Current sensor is compact and contactless

Claimed to be the industry’s smallest contactless current sensor with minimum power loss, the BM14270MUV-LB eliminates heat generation, improving safety and energy saving in industrial equipment says Rohm.

It achieves minimum power loss (no heat generation) in a compact 3.5mm² package, making it suitable for industrial equipment and consumer devices that detect operating conditions via current, explains Rohm. Potential applications include battery-driven drones, solar power systems, and servers in data centres requiring high power.

The increased awareness of energy conservation and safety, with environmental regulations require improved safety measures and power measurement in high power applications such as servers in data centres and solar power systems results in an increased demand for current sensors. Conventional current sensors using Hall elements typically feature large current consumption and low sensitivity, making it necessary to draw current within the sensing element itself. As such until now there were no current sensors on the market that provided high reliability and low loss in a compact form factor.

The BM14270MUV-LB current sensor uses a high sensitivity, low current magnetic impedance (MI) element that allows for contactless current detection. The sensor was developed by combining Rohm’s semiconductor production and sensor control technologies with Aichi Steel’s MI element. The contactless current sensor eliminates the need to draw current within the sensor to measure it.

Conventional products measurement errors that occur due to disturbance magnetic fields, such as those due to geomagnetism (i.e. terrestrial), making it necessary to use shields to block interference. The BM14270MUV-LB has a function that cancels disturbance magnetic fields using reciprocal wiring, allowing detection of only the magnetic field of the target current to enable high accuracy measurement without the use of shields, explains Rohm.

The sensor consumes just 0.07mA current which is 100x smaller than conventional products, says Rohm. A disturbance magnetic field cancellation function is included to protect against noise, making shielding unnecessary. Digital output from the built-in ADC reduces microcontroller load, for current monitoring for users to detect the current of virtually any application, from compact battery-driven devices to high power industrial equipment.

Samples will be available from January 2019, with OEM quantities available from April 2019.