Protection Circuit - Pioneer XW-NAV1-K Service Manual

1

5.4 PROTECTION CIRCUIT

QQ
3 7 63 1515 0
A
(1) DIGITAL AMP Part
Overview
Sound AMP IC (IC5501) has following functions:
1. PLL abnormal oscillatory
2. Abnormality of MDSP processing
3. Excess of the amount of SDSP processing
4. Protection from overcurrent
5. Protection from abnormally high temperature
6. DC detection
7. Abnormality of DAIF clock
When abnormality is detected, SP and AMP are protected by stopping processing, muting, stopping output of AMP.
B
In addition, pin 22 is made "L" against above-mentioned 1 to 6 abnormality.
When microcomputer detects abnormality of AMP, microcomputer initializes and reboots AMP.
Ports on the system microcomputer to be used for detection
• Pin 49 of IC3001 P4_3
This terminal becomes "L", which detects the fact that errors occurred at SoundAMP.
• Regarding Abnormality of DAIF clock, ports detect by reading out register of error information by communicating with
Sound AMP.
Operation of the protection circuits
1. PLL abnormal oscillatory
Mute in digital amplifier is set. (AMP IC set automatically.)
C
Pin 22 of Sound AMP IC (IC5501) becomes "L".
2. Abnormality of MDSP processing
3. Excess of the amount of SDSP processing
MDSP and SDSP processing are stopped and MUTE in Digital Amplifier is set. (AMP IC set automatically.)
TE
L 13942296513
Pin 22 of Sound AMP IC (IC5501) becomes "L".
4. Protection from overcurrent
A short circuit of Digital Amplifier output terminal between VSS, VDD, and +/- is detected.
All output by Digital Amplifier will be stopped (AMP IC set automatically.)
Pin 22 of Sound AMP IC (IC5501) becomes "L".
5. Protection from abnormally high temperature
MDSP and SDSP processing are stopped and MUTE in Digital Amplifier is set. Also, output by all Digital Amplifier will be
stopped. (AMP IC set automatically.)
D
Pin 22 of Sound AMP IC (IC5501) becomes "L".
6. DC detection
When the DC voltage is output for more than 1.5 seconds continuously, output by digital amplifier will be stopped.
(AMP IC set automatically.)
Pin 22 of Sound AMP IC (IC5501) becomes "L".
7. Abnormality of DAIF clock
Digital Amplifier outputs with no signal. (AMP IC set automatically)
This error can be detected by reading register out.
Processing when protection circuit is detected
SoundAMP is reseted and initialization is done.
E
www
F
28
1
http://www.xiaoyu163.com
2
x ao
y
. i
2
http://www.xiaoyu163.com
3
8
Q Q
3 6 7
u163
XW-NAV1-K
3
4
2 9 9 4
1 3 1 5 0 5 8 2 9
m
co
.
4
2 8
9 9
9 4 2 8 9 9