Technical Note
21/30
BD5446EFV
www.rohm.com
2010.05 - Rev.B
© 2010 ROHM Co., Ltd. All rights reserved.
6) DC voltage protection in the speaker
When the DC voltage in the speaker is impressed due to abnormality, this IC has the protection circuit where the speaker
is defended from destruction.
Detecting condition - It will detect when MUTE pin is set High or Low and PWM output Duty=0% or 100% ,
43msec(fs=48kHz) or above. Once detected, The PWM output instantaneously enters the state
of HiZ-Low, and IC does the latch.
Releasing method –
①
After the MUTEX pin is set Low once, the MUTEX pin is set High again.
②
Turning on the power supply again
OUT1P (50, 51pin)
Speaker output
Latch release state.
ERROR (24pin)
OUT1N (43, 44pin)
OUT2N (38, 39pin)
OUT2P (31, 32pin)
t
t
t
Soft-start
t
MUTEX(13pin)
Latch release
PWM out locked duty=100% abnormal state.
Abnormal state release.
PWM output ： IC latche with HiZ-Low.
Protection start surge current
into speaker output for 43msec
(fs=48kHz) and over.
43msec(fs=48kHz)
www.DataSheet4U.com
