TDA7491HV

Application information

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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,

Thermal protection (OTP)

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