A mode-dependent, battery-coupling switch for a subscriber line interface circuit (SLIC) selectively adjusts its current requirements to provide optimal current handling capability irrespective of the mode of operation of the SLIC. Where current demands of the SLIC are relatively minimal (e.g., on-hook idle mode), the bias is set at a relatively small, default value. During high current demand, such as ringing and off-hook signaling, the bias is set at a relatively large value, to maintain a low voltage drop across the battery-coupling switch.