Datasheet

LM5066
www.ti.com SNVS655G –JUNE 2011–REVISED FEBRUARY 2013
Table 30. DEVICE_SETUP Byte Format (continued)
Bit Name Meaning
0 Unused
In order to configure the Current Limit Setting via this register, it is necessary to set the Current Limit
Configuration bit (2) to 1 to enable the register to control the current limit function and the Current Limit Setting
bit (4) to select the desired setting. If the Current Limit Configuration bit is not set, the pin setting will be used.
The Circuit Breaker to Current Limit ratio value is set by the CB / CL Ratio bit (3). Note that if the Current Limit
Configuration is changed, the samples for the telemetry averaging function will not be reset. It is recommended
to allow a full averaging update period with the new Current Limit Configuration before processing the averaged
data.
Note that the Current Limit Configuration affects the coefficients used for the Current and Power measurements
and warning registers.
MFR_SPECIFIC_10: BLOCK_READ (DAh)
The BLOCK_READ command concatenates the DIAGNOSTIC_WORD with input and output telemetry
information (IIN, VOUT, VIN, PIN) as well as TEMPERATURE to capture all of the operating information of the
LM5066 in a single SMBus transaction. The block is 12 bytes long with telemetry information being sent out in
the same manner as if an individual READ_XXX command had been issued (shown below). The contents of the
block read register are updated every clock cycle (85ns) as long as the SMBus interface is idle. BLOCK_READ
also specifies that the VIN, VOUT, IIN and PIN measurements are all time-aligned. If separate commands are
used, individual samples may not be time-aligned, because of the delay necessary for the communication
protocol.
The Block Read command is read via the PMBus block read protocol.
Table 31. BLOCK_READ Register Format
Byte Count (always 12) (1 byte)
DIAGNOSTIC_WORD (1 Word)
IIN_BLOCK (1 Word)
VOUT_BLOCK (1 Word)
VIN_BLOCK (1 Word)
PIN_BLOCK (1 Word)
TEMP_BLOCK (1 Word)
MFR_SPECIFIC_11: SAMPLES_FOR_AVG (DBh)
The SAMPLES_FOR_AVG command is a manufacturer specific command for setting the number of samples
used in computing the average values for IIN, VIN, VOUT, PIN. The decimal equivalent of the AVGN nibble is the
power of 2 samples, (for example, AVGN=12 equates to N=4096 samples used in computing the average). The
LM5066 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 LM5066
uses simple averaging. This is accomplished by summing consecutive results up to the number programmed,
then dividing by the number of samples. Averaging is calculated according to the following sequence:
Y = (X
(N)
+ X
(N-1)
+ ... + X
(0)
) / N (36)
When the averaging has reached the end of a sequence (for example, 4096 samples are averaged), then a
whole new sequence begins that will require the same number of samples (in this example, 4096) to be taken
before the new average is ready.
Table 32. SAMPLES_FOR_AVG Register
AVGN N = 2
AVGN
Averaging/Register Update Period (ms)
0000 1 1
0001 2 2
0010 4 4
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