AMR CURRENT CLICK
PID: MIKROE-3812 Weight: 28 g
The AMR current Click is product is ±20A fully integrated bi-directional analog output
current sensors that deliver both high accuracy and high bandwidth. This state-of-the-art
Anisotropic Magneto Resistive (AMR) sensor technology provides inherently low noise,
excellent linearity and repeatability.
AMR Current click is supported by a mikroSDK compliant library, which includes
functions that simplify software development. This Click board™ comes as a fully tested
product, ready to be used on a system equipped with the mikroBUS™ socket.
HOW DOES IT WORK?
The AMR Current click is a Click board™ is based on the MCR1101-20-5 current sensor,
which is an AMR based integrated current sensor from ACEINNA. The device has
superior range and accuracy (0.6% typical total error at 25°C) and 2.0% max error over
temperature. It also features a Superior Frequency Response - 1.5 MHz (typical 3dB
BW) and a Fast output response time (300ns typical) with a Low Primary Resistance
(0.9 mΩ). The MCR1101-20-5 current sensor is factory-calibrated to achieve low offset
error and provide a precise analog voltage output that is linearly proportional to the
conduction current (AC or DC) with sensitivity (mV/A) compatible with A/D converters
and analog control loops in power systems.
VOC pin is connected directly to VOC (Reset) pin on mikroBUS™. Voltage on this pin
defines the overcurrent detection OCD threshold level. Briefly driving this pin to VCC
resets and rearms OCD circuit.
The AMR sensor device structure is designed to eliminate sensitivity to stray and
common mode magnetic fields. Anisotropic magnetoresistance (AMR) makes use of a
common material, Permalloy, to act as a magnetometer. Permalloy is an alloy
containing roughly 80% nickel and 20% iron. The alloy’s resistance depends on the
angle between the magnetization and the direction of current flow. In a magnetic field,
magnetization rotates toward the direction of the magnetic field and the rotation angle
depends on the external field’s magnitude. In a current sensor application, two of these
resistors are connected in a Wheatstone bridge configuration to permit the
measurement of the magnitude of the magnetic field produced by the current. AMR
properties are well behaved when the film’s magnetic domains are aligned in the same
direction. This configuration ensures high sensitivity, good repeatability, and minimal
hysteresis. During fabrication, the film is deposited in a strong magnetic field that sets
the preferred orientation, or “easy” axis, of the magnetization vector in the Permalloy
resistors. AMR has better sensitivity than other methods and reasonably good
temperature stability. The AMR sensor has sensitivity which is approximately a linear
function of temperature.
The AMR Current have fast and accurate overcurrent fault detection circuitry. The
overcurrent fault threshold (I ) is user-configurable via an external resistor divider (FLT
INT) and supports a range of 120% to 200% of the full-scale primary input (IP).
The sensor resistors are biased to the VCC supply voltage and produce a differential
voltage that is ratiometric to VCC. This configuration is suited to applications where the
A-to-D or other circuitry receiving the current sensor output signals are biased by and
ratiometric to the same supply voltage as the current sensor. The ratiometric
configuration provides increased gain and resolution compared to fixed gain.
The click board detects current by measuring the magnetic field generated by that
current. Therefore it’s important to consider the effect of externally generated magnetic
fields, whether from another current flowing in the system, a magnet, or electromagnetic
component.
The AMR Current click also features the MCP3221 AST, which is a A/D converter with
12-bit resolution. This device provides one single-ended input with very low power
consumption. This means that the AMR Current click can directly transfer the input from
analog do digital because it contains the A/D converter.
Also featured on the AMR Current click is the R7 resistor, which can be used if the
communication is going directly to the mikroBUS™ device and is not used if you are
using the A/D converter (MCP3221 AST).
This click can be used for various purposes, including server, telecom & industrial PWR
supplies, power aggregation, over-current protection, motor balance, remote device
monitoring and home automation control & IOT remote sensing, among others.
SPECIFICATIONS
Type
Current sensor
Applications
Server, telecom & industrial PWR supplies, power aggregation, overcurrent protection, motor balance, remote device monitoring and home
automation control & IOT remote sensing, among others
On-board
modules
MCR1101-20-5, an AMR based integrated current sensor from ACEINNA
Key Features
Low power consumption, Overcurrent fault detection, AMR based
integrated current sensor, Superior Frequency Response (1.5 MHz)
Interface
Analog,I2C
Click board
size
M (42.9 x 25.4 mm)
Input Voltage
5V
PINOUT DIAGRAM
This table shows how the pinout on AMR Current click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
Analog OUT
AN
1
AN
PWM
16
NC
Reset
VOC
2
RST
INT
15
FLT
NC
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
SCL
I2C Clock
NC
6
MOSI
SDA
11
SDA
I2C Data
NC
7
3.3V
5V
10
5V
GND
8
GND
GND
9
GND
Ground
Fault
Power Supply
Ground
ONBOARD SETTINGS AND INDICATORS
Label
Name
Default
LD1
PWR
-
J1
FLT INT
Left
TB1
IN
-
Description
Power LED Indicator
Overcurrent Fault Threshold Selector
Load Connector
AMR CURRENT CLICK ELECTRICAL SPECIFICATIONS
Description
Supply Voltage
Primary Conductor
Input Range
Sensitivity
Min
Typ
Max
Unit
4.5
5
5.5
V
-
1.3
-
mΩ
-20
-
20
A
-
100
-
mV/A
SOFTWARE SUPPORT
We provide a library for the AMR Current Click on our LibStock page, as well as a demo
application (example), developed using MikroElektronika compilers. The demo can run
on all the main MikroElektronika development boards.
Library Description
Library provides functions for reading ADC value, and function for reading converted
ADC data to mA
Key functions:
uint16_t amrcurrent_read_value ( void ) - Reads ADC current data.
float amrcurrent_get_current ( void ) - Reads current data in mA.
Examples description
The application is composed of three sections :
System Initialization - Initializes I2C module
Application Initialization - Initializations driver init
Application Task - Reading ADC data and converted current mA data from device and logs it to
device
void application_task ( )
{
read_adc_val = amrcurrent_read_value( );
WordToStr( read_adc_val, demo_txt );
mikrobus_logWrite( " ‐ ADC value: ", _LOG_TEXT );
mikrobus_logWrite( demo_txt, _LOG_LINE );
Delay_ms( 100 );
read_curr_val = amrcurrent_get_current( );
FloatToStr( read_curr_val, demo_txt );
mikrobus_logWrite( " ‐ Current value: ", _LOG_TEXT );
mikrobus_logWrite( demo_txt, _LOG_TEXT );
mikrobus_logWrite( "mA", _LOG_LINE );
Delay_ms( 100 );
mikrobus_logWrite( "‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐", _LOG_LINE );
Delay_ms( 5000 );
}
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
I2C
UART
Conversions
Additional notes and informations
Depending on the development board you are using, you may need USB UART
click, USB UART 2 click or RS232 click to connect to your PC, for development systems
with no UART to USB interface available on the board. The terminal available in all
MikroElektronika compilers, or any other terminal application of your choice, can be
used to read the message.
MIKROSDK
This Click board™ is supported with mikroSDK - MikroElektronika Software
Development Kit. To ensure proper operation of mikroSDK compliant Click board™
demo applications, mikroSDK should be downloaded from the LibStock and installed for
the compiler you are using.
For more information about mikroSDK, visit the official page.
https://www.mikroe.com/amr‐current‐click/11‐15‐19
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