ec602-chapter 1 3powersupply

8/10/2019 EC602-Chapter 1 3PowerSupply

1/38

EC602COMPUTER SYSTEMDIAGNOSIS

AND MAINTENANCE

1 MSZ Dis12


2/38

Chapter 1_3PERSONAL COMPUTERCOMPONENTS

Computer System Diagnosis and

Maintenance2

MSZ Dis12


3/38

Power Supply Unit

1.1.3-Power Supply3

MSZ Dis12


4/38

Inside PC Power Supply

MSZ Dis12

4 1.1.3-Power Supply


5/38

Power Supply Connector

MSZ Dis12



6/38

Types of Power Supply

Linear Power Supply

Switched Mode Power Supplies

MSZ Dis12



7/38

Linear Power Supply

MSZ Dis12



8/38

Operation LPS

Uses a transformerto convert the voltageto a lower voltage.

A rectifieris used to produce DC.Capacitoris used to smooth the pulsating

current from the rectifier.

Some small periodic deviations from

smooth direct current will remain, which isknown as ripple.

MSZ Dis12



9/38

Circuit Diagram

MSZ Dis12



10/38

Block Diagram

MSZ Dis12



11/38

Switching

ModePower

Supply

MSZ Dis12



12/38

Operation SMPS The AC input is rectified and filtered to give a

steady DC voltage.

This DC input to the voltage switching block iseither blocked or allowed to pass throughdepending on the state of the switch.

The resultant waveform which is a squarewave is rectified and filtered (This waveform issampled).

If the current required at the load is high, thenthe switching control ensures that the voltageswitch is on for longer periods

MSZ Dis12



13/38

Operation SMPS

The sampling is done by a comparator and

DC amplifier along with a DC reference.

The output voltage is compared with a DCreference.

If the output voltage reduces due to increase

in load current, the comparator sends a

positive signal to the pulse width modulatorand increase the on time of the pulse.

MSZ Dis12



14/38

Circuit Diagram

MSZ Dis12



15/38

Block Diagram

MSZ Dis12



16/38


17/38

Diagnose Power Supply

MSZ Dis12



18/38

PS Form Factors

MSZ Dis12



19/38

AT/Desktop PS

MSZ Dis12



20/38

ATX PS

MSZ Dis12



21/38

Comparison AT vs ATX

AT Style

Power-on switch wirefrom the front of thecomputer isconnected directlyto the power supply

No 12V Connector Turn off power supply

manually

ATX Style

the power switch onthe front of the

computer goes to

the motherboard o

With 12V Connector

Turn off power supply

using soft switch

MSZ Dis12



22/38

AT Power Connector

MSZ Dis12



23/38

AT Power Connector

Two main power connectors (P8 and P9, also

called P1 and P2), each with six pins that

attach the power supply to the motherboard. These are rated at 5A per pin, at up to 250V.

P8 and P9 connectors have them installed

end to end so that the two black wires on

both power cables are next to each other.

MSZ Dis12



24/38

ATX Main Power Connector

MSZ Dis12



25/38

ATX Main Power Connector

The industry-standard ATX power supply-to-motherboard main connector is the

Molex Mini-Fit, Jr. connector number 39-29-9202 (20 pins ATX connector).

Molex rates each pin to handle 6A, at upto 600V.

MSZ Dis12



26/38

ATX Auxiliary Power Connector

MSZ Dis12



27/38

Peripheral Power Connector

MSZ Dis12



28/38

SATA Power Connector

MSZ Dis12



29/38

SATA POWER CABLE

MSZ Dis12



30/38

Floppy Power Connector

MSZ Dis12

30

RED +5V

BLACK GND

BLACK GND

YELLOW +12V

1.1.3-Power Supply


31/38

Summary of PS Connector

MSZ Dis12



32/38

Y-Adapter Power Cable

MSZ Dis12



33/38

MSZ Dis12



34/38

MSZ Dis12



35/38

MSZ Dis12



36/38

Power Rating

MSZ Dis12


1 1 3 P S l


37/38

Surge Protectors

MSZ Dis12


1 1 3 P S l


38/38


ec602-chapter 1 3powersupply

Documents