International Rectifier IRAUDAMP4, Руководство пользователя

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RD-0617
Figure 15. Simplified Functional Block Diagram of High-Side Current Sensing (CH1)
For a complete description of calculating and designing the over-current trip limits,
please refer to the IRS20955 datasheet.
External Faults
OVP, UVP and DCP are considered external faults. In the event that any external fault
condition is detected, the shutdown circuit will activate for about three seconds, during
which time the orange “Protection” LED will turn on. If the fault condition has not cleared,
the protection circuit will hiccup until fault is removed. Once the fault is cleared, the
green “Normal” LED will turn on. There is no manual reset option.
Over-Voltage Protection (OVP)
OVP will shutdown the amplifier if the bus voltage between GND and -B exceeds 40 V.
The threshold is determined by the voltages sum of the Zener diode Z105, R140, and
V
BE
of Q109. As a result, it protects the board from bus pumping at very low audio signal
frequencies by shutting down the amplifier. OVP will automatically reset after three
seconds. Since the +B and –B supplies are assumed to be symmetrical (bus pumping,
although asymmetrical in time, will pump the bus symmetrically in voltage level). It is
sufficient to sense one of the two supply voltages only for OVP.
It is therefore up to the
user to ensure that the power supplies are symmetrical.