The thermocouple design uses a K-type thermocouple with cold junction compensation.
Intersil Corporation has joined Freescale Semiconductor to develop a new thermocouple and strain gauge application solution that delivers high precision measurement coupled with fast, low power data processing for advanced designs. The new board features two sensor applications using Intersil’s precision and power products coupled with the Freescale Kinetis L series microcontroller featuring a Cortex M0+ core. The demonstration platform consists of two separate boards — the Intersil precision and power products application board and the FRDM-KL25Z Freescale Freedom development platform.
The thermocouple design uses a K-type thermocouple with cold junction compensation. This design uses Intersil’s ISL28134 zero drift amplifier, ISL21090 voltage reference, ISL22317 DCP, the ISL26102 24-bit delta sigma converter and the Freescale KL25Z MCU, featuring 128 KB flash and 16 KB SRAM onboard.
The strain gauge design, which is also part of the demo, is a bridge solution that is able to extract a small sensor signal from a high voltage common mode signal of 10V or higher. The design uses Intersil’s 40V ISL28617 instrumentation amplifier, ISL21090 voltage reference, the ISL26102 24-bit delta sigma converter and the Freescale microcontroller for data acquisition and processing of measurement data, as well as using the onboard USB ports to make the data available, for example, a display.
The demo is powered from a mini USB connection on the Freescale Freedom development platform, providing the 5V to generate the required +12V, +10V, and ±5V supplies for the demo. The 5V supply is regulated down to a clean 3.3V supply using Intersil’s ISL80101 high performance LDO, boosted then to +12V using Intersil’s ISL97516 step-up regulator. The other voltages are generated by an ICL7660 charge pump and an ISL80138 linear regulator.
The thermocouple temperature or applied strain can be monitored using a GUI on the computer powering the demo through the mini USB cable. The display shows real time data in either numerical or a graphical representation of the temperature or strain measurement.
Both designs complement Freescale’s 32-bit Kinetis L series MCUs by the exceptional noise performance of a 24-bit delta sigma converter featuring a 3rd-order modulator, which provides up to 21.5 bit noise-free performance. The Kinetis L series combine the exceptional energy-efficiency and ease-of-use of the new ARM Cortex-M0+ processor with the performance, peripheral sets, enablement and scalability of the Kinetis 32-bit MCU portfolio. The Kinetis L series frees power-critical designs from 8- and 16-bit MCU limitations by combining dynamic and stop currents with superior processing performance, a broad selection of on-chip flash memory densities and extensive analog, connectivity, and HMI peripheral options.
Christopher Koch, technical director at Future Electronics, said: “This new application board was initiated by Future Electronics to add value to all customers that require high precision measurement in combination with fast and low power data processing with the latest 32-bit Cortex M0+ technology. Intersil and Freescale both offer state of the art technology for our customers in the industrial, medical and sensor market segments — they will like this solution.”
