Samsung DVD-811, DVD-711 Circuit Descriptions

Samsung Electronics 5-1

5. Circuit Descriptions

5-1 Power (120/127 Voltage)

5-1-1 Comparsion between Linear Power Supply and S.M.P.S.

5-1-1 (a) Linear

Vreg

Vout

+ –

(Ns)

(Np)

REGULATOR

Common power

(Ex.120/127V 60Hz)

Fig. 5-1 Linear Power Supply

◆ Waveform/Description

Fig. 5-2

Fig. 5-3

Vout

Fig. 5-4

Input : Common power to transformer (Vp).

The output Vs of transformer is determined by the ratio of 1st Np and 2nd Ns. Vs = (Ns/Np) x Vp

Vout is output (DC) by diode and condensor.

Circuit Descriptions

5-2 Samsung Electronics

◆ Advantages and disadvantages of linear power supply

1) Advantages : Little noise because the output waveform of transformer is sine wave.

2) Disadvantages : Œ Additional margin is required because Vs is chan-

ged (depending on power source). (The regulator loss is caused by margin design).

´ Greater core size and condensor capacity are ne-

eded, because the transformer works on a single power frequency.

5-1-1 (b) S.M.P.S. (Pulse width modulation method)

Vreg

Vout

Change by common power

Regulator loss

Fig. 5-5

◆ 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)

REGULATOR

Fig. 5-6

Circuit Descriptions

Samsung Electronics 5-3

5-1-2 Circuit description (FLY-Back Control)

5-1-2 (a) AC Power Rectification/Smoothing Terminal

1) PDS01, PDS02, PDS03, PDS04 : Convert AC power to DC(Wave rectification).

2) PE3 : Smooth the voltage converted to DC.

3) PCR01, PCR02, PCD01, PCD02, PCD03, PLS01, PBS01 : Noise removal at power input/output.

4) PVA1 : SMPS protection at power surge input (PVA1 pattern open is to remove noise).

5-1-2 (b) SNUBBER Circuit : PER11, PDS11, PCR11, PCD12, PRS11, PRS12

Vswitch

Toff

Inverted power by leakage inductance

Fig. 5-7

1) Prevent residual high voltage at the terminals of switch during switch off/Suppress noise.

High inverted power occurs at switch (PIC1) off, because of the 1st winding of transformer : (V= LI xdi/dt. LI : Leakage Induction) A very high residual voltage exists on both terminals of PQR11 because dt is a very short.

2) SNUBBER circuit protects PIC1 from damage through leakage voltage suppression by RC, (Charges the leakage voltage to PER11, PDS11, PCR11, PCD12, and discharges to PR15 and PR16).

5-1-2 (c) Driving circuit

When Vin supplied, driving current Ig occurs throuhg the PRR11. By this IC (=HfexIg) occurs throug the PQR11 and the Vb is inducted to base winding coil NB of PQR11. By inducted Vb, Ib start flow and the PQR11 is saturated (S/W ON). Ib is constant and Ic increases in propotion to time. After constant time passed Ib become to shotage and PQR11 is cut OFF (S/W OFF).

Fig. 5-8 Driving Circuit

Circuit Descriptions

5-4 Samsung Electronics

◆ Operation descriptions

1) Internal OP-Amp ‘+’ base potential of PICS2 is 2.5V and external “-” input potential is connected with PRS33 and PRS34 to maintain Vout of 5.8V.

2) If load of 5.8V terminal decreses (or AC inout voltage increases) and Vout increases over 5.8V, Then : PICS2 Vs potential up over 2.5V --> PICS2 Vc down --> PICS1 A-K potential down --> PICS1 C-E current up --> PQR12 base current up --> PQR11 base current down --> Vout down --> Maintain 5.8V

- PRD31, PRD32 : Reduce 5.8V overshoot.

- PRS32, PCS32 : Prevent PICS2 oscillation (for phase correction).

5-1-2 (d) Feedback Control Circuit

Fig. 5-9

Circuit Descriptions

Samsung Electronics 5-5

5-1-3 Internal Block Diagram

◆ Internal Block Diagram

Smoothing

Circuit

Rectified Circuit

Line Filter

Power IN

(120/127V)

Noise

Removal

(SNUBBER)

Power TR

Control Circuit

Converter

Voltage

Detection

Circuit

FLT Driving

Circuit

3.3V Rectified

Smoothing Circuit

5V Rectified

Smoothing Circuit

8V Rectified

Smoothing Circuit

-8V Rectified

Smoothing Circuit

3.3V Rectified VoltageCircuit

5V Rectified

VoltageCircuit (x2)

Motor 8V

1 Port

8V Rectified

VoltageCircuit

-8V Rectified

VoltageCircuit

O U T P U T

Fig. 5-10

Circuit Descriptions

5-6 Samsung Electronics

5-2 Power (Free Voltage)

5-2-1 Comparsion between Linear Power Supply and S.M.P.S.

5-2-1 (a) Linear

Vreg

Vout

–

(Ns)

(Np)

REGULATOR

Common power

(Ex.110~240V 50/60Hz)

Fig. 5-11 Linear Power Supply

◆ Waveform/Description

Fig. 5-12

Fig. 5-13

Vout

Fig. 5-14

Input : Common power to transformer (Vp).

The output Vs of transformer is determined by the ratio of 1st Np and 2nd Ns. Vs = (Ns/Np) x Vp

Vout is output (DC) by diode and condensor.

Circuit Descriptions

Samsung Electronics 5-7

◆ Advantages and disadvantages of linear power supply

1) Advantages : Little noise because the output waveform of transformer is sine wave.

2) Disadvantages : Œ Additional margin is required because Vs is chan-

ged (depending on power source). (The regulator loss is caused by margin design).

´ Greater core size and condensor capacity are ne-

eded, because the transformer works on a single power frequency.

5-2-1 (b) S.M.P.S. (Pulse width modulation method)

Vreg

Vout

Change by common power

Regulator loss

Fig. 5-15

◆ 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)

REGULATOR

Fig. 5-16

Circuit Descriptions

5-8 Samsung Electronics

5-2-2 Circuit description (FLY-Back PWM (Plise Width Modulation) Control)

5-1-2 (a) AC Power Rectification/Smoothing Terminal

1) PDS01, PDS02, PDS03, PDS04 : Convert AC power to DC(Wave rectification)

2) PEF10 : Smooth the voltage converted to DC(Refer to VIN of Fig. 5-17)

3) PLF01, PLS01, PCF01, PCF02, PCD01, PCD03, PCS03 : Noise removal at power input/output

4) PVA1 : SMPS protection at power surge input (PVA1 pattern open is to remove noise)

5) PR10 : Rush current limit resistance at the moment of power cord insertion. Œ Rush current = (AC input voltage x 1.414 - Diode drop voltage) / Pattern resistance + PLF01, PLS01

resistance + PCD01 resistance + PRF10) (AC230V based : approx. 26A)

´ Without PRF10, the bridge diode might be damaged as the rush current increases.

5-2-2 (b) SNUBBER Circuit : PRS11, PRS12, PRD12, PCD12, PDS11, PCF11

Vswitch

Toff

Inverted power by leakage inductance

Fig. 5-17

5-2-2 (c) PICF1 Vcc circuit

1) PCD11, PCF12, PCF13, PCF14 : PICF1 driving resistance (PICF1 works through driving resistance at power cord in)

2) PICF1 Vcc : PDF13, PRF16, PEF12

Use the output of transformer as Vcc, because the current starts to flow into transformer while PICF1 is active.

´ Rectify to PDF13 and smooth to PEF12. ˇ Use the output of transformer as PICF1 Vcc : The loads are different before and after PICF1 driving.

(Vcc of PICF1 decreases below OFF voltage, using only the resistance due to load increase after PICF1 driving.)

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