If the ramp driving your PWM-based controller isn't linear or monotonic, or just plain noisy, your DC/DC converter isn't going to work up to its capabilities. Here's what you need to know to get the ...

Op-amp integrators can ramp to saturation, and a capacitor-discharge switch can reset them. Alternatively, you can input-switch them to ramp up and down in triangle-waveform-generator applications.