ADE7878ACPZ Analog Devices Inc, ADE7878ACPZ Datasheet - Page 52

• Manufacturer Part Number: ADE7878ACPZ
• Description: IC ENERGY METERING 3PH 40LFCSP
• Manufacturer: Analog Devices Inc

Specifications of ADE7878ACPZ

• Input Impedance: 400 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.4V
• Current - Supply: 22mA
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-WFQFN, CSP Exposed Pad
• Meter Type: 3 Phase
• Supply Voltage Range: 3V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: LFCSP
• No. Of Pins: 40
• Msl: MSL 1 - Unlimited
• Peak Reflow Compatible (260 C): Yes
• Supply Voltage Min: 3V
• Rohs Compliant: Yes
• Leaded Process Compatible: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADE7878
APPARENT POWER CALCULATION
Apparent power is defined as the maximum power that can be
delivered to a load. One way to obtain the apparent power is by
multiplying the voltage rms value by the current rms value (also
called the arithmetic apparent power) as follows:
where:
S is the apparent power
V rms and I rms are the rms voltage and current, respectively.
The ADE7878 computes the arithmetic apparent power on each
phase. Figure 67 illustrates the signal processing in each phase
for the calculation of the apparent power in the ADE7878.
Because V rms and I rms contain all harmonic information,
the apparent power computed by the ADE7878 is a total apparent
power. The ADE7878 does not compute a fundamental apparent
power because it does not measure the rms values of the funda-
mental voltages and currents.
S = V rms × I rms
AVRMS
AIRMS
Figure 67. Apparent Power Data Flow and Apparent Energy Accumulation
DIGITAL SIGNAL PROCESSOR
AVAGAIN
(39)
Rev. 0 | Page 52 of 92
ACCUMULATOR
VATHR[47:0]
The ADE7878 stores the instantaneous phase apparent powers
into the AVA[23:0], BVA[23:0], and CVA[23:0] registers. Their
expression is
where:
U, I are the rms values of the phase voltage and current.
U
the ADC inputs are at full scale.
PMAX = 33,516,139, the instantaneous power computed when
the ADC inputs are at full scale and in phase.
The xVA[23:0] waveform registers may be accessed using
various serial ports. Refer to the Waveform Sampling Mode
section for more details.
The ADE7878 can compute the apparent power in an alternative
way by multiplying the phase rms current by an rms voltage
introduced externally. See the Apparent Power Calculation
Using VNOM section for details.
FS
, I
FS
xVA
are the rms values of the phase voltage and current when
=
U
U
FS
×
32 BIT REGISTER
I
I
FS
AVAHR[31:0]
×
PMAX
×
2
1
4
(40)