Thermal Foldback Feature on SmartAmps
Advantages of Thermal Foldback on SmartAmps
The new generation of Texas Instruments SmartAmps, TAS2110, TAS2562, TAS2563 and TAS2564, introduce a new feature called Thermal Foldback. This feature allows the device to keep playing audio even when the temperature of the device is rising. Most audio amplifiers nowadays have thermal protection, which stops the audio playback or even shuts-down the device completely, so that it is not damaged due to high temperatures exposure. Thermal Foldback will automatically attenuate the output signal, by reducing the gain, letting the device cool-down while audio is still present at the output.
This application report is purposed to provide a thorough explanation of the Thermal Foldback functionality, how it can improve the end audio applications as well as show a comparison between the feature disabled and enabled.
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1 Advantages of Thermal Foldback Feature
Some audio applications, like automotive or industrial, require devices to operate in harsh environments where temperature is higher than consumer electronic goods typically endure. Most of the modern devices have protection schemes; however this typically stops the device from functioning or disables it completely. Once the temperature is back in a safe region, the device needs to be reinitialized.
Thermal Foldback feature on TAS2110, TAS2562, TAS2563 and TAS2564 has the advantage of allowing the device to keep operating and playing audio in increasing temperature situations. The device monitors the die temperature and automatically limits the audio signal above a set threshold. This will ultimately allow the device to keep or reduce its temperature while it is still operating. This is specially useful in fire & security applications as well as automotive applications where ambient temperature can be considerably higher than other applications but the system has to be fully operational. In any case, the over-temperature protection will shut down the device if the die temperature continually increases in order to prevent damages. In addition, over-temperature protection is an auto-retry feature so the device does not have to be reinitialized when temperature is back to a safe region.
2 Temperature Monitor
TAS2110, TAS2562, TAS2563 and TAS2564 have an internal die temperature sensor that has a measurement range from -40°C to 150°C and a resolution of 8 bits. This sensor is always enabled in order to keep the device within safe operating limits.
If needed, the value of this temperature monitor can be read from register 0x2C on page 0x00; further details on how to obtain the actual temperature value are available in the SAR ADC section of each device data sheet.
3 Thermal Foldback Configuration
It is recommended to use PurePath Console 3 to configure the features of this device, this way all the necessary calculations are made by the software.
Thermal Foldback settings can be configured within the Device Control panel; the default values are as shown in Figure 1.Thermal foldback is enabled by default on TAS2110, TAS2562 and TAS2563, and it is disabled by default on TAS2564
Figure 1. Thermal Foldback Control Panel 
