Service manual CP 385 / CP785
- 46 -
When the power switch is pushed on, V
IN
increases slowly. During this time, C806 is charged through
R802.
As soon as V
IN
reaches 16V, the STR-F6653 control circuit starts operating. Then, V
IN
is obtained by
smoothing the winding voltage which appears between pin6 and pin7 of the SMPS transformer.
As this winding voltage does not increase to the set voltage immediately after the control circuit starts
operating, V
IN
starts dropping. However, as this winding voltage reaches the set value before V
IN
voltage drops to the shutdown voltage (at 11V), the control circuit continues operating (see below V
IN
voltage at start-up). R805 resistor prevents that V
IN
pin voltage varies according to the secondary side
output current.
V
IN
must be set higher than the shutdown voltage (V
IN
(off) = 11V
max
) and lower than the O.V.P.
(overvoltage protection) operating voltage
(V
OVP
= 20.5V
min
)
Shutdown voltage 11V
16V (TYP.)
O.V.P.voltage 20.5V
Vin
t
Waveform of Vin pin voltage at start-up
Summary of Contents for DTA-20 T1
Page 17: ...Service manual CP 385 CP785 16...
Page 21: ...Service manual CP 385 CP785 20...
Page 34: ...Service manual CP 385 CP785 33 5 Circuit description 5 1 Block diagram...
Page 39: ...Service manual CP 385 CP785 38 Chassis block diagram IF...
Page 43: ...Service manual CP 385 CP785 42 Sound signal flow diagram...
Page 70: ...69 Service Manual cp 385 cp 785 7 Exploded View 7 1 DTA 20T1...
Page 73: ...72 7 4 DTA 20T8 Service Manual cp 385 cp 785...
Page 74: ...73 7 5 DTA 21T1 Service Manual cp 385 cp 785...
Page 76: ...75 7 7 DTA 21T5 Service Manual cp 385 cp 785...
Page 77: ...76 7 8 DTA 21T9 Service Manual cp 385 cp 785...
Page 79: ...78 Service Manual cp 385 cp 785 7 10 DTE 25G6...
Page 80: ...79 Service Manual cp 385 cp 785 7 11 DTE 25G7...
Page 82: ...81 7 13 DTE 28G6 Service Manual cp 385 cp 785...
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