CURRENT SENSORS
Fast closed-loop control and precise waveform monitoring in a single device
Imperix current sensors offer bandwidths up to 3MHz, and combine the waveform fidelity of a laboratory probe with the accuracy of a calibrated control sensor.
As a core variable in many power electronic systems, current requires fast and precise measurement to support highly dynamic and robust feedback control. To this end, imperix sensors offer exceptional common-mode rejection, allowing placement virtually anywhere in the circuit, including at the switching nodes of high-speed SiC or GaN converters.
Optimized to unlock the full potential of the B-Box 4, these current sensors take full advantage of its high-speed analog input channels (20Msps, 3MHz analog BW) and offer true plug-and-play functionality. The B-Box 4 identifies each sensor automatically and applies its factory calibration. The sensors also work with all other B-Box controllers and the TPI8032.
Outstanding CMTI
Place sensors anywhere in the topology without fearing perturbations. Transient immunity matches that of laboratory current probes.
MHz-range bandwidth
With 3MHz bandwidth and a short response time, imperix current sensors add negligible phase lag to the fastest control loops.
Low noise
Noise levels down to 14mA RMS provide clean feedback signals for precise control and high-quality scoping in the imperix Cockpit software.
PROBE-GRADE MEASUREMENTS
The CSR series current sensors deliver performance on par with laboratory probes and outperform commonly used PCB-mounted modules. Comparative graphs are available in the CSR-40-HBW and CSR-25-LNO datasheets.
Dynamic step response
This test shows the CSR-40-HBW response to a 10 A current step.
- The CSR sensors settle cleanly, with no ringing or overshoot.
- The CSR series sensors track the signal as fast as entry-level laboratory probes.
High-frequency ripple tracking
Accurate waveform tracking is essential for both control and monitoring. In this test, a GaN-based converter is switching at 200 kHz.
- The sensors maintain a clean signal thanks to their high transient immunity.
- The waveform quality supports accurate estimation of the period-average current from a single sample taken at the midpoint of the PWM period.
- Any undesirable ringing can be quickly spotted and addressed.
TECHNICAL SPECIFICATIONS
The CSR product range comprises two complementary products, optimized for distinct applications. Both share an identical form factor, plug-and-play connectivity, factory calibration, and price. Since 2026, the DIN-50A sensor is not recommended for new designs.
Calibrated values apply with the B-Box 4, which automatically reads and applies factory calibration data stored in the sensor. With other controllers, the uncalibrated values given in the datasheets apply.
| CSR-40-HBW | CSR-25-LNO | DIN-50A | |
|---|---|---|---|
| Nominal range | ±40A RMS | ±25A RMS | ±50A pk (35 A RMS) |
| Maximum measurable current | ±56A pk | ±50A pk | ±50A pk |
| Bandwidth (selectable) | 3MHz / 300kHz | 1.5MHz / 150kHz | 200kHz |
| Step response | 180ns | 260ns | max. 2.0µs (settling time) |
| Noise (full / reduced bandwidth) | 38mA / 36mA RMS | 31mA / 14mA RMS | 50mA RMS |
| Sensitivity error (typ. / max.) | ±0.07% / ±0.25% (calibrated) | ±0.15% / ±0.4% (calibrated) | ±0.45% / ±2.4% (cal. N/A) |
| Offset (typ. / max.) | ±15mA / ±45mA (calibrated) | ±20mA / ±60mA (calibrated) | ±50mA / ±400mA (cal. N/A) |
| Technology | Hybrid (hall+coil) | AMR | Hall-effect |
| Isolation working voltage | 1.7kV / 1.06kV RMS (basic / reinforced) | 1.1kV / 0.55kV RMS (basic / reinforced) | 1kV pk (basic) |
| Compatible controllers | All B-Box controllers and TPI8032 | All B-Box controllers and TPI8032 | All B-Box controllers and TPI8032 |
| Primary connections | Wire terminals and banana plugs | Wire terminals and banana plugs | Wire terminals |
| Auto-identification | Yes (B-Box 4) | Yes (B-Box 4) | N/A |
| Factory calibration | Offset + sensitivity (B-Box 4) | Offset + sensitivity (B-Box 4) | N/A |
| Status | Active
Product Life Cycle Status: Active
| Active
Product Life Cycle Status: Active
| Not Recommended for New Design
Product Life Cycle Status: Not Recommended for New Design
|
EXPLORING THEIR FULL POTENTIAL
Imperix current sensors deliver the bandwidth and perturbation-rejection performance required to fully support the B-Box 4’s scoping and monitoring capabilities. In turn, the controller’s fast sampling rate (20Msps) and equally high analog bandwidth (3MHz) are essential to fully leverage the sensors’ capabilities. Together, they form a single platform for rapid control prototyping, high-speed data logging and precise current monitoring, without external instruments.
OVERSAMPLING
With the CSR sensors, the B-Box 4, and oversampling enabled, all of the following can be done straight from Cockpit, without requiring an oscilloscope or expensive probes:
- Compare data sampled at the CPU rate with high-bandwidth waveforms.
- Observe the currents and voltages around a medium-frequency transformer along with other control signals.
- Measure and troubleshoot filter performance by visualizing the current ripple and its non-idealities.
- Plot the harmonic performance using the FFT tool.
- Validate modulation strategies by scoping the generated PWM signals.
AUTOMATIC IDENTIFICATION
The B-Box 4 communicates with the sensors to identify which sensor is connected to any of its 24 channels. It reads the factory calibration parameters stored in the internal EEPROM, checks each channel against the control model, and lets protection limits be set directly in amperes.
On the other B-Box controllers and the TPI8032, the sensor is selected in the software, and the uncalibrated specifications apply.
PLUG AND PLAY INTEGRATION
Imperix current and voltage sensors are designed to be easy to use along with our digital controllers. A single RJ45 cable is sufficient for the controller to:
- Provide power to the sensors.
- Retrieve the analog measurement.
- Read data for auto-identification and calibration (B-Box 4).
The sensors mount on a DIN rail and offer both banana sockets and screwless terminals. The same sensors can therefore be reused across projects, in open and closed racks, with short setup times and no custom wiring.
INTEGRATED INTO SIMULINK/PLECS
Setting up imperix sensors in software takes seconds. In the ACG SDK, the sensor model is selected from a drop-down list in the ADC block, which sets the correct sensitivity for automated code generation and rapid prototyping. This works with every imperix controller.
CSR-40-HBW
±40A HIGH-BANDWIDTH CURRENT SENSOR
With 3 MHz bandwidth and transient immunity on par with laboratory probes, this sensor combines probe-level waveform fidelity with the robustness of a calibrated control sensor. The same measurement drives fast current loops and captures the fast dynamics of SiC and GaN converters.
High bandwidth
Fast dynamics can be captured thanks to the 3MHz bandwidth.
Transient immunity
High dV/dt immunity allows use at fast-switching converter nodes.
Fast response time
A 180ns delay keeps phase lag in control loops negligible.
EXAMPLE: MEASURE CURRENT RIPPLE
At a switching frequency of 100 kHz, the inductor current ripple is reproduced as faithfully as with laboratory probes, while the same measurement feeds the current controller.
CSR-25-LNO
±25A LOW-NOISE CURRENT SENSOR
Designed to deliver a clean signal, this low-noise sensor serves as a reliable control sensor and a high-fidelity laboratory probe. It delivers accurate measurements for sensitive control loops and high-resolution data logging at moderate to high switching frequencies.
Low noise
Clean measurements ideally suit sensitive control loops.
Factory calibration
High accuracy is available straight out-of-the-box.
Outstanding CMTI
High dV/dt immunity authorizes placement at switching nodes.
EXAMPLE: MEASURE RESONANT TANK CURRENTS
Resonant converters impose a high-frequency fundamental and a complex waveform. The 1.5MHz bandwidth and high transient immunity make the resonant tank current straightforward to measure.
PREVIOUS-GENERATION SENSORS
LEGACY PRODUCTS
Previous-generation imperix sensors are fully compatible with all B-Box controllers and remain available for purchase. However, newer variants are recommended for all use cases.
The DIN-mountable current sensors support DC and AC measurements.
FURTHER READINGS – VOLTAGE SENSORS
Complete your setup
To complete your rapid control prototyping setup, the VSR series offers a voltage sensor with 3MHz bandwidth (VSR-500-HBW) and a voltage sensor with a measuring range up to ±1000V (VSR-1000-ISO). Both share the same form factor and connectivity as the CSR sensors.