TIDA-00738

Extended Current and Voltage Measurement Using Shunts for Protection Relays Reference Design

TIDA-00738

Design files

Overview

This reference design demonstrates a unique approach for extending current measurement range using a single shunt and voltage measurement AMC1304Mx5 isolated delta-sigma (ΔΣ) modulator. With careful selection of a low-value shunt resistor that minimizes power dissipation, a front-end amplifier with low noise and by introducing two gain paths, both upper and lower current limit is extended.  Accuracy of < ±0.5 % for both current and voltage measurement is achieved by interfacing the modulator output to AM437x host processor which performs the Sinc3 filtering.

Features
  • Single-phase voltage and current measurement (shunt based) using isolated delta-sigma modulator (AMC1304Mx5)
  • Measurement accuracy:
    • AC current: < ± 0.5% from 0.1 A to 40 A (or 60 A) for In = 1 A
    • AC voltage: < ± 0.5% from 10 V to 300 V
  • AFE interfaced to host MCU (AM437x Sitara™ ARM® Cortex®-A9 processor) which performs Sinc3 digital filtering using PRU-ICSS
  • Onboard isolated ± 2.5-V and +5.0-V Power supply for AMC1304Mx5 and OPA188 using transformer driver and LDOs
  • Designed to work from 0.1 A to 60 A (In = 1 A) and can be extended for wider range (In = 5 A) by changing shunt and gain values.

A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDRJM5.PDF (1107 K)

Detailed schematic diagram for design layout and components

TIDRJM6.PDF (276 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDRJM7.PDF (505 K)

Detailed overview of design layout for component placement

TIDRJM8.PDF (910 K)

Detailed overview of design layout for component placement

TIDRJN0.ZIP (2563 K)

Files used for 3D models or 2D drawings of IC components

TIDCBM7.ZIP (330 K)

Design file that contains information on physical board layer of design PCB

TIDRJM9.PDF (3666 K)

PCB layer plot file used for generating PCB design layout

Products

Includes TI products in the design and potential alternatives.

Isolated ADCs

AMC1304M05Reinforced Isolated Modulator With LDO Regulator, ±50mV Input, and CMOS Interface

Data sheet document-pdfAcrobat PDF open-in-new HTML
Isolated ADCs

AMC1304M25Reinforced Isolated Modulator With LDO Regulator, ±250mV Input, and CMOS Interface

Data sheet document-pdfAcrobat PDF open-in-new HTML
Clock buffers

CDCLVC1104Low jitter, 1:4 LVCMOS fan-out clock buffer

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TLV704150-mA, 24-V, ultra-low-IQ, low-dropout voltage regulator

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS709150-mA, 30-V, ultra-low-IQ, low-dropout voltage regulator with reverse current protection and enable

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS7A3001-EPEnhanced Product Negative Vin, -200mA, Ultra-Low-Noise, High-PSRR, Low-Dropout Linear Regulator

Data sheet document-pdfAcrobat PDF
Precision op amps (Vos<1mV)

OPA188Precision, Low-Noise, Rail-to-Rail Output, 36V Zero-Drift Operational Amplifier

Data sheet document-pdfAcrobat PDF open-in-new HTML
Transformer drivers

SN6501Low-noise, 350-mA, 410-kHz transformer driver for isolated power supplies

Data sheet document-pdfAcrobat PDF open-in-new HTML

Technical documentation

star
= Top documentation selected by TI
No results found. Please clear your search and try again.
View all 2
Type Title Date
* User guide Wide Input Current Using Shunts and Voltage Measurement for Protection Relays Dec. 04, 2015
Technical article A smarter way for solar to power the grid – think inside the box May 05, 2016

Related design resources

Reference designs

REFERENCE DESIGN
TIDA-00080 Isolated delta-sigma modulator based AC/DC voltage and current measurement module reference design TIDA-00555 Isolated Current & Voltage Measurement Using Fully Differential Isolation Amplifier Reference Design

Support & training

TI E2E™ forums with technical support from TI engineers

View all forum topics

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​

Videos