The disclosed embodiments provide a system that facilitates the use of a portable electronic device. During operation, the system detects a coupling of a power supply to the portable electronic device through a set of wires. Next, the system uses the set of wires to identify a type of the power supply. The system then periodically determines a switching frequency of the power supply based on the type of the power supply and a current drawn from the power supply. Finally, the system uses the switching frequency to facilitate the operation of a touch control in the portable electronic device. For example, if the switching frequency corresponds to a sensing frequency of the touch control, the system may change the sensing frequency to an alternative sensing frequency.