Home

Digitally Controlled, 12-V Precision Current Source for Extreme-Temperature Operation

NASA’s Jet Propulsion Laboratory, Pasadena, California

Many control applications require precision, high-voltage-capable stimulus current drivers for sensor excitation. In particular, a requirement for a stimulus driver that can be primarily integrated into a motor feedback signal conditioning ASIC (application specific integrated circuit) for Martian environments is satisfied by this development.

Wide-temperature and extreme-environment electronics are crucial to future missions. These missions will not have the weight and power budget for heavy harnesses and large, inefficient warm boxes. In addition, extreme-environment electronics, by their inherent nature, allow operation next to sensors in the ambient environment, reducing noise and improving precision over the warm-box-based systems employed today.

A system that allows the driving of a regulated current from a 12-V supply into a sensor bridge from 0 to 9 V is disclosed. This current source is designed to operate from –180 to +125 °C, in keeping with specifications for operation in lunar and Martian environments.

The basic function of this circuit is that of a current regulator that sets the voltage across an off-chip control resistor, thus setting the current into the sensor bridge. The off-chip resistor is chosen at design time to set the current range and precision required by the application. During operation, the user may modulate the DAC voltage to produce a similarly modulated bridge current for AC-type bridge applications.

This process allows this device to be included in system-on-chip implementations where high-voltage devices are not readily available. Extreme-environment electronics are valuable to a number of disciplines, including military/aerospace, automotive, scientific research, and energy.

This work was done by Jeremy A Yager, Tuan A. Vo, and Mohammad Mojarradi of Caltech for NASA’s Jet Propulsion Laboratory. NPO-48537

This Brief includes a Technical Support Package (TSP).

Digitally Controlled, 12-V Precision Current Source for Extreme-Temperature Operation (reference NPO-48537) is currently available for download from the TSP library.

Please Login at the top of the page to download.

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.