TDA7491HV Datasheet, PDF (23/26 Pages) STMicroelectronics – 20 W + 20 W dual BTL class-D audio amplifier

TDA7491HV
Application information
7.7
Protection function
The TDA7491HV is fully protected against over-voltages, under-voltages, over- currents and
thermal overloads as explained here. See also Table 5: Electrical specifications on page 7.
Over-voltage protection (OVP)
If the supply voltage exceeds 20 V (nominal) the over-voltage protection is activated which
forces the outputs to the high-impedance state. When the supply voltage drops to below the
threshold value the device restarts.
Under-voltage protection (UVP)
If the supply voltage drops below 4 V (nominal) the under-voltage protection is activated
which forces the outputs to the high-impedance state. When the supply voltage recovers the
device restarts.
Over-current protection (OCP)
If the output current exceeds 4 A (nominal) the over-current protection is activated which
forces the outputs to the high-impedance state. Periodically, the device attempts to restart. If
the over-current condition is still present then the OCP remains active. The restart time,
T_OC, is determined by the R-C components connected to pin STBY.
Thermal protection (OTP)
If the junction temperature, T_j, reaches 145° C (nominally), the device goes to mute mode
and the positive and negative PWM outputs are forced to 50% duty cycle. At Tj = 155° C
(nominally), the device shuts down and the output is forced to the high impedance state.
When the device cools sufficiently the device restarts.
7.8
Diagnostic output
The output pin DIAG is an open drain transistor. When the protection is activated it is in the
high-impedance state. The pin can be connected to a power supply (< 20 V) by a pull-up
resistor whose value is limited by the maximum sinking current (200 µA) of the pin.
Figure 30. Behavior of pin DIAG for various protection conditions
TDA7491HV
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