A new peak-current injected digital control circuit for dc-dc converter

The purpose of this paper is to present a new peak-current injected digital control circuit for dc-dc converter and its dynamic characteristics. The proposed circuit is able to detect the peak point of the switch current in real time only by comparing two pulse trains. At the moment when the peak switch current is detected, the proposed circuit generates the turn off signal of the main switch. The circuit principle is very simple. It is composed of the voltage controlled oscillator (VCO) using as the V-F signal converter, the programmable delay circuit and a few flip-flops. In the experiment, it is confirmed the main switch is turned off when the peak switch current is detected. Additionally, it is shown in simulation that the proposed digital control circuit provides the good transient responses of dc-dc converter. As a result, it is seen that the proposed method has no overshoot of the output voltage and the convergence time that the output voltage is settled to steady-state is only 129μs. This result is approximately 89% smaller than the conventional voltage mode digital control dc-dc converter.