Electronics > Projects, Designs, and Technical Stuff
14.4V ground reference for ADC
Simon:
--- Quote from: Arjunan M R on May 20, 2019, 03:37:06 pm ---
--- Quote from: Simon on May 20, 2019, 03:34:00 pm ---I was refering to your current limits. This is usually done in analogue so reacts instantly. There are smart mosfets that will cut out in 1µs if overloaded. if the current limit does not react fast enough it can still damage stuff.
PWM DAC is easy. the output voltage will be the averaged PWM value, you use a low pass filter that has a cut off frequency 10-100 times lower than the PWM, simple matter of physics.
--- End quote ---
Can you tell me a part number of any of that smart mosfets?
--- End quote ---
No I don't. Look them up yourself and learn about them before throwing them around. a smart mosfet datasheet can be 50 pages long. a smart mosfet is not what you want. for example an Infineon mosfet rated for 10A will not cut out through over current for over 50A.
Arjunan M R:
--- Quote from: Simon on May 20, 2019, 05:12:48 pm ---
--- Quote from: Arjunan M R on May 20, 2019, 03:52:47 pm ---
--- Quote from: Simon on May 20, 2019, 03:34:00 pm ---I was refering to your current limits. This is usually done in analogue so reacts instantly. There are smart mosfets that will cut out in 1µs if overloaded. if the current limit does not react fast enough it can still damage stuff.
PWM DAC is easy. the output voltage will be the averaged PWM value, you use a low pass filter that has a cut off frequency 10-100 times lower than the PWM, simple matter of physics.
--- End quote ---
What can i do about it. I still need to use the DAC.
--- End quote ---
You could learn what you are doing before making stuff up. You have done nothing but emphasize the cost has to be low yet you have thrown parts at this like there is no tomorrow. Why not do the simpler design first that you talked about.
--- End quote ---
I have already done a simpler one a 2 channel PSU with one channel using LM317(1.25-12V)and another with (1-44V) using buck and boost convereter . And with maximum current(two channels)900mA.
It has no current limit.
Arjunan M R:
--- Quote from: Simon on May 20, 2019, 05:12:48 pm ---
--- Quote from: Arjunan M R on May 20, 2019, 03:52:47 pm ---
--- Quote from: Simon on May 20, 2019, 03:34:00 pm ---I was refering to your current limits. This is usually done in analogue so reacts instantly. There are smart mosfets that will cut out in 1µs if overloaded. if the current limit does not react fast enough it can still damage stuff.
PWM DAC is easy. the output voltage will be the averaged PWM value, you use a low pass filter that has a cut off frequency 10-100 times lower than the PWM, simple matter of physics.
--- End quote ---
What can i do about it. I still need to use the DAC.
--- End quote ---
You could learn what you are doing before making stuff up. You have done nothing but emphasize the cost has to be low yet you have thrown parts at this like there is no tomorrow. Why not do the simpler design first that you talked about.
--- End quote ---
Yeah, thats my problem ;D :--
Arjunan M R:
I don't understand what you are talking about mosfet :-//
Arjunan M R:
The output setling time of the current sense amp is 5µs..And the risetime+ turn on delay time of the irfz44n is only 72ns. and the settling time of the opamp i am using is 1.1µs. So total delay of 6.172µs.Is that a big delay?? :-//
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