Datasheet

ADE7763 Data Sheet
Rev. C | Page 44 of 56
CALCULATE CFDEN VALUE FOR DESIGN
WRITE CFDEN VALUE TO CFDEN REGISTER
ADDR. 0x15 = CFDEN
SET HALF LINE CYCLES FOR ACCUMULATION
IN LINECYC REGISTER ADDR. 0x1C
SET I
TEST
= I
b
, V
TEST
= V
NOM
, PF = 1
CALCULATE WGAIN. SEE EQUATION 43.
SET MODE FOR LINE CYCLE
ACCUMULATION ADDR. 0x09 = 0x0080
ENABLE LINE CYCLE ACCUMULATION
INTERRUPT ADDR. 0x0A = 0x04
READ LINE ACCUMULATION ENERGY
ACTIVE ENERGY: ADDR. 0x04
APPARENT ENERGY: ADDR. 0x07
RESET THE INTERRUPT STATUS
READ REGISTER ADDR. = 0x0C
INTERRUPT?
NO
NO
YES
YES
04481-A-092
RESET THE INTERRUPT STATUS
READ REGISTER ADDR. = 0x0C
INTERRUPT?
WRITE WGAIN VALUE TO ADDR. 0x12
CALCULATE VAGAIN. SEE EQUATION 65.
WRITE VGAIN VALUE TO ADDR. 0x1A
Figure 78. Active/Apparent Gain Calibration
CLKIN FREQUENCY
In this data sheet, the characteristics of the ADE7763 are shown
when CLKIN frequency equals 3.579545 MHz. However, the
ADE7763 is designed to have the same accuracy at any CLKIN
frequency within the specified range. If the CLKIN frequency is
not 3.579545 MHz, various timing and filter characteristics will
need to be redefined with the new CLKIN frequency. For
example, the cutoff frequencies of all digital filters, such as
LPF1, LPF2, or HPF1, shift in proportion to the change in
CLKIN frequency according to the following equation:
MHz579545.3
FrequencyCLKIN
FrequencyOriginalFrequencyNew ×=
(69)
The change in CLKIN frequency does not affect the timing
characteristics of the serial interface because the data transfer is
synchronized with the serial clock signal (SCLK). However, it is
important to observe the read/write timing of the serial data
transfer—see the timing characteristics in Table 2. Table 8 lists
various timing changes that are affected by CLKIN frequency.
Table 8. Frequency Dependencies of the ADE7763
Parameters
Parameter CLKIN Dependency
Nyquist Frequency for CH 1, CH 2 ADCs CLKIN/8
PHCAL Resolution (seconds per LSB) 4/CLKIN
Active Energy Register Update Rate (Hz) CLKIN/4
Waveform Sampling Rate (per second)
WAVSEL 1,0 = 0 0 CLKIN/128
0 1 CLKIN/256
1 0 CLKIN/512
1 1 CLKIN/1024
Maximum ZXTOUT Period 524,288/CLKIN