The ACS712 IC from Allegro is a Hall Effect Sensor that has been popular for the last few years. This is because of its compactness, cost effectiveness, and precise solution for AC or DC current sensing in industrial, commercial, and communication systems, being able to measure current that ranges from 5A, 20A, and 30A.
How does a Hall Effect Sensor Work?
The AC712 uses a precise, low-offset, linear Hall sensor circuit in order to measure the current passing through the IC. It’s called a Hall sensor because it uses the theory of the “Hall Effect”, where an electric current goes through an electrical conductor and a magnetic field is applied perpendicular to the electrical conductor. This then produces a voltage difference across the electrical conductor.
When there is no magnetic field, the current flows in a “straight line” across the electrical conductor. When you apply a magnetic field perpendicular to the electrical conductor, the current does not flow straight any more. It causes the current to “curve”, thus moving positive charges on one end and moving negative charges to the other end, which causes this to have a voltage difference on the electrical conductor. Figure 1 shows an illustration on how the Hall Effect works.
The Allegro ACS712 IC
The ACS712 senses the current by having current flow in and out of the package. The current flow generates a magnetic field around a loop inside the IC that is proportional to the magnitude of the current flowing in the electric conductor. The Hall-Effect sensor senses the magnetic field generated by the current flowing in the conductor, turning the magnetic field into a voltage. The power loss is very low, making the ACS712 highly efficient in sensing current.
With its flip-chip technology, the sensor allows the Hall transducer to be placed right over the portion of the loop where the magnetic field is the strongest. This also allows for the connections between the signal leads of the IC, to the package leads on the other side of the package. While the Hall sensor is close to the current loop, there is an insulating layer of plastic in between the two, providing high-voltage isolation and allowing it to be used in AC tight applications. Figure 2 shows the current going in and out of the package and producing a voltage signal.
Features for the Allegro ACS712 (from Allegro Micro’s site) include:
• Low-noise analog signal path
• Device bandwidth is set via the new FILTER pin
• 5 µs output rise time in response to step input current
• 80 kHz bandwidth
• Total output error 1.5% at TA = 25°C
• Small footprint, low-profile SOIC8 package
• 1.2 mΩ internal conductor resistance
• 2.1 kVRMS minimum isolation voltage from pins 1-4 to pins 5-8
• 5.0 V, single supply operation
• 66 to 185 mV/A output sensitivity
• Output voltage proportional to AC or DC currents
• Factory-trimmed for accuracy
• Extremely stable output offset voltage
• Nearly zero magnetic hysteresis
• Ratiometric output from supply voltage
参阅相关产品
Other Allegro Hall Current Sensors
While the ACS712 IC is still being used as a current sensor for projects, if you are creating a new design application, it is recommended that you use the ACS723. This Hall-Effect current sensor has a range that can measure up to 40 A.
参阅相关产品
If you’re looking for a current sensor for automotive applications, the ACS724 is a great choice. It is an automotive-grade, Galvanically isolated current sensor IC with common-mode field rejection all in a small-footprint SOIC8 package. It can sense a range up to 10A, 30A, or 50A.
参阅相关产品
参阅相关产品
参阅相关产品