EVAL-ADE7880EBZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-ADE7880EBZ' PDF : 107 Pages View PDF
ADE7880
Data Sheet
+V p-p/2
IxP
–V p-p/2
+V p-p/2
IxN
–V p-p/2
+V p-p
IxP – IxN
–V p-p
(a)
IxP
VREF
PEAK DETECT CIRCUIT
TAMPER
INDICATION
(b)
Figure 34. PSM2 Low Power Mode Peak Detection
The PSM2 level threshold comparison works based on a peak
detection methodology. The peak detect circuit makes the
comparison based on the positive terminal current channel
input, IAP, IBP, and ICP (see Figure 34). In case of differential
inputs being applied to the current channels, Figure 34 shows
the differential antiphase signals at each of the current input
terminals, IxP and IxN, and the net differential current, IxP − IxN.
The I2C or SPI port is not functional during this mode. The PSM2
mode reduces the power consumption required to monitor the
currents when there is no voltage input and the voltage supply
of the ADE7880 is provided by an external battery. If the IRQ0
pin is triggered low at the end of a measurement period, it signifies
all phase currents stayed below threshold and, therefore, there is
no current flowing through the system. At this point, the external
microprocessor sets the ADE7880 into sleep mode PSM3. If the
IRQ1 pin is triggered low at the end of the measurement period,
it signifies that at least one current input is above the defined
threshold and current is flowing through the system, although
no voltage is present at the ADE7880 pins. This situation is often
called missing neutral and is considered a tampering situation,
at which point the external microprocessor sets the ADE7880
into PSM1 mode, measures the mean absolute values of phase
currents, and integrates the energy based on their values and the
nominal voltage.
It is recommended to use the ADE7880 in PSM2 mode when
Bits[2:0] (PGA1[2:0]) of the Gain register are equal to 1 or 2.
These bits represent the gain in the current channel data path. It
is not recommended to use the ADE7880 in PSM2 mode when
the PGA1[2:0] bits are equal to 4, 8, or 16.
PSM3—SLEEP MODE (ALL PARTS)
In sleep mode, the ADE7880 has most of its internal circuits
turned off and the current consumption is at its lowest level.
The I2C, HSDC, and SPI ports are not functional during this
mode, and the RESET, SCLK/SCL, MOSI/SDA, and SS/HSA pins
must be set high.
Table 10. Power Modes and Related Characteristics
Power Mode
All Registers1 LPOILVL, CONFIG2
PSM0
State After Hardware Reset Set to default Set to default
I2C/SPI
I2C enabled
State After Software Reset
PSM1
Set to default
Not available
Unchanged
PSM0 values retained
Active serial port is
unchanged if lock-in
procedure has been
previously executed
Enabled
PSM2
Not available PSM0 values retained Disabled
PSM3
Not available PSM0 values retained Disabled
1 Setting for all registers except the LPOILVL and CONFIG2 registers.
Functionality
All circuits are active and DSP is in idle
mode.
All circuits are active and DSP is in idle
mode.
Current mean absolute values are
computed and the results are stored
in the AIMAV, BIMAV, and CIMAV
registers. The I2C or SPI serial port is
enabled with limited functionality.
Compares phase currents against the
threshold set in LPOILVL. Triggers
IRQ0or IRQ1 pins accordingly. The
serial ports are not available.
Internal circuits shut down and the
serial ports are not available.
Rev. C | Page 22 of 107
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