Microchip Technology PAC1921, Руководство пользователя

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PAC1921 High-Side Current/Power Sensor Evaluation Board User’s Guide
DS50002376A-page 36

2015 Microchip Technology Inc.
4.3.3 Calculations/File IO Tab
The Calculations/File IO tab, shown in Figure 4-15 , displays register data (in decimal
by default). It also shows calculated results which were obtained by applying the data
sheet equations to the register data.
FIGURE 4-15: Calculations/File IO Tab.
An example of using the equations to calculate power is as follows.
The value of one LSB in the V
POWER
Result registers, in watts, can be calculated
according to Equation 4-1 .
EQUATION 4-1: LSB CALCULATION
1LSB
0.1V
R

DI_GAIN

----------------------------------------
32V
DV_GAIN
---------------------------

1023 2
6

-------------------------------------------------------------------------- =
Where:
1LSB = LSB value in watts for V
POWER
Result Registers 1Dh and 1Eh
0.1V = Maximum V
SENSE
voltage
R = Value of R
SENSE
resistor in ohms
DI_GAIN = Digital current gain
32V/DV_GAIN = Maximum voltage
1023 = (210 – 1) = 10-bit FSR
2
6
= Adjustment for 6 unused register bits when read as a 16-bit number