Protection
The IRAUDAMP1 includes protection features for overvoltage (OVP), overcurrent (OCP), and DC
current protection. All of the protection uses OR logic so that any of the protection features when
activated will disengage the output relay to cut off the load and protect the speakers. OCP and
OVP functions are latched, DC protection is unlatched. To reset the protection, the bus voltage
has to be reset to zero volts before re-applying power. The protection circuitry will also shutdown
the amplifier if a fault condition is detected.
Fig.4 Functional Block Diagram of Protection
DC protection
DC voltage output protection is provided to protect the speakers from DC current. This abnormal
condition occurs only when the power amplifier fails and one of the MOSFETs remains in the ON
state. DC protection is activated if the output has more than ±3V DC offset. DC protection is
unltached, and the amplifier will resume normal operation about 2 seconds after a fault condition
has been removed.
Over Current Protection
Over Current Protection will activate and shut down the entire amplifier if the amount of current
sensed at the positive power supply in either channel exceeds the preset value. If an overcurrent
condition occurs, the voltage generated across a shunt resistor turns on the OCP detection
transistors, Q2 and Q4 to send a signal to the protection logic.
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