current source

  1. D

    Current source for pulse oximeter purpose

    Hi, I'm designing LED driver in my pulse oximeter. It would be two LED's, I would like to auto adjust current by DAC and be able to turn off one LED at time. I came up with an idea. In simulation, I got what I wanted. What about real circuit? The mosfet is actaully IRLML6244TR. 5V is for. ex...
  2. M

    Quad 100k Digital Rheostat - Can it be wired for 300k?

    Hi, I have a Fairchild FL51x0 which has a control pin where the voltage at the pin is input to an 8 bit ADC with 2.5V reference. The pin sources 10uA current, so that an external resistor can be used to set the voltage (0-250k). I'd like to use a Digital Potentiometer/Rheostat. However, the...
  3. J

    Understanding noise RMS and picking an appropriate current source for Hall probes

    Hi Everyone, I am trying to define the most suitable current source for my application. Essentially, I need a high stability current source to feed Hall probes sensors. The probes' nominal current is 10 mA. A stability of 100 ppm (i.e., 1 uA) for short term (a few hours) is desired. Usually, I...
  4. M

    Using an Opto to Control a Current Source to Create a Voltage Input

    Hi, I am using an FL5150 IC, that has a control pin ('dim') with a 10uA current source on it. Their datasheet shows a variable resistor 0-250k which creates a voltage of 0-2.5V. I want to drive/control this using an isolated PWM signal. I've simulated many circuits using the Vdd pin...
  5. C

    Driving solid state relay input

    Can a 4-20 mA (constant VDC) analog output on an industrial controller be used as an input on a solid state relay? I wasn’t sure how a device behaving as a variable current source might interact with a load such as the LED in an solid state relay that varies in its current draw. For example...