The theoretical maximum power transfer capability of the phase-locked loop (PLL)-based grid-following inverters can be limited under weak-grid conditions due to the non passivity of control loops. This article aims to reveal the passivity violation mechanism and develop passivity oriented feed-forward control to cancel out the negative effects of inner current control and PLL on low-frequency passivity. To this end, the contributions of these control loops and the mutual interactions among individual control loops to inverter terminal admittance are identified using the admittance decomposition technique, based on which the nonpassivity effect of each control loop is canceled out using a point of common coupling voltage feed-forward loop. The effectiveness of the presented control loops passivation method is validated by eigenvalue analysis, simulation studies, and experiments.