Datasheet

Technical Note
23/31
BD5446EFV
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2011.06 - Rev.C
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●Output power limiter function
This IC is provided with an output power limiter function to protect speakers from destruction by an excessive output.
Limiter values are freely specified by changing external resistors R1/R2 as shown in Fig-26. Fig-27 shows a speaker output
waveform that is generated with use of the output limiter function. Because the waveform is soft-clipped, unusual noises on
audible signals are significantly reduced under operation of limiter.
Use resistors with a high degree of accuracy for R1 and R2 (±1% or higher accuracy is recommended). The capacitor C is
for the noise removal of output power limitation terminal (3pin). Provide grounding with a 1µF capacitor. Specify a resistor of
10kΩ or higher resistor R1 and R2. If the output power limiter function is not used, R1, R2 and C is unnecessary. However,
connect 3pin with GNDA.
Fig-29
Fig-30
0
1
2
3
4
5
6
7
8
9
10
1 1.2 1.4 1.6 1.8 2
3pin terminal voltage [V]
OUTPUT POWER(W/ch) .
Fig.31
Output power
–
3
p
in terminal volta
g
e
3
5
1μF
1μF
R2
R1
REG_3
Power
Limiter
C
GNDA
5pin
3.3V
Speaker
output
Soft Clip
VCC=13V, RL=8Ω, f=1kHz
Gain=20dB, 5pin=3.3V