Isolated 16-Channel AC Analog Input Module Reference Design Using Dual Simultaneously Sampled ADCs

1 января 2018

This reference design accurately measures 16-channel AC voltage and current inputs using a precision 16-bit SAR ADC over a wide input range. This range covers protection and measurement requirements (including sampling requirements as per IEC 61850-9-2), which simplifies system design and improves trip time repeatability, performance, and reliability. The AC analog input module (AIM) is isolated from the host processor using a digital isolator with an integrated power converter or using a six-channel digital isolator. In its simplest configuration, a complete AC AIM can be designed using only five TI products to optimize system cost and size. The alarm feature identifies the AC AIM faults on a sample basis for faster fault detection. The ADC has an additional auxiliary channel to diagnose the output of the digital isolator supply or to compensate the measured analog inputs for temperature drift.

Особенности

Based on ADS8688A 16-bit ADC (compatible with ADS8668 or ADS8698) and supports up to 16 analog inputs by daisy chaining two ADCs or connecting two ADCs in dual SDO output configuration AC analog input module provides spectral performance of ENOB of > 14.9 bits, SNR of > 91 DB and THD of > -110 DB with isolated interface ADC interface is isolated from the host for improved system safety in harsh operating conditions using ISOW7841 digital isolator with integrated power converter and provides current output of > 60mA with efficiency >=45 % or ISO7763 digital isolator with external isolated power Diagnostics features included monitoring supply output and ripple, voltage supervisor, on-board temperature sensor, LEDs for power and alarm output PHI Precision Host Interface processor Board connected to TIDA-01576 and GUI using Breakout Board for Quick Performance Evaluation. Phase Compensation Using GUI for Simultaneous Sampling of input samples