MFR_VLTO (DFh)
The Voltage Loop Timeout command sets the time
between each of the five ADC conversions. The time
(VLTO) is calculated as VLTO = N x 250ns, where N is
the 16-bit data included in the command. The range of
values is 0 to 16.38ms. The default value at power-up is
100, or 25µs. The total ADC acquisition time is:
(1.75µs + 0.25µs x MFR_VLTO)+ 4 x (4 x 1.75µs +
0.25µs x MFR_VLTO) (filtering on)
(1.75µs + 0.25µs x MFR_VLTO)+ 4 x (1.75µs + 0.25µs x
MFR_VLTO) (filtering off)
where 1.75µs represents a single ADC conversion time
and MFR_VLTO is the value contained in the register.
The internal ADC conversion registers are updated at
this rate. However, the voltages and temperatures are
monitored at another rate that is controlled by
MFR_SAMPLE_RATE.
MFR_DAC_ACT_CNT (E0h)
The MFR_DAC_ACT_CNT command sets the number of
ADC samples taken before updating the DAC output
voltage during AVOC mode. The resulting adjustment
rate is:
where f
AVOC
is the update period, in Hertz. This formu-
la applies only when input filtering is turned on
(MFR_MODE[1] = 0). When the filter is turned off, the
following formula applies:
MFR_RESET_OUTPUT (E1h)
RESET is an active-low open-drain output that is low when
the device is powering on. RESET is assigned to one of
the power supplies using the MFR_RESET_OUTPUT
command. When that power-supply output is at the target
voltage, RESET goes high after the reset timeout period
(see Figure 9). The reset timeout period is set by the
MFR_RESET_DELAY command.
The MFR_RESET_OUTPUT value defines which power-
supply output affects RESET. If MFR_RESET_OUTPUT is
set to 0, 1, 2, or 3, then RESET goes high
MFR_RESET_DELAY after that output has reached its tar-
get value. If MFR_RESET_OUTPUT is any other value,
RESET is permanently low.
If the power-supply output selected by
MFR_RESET_OUTPUT is later disabled for any reason
(either due to a fault condition, or an OPERATION OFF
command), then RESET goes low. To enable faults on
any power supply to cause RESET to go low, set the
MFR_MODE_OUTPUT.GLOBALFAULTS bit to a 1 for all
the supplies.
MFR_FAULT_REASON (E2h)
The MFR_FAULT_REASON command returns the
results of the voltage threshold comparisons for all
channels following a fault condition.
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