Current Sensor Use Case: ATM Machines

USE CASE

 

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This use case considers the application of MPS’s ultra-small, linear Hall-effect current sensors in ATM machines.

The MCS1823 is ideal for non-isolated applications that require a combination of high-current monitoring and small form factor.

Current sensors allow the ability to detect quickly and accurately the current in power electronics systems. The current sensor market is growing rapidly as high-accuracy, compact sensors are required in industrial, automotive, and commercial applications. ATM machines require the ability to sense the current on the motor for dispensing cash or accepting and returning the ATM card. Since the motors inside an ATM run off a secondary voltage, they do not require high isolation. Instead, ATM applications require a small footprint for the loop control of the motor. Traditional shunt solutions can be complicated to design as they require board space for an amplifier and shunt resistor.

The MCS1823 is a linear Hall-effect current sensor IC for AC or DC current sensing between 5A and 50A. The MCS1823 is ideal for non-isolated applications that require a combination of high-current monitoring and small form factor. This ultra-small current sensor replaces larger, traditional solutions with a single integrated IC solution in a tiny 3mmx3mm QFN package. The Hall array is differential to cancel out any stray magnetic field. This is especially important in compact designs with dense circuitry in close proximity.

A low-resistance (0.6mΩ) ) primary conductor allows a large current to flow within close proximity to the integrated circuit containing high-accuracy Hall sensors. This current generates a magnetic field that is sensed at two different points by the integrated Hall transducers. The magnetic field difference between these two points is then converted into a voltage that is proportional to the applied current.

The MCS1823 also implements over-current detection (OCD) to easily monitor the system for over-current faults with an extremely fast 1µs response time.