Daewoo Dtf 2950 Service Manual

CP-850FX Service Manual 
 
Europe R&D 
70 5.10.3 FB Terminal (Pin. 6) 
The operation of FB terminal is divided into normal (constant voltage control circuit operation) 
and stand-by operation control.  Refer to item No. 8.6 for the controlling at stand-by operation. 
 
5.10.3.1 Constant Voltage Control Circuit 
The STR-W6700 series adopts the current mode controlling circuit for the constant voltage 
control, which proves its superiority in a heavy load.  The MOSFET drain current peak value (  ≒
ON time)...

CP-850FX Service Manual 
 
Europe R&D 
71 5.10.4 OCP/BD Terminal (Pin 7) 
The functions of OCP/BD terminal are categorized as Overcurrent Protection (OCP), Bottom-
Skip, and Quasi-Resonant Operation control.  Refer to item No. 8.5 for Bottom-Skip and Quasi-
Resonant operation.  
 
8.4.1. Minus-Detection Type OCP Circuit 
The OCP of the STR-W6700 series is pulse-by-pulse 
type Overcurrent protection circuit, which detects the 
peak value of the MOSFET drain current per pulse and 
reverses oscillator...

CP-850FX Service Manual 
 
Europe R&D 
72 5.10.5 Quasi-Resonant and Bottom-Skip Operation 
5.10.5.1 Quasi-Resonant Operation 
The Quasi-Resonant operation is to match the timing of 
the MOSFET Turn-ON to the bottom point of the voltage 
resonant waveform after a transformer releases the 
energy (i.e., 1/2 cycle of the resonant-frequency). 
As shown in Fig.15, the voltage resonant condenser C4 
is connected between the drain and source, and the 
delay circuit, C10, D3, D4, and R9 are connected 
between...

CP-850FX Service Manual 
 
Europe R&D 
73 5.10.5.2   Bottom-Skip Operation (Switching from Quasi-Resonant Operation)
 
The basic bottom-skip operation is that the load of the secondary side is detected by the drain 
current value (actually OCP/BD terminal voltage), which switches to the Quasi-Resonant (at 
heavy load) and the Bottom-Skip operation (at light load).  The timing of distinguishing is made 
by taking the OCP/BD terminal voltage in at start-down of the MOSFET gate voltage of the HIC....

CP-850FX Service Manual 
 
Europe R&D 
74 rating, and the standard voltage is automatically changed to VOCPBD(BS2). 
Besides, the VOCP is OCP/BD terminal voltage at that time when the MOSFET gate voltage 
starts down.   
As described above, the standard voltage (VOCPBD(BS1), VOCPBD(BS2)) realizing the Bottom-
Skip operation provides the hysteresis operation automatically and makes it possible to have the 
stabilized operation.  Fig.17 shows the above operation switching changing mode. 
 
5.10.6 Stand-By...

CP-850FX Service Manual 
 
Europe R&D 
75 continues falling because the HIC’s oscillation is suspended until the Vcc terminal voltage (Pin 4) 
reaches the operation start-up voltage 18V (TYP).  Thus it is required to secure the voltage 
exceeding the required output voltage of secondary side. 
 
 
 
Fig.18. Timing-Chart at Operation 
Switching 
Normal Operation
Feedback
Stop
VoltageStart-up
Voltage
Normal Operation Standby Operation
Power MOSFET
Waveform  Secondary
Output Voltage
Stand-by
detection...

CP-850FX Service Manual 
 
Europe R&D 
76 At the stand-by mode, as mentioned above, due to the burst-mode of the HIC’s intermittent 
operation, the output voltage falls since the HIC stops its operation during the oscillation stop 
period.  While, during the stand-by operation, the intermittent operation repeating oscillation and 
stop through the start-up resistor is provided because the transformer’s auxiliary winding voltage 
supplying the power supply to the HIC is extremely decreased.  Accordingly,...

Important Safety Notice 
Components Identified by  mark have special characteristics inportant for safety. 
When replacing any of these components, use only manufacturers specified parts. In case of Ordering these spare parts,
please always add the complete Model-Type number to your order. 
LOC PART CODE PART NAME DESCRIPTION REMARKLOC PART CODE PART NAME DESCRIPTION REMARKZZ100 PTACPWT2950F ACCESSORY AS DTF-2950FZF-SB12000 48B5849C1001 TRANSMITTER REMOCON R-49C1013000 4850Q00910 BATTERY AAA R03...

CP-850/F Service Manual
79Europe R&D
LOC PART CODE PART NAME DESCRIPTION REMARKLOC PART CODE PART NAME DESCRIPTION REMARK
C604 CEXF1E102V C ELECTRO 25V RSS 1000MF (13X20) TPC805 CEYD2G181D C ELECTRO 400V FHS 180MF
C812 CH1BFE472M C CERA AC AC400V 4700PF M U/C/VC813 CEXF2E101V C ELECTRO 250V RSS 100MF 18X35.5C814 CEYF2E470V C ELECTRO 250V RSS 47MF (16X25C820 CCXR3D221K C CERA 2KV R 220PF K125CC823 CEXF1E222V C ELECTRO 25V RSS 2200MF (16X25) TPC840 CEXF1C102V C ELECTRO 16V RSS 1000MF (10X20) TPC861...

CP-850/F Service Manual
80Europe R&D
LOC PART CODE PART NAME DESCRIPTION REMARKLOC PART CODE PART NAME DESCRIPTION REMARK
E58 4856310300 EYE LET BSR T0.2 (R1.6) SMALLE6 4856310600 EYE LET BSR 2.3(R2.3) BIGE62 4856310300 EYE LET BSR T0.2 (R1.6) SMALLE63 4856310300 EYE LET BSR T0.2 (R1.6) SMALLE7 4856310600 EYE LET BSR 2.3(R2.3) BIGE8 4856310300 EYE LET BSR T0.2 (R1.6) SMALLE9 4856310300 EYE LET BSR T0.2 (R1.6) SMALLZZ200 PTMPJ2T2950FS PCB CHIP MOUNT B AS DTF-2950FZS-SBCC01 HCBK471KBA C CHIP CERA 50V X7R...