Design oriented model for constant on-time V2 control

V2 type constant on-time control is a practical implementation for current mode control. Equivalent series resistor (ESR) of the output capacitors is used as the sensing resistor for inductor current. Along with inductor current information, capacitor voltage is also fed back to the modulator. Previously CPES proposed a model for V2 control based on describing function. Although the model is very accurate, the derivation process is complicated. This paper tries to propose a simplified but less accurate model for practical design purpose. The new modeling method separates current feedback information and capacitor voltage feedback information. The analytical results are verified using Simplis simulation.

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