Circuit Descriptions - Pioneer DEH-P8MP Service Manual

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7.3.2 CIRCUIT DESCRIPTIONS

- Power Amp Secsion
A
14.4V
BACKUP 10A
B
14.4V
ACC 10A
GND
IC201 incorporates a 4channel power amplifier and a DC/DC converter driver. Current for channels 1 and 2 is
supplied from the BACKUP power supply and current for channels 3 and 4 from the ACC power supply.
This is because when current is supplied with voltage increase in the BACKUP power supply as it is done
C
conventionally, 10A which is the limit to the vehicle fuse is exceeded.
Thus ACC power supply was enabled to supply current so that there are two power supplies of BACUP and
ACC and output of 60W x 4channel is expressed. Increased voltage (VCC1, VCC2) is controlled individually by
separate DC/DC converters. Therefore, different voltages occur when there is difference between the outputs
from L channel and R channel. A diode was hence connected between VCC1 and VCC2 so that voltage difference
will not occur.
- DC/DC converter 1
D
Power AMP
VOLTAGE
DIVIDER
REFERENCE
VOLTAGE
E
Only one DC/DC converter driver is incorporated in IC201. Therefore, another DC/DC converter driver was
prepared externally to be synchronized with the DC/DC converter driver for IC201 and eliminate noise.
F
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DC/DC CONVERTER 1
for BACKUP
DC/DC CONVERTER 2
for ACC
IC201 PAL008A
ERROR AMP
COMPARATOR
TRIANGULAR
WAVE OSCILLATOR
DEH-P8MP/XN/UC
2
3
VCC2(CH3,4)
VCC1(CH1,2)
PAL008A
MOSFET60
4CH POWER AMP
DC/DC CONVERTER
DRIVER
IC241
UPC494GS
DRIVER
DC/DC
CONVERTOR 1
PULSE VOLTAGE
OUTPUT BOOSTER
BATTERY
VOLTAGE
3
4
17.5V
17.5V
IC201
VCC1
RECTIFICATION
CIRCUIT
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