A new high performance digitally controlled dc-dc converter with peak current-injected control

The current mode dc-dc converter is useful in order to perform the superior dynamic characteristics. However, these studies have focused on sensing the average value of the switch/reactor current because it is very difficult to sample the data of accurate peak point of switch/reactor current in the digitally controlled high switching converter. Therefore, it has been reported that the peak point is estimated from the slope of reactor current, but there has been no study that tried to detect the peak value of reactor/switch current in the fast switching dc-dc converter. This paper presents a new digital control circuit which is able to detect not only the average output voltage but also the peak switch current of the high frequency switching dc-dc converter. In this proposed digital control circuit, the peak current-injected control is realized using the combination of the simple dual pulse width modulation analog-to-digital signal converter and the programmed delay circuit. In 100 kHz digitally controlled dc-dc converter, it is seen in simulation 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 30 mus. The difference between the transient time of the proposed circuit and that of the conventional method is an order of magnitude.