Rainbow Electronics MAX16064 - Manual (Page 40)

MAX16064
±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface
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Table 9. STATUS_BYTE Message Contents
BIT NUMBER STATUS BIT NAME MEANING
7 BUSY
A fault was declared because the device was busy and unable to respond.
(The BUSY bit is not supported. This bit always returns 0).
6 OFF
This bit is asserted if ENOUT is presently disabling the power supply, regardless of the
reason, including simply not being enabled.
5 VOUT_OV An output overvoltage fault has occurred.
4 IOUT_OC
An output overcurrent fault has occurred.
(The IOUT_OC bit is not supported. This bit always returns 0).
3 VIN_UV
An input undervoltage fault has occurred.
(The VIN_UV bit is not supported. This bit always returns 0).
2 TEMPERATURE A temperature fault or warning has occurred.
1 CML A communication, memory, or logic fault has occurred.
0 OTHER
A fault or warning not listed in bits [7:1] has occurred. See the MFR_STATUS_WORD (D8h)
section for more information.
In feedback mode, the MAX16064 leaves the S_ switch
on the DAC open during soft-start. It waits for the
TON_RISE time to expire before adjusting the DAC out-
put to equal the DACOUT_ feedback and then closes
the S_ switch.
The 2 data bytes are in DIRECT format. In REFIN mode,
the TON_RISE parameter is a 16-bit value and the valid
values are from 0.01ms to 32.767ms. In FB mode, the
TON_RISE is a 14-bit value and the valid values are
from 0.01ms to 16.383ms (the upper 2 bits are ignored).
The default TON_RISE value is 0.01ms. Setting any
value less than this minimum value defaults to 0.01ms.
TOFF_DELAY (64h)
The TOFF_DELAY sets the time, in milliseconds, from
when a STOP condition is received (a soft-off OPERA-
TION command or through A3/CONTROL when
enabled) until the power supply stops transferring ener-
gy to the output.
When commanded to turn off immediately through the
OPERATION command, the TOFF_DELAY value is
ignored. When commanded to turn off through
A3/CONTROL (when enabled) or EN, the TOFF_DELAY
parameter is used.
The 2 data bytes are in DIRECT format. Valid values are
from 0 to 3276.7ms.
The default TOFF_DELAY value is 0.
TOFF_FALL (65h)
The TOFF_FALL command sets the time, in millisec-
onds, from the end of the turn-off delay time until the
output voltage is commanded to zero. Note that this
command can only be used with a device whose output
can sink enough current to cause the output voltage to
decrease at a controlled rate.
When commanded to turn off immediately through the
OPERATION command, the TOFF_FALL value is
ignored. When commanded to turn off through the
OPERATION soft-off command or A3/CONTROL (when
enabled) or EN, the TOFF_FALL parameter is used. If a
TOFF_FALL parameter results in the DAC outputting an
out-of-range value (valid range 0 to 4090) immediately
during TOFF_FALL, the CML flag is set and SMBALERT
asserts to issue a warning.
In feedback mode, this value is not used. The
MAX16064 disables ENOUT_ and opens the DAC
switch immediately after the TOFF_DELAY.
The 2 data bytes are in DIRECT format. Valid values are
from 0.01ms to 32.767ms.
Do not set TOFF_FALL to any value less than 0.1ms.
STATUS_BYTE (78h)
The STATUS_BYTE command returns 1 byte of informa-
tion with a summary of the most critical faults. A value
of 1 indicates that a fault or warning event has occurred
and a 0 indicates otherwise. Bits for unsupported fea-
tures shall be reported as 0.
The STATUS_BYTE cannot be restored by
RESTORE_DEFAULT_ALL command. The STATUS_BYTE
message content is described in Table 9.
This command is read only.
The default STATUS_BYTE value is 40h (power supply
is off).