Navigating Capacitor Choices in My Synchronous Buck Converter Design
Hello everyone. I am designing a synchronous buck converter using stm32f103c8t6 chip. I intend to use timer 1, i have setup my registers already and tested my output signals all seems fine with dead time included. I moved on to calculating the required inductance and output capacitance. I got 42uH for the inductance and the capacitance to be 73uF. I observed some designs done, and I did the calculations the capacitance falls in the same range, but they ended up using between 330uf and 470uf. I thought my calculation was wrong, but it seems it is not wrong. Can anyone point me in the right direction as to why almost all the time, the calculated output capacitor value is not used? my switching frequency is 35khz, my output voltage is 14.6, my input voltage is 21v, output current is 15A. The intended application is for an MPPt charge controller.
5 Replies
The calculated value may not be used in practice some times, because there are other factors which can influence the entire system design such as, ripple current rating, transient response, ESR, capacitor tolerance, noise also, using a higher capacitance value compensates for real-world capacitor imperfections. But this also should be consider careful, to not alter or change the normal system functionality.
Thank you chief
I was able to put together a circuit to test my signals and also the working of the synchronous buck converter.
I added the feedback to it and it was relatively responding, I'm going to add PID algorithm to take care of the feedback and move on to ensuring I work on having a C.C at the output
Great job 👍