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VP
2 +20V
Ft
1
~4.3VAC
F2
1 -4.3VAC
VDISP_
: -25V
VCC
1 4+5V
VDD
: +5V
2) Regulator circuit
TR
1769
Fig. 2-17
1) If VO-P-ON was not shorted within the mode switch (power
aff), TR1 remains inactive as no voltage is applied to the base
of TAI.
2) If VO-P-ON was shorted, TR1 comes active as voltage is
added to the base of TR1.
3) With activation of TR1, the voltage VM begins to increase.
8) DC-DC converter
Fig. 2-18
The bias is added to the base of TR2 when the power switch is
tumed on, so that TR2 starts self-oscillation. VOISP from the
secondary side is fed back. through the zener ZD4'to sippress
voltage fluctuation on the secondary side.
-27-
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