Simulation and Characterization of Singing Capacitors in Consumer Electronics

Acoustic noises in the audible range produced by ceramic capacitors has become an increasingly important concern in consumer electronics. The audible noises deteriorate the consumer experience. In order to locate the ceramic capacitors on a printed circuit board (PCB) that cause acoustic noises, we proposed a three-dimensional (3-D) simulation methodology, which is based on the finite element method. The proposed simulation methodology takes into account the product design, the board design, and the detailed component information. The simulation methodology accurately models the board vibrations, which is considered as the primary and the direct cause of acoustic noises. We conduct sound pressure level and laser Doppler vibrometer measurements to benchmark the accuracy and capability of the proposed simulation methodology. On a testing board, the velocity distributions obtained from the proposed simulation agree very well with the measurement results. Through the proposed simulation methodology, we can characterize the board vibrations and extrapolate design guidelines in order to prevent acoustic noise in the early design stage.