IWATSU OPECS Optically Isolated Current Probe

OpECS optically isolated current probe

■ Ultra-small probe tip (tip circumference approx. 0.45 mm)

■ Current detection can be performed without clamping for short-range non-contact measurement

■ Bandwidth up to 150 MHz, maximum measured current up to 140 A

Recommended application scenarios:

◆  Current measurement on power semiconductor wiring packages

◆  Current measurement on high-density PCB boards

◆  Measurement of switching waveforms of SiC/GaN devices

◆  Measurement of current flowing through wires such as air-core coils

OpEOSIt is an optical current sensor that performs current measurement by capturing the magnetic field generated around the current. This series uses the Faraday effect (or magneto-optic effect). When the sensor is in a magnetic field, the oscillation direction of linearly polarized light changes under the influence of the magnetic field. Depending on the direction of the magnetic field, the oscillation direction follows an elliptical path, and the change in direction is proportional to the magnetic field strength. The signal is sent to the control unit at a later stage, where it is converted from an optical signal to an electrical signal. The converted electrical signal can then be input to an oscilloscope or other equipment to measure current.

OpECSsensitivity and measurable current range

Positional relationship between the wire and the sensor

As shown in1the figure at position ①, when the probe portion contacts the center of the wire, maximum sensitivity is obtained. When placed as in ①, a positive output is obtained relative to the current direction through the wire; when placed as in ②, an inverted output is obtained. When the probe tip is moved away from the wire center, as shown in ③, the magnetic field weakens and the sensitivity changes, as shown in2the figure. Therefore, by maintaining an appropriate distance, the desired sensitivity can be obtained.

  Figure 1.Connection between the wire and the probe   Figure 2. Distance from the wire center and sensitivity (x-axis unit:mm, y-axis unit:mV/A）

In addition, if the distance between the wire center and the probe remains constant, even if the wire diameter changes, the probe measurement resultwill not change either, as shown in3the figure.

  Figure 3. Relationship between sensing distance and wire diameter

Probe linearity

OpECSThe linearity of the current probe is shown in4the figure. At ±140Amaintains ± within the range1%linearity.

              Figure 4. Linearity of the current sensor output

Data sheet

Sensor heads in various shapes are still under development.