Kenwood KDC-138/138CR Service Manual page 4

KDC-138/138CR/139/139S
Ref. No. Application / Function
Q3 5V-3.3V Level Shift
Q4 5V-3.3V Level Shift
Q6 BU3.3V SW
Q7 APC (Auto Power Control)
Q8 Power Supply Control
Q9 Power Supply Control
D1,2 5V Force Voltage Prevention
D3 Laser Diode Protection
D4 Static Electricity Countermeasure
4
COMPONENTS DESCRIPTION
Shifts 5V to 3.3V, or 3.3V to 5V.
Shifts 3.3V to 5V.
Q6 is ON when Q8 or Q9 is ON.
Drives LD (Laser Diode).
Power Supply Control from MECHA µ-COM. Q6 is ON when pin 63 (P_ON1) of IC1 is Hi.
Power Supply Control from system µ-COM. Q6 is ON when pin 125 (MSTOP) of IC1 is Hi.
5V Force Voltage Prevention from MECHA µ-COM side.
Prevents reverse bias which is applied to laser. Laser destruction prevention.
Prevents malfunction by static electricity.
Operation / Condition / Compatibility