Functional description

TDA7576B

14/17

Doc ID 023511 Rev 3

6

Functional description

6.1

Diagnostics pins description

TDA7576B includes an offset detector pin and a clip detector and diagnostic pin.

DC offset detector is intended to avoid that an anomalous DC offset on the inputs of the

amplifier may be multiplied by the gain and result in a dangerous large offset on the outputs.

This may lead to speakers damage due to overheating.

The feature works with the amplifier unmuted and no signal at the inputs.

Moreover there is a pin named CD/Diag: the behavior of this pin is showed on Figure 4.

Whenever a failure condition (between thermal warning, output waveform clipping, short

6.2

Thermal protections

Thermal protection function is triggered when junction temperature rises above the normal

operating range, thus avoiding chip damaging.

For behavior description, refer to Figure 4 and 12. When temperature is reaching thermal

the audio input to the amplifier stage, this effectively limits the output power capability of the

device thus reducing the temperature to acceptable levels without totally interrupting the

operation of the device. Thermal mute is temperature when -6 dB output attenuation is

The output power will decrease to the point at which thermal equilibrium is reached.

Thermal equilibrium will be reached when the reduction in output power reduces the

dissipated power such that the die temperature falls below the thermal foldback threshold.

Figure 12.

Thermal protection diagram