What Are the Main Threats to the Power Port of an Audiometer, and How Should a Protection Circuit Be Constructed?

The power port primarily faces threats from surge impacts and fast transient burst interference originating from the power grid or adapters. These high-energy transient overvoltages can damage the front-end DC-DC power module, leading to system power loss or reset. Effective protection requires a graded absorption strategy. At the first stage, varistors or high-power TVS diodes with high current-handling capability and relatively slower response times should be selected to absorb the majority of the surge energy. At the second stage, closer to the subsequent circuitry, faster-responding TVS diodes or transient suppression arrays must be used to finely clamp the residual voltage, ensuring that the voltage input to the DC-DC converter remains within a safe range. The ground connections of all protection devices must be connected to a low-impedance power ground plane to ensure an unobstructed discharge path.