Daewoo-Sony VX 14A1 – VX14AW1 – VX21AW1 – Circuit Diagram – TV-VCR combo: Service Mode - STR F6626 - SMPS - working principle
Used
ICs: STR-F6626 – LA78041 – 24LC08B – LA71076AM – LA76834 – TDA7442 – MM1053 -
TDA7267: Working Principle of SMPS power Regulator Circuit, using STR F6626
Features
of the model
1)
Chip for TV / video are all 1-Chip.
2)
Light / NO adopt the deck of CONNECTOR.
3)
Easy to adjustment in the non-adjustment or the remote control.
4)
during the operation of the protector circuit, displayed on the LED (vertical
protector service during the on / off possible).
5)
It can operate without deck.
6)
Can service only in the user remote control.
SMPS and Deflection PWB and Circuit Diagram
SMPS Working
Power
supply unit Operation (STR-F6626-related)
Vin
terminal
START
circuit detects the Vin terminal voltage, a circuit for performing the
operation start and stop control the IC.
Initial
AC power input, and by the condenser (C810) starting resistance of control
outside the IC (R806), rising Vin terminal until the operation start voltage
(14V) from the control circuit in the IC
to work. After the control circuit
operation, the Vin terminal by TURN ratio wrapped in proportion to the
secondary side B + join a stable BACK UP power.
When the B + power on the secondary side drops to about 1/10 than normal
(11V), 1 order of Vin fall even in the same proportion UVLO (Under Voltage Lock
Out) is to operate . Then, joined by Vin through the start-up resistance again,
this voltage is operates in the same manner as the first and leading to 16V.
Oscillator
and OCP / FB pin 1
Oscillator
of the internal control IC is the reference voltage input terminal is OFF.
IC
will start operation by the internal oscillator and Vin voltage reaches the
operation start voltage (14V). Internal oscillator, when the charging voltage
of the internal C1 is 3.7V
OSC
is turned ON, the voltage of C1 is increased to 6.5V.
When
the internal oscillator to oscillate MOSFET can Vocp turns ON. This voltage is
led OCP / FB terminal, internal OCP / FB COMP voltage
There
MOSFET is turned OFF when it comes to 0.73V.
Voltage
of C1 is maintained at 6.5V when ON of the MOSFET, to gradually discharge and
turned OFF. Discharge time is determined by an internal RC, 50uS
When
the discharge to become 3.7V MOSFET is turned ON, IC performs the basic
operation by repeating this kind of behavior.
Over-current
protection circuit (OCP = Over Current Protector)
OCP
circuit operates in PULSE BY PULSE system detects the DRAIN current directly. Circuit is constituted by COMPARATOR as in
Figure 2. Detection voltage Yes is set to -1.37V with respect to the GND of the
internal control IC. No more voltage is
turned OFF the internal oscillation operation and participate.
LATCH function
OVP = Over Voltage Protector
OVP
(overvoltage protection) circuit and TSD (overheat protection) circuit during
operation, a circuit for stopping the operation of the power supply circuit to
maintain the output of the oscillator to OFF.
If
the operation of the OVP and TSD persists more than 8uS to prevent malfunction
due to noise, it is set to work. When
the LATCH circuit operates, Vin voltage of the IC drops to sharply stops
operation voltage. Motion also internal constant-voltage circuit is followed by
the LATCH circuit operates. The other
hand to work, is because the Vin voltage is not applied to continue.
When
the Vin voltage drops to less than the operation stop voltage, IC is asked to
supply the Vin through the start-up resistor for the restart, to 16V of
operation start voltage reach and, Vin is rapidly decreases with increasing
again circuit current. In this case, Vin repeats the UVLO, IC does not operate.
After
the order to release the LATCH state, but it should go up from down Vin until
less than 6.5V, in general turn off the AC INPUT, comeback It must be dynamic. (Refer the above given circuit)
Click on the pictures to zoom in
Circuit Diagram (Syscon - Tuner VIF and Chroma) & PWB
How
to enter and the attitude to the service mode
User
remocon sequentially enter in the button input of.
"Menu"
=> "10" => "11" => "Volume (+ or ►) within 3 seconds.
Currently,
the term that has been selected is displayed in red, it can move to the
adjustment in the direction button. At the time of the service mode is canceled
Press
and hold until exiting the "menu" key.
Or
press the "Power" key. ( after the adjustment, the memory of the Data
is separately required)
