LM5066_16 Datasheet, PDF (41/65 Pages) Texas Instruments – Hotswap Controller With I/V/P Monitoring and PMBus Interface

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LM5066
SNVS655I – JUNE 2011 – REVISED JANUARY 2016
step, the decimal point would be shifted to the right once hence R = –1.
5. After the R coefficient has been determined, the b coefficient is found by multiplying the y-intercept by 10 ^–R.
In this case the value of b = 295.
– Calculated current coefficients:
– m = 5389
– b = 295
– R = –1
( ) x = 1 Y ´10-R - b
m
where
• X = The calculated real-world value (volts, amps, watts, temperature)
• m = The slope coefficient, is the 2-byte, two's complement integer
• Y = A 2-byte two's complement integer received from device
• b = The offset, a 2-byte two's complement integer
• R = The exponent, a 1-byte two's complement integer
(3)
This procedure can be repeated to determine the coefficients of any telemetry channel simply by substituting
measured current for some other parameter (for example, power or voltage).
8.5.6 Writing Telemetry Data
There are several locations that require writing data if their optional usage is desired. Use the same coefficients
previously calculated for your application, and apply them using this method as prescribed by the PMBus revision
section 7.2.2 Sending a Value
Y = (mX + b)´10^R
where
• X = The calculated real-world value (volts, amps, watts, temperature)
• m = The slope coefficient is the 2-byte, two's complement integer
• Y = A 2-byte two's complement integer received from device
• b = The offset, a 2-byte two's complement integer
• R = The exponent, a 1-byte two's complement integer
(4)
8.5.7 PMBus Address Lines (ADR0, ADR1, ADR2)
The three address lines are to be set high (connect to VDD), low (connect to GND), or open to select one of 27
addresses for communicating with the LM5066. Table 45 depicts 7-bit addresses (eighth bit is read/write bit).
ADR2
Z
Z
Z
Z
Z
Z
Z
Z
Z
0
0
0
0
Table 45. Device Addressing
ADR1
Z
Z
Z
0
0
0
1
1
1
Z
Z
Z
0
ADR0
Z
0
1
Z
0
1
Z
0
1
Z
0
1
Z
DECODED ADDRESS
40h
41h
42h
43h
44h
45h
46h
47h
10h
11h
12h
13h
14h
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