Switching Regulator Unit - NEC MultiSync 3D JC-1404HME Service Manual

(2-1-1) SWITCHING REGULATOR UNIT
(a) Rectifying & filtering circuit
AC input is rectified by D601. Then, it is filtered by C606. The resulting DC voltage is supplied
to the converter circuit.
+
C606
(Fig. 2-1-1) Rectifying & Filtering Circuit
(b) Auxiliary power supply circuit
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The auxiliary power supply circuit is needed to activate IC601. At the time of power ON,
charging current flows into the capacitor C619 via R603. Oscillation starts when the voltage of
IC601 pin 16 reaches 17V by this charging operation.
After the start of oscillation, the toward voltage of the auxiliary coil for the switching trans-
former is rectified and filtered by D604 and C611, and regulated by Q601. The resultant DC
voltage is supplied to IC601.
R603
D604
C611
C619
R609
IC601
(Fig. 2-1-2) Auxiliary Power Supply Circuit
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