Low-voltage power supply

The low-voltage power-supply circuit converts the AC power from the wall receptacle into the DC voltage that the product components use. The product has two low-voltage power-supplies for 110 Volt or 220 Volt input.

Figure 1-5Low-voltage power-supply circuit

AC input

 

DC controller

Fuse

 

 

Noise filter

Fuser control

 

Fuse

circuit

 

 

 

Noise filter

 

 

 

PSTYP100

 

Zerocross

ZEROX

+24VB

circuit

24RMT

 

SW2

 

+24VA

 

 

Rectifying

+24V

+5V

+5VB

 

SW1

 

 

generation

generation

 

 

circuit

 

 

 

 

 

circuit

circuit

 

 

+5VC

 

 

 

 

 

 

 

 

 

 

Rectifying

 

 

 

 

 

 

circuit

 

Protection circuit

 

 

 

+12V

 

+3.3V

 

+3.3V

 

 

generation

 

generation

 

 

 

 

 

 

 

 

circuit

 

circuit

 

 

 

 

 

 

 

 

Switching

 

 

 

 

 

 

circuit

 

 

Protection circuit

 

 

 

+3.3VS

 

 

 

 

PWROFF

Remote switch

 

 

 

PWRSWON

 

Low-voltage power supply

control circuit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+12VA

ICB

Formatter

 

 

 

 

 

Power switch

The low-voltage power supply converts the AC power into three DC voltages, which it then subdivides, as described in the following table.

Table 1-8Converted DC voltages

Main DC voltage

Sub-voltage

Behavior

 

 

 

+24 V

+24 VA

Constantly supplied

 

 

 

12 Chapter 1 Theory of operation

ENWW

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Image 44
HP Enterprise CC490A manual Low-voltage power supply, 8Converted DC voltages