Caple C702G Manuel de service télécharger pdf (Page 178)

8-53

8-16. Second Over Voltage Protection

If some failure occurs and the output voltage of the secondary windings of T651 increase, the voltage of

the auxiliary winding of T651 also increase proportionally. When the voltage of C651 increase about +13V.

This action will stop the oscillator with in IC651.

(Fig.8-17) Second Over Voltage Protection

8-17. Second Over Current Protection

If some failure occurs and the total power of secondary outputs increase, the peak current of IC651 pin3

increases.

And when the peak current of IC651 pin3 reaches about 1.5A,the voltage of IC651 pin 1 decrease.

When the the voltage of IC651 pin 1 decreases below 4.7V, IC651 operation stop.

Next,the charging current flows into C653 and the voltage of IC651 pin 1 increase about 5.7V.

IC651 continues the movement of decreasing and increasing voltages 8 times.

After IC651 repeats the intermittent oscillation.

(Fig.8-18) Second Over Current Protection

R652

Q651

Q652

ZD651

R653

CONTROL

IC651

SOURCE

PC651

T651

C651

D601(+)

C609

T651

R659

R657

R660

C660

C656

D653

IC651

C653

PWM

Control

Circuit

C610

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Caple C702G Manuel de service Page 178