Datasheet

PMBus 5-Channel Power-Supply Manager
and Intelligent Fan Controller
MAX34441
27
Table 9. OPERATION Command Byte (When Bit 3 of ON_OFF_CONFIG = 1)
Table 10. OPERATION Command Byte (When Bit 3 of ON_OFF_CONFIG = 0)
Note: The device only takes action if the supply is enabled. The VOUT of all enabled channels must exceed POWER_GOOD_ON
for margining to begin.
Note: The device only takes action if the supply is enabled. The VOUT of all enabled channels must exceed POWER_GOOD_ON
for margining to begin.
OPERATION (01h)
The OPERATION command is used to turn the power supply on and off in conjunction with the CONTROL input pin. The
OPERATION command is also used to cause the power supply to set the output voltage to the upper or lower margin voltag-
es. The power supply stays in the commanded operating mode until a subsequent OPERATION command or until a change
in the state of the CONTROL pin (if enabled) instructs the power supply to change to another state. The valid OPERATION
command byte values are shown in Tables 9 and 10. The OPERATION command controls how the device responds when
commanded to change the output. When the command byte is 00h, the device immediately turns the power supply off and
ignores any programmed turn-off delay. When the command byte is set to 40h, the device powers down according to the
programmed turn-off delay. In Tables 9 and 10, “act on any fault” means that if any warning or fault on the selected power
supply is detected when the output is margined, the device treats this as a warning or fault and responds as programmed.
“Ignore all faults” means that overvoltage, overcurrent, and undervoltage warnings and faults on the selected power supply
are ignored and not reported. Any command value not shown in Tables 9 and 10 is an invalid command. If the device receives
a data byte that is not listed in Tables 9 and 10, then it treats this as invalid data, declares a data fault (set CML bit and assert
ALERT), and responds as described in the Fault Management and Reporting section.
USER NOTE: All power supplies tagged as GLOBAL supplies (see MFR_FAULT_RESPONSE) should be turned
on and off at the same time.
COMMAND BYTE POWER SUPPLY ON OR OFF MARGIN STATE
00h Immediate Off (No Sequencing) N/A
40h Soft Off (with Sequencing) N/A
80h On Margin Off
94h On Margin Low (Ignore All Faults)
98h On Margin Low (Act On Any Fault)
A4h On Margin High (Ignore All Faults)
A8h On Margin High (Act On Any Fault)
COMMAND BYTE POWER SUPPLY ON OR OFF MARGIN STATE
00h Command Has No Effect N/A
40h Command Has No Effect N/A
80h Command Has No Effect Margin Off
94h Command Has No Effect Margin Low (Ignore All Faults)
98h Command Has No Effect Margin Low (Act On Any Fault)
A4h Command Has No Effect Margin High (Ignore All Faults)
A8h Command Has No Effect Margin High (Act On Any Fault)