The droplet dynamics in a straight microchannel under the combined influence of pressure driven flow and an alternating current (AC) electric field has been studied numerically. The interface of the droplet has been captured using Cahn-Hilliard equation, while the effect of electric force at the droplet interface has been incorporated by modeling it as a body force term in the momentum equation. The present study shows that the application of AC electric field causes droplet deformation, stretching, necking, pinning, and disintegration into smaller daughter droplets. With the variation of frequency (ƒ) and amplitude of the AC electric field it is possible to control the transition from non-breakup to breakup regimes. As the frequency increases, the occurrence of rapid periodic disturbances, especially in proximity to the electrode, leads to splitting of droplets. Additionally, we have identified a critical electrical field frequency above which there is barely any alteration in the droplet breakdown regime. The augmentation of the electric field intensity induces an enhanced stretching of the droplet and a delay in detachment from the walls of the channel, thereby facilitating the fragmentation of the droplet. By increasing the intensity of the electric field, three distinct modes of droplet breakage have been found: single mode, double mode, and multi-mode. The suggested technique offers a straightforward and effective way for droplet miniaturization in microchannel. Our results may have significant implications in applications such as microreactors and manufacturing of microemulsions, which requires advanced fluidic manipulation.