Allegro's ACS712 fully integrated current sense ICs are offered in automotive qualified packages.
These tiny chips use flip chip technology to keep internal resistance down as low as 1mOhm, allowing them to measure 50A continuously with proper PCB design. The highly insulating plastic package enables the sensors to be used in direct AC applications, even in industrial settings up to 2000Vrms.
ACS712 Low Noise 2100
Allegro has developed an innovated line of fully integrated current sensor IC’s that offered several advanced of other sensor solutions. These allegro sensors are incredibly small and offered in standard automotive qualified surface small packages. Their construction provides high voltage isolation and exceptional accuracy. These packages are also highly efficient due to their low series resistance. In fact, these sensors are fully integrated system on chip current sensing solutions that are programmed at Allegro for optimum sensor accuracy over temperature. These fully integrated (WORDS???) sensors make it easy for current designers to implement current sensing into their applications.
This technology is really unique. Let me show you how it works. Current flows in and out of the package. It travels in the package through a three quarter loop inside the package and then back out again. This current flow generates a magnetic field around the loop that is proportional to the magnitude of the current flowing in the conductor. The resistance of these Allegro sensor IC’s is only about one (WORD?) and therefore the power loss is extremely low, making them highly efficient in sensing current as high as fifty amps of continuous current. Allegro (WORDS?) is integrated into the package and scenes the magnetic field generated by the current flowing in the conductor. The haul transducer converts the magnetic field into a voltage. Flip chip technology allows the haul transducer to be placed over the portion of the loop where the magnetic field is strongest. The flip chip technology also allows for the connection of the signal leads of the IC to the package leads on the other side of the package. This also provides the high isolation of the surface mount sensor IC packaging. While the haul sensor IC is in close proximity to the current loop, there is an insulating layer of plastic between the two. This insulating layer provides high voltage isolation and allows allegro current IC’s to be used in AC line tight applications. This unique technology, designed by Allegro, provides a fully integrated system on chip solution with high isolation in a very small footprint. You can see how small these sensors are compared to a current transformer or a competing active sensor solution. If you have an application with limited pc board area or vertical headroom, the Allegro device provides an optimum solution, in fact, when people see these Allegro current sensor IC’s they have a hard time believing that they can be tied directly into an AC line and can handle up to fifty amps continuous current without damage, but they certainly can.
We have an Allegro ACS712 in an SYC8 package on an evaluation board, which can be found on the Allegro website. We have connected a load that’s going to draw about 10 -15 amps directly off line voltage. The load is four of five hundred watt flood lights each drawing about three or four amps. The current meter will show about the RMS current flowing through our device into the load. The power supply is applying five volts to the ACS712. The digital multi reader is going to read the RMS current through the sensor to the load and the analog output of the ACSA712 is monitored by the oscilloscope. As you can see on the multi reader there is no load connected so there is zero current at this time. The output on the oscilloscope is just showing VCC over two, which is the normal zero amp upward voltage of the ACS712. Now we’re going to connect the loads to the ACS712. You can see that we have nearly fourteen amps RMS of current flowing to the center to the load. The analog output of the ACS712 is now clearly seen on the oscilloscope.
This simple demonstration highlights the key features of this unique Allegro current sensing technology. These current sensor IC’s offer extremely small PCB footprints, high voltage isolation through patented flip chip packaging technology, high efficiency due to the one(WORD?) of these small packages . These packages can really take the heat, and optimize accuracy in ease of design into your application with Allegro factory program…
Samples and evaluation boards are available with detailed technical information at allegromico.com. Again Allegro systems application assistance is available worldwide.