HP LaserJet Pro M402d - Page 27

Low-voltage power supply
The low-voltage power-supply (LVPS) circuit converts the AC power from the wall receptacle into the DC
voltage that the printer components use.
Figure 1-4 Low-voltage power-supply circuit
AC input
+24VA
FET
FET
+24VB
+24VC
+24VD
+24VBSNS
+24VA
FET
PWRSW
+3.3VA
FET
+3.3VC
+3.3VB
+3.3VA
+24VA
Low-voltage power supply
Rectifying
circuit
Protection
circuit
+24V
generation
circuit
Fuse
FU101
Fuse
FU102
+3.3V
generation
circuit
Fuser
Power switch
SW1
DC controller
High-voltage power supply
Interlock switch
SW101
Fuser control
circuit
FREQSNS_LVT
Frequency
detection circuit
Table 1-4 List of DC voltages
DC power supply Description
+24V +24VA Constantly supplied
Becomes 4.5V during active OFF or inactive OFF
ENWW Engine-control system 9