EMC1704 Datasheet, PDF (25/68 Pages) Microchip Technology – High-Side Current-Sense and Multiple 1°C Temperature Monitor

4.1.3
High-Side Current-Sense and Multiple 1°C Temperature Monitor
Datasheet
Actual source voltage at the SENSE+ pin can be calculated using:
where:
Source Voltage is the voltage at the
SENSE+ pin
Source
Voltage
=
FSV

V_{-----S---O----U----R----C---E--}
4 094
FSV is the Full-Scale Voltage (from
Equation [3])
[4]
V_SOURCE is the digital value read from
the Source Voltage Registers. Note that
the lowest five bits are always zero (see
Section 5.23)
For example: Suppose that the actual source voltage is 10.65V. The Source Voltage Registers are read
as V_SOURCE = 71_Ah (0111_0001_1010b or 1818d) which is 44.4% of the full scale source voltage.
This results in a calculated source voltage of 10.65V using Equation [4].
Note that the actual source voltage may also be determined by scaling each bit set by the indicated
bit weighting as described in Section 5.23.
Power Calculation
The EMC1704 may be used to determine the average power provided at the source side of R_SENSE
(SENSE+) using the value, P_RATIO, contained in the Power Ratio Registers (see Section 5.24). The
value represents the % of maximum calculable power.
P_RATIO is mathematically generated by multiplying the absolute values of V_SENSE and V_SOURCE (see
Section 4.1.1 and Section 4.1.2) and stored as a shifted 16-bit unsigned number. P_RATIO is updated
whenever either V_SENSE or V_SOURCE is updated.
Full Scale Power can be calculated from:
FSP = FSC  FSV
where:
FSP is the Full-Scale Power
FSC is the Full-Scale Current (from
[5]
Equation [1])
FSV is the Full-Scale Voltage (from
Equation [3])
Actual power drawn from the source can be calculated using:
where:
P_SOURCE is the actual power
provided by the source
P_SOURCE =
FSP

P_{-----R---A----T---I--O--}
65 535
measured at SENSE+
FSP is the Full-Scale Power
[6]
(from Equation [5])
P_RATIO is the value read from
the Power Ratio Registers
(see Section 5.24)
DS20005239A
25
DATASHEET
EMC1704