HP CP4525DN Laser CC494A#ABA manual Overcurrent/overvoltage protection, Safety, Voltage detection

Table 1-8Converted DC voltages (continued)

Main DC voltage	Sub-voltage		Behavior
	+24 VB		Interrupted when the front door or right
			door open
+5 V	+5 VB		Constantly supplied
	+5 VC		Interrupted when the front door or right
			door open
+3.3 V	3.3	V	Constantly supplied
	3.3	VS	Stopped during Sleep (powersave)
			mode

Overcurrent/overvoltage protection

The low-voltage power supply stops supplying the DC voltage to the product components whenever it detects excessive current or abnormal voltage from the power source. If DC voltage is not being supplied from the low-voltage power supply, the protective function might be running. In this case, turn the power off and unplug the power cord. Do not turn the power switch on until the root cause is found. The DC controller notifies the formatter of a low-voltage power supply failure when the protective function is activated. In addition, the low-voltage power supply circuit and the fuser control unit have a fuse to protect against overcurrent. If overcurrent flows into the AC line, the fuse blows to stop AC power.

Safety

For personal safety, the product interrupts 24 VB power to the fuser, high-voltage power supply, and motors, in addition to +5 VC to the laser scanners when the front or right door is opened. The power switch is on the dc line so that the ac power flows even if the power switch is turned off. Unplug the power cord before disassembling the product.

Voltage detection

The product detects the power supply voltage that is connected to the product. The DC controller monitors the POWER SUPPLY VOLTAGE (PSTYP100) signal and detects power supply voltage, whether 100 V or 200 V, to control the fuser operation.

Sleep (powersave) mode

Sleep mode conserves energy by stopping the power to several components when the product is idle. If the DC controller detects voltage that is too high when the product is in Sleep mode, it determines that the low-voltage power supply has failed, and it notifies the formatter.

Low-voltage power supply failure

The DC controller determines a low-voltage power supply failure and notifies the formatter when the low-voltage power supply does not supply +24 V.

ENWW Engine-control system 13