ADE7761 Ver la hoja de datos (PDF) - Analog Devices

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Fabricante

ADE7761

Energy Metering IC with On-Chip Fault and Missing Neutral Detection

Analog Devices 

ADE7761

TERMINOLOGY

Measurement Error

For the dc PSR measurement, a reading at nominal supplies

The error associated with the energy measurement made by the

(5 V) is taken. A second reading is obtained with the same input

ADE7761 is defined by the following formula:

signal levels when the power supplies are varied ±5%. Any error

Percentage Error =

introduced is again expressed as a percentage of reading.

⎜⎛

⎜⎝

Energy

registered by ADE7761

True Energy

−

True

Energy

×

100%

⎟⎞

⎟⎠

ADC Offset Error

This refers to the dc offset associated with the analog inputs to

the ADCs. It means that with the analog inputs connected to

AGND, the ADCs still see a dc analog input signal. The magni-

Phase Error between Channels

The high-pass filter (HPF) in the current channel has a phase

lead response. To offset this phase response and equalize the

phase response between channels, a phase correction network is

also placed in the current channel. The phase correction net-

E work ensures a phase match between the current channels and

voltage channels to within ±0.1° over a range of 45 Hz to 65 Hz

and ±0.2° over a range 40 Hz to 1 kHz.

T Power Supply Rejection

This quantifies the ADE7761 measurement error as a percent-

age of reading when the power supplies are varied. For the ac

E PSR measurement, a reading at nominal supplies (5 V) is taken.

A second reading is obtained with the same input signal levels

when an ac (175 mV rms/100 Hz) signal is introduced onto the

supplies. Any error introduced by this ac signal is expressed as a

L percentage of reading (see the Measurement Error definition

OBSO above).

tude of the offset depends on the input range selection (see the

Typical Performance Characteristics section). However, when

HPFs are switched on, the offset is removed from the current

channels and the power calculation is not affected by this offset.

Gain Error

The gain error in the ADE7761 ADCs is defined as the differ-

ence between the measured output frequency (minus the offset)

and the ideal output frequency. The difference is expressed as a

percentage of the ideal frequency, which is obtained from the

transfer function (see the Transfer Function section).

Rev. A | Page 8 of 28

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