This paper presents a new simplified Routh approximation technique for the MOR of large scale linear time-invariant systems that involves only alpha parameters to make the proposed technique simple. In reduced order modelling, the Routh approximation technique described in the literature is based on the alpha and beta parameters. In this technique, the denominator polynomial of the lower order system is obtained by the Routh approximation technique and the numerator polynomial is computed by a simple mathematical algorithm as discussed in the proposed scenario. To illustrate the proposed method, the fourth-order DC–DC converter model is reduced to its second-order reduced model. The modeling of DC–DC converter in continuous conduction mode is also developed and whose final output is a complete linear circuit model. In order to check the effectiveness and accuracy competitive to other popular and recent techniques in the literature, the proposed method has been applied on various standard numerical examples.