This is a high accuracy current sensor project build using ACS37002 IC from Allegro, which is a fully integrated Hall-effect current sensor with 0.85mOhms integrated conductor. A fast overcurrent alert output, programmable gain settings and analog linear voltage outputs are key features of this project. The sensor has optimized accuracy for current ranges +/-33A to +/-66 A and the analog voltage output is linear for the current of this range. The operating voltage of the project is 5V DC. The output voltage of this sensor is centered at VCC/2 =2.5V. Output sensitivity depends on the jumper settings, please refer to the table below for sensitivity/Gain configuration. CN2 6-pin header connector provided for power input and outputs. D1 is the power LED. Overcurrent alert is set to a minimum but it can be set as per user requirement by changing resistor divider R4 and R5, more information provided below.
CONNECTOR CN2 CONNECTIONS DETAILS
- Pin1=VCC 5V DC
- Pin2=GND
- Pin3= VREF 2.5V For ADC (Can be used for Microcontroller Interface Left Unused for Stand Alone Use)
- Pin4=Sensor Voltage Output
- Pin5= Over Current/Fault Output
Connector CN1 = Current Source Connections (Use 5 mm Ring Terminal with 4 mm Screws and Nuts)
FEATURES
- Operating Supply 5V DC
- Output-VO 40mV/A, 50mV/A, 60mV/A, 30mV/A (50A,40A,33.3A,66.7A)
- Four Configurable Gain Settings Using Jumper J1, J2
- Adjustable Fast Over Current Fault 1us Response Time
- Over Current Output Normally High Goes Low @ Fault Condition (OCF)
- High Operating Bandwidth for Fast Control Loops
- 400Kz Frequency Bandwidth, 2us Response Time
- Very Low Sensitivity Error 1%
- 6mV Maximum Offset Voltage Over Temperature
- PCB DIMENSIONS 42.55 X 41.59 mm
ACS37002: 400 KHZ, HIGH ACCURACY CURRENT SENSOR WITH PIN-SELECTABLE GAINS
The ACS37002 is a fully integrated Hall-effect current sensor in SOICW-16 package that is factory-trimmed to provide high accuracy over the entire operating range without the need for customer programming. The current is sensed differentially by two Hall plates that subtract out interfering external common mode magnetic fields. The package construction provides high isolation by magnetically coupling the field generated by the current in the conductor to the monolithic Hall sensor IC which has no physical connection to the integrated current conductor. The MA package is optimized for higher isolation with withstand voltage, 4.8 kVRMS, and 0.85 mΩ conductor resistance. The LA package is optimized for lower noise with 3.6 kVRMS withstand voltage and 1 mΩ conductor resistance. The ACS37002 has functional features that are externally configurable and robust without the need for programming. Two logic gain selection pins can be used to configure the device to one of four defined sensitivities and corresponding current ranges. A fast overcurrent fault output provides short-circuit detection for system protection with a fault threshold that is proportional to the current range and can be set with an analog input. The reference pin provides a stable voltage that corresponds to the 0A output voltage. This reference voltage allows for differential measurements as well as a device-referred voltage to set the overcurrent fault threshold.
Read more: HIGH ACCURACY CURRENT SENSOR WITH 400KHZ BANDWIDTH USING ACS37002
