I am using a BS-2e
burtshulman
Posts: 1
Hello,
I am using a BS-2e. I need· a 1ma output at 6VDC from an output pin. Can I use a 2 resistor·divider between the output pin and +9VDC, such that when the output pin is logic 0, the voltage·in the middle of··the divider is let's say 2V and when the output is logic 1, the·divider··is 6V. Do I need a transistor to do this level shift?
Thanks
burt
Post Edited By Moderator (Joshua Donelson (Parallax)) : 10/23/2009 4:56:45 AM GMT
I am using a BS-2e. I need· a 1ma output at 6VDC from an output pin. Can I use a 2 resistor·divider between the output pin and +9VDC, such that when the output pin is logic 0, the voltage·in the middle of··the divider is let's say 2V and when the output is logic 1, the·divider··is 6V. Do I need a transistor to do this level shift?
Thanks
burt
Post Edited By Moderator (Joshua Donelson (Parallax)) : 10/23/2009 4:56:45 AM GMT
Comments
When your BS2e powers up, that pin will be an input and will "see" the entire 9V through the divider resistors. Since the resistors need to be small enough to source 1mA, and since the maximum allowable current through the BS2e's protection diodes is 500uA, I think you will need to use a transistor or other buffer for your output.
-Phil
Here's a circuit that will switch between 0V and about 6.12V @ 1mA, assuming a constant load:
If the load is inconstant, you can replace the 3.3K resistor with a 6V zener.
-Phil