PIEZO KEY SENSING CIRCUIT AND METHOD FOR TESTING THE PIEZO KEY SENSING CIRCUIT

摘要

A method tests a piezo key sensing circuit having a piezo element and verifies that it is properly functioning. A capacitance of the piezo element is discharged. Then the capacitance of the piezo element is charged during a predetermined time period. An output signal of the piezo element is measured during the predetermined time period resulting in a measured output signal. An operating condition of the piezo key sensing circuit is determined based on the measured output signal.