A novel loop gain correction method for digitally controlled DC-DC power converters

One of the problems in a digitally controlled DC-DC power converter is relatively low low-frequency loop gain achievable unless a digital compensator of large number of bits is used. As a result of this, the low-frequency line regulation and output impedance performance of the DC-DC power converter suffers unless an expensive compensator is used. In the paper, the cause of this problem is traced to the truncation error of the digital compensator used in the DC-DC power converter feedback control loop. A method is then proposed to correct this problem. Experimental results verified the validity of the proposed method.