can someone help me to find the transfer function of this circuit (i want to have the tension through the capacitor i think) and the step response in order to get the voltage in function of the time because i have a comparator (the block to the right with " ??? ") and it compares the tension between V1 ( voltage divider ) and V2 (tension i try to express with respect to time) and i want to know WHEN V1 = V2...

V1 is obtained by a voltage divider then it's a constant voltage

V2 can be expressed with respect to time but the cicuit is too complex for me (simulink seems to calculate this tension with the diod D7, R12, R10 and maybe R6 and R 100k...) Could someone help me to find the transfer function and also the step function because i can't find the constant of time

(t= 0.497s when V1=V2) I'm sorry if i made mistakes i'm not english (and i'm not an engineer too then forgive me)

Here are the pictures

The Circuit: enter image description here

V2: enter image description here

And V1 (i can express the voltage divider and find by myself the tension given by matlab): enter image description here

And at t=0.497 reached (with V3), the voltage is zero as you can see before the diod because of the comparators and the block "NOT" with the MOSFET in the right corner:

enter image description here

Thanks in advance.

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  • \$\begingroup\$ Welcome to EE SE! Use the system identification app or tftest to estimate a transfer function. \$\endgroup\$ – Unknown123 Apr 15 at 19:42
  • \$\begingroup\$ Thanks for the system identification app but i can't export my workspace variable (i have a scope which logs the data to a variable in the workspace) because the format is incorrect (not an IDDATA nor IDFRD variable). \$\endgroup\$ – YuGo Apr 16 at 9:08
  • \$\begingroup\$ So you've got a vector. Then use tfestimate function instead. \$\endgroup\$ – Unknown123 Apr 16 at 16:55
  • \$\begingroup\$ Ok it doesn't work well then is there any chance to get the SYMBOLICAL differential equation of my circuit solved by simulink ? I just want to know which resistance is processed to get the tension V2 \$\endgroup\$ – YuGo Apr 16 at 20:55
  • \$\begingroup\$ What do you mean by doesn't work well? You can derive the differential equation easily using Inverse Laplace Transform if you have the Transfer Function. See Transfer Function to Single Differential Equation. \$\endgroup\$ – Unknown123 yesterday

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