Circuit Description Of Digital Amp. Section - Pioneer XV-DV358 Service Manual

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7.1.10 CIRCUIT DESCRIPTION OF DIGITAL AMP. SECTION

A
TAS5508BPAG
B
Filter
PCM Signal and
Volume
From
DVD or ADC
PWM Processor section
C
PWM Processor section
The PCM signals output from the DVD decoder or AD converter are input to this section, and their volume and sound
quality are digitally adjusted. At the output stage, after conversion from PCM to PWM, the signals are output to the Power
stage.
Power Stage section
In this section, timing is controlled so that the MOSFETs on the high and low sides will not be turned on simultaneously.
The voltage of the PWM signals are raised to drive the gates of the MOSFET, and the PWM signals to drive the speakers
are output from the MOSFET at the output stage. Detection and protection functions against short-circuiting of the output
D
signals and temperature exceeding the standard value are also provided.
If the detection and protection work, the ports of the power stage ICs become the following state.
Output LPF section
The carrier elements, high-frequency signals that are unnecessary for these speakers, are eliminated. The signals passed
through the LPF will become sine-wave signals, as shown in the figure above.
E
Attention
As a signal to drive the BTL is output from the negative speaker terminal, DO NOT short-circuit between the
negative speaker terminal and ground, such as the chassis.
F
82
1
2
To UCOM
XSD
XOTW
PCM → PWM
IC3101
Power Stage ICs No.
IC3201
IC3301
IC3401
LINE 2
LINE 1
LINE 1
AV CONNECTOR
VIDEO OUT VIDEO OUT
AUDIO IN
Do not short-circuit
2
3
3.3V
0V
*1
*2
TAS5122DCA
Gate
Drive
Timing
Control
Gate
Drive
Protection
IC3201, IC3301, IC3401
*1 XSD : SD_AB (23pin), SD_CD (24pin)
*2 XOTW : OTW (25pin)
Power Stage section
Protection Enable State
SD_AB (23pin) ⇒ L
SD_CD (24pin) ⇒ L
OTW (25pin) ⇒ L
R L
FRONT
CENTER
L
R
SUB
R L
SURROUND WOOFER
SPEAKERS
Negative Speaker Terminal
Ground (Chassis)
XV-DV353
3
4
20V
0V 0V
0V
Output LPF section
AC IN
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