In an audio system with speaker I/V sense function, the speaker resistance Re can be measured in real time, whlie the ambient temperature can also be calculated. TAS5825M does not support I/V sense function, so the speaker Re cannot be automatically captured using the real-time IV data. But TAS5825M smart amp algorithm can use the audio data and speaker models to predict the temperature of the speaker voice coil, and reserve some margin to achieve thermal protection.

Table 5-1 and Figure 5-18 show the protection verifications of TAS5825M's thermal protection functions with single frequency audio signals. With different power limit settings (temperature increase margin), the algorithm can automatically limit the output power of TAS5825M to avoid thermal damage to speaker voice coils. In practice, TAS5825M takes the speaker Re in 25°C to calculate the output active power into speaker voice coils, and does not consider the increase of Re along with the rise of voice coil temperature, so the actual output power can be lower than expectations of the protection algorithm, which can cause the protection behavior to be more aggressive when temperature rises. As a result, like shown in Table 5-1, the actual temperature increase of voice coil is lower than the thermal limit settings, and the gap increases grows when temperature grows, which results in a more conservative protection mechanism.