Component Description - Kenwood KAC-649S Service Manual

KAC-649S
AUDIO UNIT (X09-5420-10)
REF. No.
Q1-4 MUTE
Q5-12 DIFFERENTIAL AMPLIFIER
Q13 RIPPLE FILTER
Q14-17 DIFFERENTIAL AMPLIFIER
Q18-21 TEMPERATURE COMPENSATION
Q22-29 OVER-CURRENT PROTECTION
Q30-37 POWER AMPLIFIER DRIVER
Q38-45 POWER STAGE
Q46 P.CON. DETECTION
Q47 POWER SWITCH
Q48 MUTE ON/OFF
Q49 MUTE DRIVER
Q50,51 SWITCHING POWER STAGE
Q52 OVER-CURRENT PROTECTION
Q53 OVER-VOLTAGE PROTECTION
Q54,55 CONSTANT VOLTAGE POWER SUPPLY
Q56,57 SWITCHING DRIVER
Q58-61 DIFFERENTIAL AMPLIFIER
IC1,2 INPUT BUFFER / ISOLATION AMPLIFIER
IC3,4 (1/2) : LPF
IC3,4
IC3,4 (2/2) : INVERTER
IC5 SWITCHING REGULATOR
2

COMPONENT DESCRIPTION

FUNCTION OPERATION
Decreases shock noise in first moment when P.CON. turns on or off.
Detects temperature of the heat sink, and protects bias current drift.
Detects over-current, and limits the power stage current.
Detects P.CON-ON, and turns Q47 on or off.
Supplies power to IC5.
Turns Q49 on or off.
The detected over-current stops IC5's working.
When over-voltage puts on BATT, Q53 turns P.CON. off.
Supplies + and - 15V power.
Makes an input signal 6 more dB signal,
and cancels automobile noise.
Oscillator for DC/DC converter.