Studying the Dynamics of the Second-Order DC-DC Converter with Single and Multi-loop Feedback for the Optimum Bandwidth

As far as the complexity of the current mode control is concerned, illogical choosing of the phase cross over frequency for a converter doesn´t bring any significant advantages over the voltage mode control. So, one has to select the bandwidth carefully so that benefits of the current mode control will trade off with the complexity of implementing the scheme. The reported work emphasizes on the importance of choosing the optimum bandwidth in the current mode control which can claim all the benefits of this complex current mode control scheme. The advantages are: (a) reduction in the order of the controller due to decreased phase boost demand (b) scaling down in the size of the capacitor, inversely proportional to cross over frequency, of the compensator network and consequently demands very less current to drive as a network which prevents overloading of the output of the operational amplifier and, (c) improved response speed. In this paper, for demonstration purpose, the dynamic performance of the non inverting synchronous up down converter, second order converter, is carried out for both the voltage mode and the current mode feedback with different cross over frequencies. The simulation is carried out in Pspice.