11

Phase

comparator

output

R5

R4

Vcc1

Figure 3 : Line Oscillator

The oscillator thresholds are internally fixed by

resistors. The discharge of the capacitor depends

on the internal resistor R4. The control voltage is

applied on resistor R5.

Line

Flyback

Sync pulse

Output

Current

Vc

Integrated

Flyback

Figure 4 : Phase Comparator

The sync-pulse drives the current in the compara-

tor. The line flyback integrated by the external net

work gives on pin 13 a saw tooth, the DC offset of

this saw tooth is fixed by VC. The comparator

output provides a positive current for the part of the

signal on pin 13 greater than to VC and a negative

current for the other part. When the line flyback and

the video signal are synchronized, the output of the

comparator is an alternatively negative and positive

current. The frame sync-pulse inhibits the compa-

rator to prevent frequency drift of the line oscillator

on the frame beginning.

13

12

Vcc1

Vc

SL2

ST1

Figure 5

Line output (Pin 17)

It is an open-collector output. The output positive

pulse time is 29

µs for a 64µs period.

The oscillator thresholds are internally fixed by

resistors. The oscillator is synchronized during the

last half free run period. The input current during

the charge of the capacitor is less than 100nA.

TDA8214B

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