Casio A-10 - 5 V Circuit

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BATDTCT
Changeover circuit for the load
Alkaline = OPEN
NiMH = CLOSE
SW3
Q46
U63
Q47
D43
D2
D42
FS1
Q13
Q12
Q9
Q10
Q11
SHDN EXT
CS
V+
DC-DC converter
MAX608 (U20)
Primary Circuit
P5VRB
(SYSTEM LSI pin 171)
BATDTCT = OPEN
Q46 ON
U63 OFF
Load: Min.
BATDTCT = CLOSE
Q46 OFF
U63 ON
Load: Max.
V5MAIN
V5SYS (To U4, 3pin)
P5V (Normally H)
PCRD (Normally H)
V5CARD (To PCMCIA)
✽
✽
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.