current managed completely using microcontroller and not external resistor.
Hi,
I can´t think of a current source without resistor.
Can you draw a picture of your desired circuit?
I´d use a DAC (I2C, SPI) to generate an adjustable voltage. Then i´d use an OPAMP and some resistors and a FET to generate a current source.
Klaus
Thanks for the reply Klaus..Hi,
I´d use B).
(To be correct this is a current sink, but you can also similarely build a curent source)
You can use almost any voltage output DAC with at least 9 bits resolution. 9 bits because of your 1mA/500mA resolution. I´d go for a 10 bit DAC.
Then a voltage divider to generate the same voltage as the shunt. (here 0.5V for a 1Ohms with 500mA)
In the feedbalck of the OPAMP you can build a R-C-R combination to improve stbility.
A comparator at the OPAMP output can show a "output OK" LED.
Klaus
Hi,
SMD or THM components?
***
The comparator can drive a LED just to indicate if the output current (regulation) is OK.
Klaus
Hello All,
current managed completely using microcontroller and not external resistor.
Thanks in Advance..
Hi,
please go to your preferred distributor´s site.
Look for "DAC, 10bit". You will find a lot different types.
Then look for the preferred interface. I´d recommend an internal reference. Pincount should be <10 for simple connections.
Also check
* supply voltage,
* supply curren(if of interest),
* output should be "voltage" type
* data update rate
* linearity/precision/accuracy
...
availability
price
a lot of parameters that only you know.
***
The OPAMPshould have:
* common mode input voltage range: including ground
* output voltage low: Rail
* unity gain stable
Klaus
Yes, but only in the special case that the supply voltage is already fixed. It still affects output voltage range.The sense resistor value does not influence overall power dissipation.
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