TDA7498L
Applications information
5.7
Protection functions
The TDA7498L 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
given in Table 6: Electrical specifications on
OVP
page 9 the overvoltage protection is activated which forces the outputs to the
high-impedance state. When the supply voltage falls back to within the operating range, the
device restarts.
Undervoltage protection (UVP)
If the supply voltage drops below the value for V
given in Table 6: Electrical
UVP
specifications on page 9 the undervoltage protection is activated which forces the outputs to
the high-impedance state. When the supply voltage recovers to within the operating range,
the device restarts.
Overcurrent protection (OCP)
If the output current exceeds the value for I
given in Table 6: Electrical specifications on
OCP
page 9 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 , is determined
OC
by the R-C components connected to pin STBY.
Thermal protection (OTP)
If the junction temperature, T , reaches 145 °C (nominally), the device goes to mute mode
j
and the positive and negative PWM outputs are forced to 50% duty cycle. If the junction
temperature reaches the value for T given in Table 6: Electrical specifications on page 9 the
j
device shuts down and the output is forced to the high-impedance state. When the device
cools sufficiently, the device restarts.
5.8
Diagnostic output
The output pin DIAG is an open-drain transistor. When any protection is activated it switches
to the high-impedance state. The pin can be connected to a power supply (< 36 V) by a pull-
up resistor whose value is limited by the maximum sinking current (200 µA) of the pin.
Figure 27. Behavior of pin DIAG for various protection conditions
VDD
TDA7498L
R1
DIAG
Protection logic
VDD
Restart
Restart
Overcurrent
protection
OV, UV, OT
protection
Doc ID 16504 Rev 3
23/27
STMICROELECTRONICS [ ST ]
