TDA7491MV Datasheet, PDF (25/28 Pages) STMicroelectronics – 25 W mono BTL class-D audio amplifier

TDA7491MV
Application information
7.7
Protection function
The TDA7491MV is fully protected against overvoltages, undervoltages, overcurrents and
thermal overloads as explained here.
Overvoltage protection (OVP)
If the supply voltage exceeds the value for V_OVP given in Table 5: Electrical specifications on
page 8 the overvoltage 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.
Undervoltage protection (UVP)
If the supply voltage drops below the value for V_UVP given in Table 5: Electrical
specifications on page 8 the undervoltage protection is activated which forces the outputs to
the high-impedance state. When the supply voltage recovers the device restarts.
Overcurrent protection (OCP)
If the output current exceeds the value for I_OCP given in Table 5: Electrical specifications on
page 8 the overcurrent protection is activated which forces the outputs to the
high-impedance state. Periodically, the device attempts to restart. If the overcurrent
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 (nominal), the device goes to mute mode and
the positive and negative PWM outputs are forced to 50% duty cycle. If the junction
temperature exceeds the value for Tj given in Table 5: Electrical specifications on page 8 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 (< 18 V) by a pull-up
resistor whose value is limited by the maximum sinking current (200 µA) of the pin.
Figure 26. Behavior of pin DIAG for various protection conditions
VDD
TDA7491MV
R1
Protection logic
DIAG
VDD
Overcurrent
protection
Restart
Doc ID 14576 Rev 2
Restart
OV, UV, OT
protection
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