Crocus Technology‘s CT430 TMR isolated current sensor Reference Design with Digital Output Simplifies Implementation

Milpitas, CA, May. 24, 2022 — Crocus Technology Inc., developer of XtremeSense® TMR sensors, today announced the release of a high accuracy energy metering solution with isolated current sensing and digital output.  The solution is capable of measuring power, voltage, and current while providing 1,820 VPK isolation in AC or DC applications.  The result is a smaller and more efficient design without using large current transformers.  The solution is ideal for a range of smart devices such as power supply monitors, electric vehicle chargers, household appliances, motor control, and smart lighting.

The solution consists of the Crocus’ CT430 TMR isolated current sensor, Microchip’s ATtiny426 microcontroller, Printed Circuit Board (PCB), design files, microcontroller firmware, Bill of Materials (BoM) list, user guide, and relevant support for designing a fully functional power monitoring solution.  The design solution has been verified to accurately read and quantize the voltage and current values before calculating the instantaneous and Root Mean Square (RMS) power components, active and reactive power, and power factor. These power values are stored in registers that can be accessed by an external microcontroller via the SPI interface. By offloading the design effort of measuring and calculating power, the Crocus metering solution simplifies the addition of metering capabilities to any smart device.

The key to precise power measurements is the CT430 current sensor which provides better than 1% current measurement accuracy over the -40℃ to +125℃ operating range.  It is available in a small 16-lead SOIC-Wide package, eliminating the need for bulky current transformers and allowing for more compact designs. The CT430 solution can also be customized with different bus interfaces such as I²C, SENT, and CAN. By leveraging the solution, manufacturers and designers can quickly develop accurate and compact power monitoring capabilities for their products. See the figure below for the system diagram of the Crocus reference design kit for power measurements.

“Being able to accurately measure power and communicate this data within a system continues to be a challenge for designers,” said Tim Kaske Crocus Vice President, Sales & Marketing. “The Crocus solution with the CT430 current sensor provides improved accuracy over existing magnetic sensor-based designs.  With a validated design solution and a 12-week lead-time, OEM design customers are able to quickly integrate the energy metering solution into their end products.”

Design files required for manufacturing or customizing this power meter PCB are available for download. https://crocus-technology.com/powermeter/.

Also available for download is the AN136 CT430 Power Measurement Module user guide, https://www.crocus-technology.com/wp-content/uploads/2022/05/AN136-CT430-Power-Measurement-Module-Rev0.0.pdf.