lm25066apsqx National Semiconductor Corporation, lm25066apsqx Datasheet - Page 37

• Manufacturer Part Number: lm25066apsqx
• Description: Lm25066a System Power Management And Protection Ic With Pmbus
• Manufacturer: National Semiconductor Corporation

AVGN=12 equates to 4096 samples used in computing the
average). The LM25066A supports average numbers of 1, 2,
4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096. The
SAMPLES_FOR_AVG number applies to average values of
IIN, VIN, VOUT, PIN simultaneously. The LM25066A uses
simple averaging. This is accomplished by summing consec-
utive results up to the number programmed, then dividing by
the number of samples. Averaging is calculated according to
the following sequence:
When the averaging has reached the end of a sequence (for
example, 4096 samples are averaged), then a whole new se-
quence begins that will require the same number of samples
(in this example, 4096) to be taken before the new average is
ready.
Note that a change in the SAMPLES_FOR_AVG register will
not be reflected in the average telemetry measurements until
the present averaging interval has completed. The default
setting for AVGN is 0000 and therefore the average telemetry
will mirror the instantaneous telemetry until a value higher
than zero is programmed.
The Samples For Average register is accessed via the
PMBus™ read / write byte protocol.
MFR_SPECIFIC_12: READ_AVG_VIN
The READ AVG VIN command will report the 12-bit ADC
measured input average voltage. If the data is not ready, the
returned value will be the previous averaged data. However,
if there is no previously averaged data the default value
(0000h) will be returned. This data is read with the PMBus™
Read Word protocol. This register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table.
Value
0h – 0Ch
AVGN
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
TABLE 33. SAMPLES FOR AVG Register
TABLE 32. SAMPLES_FOR_AVERAGE
Y = (X
(N)
Meaning
Exponent for
number of samples
to average over
2
+ X
N
averages
(N-1)
10
11
12
0
1
2
3
4
5
6
7
8
9
+ ... + X
(0)
Averaging/Register
Update Period (ms)
) / AVGN
Default
00h
1024
2048
4096
128
256
512
16
32
64
1
2
4
8
37
MFR_SPECIFIC_13: READ_AVG_VOUT
The READ AVG IIN command will report the 12-bit ADC mea-
sured current sense average voltage. The returned value will
be the default value (0000h) or previous data when the aver-
age data is not ready. This data is read with the PMBus™
Read Word protocol. This register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table.
MFR_SPECIFIC_14: READ_AVG_IIN
The READ AVG IIN command will report the 12-bit ADC mea-
sured current sense average voltage. The returned value will
be the default value (0000h) or previous data when the aver-
age data is not ready. This data is read with the PMBus™
Read Word protocol. This register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table.
MFR_SPECIFIC_15: READ_AVG_PIN
The READ AVG PIN command will report the upper 12-bits
of the average VIN x IIN product as measured by the 12-bit
ADC. You will read the default value (0000h) or previous data
when the average data is not ready. This data is read with the
PMBus™ Read Word protocol. This register should use the
coefficients shown in the Telemetry and Warning Conversion
Coefficients Table.
MFR_SPECIFIC_16: BLACK_BOX_READ
The BLACK BOX READ command retrieves the BLOCK
READ data which was latched in at the first assertion of SM-
BALERT. It is re-set with the CLEAR FAULTS command. It is
the same format as the BLOCK READ registers, the only dif-
ference being that its contents are updated with the SM-
BALERT edge rather than the internal clock edge. This
command is read with the PMBus™ Block Read protocol.
Value
0h – 0FFFh
Value
0h – 0FFFh
Value
0h – 0FFFh
Value
0h – 0FFFh
TABLE 35. READ AVG VOUT Register
TABLE 37. READ_AVG_PIN Register
TABLE 36. READ_AVG_IIN Register
TABLE 34. READ AVG VIN Register
Meaning
Average of
measured values
for input voltage
Meaning
Average of
measured values
for output voltage
Meaning
Average of
measured values
for current sense
voltage
Meaning
Average of
measured value
for input voltage x
input current sense
voltage
Default
0000h
Default
0000h
Default
0000h
Default
0000h
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