3-1. Basic Operation and Current Path

3-1-1. Later Half Scanning Period

When the power is turned on, the power supply voltage VB is applied to CS and Csm, and the CS acts as a power source for a later half of the scanning period for which the H. OUT transistor is turned on, and the deflection current IY flows in the path as shown below.

 

 

VA

 

 

 

FBT

 

 

 

LDY

H.OUT

IY

 

lP

 

 

 

 

 

 

+

 

 

 

Cs

 

 

 

VB

 

 

 

VB

 

IM

 

LM

 

 

 

 

DM

 

IDC

 

 

+

CSM

3-1-2. First Half Scanning Period

When the base drive current decreases and the H. OUT tran- sistor is turned off, each energy stored in LDY, Lm, LP of FTB is transferred to C1, C2 and C3, respectively, and the resonant current becomes zero at a center of the flyback pe- riod. Then, VA and VB pulses show a maximum amplitude.

VA

FBT

LDY lP

IP1

C1

IY

 

 

C2

 

 

IP2

IY2

 

 

 

 

 

Cs

VB

 

 

 

VB

IM LM

IDC

CSM

Fig. 10-7

Voltage & current waveform in H period.

IY 0

VA 0

IM 0

IDC

VB 0

Fig. 10-8

IY 0

VA 0

IM 0

IDC

VB 0

C1

C2 0

C3 0

Fig. 10-9

C1: IY1+IP1

C2: IY2+IP2

C3: IP2-IY1-IM

Fig. 10-10

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Toshiba TW40F80 manual Basic Operation and Current Path, Later Half Scanning Period, First Half Scanning Period