Hi all,
I am running a laser diode off a varialbe pulsed current source with a variable current output and pulse width. I want to run my laser at 1mA or less, however the current driver is designed for high power current applications and on switch on with no selected current output it has a 6mA d.c. offset. In other words there is a 6mA floor to the lowest current I can drive the laser. Is it possible to put a blocking capacitor in series with the +'ve output lead inorder to only have the a.c. component of the current? Will this likely damage the current driver or cause it any loading issues if the dc offset blocked?
Pulse frequencies necessary for me are ~1MHz down to 500KHz. Am I right in thinking that using the formula:
C=1/(2*PI*Res*Freq)
with system impedence of 50ohms and using 500KHz as lowest frequency, the capacitor I would need is 30pF, providing its power rating is high enough?
Thank you in advance,
Ryan