Commodore CM-141 - Page 10

(3) It IS possible to use the former SMPS at free running frequen-
cy as mentioned above. But it IS also possible to lock the swit-
ching frequency to hOrizontal frequency
In the latter case, frequency is constant and only Ton IS chang-
ed. This
IS pulse Width MOdulation (PWM) tf this IS applied
to CTV, the time of sWitch on
IS met to blanking time of CRT
and
nOise suppression IS easier than free frequency
If locking to some frequency IS needed, the primary Induc-
(5) Operation circuit for frequency iock;ng
0907
R902
C914
?C913
V,n
I
I
R904
I
I
I
I
t _ ______
P
tance shall be determined so that the free running frequency
before locking
may be smaller than the honzontal frequency
even
if at worst case. 0Norst case means that Vin IS maximum
and
10 IS minimum. The Fo will be the highest dunng free run-
ning without locking.)
(4) The wave shape of voltage and current at free Fa and lock-
Ing respectively.
I
I
I
0909
I(s c:+ ::"
R909 0908
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