U-RD DC current sensor series are basic structure combination with ring shape gap metallic core and hall element as the magnetic sensor. It can measure the current from DC to high frequency AC sequentially, and can be used for the application of wide range of 3A-2000A.

DC current sensor series line-up, features, and application

Principle of hall element sensor

The magnetic flux proportional to penetrated current (Io) is converged to the metallic core, and goes through the hall element inserted into the gap, and finally, the hall voltage (V_H) is occurring.

[Design example]
·The flux density (B) which is occurred in gap is
B=Io·µo/ℓ(T)
If ℓ=1.6mm:B=Io·4πX10^-7/1.6X10^-3
· Typical sensitivity of GaAs type hall element (Vh) is
Ic=5mA;Vh=800mV/T
·Current sensitivity (V_H)as sensor is
V_H=B·Vh=0.628·Io(mV)

Circuit example-1 (hall amp type)

(Points)
· Output voltage is gotten by direct amplification from hall voltage.
· A₁:Offset adjustment.
· A₂:Output amplifier
Amp gain AV=(R5+R6+FS)/R5
Not recommend more than AV=150
· C₂:For protection of overshoot. It is decided by frequency characteristic.
· Enough examination is necessary for PCB design toward the noise strength.

Circuit example-2 (servo amp type)

(Points)
· It configures the servo circuit with compensation of magnetic flux in the metal core by the feedback to hall sensor's output to the feedback coil.
· The current (AT) flowing into coil is equal to the primary current at that time.
The output is detected by the resistor Rs.
Eo=Rs·Io/n(V).
· Attention about that the power supply should be over (Io/n+operating current for the circuit).
· Q₁ and Q₂ are the buffer driver to drive Io/n(A).
· It can be current output without connection of Rs.
· Enough examination is necessary for PCB design toward the noise strength.

The example of model description and function explanation

DC current sensor · Main product list