating circuits
I have a 12V battery regulated to 2mA with an LM334Z current regulator.
Here are the docs for the current regulator: http://www.ti.com/lit/ds/symlink/lm134.pdf
I would like to create a soft start, so that when I turn the device on there is not a rush of current.
I’d like it to ramp up over 5 seconds.
I’ve breadboarded a few schematics I found online but I can’t get them working. Even if the battery power is slowly ramped up, the LM334 rams the voltage to get the current at exactly 2mA. (my Rset w/ a 33ohm resistor)
Here’s a couple I’ve tried unsuccessfully.
http://dl.dropbox.com/u/5822/softstart1.gif (might be b/c the 317 is different?)
I even tried this schematic to no avail:
But I was using different transistors, didn’t think that mattered- let me know if it does
Can anyone help me figure this out? I’ve been stumped for days. Starting to pull my hair out :)