TDA7561
Diagnostics functional description
4.3
Output DC offset detection
Any DC output offset exceeding ±2 V are signalled out. This inconvenient might occur as a
consequence of initially defective or aged and worn-out input capacitors feeding a DC
component to the inputs, so putting the speakers at risk of overheating.
This diagnostic has to be performed with low-level output AC signal (or Vin = 0).
The test is run with selectable time duration by microprocessor (from a "start" to a "stop"
command):
● Start = Last reading operation or setting IB1 - D5 - (offset enable) to 1
● Stop = Actual reading operation
Excess offset is signalled out if persistent throughout the assigned testing time. This feature
is disabled if any overloads leading to activation of the short-circuit protection occurs in the
process.
Doc ID 8326 Rev 6
15/27