QBDW025A0B Datasheet, PDF (18/32 Pages) Lineage Power Corporation – 36-75Vdc Input; 12.0Vdc, 25.0A, 300W Output

GE
Data Sheet
QBDW025A0B Barracuda Series; DC-DC Converter Power Modules
36-75Vdc Input; 12.0Vdc, 25.0A, 300W Output
high data byte form the two’s complement representation of
the exponent, which is fixed at –1 (decimal). The remaining 11
bits are used for two’s complement representation of the
mantissa, with the 11^th bit fixed at zero since only positive
numbers are valid. The data associated with TON_RISE and
TON_DELAY can be stored to non-volatile memory using the
STORE_DEFAULT_ALL command.
Output Voltage Adjustment Using the PMBus
The QBDW033A0B module output voltage set point is
adjusted using the VOUT_COMMAND. The output voltage
setting uses the Linear data format, with the 16 bits of the
VOUT_COMMAND formatted as an unsigned mantissa, and a
fixed exponent of -12 (decimal) (read from VOUT_MODE).
VOUT = Mantissa x 2^-12
The range limits for VOUT_COMMAND are 8.10V to 13.20V,
and the resolution is 0.244mV.
The data associated with VOUT_COMMAND can be stored to
non-volatile memory using the STORE_DEFAULT_ALL
command.
Output Voltage Margining Using the PMBus
The QBDW033A0B module can also have its output voltage
margined via PMBus commands. The command
VOUT_MARGIN_HIGH sets the margin high voltage, while the
command VOUT_MARGIN_LOW sets the margin low voltage.
Both the VOUT_MARGIN_HIGH and VOUT_MARGIN_LOW
commands use the “Linear” mode with the exponent fixed at
–12 (decimal). The data associated with VOUT_MARGIN_HIGH
and VOUT_MARGIN_LOW can be stored to non-volatile
memory using the STORE_DEFAULT_ALL command.
The module is commanded to go to the margined high or low
voltages using the OPERATION command. Bits [5:2] are used
to enable margining as follows:
00XX :
0110 :
1010 :
Margin Off
Margin Low (Act on Fault)
Margin High (Act on Fault)
Measuring Output Voltage Using the PMBus
The module can provide output voltage information using the
READ_VOUT command. The command returns two bytes of
data in the linear format, with the 16 bits of the READ_VOUT
formatted as an unsigned mantissa, and a fixed exponent of
-12 (decimal).
During module manufacture, an offset correction value is
written into the non-volatile memory of the module to null
errors in the tolerance and A/D conversion of VOUT. The
command MFR_VOUT_READ_CAL_OFFSET can be used to
read the offset - two bytes consisting of a signed 16-bit
mantissa in two’s complement format, using a fixed
exponent of -12 (decimal). The resolution is 0.244mV. The
corrected Output voltage reading is then given by:
V_OUT (Read)  [V_OUT (A/ D) 
MFR_VOUT _ READ_ CAL_ OFFSET
Measuring Input Voltage Using the PMBus
The module can provide input voltage information using the
READ_VIN command. The command returns two bytes of
data in the linear format. The upper five bits [7:3] of the high
data byte form the two’s complement representation of the
exponent, which is fixed at –3 (decimal). The remaining 11
bits are used for two’s complement representation of the
mantissa, with the 11^th bit fixed at zero since only positive
numbers are valid.
During module manufacture, offset and gain correction
values are written into the non-volatile memory of the
module to null errors in the tolerance and A/D conversion of
Vin. The command MFR_VIN_READ_CAL_OFFSET can be used
to read the offset - two bytes consisting of a five-bit exponent
(fixed at -3) and a 11-bit mantissa in two’s complement
format. The resolution is 125mV. The command
MFR_VIN_READ_CAL_GAIN can be used to read the gain
correction - two bytes consisting of a unsigned 16 bit
number. The resolution of this correction factor 0.000122. The
corrected input voltage reading is then given by:
V_IN (Read) 
[V_IN (A/ D)(MFR_VIN_ READ_CAL_GAIN/8192)]
 MFR_VIN_ READ_CAL_OFFSET
Measuring Output Current Using the PMBus
The module measures output current by using the output
filter inductor winding resistance as a current sense element.
The module can provide output current information using the
READ_IOUT command. The command returns two bytes of
data in the linear format. The upper five bits [7:3] of the high
data byte form the two’s complement representation of the
exponent, which is fixed at –4 (decimal). The remaining 11
bits are used for two’s complement representation of the
mantissa, with the 11^th bit fixed at zero since only positive
numbers are valid. Output current readings are blanked
below 1.65A.
During module manufacture, offset and gain correction
values are written into the non-volatile memory of the
module to null errors in the tolerance and A/D conversion of
IOUT. The command MFR_IOUT_CAL_OFFSET can be used to
read the offset - two bytes consisting of a five-bit exponent
(fixed at -4) and a 11-bit mantissa in two’s complement
format. The resolution is 62.5mA. The command
MFR_IOUT_CAL_GAIN can be used to read the gain correction
- two bytes consisting of a unsigned 16 bit number. The
resolution of this correction factor 0.000122. The READ_IOUT
command provides module average output current
information. This command only supports positive current
sourced from the module. If the converter is sinking current a
reading of 0 is provided.
I_OUT (Re ad ) 
[I_OUT (A / D)  (MFR _ IOUT _ CAL _ GAIN / 8192)]
 MFR _ IOUT _ CAL _ OFFSET
Note that the current reading provided by the module is
corrected for temperature.
Measuring the Temperature using the PMBus
May 9, 2013
©2012 General Electric Company. All rights reserved.
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