Data Sheet
ADE7880
–15
–20
–25
–30
30
35
40
45
50
55
60
65 70
FREQUENCY (Hz)
–89.96
–89.97
–89.98
–89.99
30
35 40
45
50
55
60
65
70
FREQUENCY (Hz)
Figure 47. Combined Gain and Phase Response of the
Digital Integrator (40 Hz to 70 Hz)
As stated in the Current Waveform Gain Registers section, the
serial ports of the ADE7880 work on 32-, 16-, or 8-bit words.
Similar to the registers shown in Figure 43, the DICOEFF 24-bit
signed register is accessed as a 32-bit register with four MSBs
padded with 0s and sign extended to 28 bits, which practically
means it is transmitted equal to 0x0FFF8000.
When the digital integrator is switched off, the ADE7880 can
be used directly with a conventional current sensor, such as
a current transformer (CT).
VOLTAGE CHANNEL ADC
Figure 48 shows the ADC and signal processing chain for
Input VA in the voltage channel. The VB and VC channels
have similar processing chains. The ADC outputs are signed
twos complement 24-bit words and are available at a rate of
8 kSPS. With the specified full-scale analog input signal of
±0.5 V, the ADC produces its maximum output code value.
Figure 48 shows a full-scale voltage signal being applied to the
differential inputs (VA and VN). The ADC output swings
between −5,326,737 (0xAEB86F) and +5,326,737 (0x514791).
Note these are nominal values and every ADE7880 varies
around these values.
VOLTAGE PEAK,
OVERVOLTAGE,
SAG DETECT
VAP
VIN
VN
PGA3 BITS
GAIN[8:6]
×1, ×2, ×4, ×8, ×16
PGA3
REFERENCE
DSP
HPFEN BIT
AVGAIN[23:0] CONFIG3[0]
ADC
HPF
CURRENT RMS (VRMS)
CALCULATION
VAWV WAVEFORM
SAMPLE REGISTER
TOTAL/FUNDAMENTAL
ACTIVE AND REACTIVE
POWER CALCULATION
VIN
+0.5V/GAIN
0V
0x514791 =
+5,326,737
VOLTAGE CHANNEL
DATA RANGE
0V
LPF1
ZX DETECTION
ZX SIGNAL
DATA RANGE
0x514791 =
+5,326,737
–0.5V/GAIN
0xAEB86F =
–5,326,737
0V
ANALOG INPUT RANGE
ANALOG OUTPUT RANGE
Figure 48. Voltage Channel Datapath
0xAEB86F =
–5,326,737
Rev. A | Page 29 of 104