Cpu Ic (Sn28720) - Canon A-1 Repair Manual

Ve'
+
ccc
Vc
I<Vc
Fig . 3-17
3 . 3 CPU IC (SN28720)
,
1. E1LK (lP)
Fig. 3-18
62
REF REG
AND
CCC DET
MODEl
Standard voltage
(same as
VC
=
1. 219
' * '
38 mY)
MODE2
El LK is the power supply
(EL) latch-in circuit. It
l o c ks the El supply on for
long enough to cover the
shutte r operation time plus
the cycle time before and
after the actual shutter
operation.
(Th is provides a power sup-
pl y even if the shutter
butto n is not pressed
thro ghout the operation.)
Ex: For 1/2 sec. shutter,
the El LK gate is
approx. 600 mS long.
I
I _ _
.-...J~I- 2-2.~V
- . D-D.IV