3 Class-D amplifier selection

The Texas Instruments TAS5431-Q1 Class-D amplifier can deliver up to 8 W of power to a car speaker and protect itself and the TCU module from four fault conditions, as well as diagnose all four fault types at startup (also known as “deassertion of standby mode”). After startup, the amplifier can detect a positive or negative output shorted to ground, a positive or negative output shorted to the vehicle battery, and a positive output shorted to a negative output only while audio is playing. More details on how the TAS5431-Q1 diagnoses these fault conditions can be found in section 7.3.5 “Load Diagnostics” of the TAS5431-Q1 datasheet.

Although the TAS5431-Q1 is capable of diagnosing these fault conditions at startup, it cannot implement the full RTD suite on its own. A notable shortcoming is the inability to detect a positive output shorted to a negative output or an open speaker/load after deassertion of standby mode. Table 1 summarizes the standard capabilities of TAS5431-Q1 diagnostics.