IRF IRAUDAMP6, Руководство пользователя, Страница: 16 / 47

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IRAUDAMP6 REV 1
.0
Gain Setting / Volume Control
The IRAUDAMP6 has an internal volume control (potentiometer R130 labeled, “VOLUME”) for
gain adjustment. Gain settings for both channels are tracked and controlled by the volume control
IC (U_2) setting the gain from the microcontroller IC (U_3). The total gain is a product of the
power-stage gain, which is constant (+33 dB), and the input-stage gain that is directly-controlled
by the volume adjustment. The volume range is about 100 dB with minimum volume setting to
mute the system with an overall gain of less than -60 dB. For best performance in testing, the
internal volume control should be set to 1 Vrms input will result in rated output power (250 W into
8
Ω
).
Efficiency
Fig 11 shows efficiency characteristics of the IRAUDAMP6. The high efficiency is achieved by
following major factors:
1) Low conduction loss due to the DirectFETs offering low R
DS(ON)
2) Low switching loss due to the DirectFETs offering low input capacitance for fast rise and
fall times
Secure dead-time provided by the IRS20957, avoiding cross-conduction
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 50 100 150 200 250 300 350 400
Output Power(W)
E
ff
ic
ie
n
c
y
(
%
)
Class D Efficiency
Fig 11, IRAUDAMP6 8 ohms load Stereo, ±B supply = ±73.5V