Thermal considerations matter for Class D amplifiers

摘要

A Class D amplifier provides better efficiency and thermal performance than a comparable Class AB amplifier, but implementing a Class D amplifier still requires attention to good electrical- and thermal-design practices. Most engineers use a continuous-sine-wave-input signal to evaluate a Class D amplifier's performance in the lab. Although convenient for measurement purposes, a sine wave represents a worst-case scenario for the amplifier's thermal load. If you drive a Class D amplifier near maximum output power with a continuous sine wave, it's not uncommon for the amplifier to enter thermal shutdown.