Rainbow Electronics MAX34440 - Manual (Page 24)

PMBus 6-Channel Power-Supply Manager
MAX34440
24
Table 8. OPERATION Command Byte (When Bit 3 of ON_OFF_CONFIG = 1)
Table 9. OPERATION Command Byte (When Bit 3 of ON_OFF_CONFIG = 0)
Note: 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
voltages. 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 8 and 9. 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 8 and 9, “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 undervolt-
age warnings and faults on the selected power supply are ignored and not reported. Any command value not shown
in Tables 8 and 9 is an invalid command. If the device receives a data byte that is not listed in Tables 8 and 9, 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)