There's no easy circuit that conditionally limits current like this,
I can generate some real analog values
Quote from: dammien on Feb 26, 2013, 06:05 pmI can generate some real analog valuesYes and no. The arduino board have only two state, high (5V) and low(0V). It only plays with the time you're high and low.See here for more information : http://wiki.t-o-f.info/Arduino/SortieAnalogique?from=Arduino.PWM
A quick search threw up the AD8031 / AD8032 as possible candidates (and avail in DIP package)
I assume the idea is to protect the DAC from shorts?If you don't need absolute accuracy (such as an audio application)...
If you need absolute accuracy, you can use a current-limiting resistor on the output of an op-amp buffer, with the resistor inside the feedback loop. The feedback will maintain low effective output impedance (holding your output voltage) as long as the voltage drop across resistor & op-amp output-stage is not so great that there is not enough voltage left for the load.
Yes and no. The arduino board have only two state, high (5V) and low(0V). It only plays with the time you're high and low.
it doesn't tell me if the device protects itself when short-circuited (by lowering output for example), of it it burns immediatly.
You can use a series resistor providing the resistor's value is very small in comparison with the impedance you are driving it into. Therefore putting it into an op amp configured as a voltage follower is your best bet.
but then the question is the same for the op amp : it must be able to accept short circuit on its output
Hi all, Thanks to my Arduinos I can generate some real analog values. It can be made through the onboard DAC of the DUE, or with an external DAC like MCP4912.I am looking for a component to put after the DAC, that does the following job :- under a certain amount of current (for ex 10mA), the output voltage is exactly the DAC output- when there is an overload, more than 10mA, the output voltage can deviate from the DAC output to limit current to 10mA- as soon as load is back to normal, output voltage is back equal to the DAC outputTo sum up, from the DAC point of view, there is no overload. this one always outputs its voltage in safe circumstances.So, what is the best and easy way to do this ? are there integrated circuit for this ? Should I use an operationnal amplifier ?THanks for your answers.