Help needed regarding programmable power supply(4x3 keypad & rotary encoder based input) project

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SHARANYADAS

Joined Apr 13, 2017
53
Hi experts
I am currently building a programmable power supply based on atmega328p/dac8574(16 bit dac)/mcp3424(18 bit adc)/LT1013 op amp.The output range is 0-30v/0-4A.I burnt the INA169(1000mv/A) current sensor and currently using acs714(0.185mv/A).
The CV/CC control part is totally based on analog electronics(LT1013 op-amp+some BJTs).
By far,my setup is working correctly on the breadboard setup(except the precision of 2nd decimal digit on both the voltage & current range).

Now,my main question is how to let the atmega328p know that the control part is in CV/CC mode?Is it by checking the voltage(both set & actual output) or by checking the current(both set & actual flowing) or by checking both?What is the general rule?

Also,as far as i have understand,the LT1013 is not a very good choice for this control loop.Please suggest some good precision op amps which are generally used in this sort of application.Will OP295 be a good choice?(I have read in the datasheet that they are used in power supplies!)

Also I added buffers previously (using LT1013 op amps) after the DAC & the current sensor INA169 to protect it's output.But there are significant change in the decimal digits (specially in lower range) of the output due to the offset error of the op-amp.So currently i removed the buffer.
As for buffer choice,should I use AD8630 (as they have a ultra low offset error and they are rail to rail)?
 
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