Hello guys!
So, I am building a Buck converter from separate blocks, and i need to feed the comparator after the error amplifier with a sawtooth signal. Here is for reference a schematic for the Buck.
Now, when computing loop stability, you can make the transfer function of the comparator a constant 1, if the sawtooth maximum amplitude is scaled to 0.1*Vin. I am planning on using a 555 timer to generate the sawtooth (150KHz), but i have no idea how to make this variable amplitude.
So, for example, if the input voltage is 10V, I would like the sawtooth to go from 0.18V to 1V. If input voltage is 20V, from 0.36V to 2V, and so on, I think you get the idea. I was thinking of keeping the timer as it is in the simulation and just do the scaling outside. I'd rather not use an opamp, as i would need a very fast (expensive) one. I feel like there is a simple way of doing it that I am missing but I've been searching for three days on the internet and found nothing.
Any ideas? Thank you very much
So, I am building a Buck converter from separate blocks, and i need to feed the comparator after the error amplifier with a sawtooth signal. Here is for reference a schematic for the Buck.
Now, when computing loop stability, you can make the transfer function of the comparator a constant 1, if the sawtooth maximum amplitude is scaled to 0.1*Vin. I am planning on using a 555 timer to generate the sawtooth (150KHz), but i have no idea how to make this variable amplitude.
So, for example, if the input voltage is 10V, I would like the sawtooth to go from 0.18V to 1V. If input voltage is 20V, from 0.36V to 2V, and so on, I think you get the idea. I was thinking of keeping the timer as it is in the simulation and just do the scaling outside. I'd rather not use an opamp, as i would need a very fast (expensive) one. I feel like there is a simple way of doing it that I am missing but I've been searching for three days on the internet and found nothing.
Any ideas? Thank you very much