Samsung DVD-R129, Service Manual, Page: 115 / 208

Samsung Electronics 13-1
13. Circuit Operating Descriptions
13-1 Power
13-1-1 About S.M.P.S (Ringing Choke Converter Method)
◆ Terms
1) 1st : Common power input to 1st winding.
2) 2nd : Circuit followings output winding of transformer.
3) f (Frequency) : Switching frequency (T : Switching cycle)
4) Duty : (Ton/T) x 100
Transformer
Vout
(Np)
(Vp)
Switch
Vs switch
I switch
Vin
ON/OFF Control
+
–
+
–
+
+
+
–
(Vs)
(Ns)
Vreg
REGULATOR
Fig. 13-1
13-1-2 Circuit description [FLY-Back RCC(Ringing Choke Converter)] Control
(a) AC Power Rectification/Smoothing Terminal
1) PADT1, PADT2, PADT3, PADT4 : Convert AC power to DC (Wave rectification).
2) PRCU1 : Smooth the voltage converted to DC.
3) PALT1, PALT2, PACT1, PACT2 : Noise removal at power input/output.
4) PLRU1 : Rush current limit resistance at the momemt of power cord insertion.
· Without PLRT1, the bridge diode might be damaged as the rush current increases.