Single-Phase Power-Measurement

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Detailed Description

The MAXQ314 is a dedicated analog front-end (AFE) that

measures voltage, current, and temperature. The internal

DSP then derives calculated values. It communicates

col, and continuously executes the following operations:

• Scans AFE channels and collects raw voltage and

current samples

• Calculates power (real, reactive, apparent)

• Responds to register write and read commands from

the master

It is the master device’s responsibility to ensure that all

configuration registers have been set to their correct val-

ues in order to achieve the specified accuracy.

Clock Source

An internal oscillator supplies a system clock of approxi-

mately 8MHz, varying slightly over temperature and volt-

age. No external components are needed.

Reset Sources

External Reset

An external reset is generated by driving the RST pin

low for at least 1Fs and remains as long as RST is held

low. Once the external reset has been released, all reg-

isters are cleared to their default states, and the device

resumes execution.

Voltage Monitor

The device is held in reset any time the power supply

AVDD drops below the supply voltage power-fail thresh-

old. Once the power supply rises above the supply volt-

age power-fail level, the device exits reset, and all reg-

isters are reset to their defaults and execution resumes.

using commands to read and write values to internal

registers. These registers contain:

• Operating mode settings

• Calibration parameters (supplied by the master)

• Read-only registers containing power, current, and

voltage data

During operation, voltage and current measurements are

taken, filtered, and the collected data is processed. The

output results then can be read by the master from read-

only registers in parallel with the ongoing measurement

and processing operations.

The device must be initialized by the master with con-

figuration and calibration parameters following every

power-up or reset cycle.

Pin Description (continued)

PIN

NAME

FUNCTION

VOLTAGE AND CURRENT MEASUREMENT PINS

15

VN

Differential Voltage Negative Input

16

VP

Differential Voltage Positive Input

19

IL

Single-Ended Current Input, Low Frequency

NO CONNECTION PINS

2, 5, 6,

9, 20

N.C.

No Connection. Do not connect any signal to this pin.