ADE9078 datasheet(28/108 Pages) AD

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Data Sheet

ADE9078

Rev. 0 | Page 27 of 107

Reset

If the RESET pin goes low for 1 μs, the AVDD and DVDD LDOs

turn off. The power on sequence resumes from the point where

the AVDD and DVDD LDOs are turned on (see the Power-On

Sequence section for details). A software reset is initiated by

writing the SWRST bit in the CONFIG1 register, which resets

the digital logic and takes ~60 μs to complete.

For applications that require putting the ADE9078 into a low

power mode, it is recommended to use PSM3. In this mode, the

ADE9078 consumes approximately 2 μA, much lower than the

100 μA current consumption obtained when the ADE9078

RESET pin is held low (see Table 1 for the exact PSM3 current

consumption).

Changing to PSM2 or PSM3

The state of the PM1 and PM0 pins is continuously monitored.

If the power mode changes from PSM0 or PSM1 to PSM2 or

PSM3 (PM1, PM0 = 10 or 11) for 1 μs, the AVDD and DVDD

LDOs are turned off. When the power mode switches back to

PSM0 or PSM1, the power on sequence resumes from the point

where AVDD and DVDD LDOs are turned on (see the Power-

On Sequence section for details).

MEASUREMENTS (NORMAL MODE)

The ADE9078 offers per phase total IRMS and VRMS as well as

total active power, VAR, VA, and fundamental VAR powers. The

instantaneous low-pass filtered powers can be accumulated into

power or energy registers and are available in pulsed outputs,

CF1 through CF4.

Power quality information, such as zero-crossing detection, line

period, and angle measurements, is also available.

A waveform buffer stores samples directly from the ADC,

calculated resampled data, or processed current and voltage

samples.

The measurements described are available in PSM0, the normal

operating mode. A reduced set of features is available in PSM1

and PSM2 (see the Power Modes section for more details on

these operating modes).

SINC4

AND

DECIMATION

AVDD

LDO

DVDD

LDO

SPI

1.25V

REFERENCE

TEMP

SENSOR

CF1

TO CF4

IRQ0

IRQ1

SPI

PM1

PM0

ADE9078

PGA

ADC

PGA

ADC

SAR

AVAILABLE IN PSM0

AVAILABLE IN PSM2

DISABLED IN PSM1

PGA

ADC

PGA

ADC

PGA

ADC

PGA

ADC

PGA

ADC

METROLOGY FEATURES

(PER PHASE)

IRMS, VRMS

ACTIVE POWER, VA

YX, ANGLE

WAVEFORM BUFFER

ENERGY/POWER/CF

ACCUMULATION

LINE FREQUENCY

ETC.

LOW

POWER

COMPARATOR

Figure 40. Features Available in Each Operating Mode

Current Channel

The current channel datapath for IA, IB, and IC is shown in

Figure 41. The current channel ADC waveforms can be sampled

at the sinc4 output in the xI_SINC_DAT registers at 16 kSPS, or

further decimated by an IIR low-pass filter in the xI_LPF_DAT

registers at 4 kSPS. Gain and phase compensation are applied,

creating the xI_PCF instantaneous current waveforms that update

at 4 kSPS. The xI_PCF waveforms are used for total active power,

VAR, IRMS, VA, and fundamental VAR calculations. The xI_PCF

value is also monitored in the current peak detection circuit. The

rms of the sum of instantaneous currents measurement uses the

AI_PCF, BI_PCF, and CI_PCF current channel waveforms to

calculate the neutral current or ro calculate the net vector current

sum including the neutral current measurement, NI_PCF (see

the Neutral Current RMS, RMS of Sum of Instantaneous Currents

section for more information). Finally, the angle measurements

indicate the time between the current channel zero crossing and

the voltage channel zero crossing on the same phase or current

channels on the other phases, updating at 512 kSPS in the

ANGLx_x registers.

The neutral current channel, Channel IN, offers a neutral

current sum rms and is used in an rms of instantaneous current

measurement, as shown in Figure 42. For more information

about these calculations, see the Neutral Current RMS, RMS of

Sum of Instantaneous Currents section. Channel IN offers a

gain calibration (NIGAIN) and a phase calibration (NPHCAL).

The digital integrator on Channel IN is enabled by setting the

ININTEN bit in the CONFIG0 register. Note that the Channel IN

neutral current modulator is turned off in PSM1.

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