International Rectifier IRAUDAMP4, Manual

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RD-0617
+B
-B
Speaker Mute
Figure 9. Class D Output Stage with Click-Noise Reduction Circuit
Startup and Shutdown Sequencing
The IRAUDAMP4 sequencing is achieved through the charging and discharging of the
CStart capacitor C117. This, coupled to the charging and discharging of the voltage of
CSD (C3 on daughter board for CH1) of the IRS20955, is all that is required for complete
sequencing. The conceptual startup and shutdown timing diagrams are show in Figure
10.
Figure 10. Conceptual Startup Sequencing of Power Supplies and Audio Section Timing
V
CC
-B
+B
+5 V
-5 V
CStart
CSD
UVP@-20 V
CSD= 2/3V
DD
CStart Ref2 CStart Ref1
Audio MUTE
SP MUTE
CHx_O
Class D startup
Time
Music startup
Over Current
Protection
Click noise
reduction circuit
Transient
current paths