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EET 450 – Advanced Digital. Chapter 24 Power. Power Supplies. Power conversion Performs a voltage conversion from either 120vAC to desired or 12vDC to desired voltages Technologies Linear Not efficient – heat generated Switching. Power Supplies. Power requirements
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EET 450 – Advanced Digital Chapter 24 Power
Power Supplies • Power conversion • Performs a voltage conversion from either 120vAC to desired or 12vDC to desired voltages • Technologies • Linear • Not efficient – heat generated • Switching
Power Supplies • Power requirements • Supplying adequate power (watts) • Total ~ 150-350 watts • Supply constant voltages • + 5V • -5 V • + 12V • - 12V • +3.3V (ATX)
Power Supplies • Device Power needs • Table 24.1 • Floppy – 1.4 W • Video – 6.5 W • HD – 2.2W – 6.5 W • Memory 16.8 W/8M • System Board – 25 W
Supply Voltage • US Standard – 115 V – 60 Hz • 100-240, 50/60 Hz is common • Regulated supplies for AC • Fairly uncommon – complex • Regulation is typically done by converting to DC, regulating, then converting back to AC
Portable Power • Batteries • NiCad • Lithium Ion • NiMH – • Smart Battery • Notebook Power • 2-6 hours
Power Connections • Standard P/S • D shaped device power connector • +5/+12 • 3.5” power connector • +5/+12 • Main Board Power Connector • See tables 24.3, 24.4
Power Management • States of APM • Full On • APM Standby – memory powered • APM Suspend - vegetable • Hibernation – allows restoration to memory/ program state • Off State
Energy Star • PC Monitor able to switch to a low power mode. • < 30 watts after 15 to 30 minutes • Combo of PC/monitor < 60 watts • Printer based on PPM
Power Protection • Irregularities • Overvoltage • Surges • Undervoltage • brownout • Noise • RF
Surge Suppression • Sinking energy spikes away from PC • Sacrificial • MOV • Active • Zener Diode
UPS • Battery System • Backup Power Supply • Regulation and ‘clean’ output • waveform • True UPS • Continuous power • Switching power • Computer Interface (network)
Other Considerations • Phone Lines • Static Electricity • Network Interface
Cases • The case dictates what can kind of power supply can be used.
Older case Styles • PC/XT – • Small Power Supply (63 watts) • AT Style • Desktop • Tower • Baby AT form factor • LPX Style • PS2 Style
Current case styles • ATX form factor • Power Supply used in ATX and NLX systems • Power connector is substantially changed • NLX style • Low profile ATX • SFX style • Micro-ATX motherboards
Power Supply Connectors • Standard M/B connector • AT • ATX • Power expansion • Y – cable • ATX Auxiliary and Optional connector
Disk Drive Power Connectors • Conventional drive • D-shaped • New ‘3.5”’ connector • Keyed pin connector