Hello,
I am trying to create a pwm controlled current source, but I can't have the diode turning on and off as you might do with a transistor and LED where your eye "filters" the on and off to a constant on. I am trying to drive a laser and it needs to be on constantly.
Similar circuit except the voltage source is an RC low pass filter with Vin over the cap. Current issue is that Vin and Vout do not follow each other as the PWM changes duty cycle.
http://www.ecircuitcenter.com/Circuits/curr_src1/curr_src1.htm
I need a 10mA - 100mA range over the load (laser diode). Currently using the AD842JN op amp, and the 2n2907 transistor.
Thoughts, insight, wisdom?
Thanks,
Nathan
I am trying to create a pwm controlled current source, but I can't have the diode turning on and off as you might do with a transistor and LED where your eye "filters" the on and off to a constant on. I am trying to drive a laser and it needs to be on constantly.
Similar circuit except the voltage source is an RC low pass filter with Vin over the cap. Current issue is that Vin and Vout do not follow each other as the PWM changes duty cycle.
http://www.ecircuitcenter.com/Circuits/curr_src1/curr_src1.htm
I need a 10mA - 100mA range over the load (laser diode). Currently using the AD842JN op amp, and the 2n2907 transistor.
Thoughts, insight, wisdom?
Thanks,
Nathan
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