Hello
I would like to control the controller of the eval board converter from the comp pin, in open loop, skipping the compensator.
So I have removed the optocoupler from the PCB and connected a voltage supply to com pin. The datasheet indicates:
It says that duty cycle is maximum when current is 0A, is this maximum duty cycle 80% or 100%?
Also in regards to the com pin the datasheet says:
From that I understand that inside the controller there is a resistor of 1700ohm as per the following scheme:
Is this assumption correct? I have used this resistor value to calculate the proper voltage over the comp pin.
For an input voltage of 40V and applying 780mV on the COMP pin I got an output voltage of 3V. But I´m not sure about my calculations. Could you please let me know the proper way to calcualte the voltage value to be applied on the comp pin to set the desired duty cycle? what is the voltage value in order to achieve a 50% of duty cycle for instance?
I´m doing this test because I’m going to change the components of the eval board in order to move the output voltage from 3-3V to 5V, so once the HW changes are completed, before closing the loop I prefer to set the duty cycle from the comp pin working in open loop and measure the plant to calculate the compensator.
Thanks in advance !!
