CN0218 Evaluation Board Guide

Overview

CN0218 is a circuit that monitors current in systems with high positive common-mode dc voltages of up to +500 V with less than 0.2% error. The load current passes through a shunt resistor, which is external to the circuit. The circuit is designed for a full-scale shunt voltage of 500 mV at maximum load current Imax.

The AD8212 is a high common-mode voltage, current shunt monitor. It accurately amplifies a small differential input voltage in the presence of large common-mode voltages up to 65 V (>500 V with an external PNP transistor). The AD8605 is a single rail-to-rail input and output, single-supply amplifier. It features very low offset voltage, low input voltage and current noise, and wide signal bandwidth.

The AD7171 is a very low power, 16-bit, analog-to-digital converter (ADC). It contains a precision, 16-bit, Σ-Δ ADC and an on-chip oscillator. The measurement result from AD7171 is provided as a digital code utilizing a simple 2-wire, SPI-compatible serial interface.

ADuM5402 is a quad channel isolator that provides galvanic isolation for the circuit. This is not only for protection but to isolate the downstream circuitry from the high common-mode voltage. In addition to isolating the output data, the digital isolator can also supply isolated +3.3 V for the circuit. ADR381 is precision 2.500 V band gap voltage reference featuring high accuracy, high stability, and low power consumption in a tiny footprint. It is a micropower, low dropout voltage (LDV) device that provides a stable output voltage from supplies as low as 300 mV above the output voltage.

The EVAL-CN0218-SDPZ Board connects to ADI’s System Demonstration Platform (SDP) and is powered by a +6 V supply or +6 V “wall wart”.

Required Equipment

EVAL-CN0218-SDPZ Evaluation Board
EVAL-SDP-CB1Z Controller Board (SDP-B Board)
CN0218 Evaluation Software
Power Supply
- 6 V or 6 V Wall wart
PC with the following Minimum Requirements
- Windows 7 (32-bit), Windows Vista (32-bit) or Windows XP
- USB interface
Shunt resistor with maximum voltage of 500 mV at the maximum load current
Electronic load

General Setup

Block assignments

The EVAL-CN0150-SDPZ (CN-0150 Board) connects to the EVAL-SDP-CB1Z (SDP-B Board) via the 120-Pin connector
The EVAL-SDP-CB1Z (SDP-B Board) connects to the PC via the USB cable.
Terminal block J1 is the SDP connector
Terminal block J2 is the +6 V barrel connector for wall wart supply input
Terminal block J3 is the 6 V DC power supply
Terminal block J5 contains the input terminals for Rshunt and load to ground

High voltage! This circuit may contain lethal voltages. Do not operate, evaluate, or test this circuit, or board assembly, unless you are a trained professional, who is qualified to handle high voltage circuitry. Before applying power, you must be familiar with the circuitry and all required precautions for working with high voltage circuits.

Test setup

Connect the 120-pin connector on the EVAL-CN0218-SDPZ Evaluation Board to the connector marked “CON A” on the EVAL-SDP-CB1Z evaluation (SDP) board
Connect a shunt resistor across the input terminals with a load to ground as indicated in figure above
With power to the supply off, connect a +6 V power supply to the pins marked “+6V” and “GND” on the board
- If available, a +6 V “wall wart” can be connected to the barrel connector on the board and used in place of the +6 V power supply
Connect the USB cable supplied with the SDP board to the USB port on the PC
Apply power to the +6 V supply (or “wall wart”) connected to EVAL-CN0218-SDPZ Evaluation Board
Launch the evaluation software
Connect the USB cable from the PC to the USB mini connector on the SDP board

Connect the system ground and the PCB isolated ground to guarantee correct voltage levels and operation. Test point 31 and test point 32 give access to the GND_ISO required to properly make this connection.

Installing the Evaluation Software

Extract the file CN0218_Evaluation_Software.zip and open the file setup.exe.

NOTE: It is recommended that you install the CN0218 Evaluation Software to the default directory path C:\Program Files (x86)\Analog Devices\CN0218\ and all National Instruments products to C:\Program Files\National Instruments\
Click Next to view the installation review page
Click Next to start the installation
Upon completion of the installation of the CN-0218 Evaluation Software, the installer for the ADI SDP Drivers will execute.

NOTE: It is recommended that you close all other applications before clicking “Next”. This will make it possible to update relevant system files without having to reboot your computer.
Press “Next” to set the installation location for the SDP Drivers.

It is recommended that you install the drivers to the default directory path
C:\Program Files\Analog Devices\SDP\Drivers
Press “Install” to install the SDP Drivers and complete the installation of all software. Click “Finish” when done.

Using the Evaluation Software

Main Window

Connect Button - Starts the connection between the CN0218 Evaluation Board and SDP-B Controller Board.
Reset and Disconnect - Resets the board and ends the connection between the CN0218 Evaluation Board and SDP-B Controller Board
Stop Button - Stop collecting data from the CN0218 Board
Test Setup Tab - Shows the acquired measurement data in terms of shunt voltage with respect to the samples
- Shunt Voltage - Shunt voltage measurement output from ADC
- Click to Start Sampling - Starts acquisition of measurement data
- Clear Data - Clear all data collected from the chart history
- Save Data to File - Save measurement data to file
Configure Tab
- Flash LED - Flashes the LED on the SDP controller board
- Read Firmware - Reads the firmware of CN0218 Evaluation Board
Plot Options - Edit plot display and options like interpolation and color of output waveform

Schematic, PCB Layout, Bill of Materials

EVAL-CN0218-SDPZ Design & Integration Files

Schematics
PCB Layout
Bill of Materials
PADS project

End of Document

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Table of Contents

CN0218 Evaluation Board Guide

Overview

Required Equipment