5 V Circuit - Casio A-10 Operation, Service Manual & Parts List

5 V Circuit

DC-DC converter MAX608ESA (U20) generates +5.11 V and it makes up 5 V system.
V5MAIN : The reference voltage for the detector.
V5SYS : +5 V source for U4 and 3-pin jack.
P5V : Controls ON/OFF of V5SYS. From pin 170 of SYSTEM LSI.
V5CARD : +5 V source for PCMCIA Card.
PCRD : Controls ON/OFF of V5CARD. From pin 166 of SYSTEM LSI.
BATDTCT: It distinguishes alkaline and NiMH to change the load according to the battery. When alkaline
is used, it is H. When NiMH, it is L.
P5VRB : Controls ON/OFF of DC-DC converter (U20). From pin 171 of SYSTEM LSI.
BATDTCT
SW3
Alkaline = OPEN
NiMH = CLOSE
FS1
Primary Circuit
D42
P5VRB
(SYSTEM LSI pin 171)
DC-DC converter
Changeover circuit for the load
Q46
U63
D2
Q9
SHDN EXT
MAX608 (U20)
V+
CS
— 35 —
BATDTCT = OPEN
Q46 ON
D43
U63 OFF
BATDTCT = CLOSE
Q47
Q46 OFF
U63 ON
Q13
Q11
Q12
Q10
Load: Min.
Load: Max.
V5MAIN
V5SYS (To U4, 3pin)
P5V (Normally H)
V5CARD (To PCMCIA)
PCRD (Normally H)