Datasheet

Data Sheet ADE7953
Rev. B | Page 39 of 72
ANGLE MEASUREMENT
The ADE7953 can measure the time delay between the current
and voltage inputs. This feature is available on both Current
Channel A and Current Channel B. The negative-to-positive
transitions identified by the zero-crossing detection circuit are
used as a start and stop for the measurement (see Figure 60).
PHASE A
CURRENT
ANGLE_x
PHASE A
VOLTAGE
09320-031
Figure 60. Current-to-Voltage Time Delay
The ADE7953 provides a time delay measurement on Current
Channel A and Current Channel B simultaneously. The result-
ing measurements are available in the 16-bit, signed registers
ANGLE_A (Address 0x10C) and ANGLE_B (Address 0x10D).
One LSB of the ANGLE_A or ANGLE_B register corresponds
to 4.47 μs (223 kHz clock). This results in a resolution of
0.0807° at 50 Hz ((360 × 50)/223 kHz) and 0.0969° at 60 Hz
((360 × 60)/223 kHz).
The time delay between the current and voltage inputs can be
used to characterize how balanced the load is. The delays between
phase voltages and currents can be used to compute the power
factor on Current Channel A and Current Channel B, respec-
tively, as shown in Equation 38.










kHz223
360
_coscos
LINE
x
f
xANGLE

(38)
where:
x = A or B.
f
LINE
is 50 Hz or 60 Hz.
This method of determining the power factor does not take into
account the effect of any harmonics. Therefore, it may not be
equal to the true definition of power factor shown in Equation 37.