Thermostatic controller for thermoelectric assemblies
Microcontroller-based device from Laird Technologies adds integrated temperature control to protect assemblies.
Laird Technologies, Inc., designers and manufacturers of customized, performance-critical components for wireless systems and other electronics applications, has announced its new Q Series thermostatic controller for most of its thermoelectric assemblies (TEAs) . Such TEAs are used to raise or lower the temperature of enclosures or even small process devices using thermoelectric modules (TEMs). Units can either heat or cool as needed without refrigerants and are used in many applications where small-scale climate control is needed.
The Q Series is a microcontroller-based device line that adds integrated temperature control to a TEA. The controller functions as a single directional unit that offers heating or cooling temperature control for the application. "The Q Series removes the complexity of designing a closed loop feedback control system to drive a TEA in a thermal management system," says Andrew Dereka, product manager for Laird Technologies . "The controller reduces power consumption of the TEA over time and extends its operational life, which benefits total cost of ownership."
Programming for advanced controller options and features is available to meet unique application configurations. All programming is conducted in-house by Laird, and can include functions such as alarm shutoff, upper and lower temperature limits, upper and lower voltage limits, and tachometer limits.
The temperature set point ranges from -20 to 50 °C (-4 to 122 °F) and can be adjusted with an internal or external potentiometer. The controller operates in one of three temperature regulation modes:
• On/Off - Switches TEM output between full power and zero power at the programmed set point and hysteresis;
• PWM - Uses 8 kHz pulse-width modulation to control voltage for the main output; and
• Proportional - Uses a variable dc-voltage (a PWM varied voltage filtered with a required external capacitor parallel to the load in order to function) for the main output.
The input power of the controller accommodates a supply voltage ranging from 12 to 58 Vdc. Outputs power the TEMs and two dc fans from the supply voltage with a maximum available current of 16 A and 2 A respectively. Thermoelectric devices are used in many applications, including medical diagnostic machines, analytical instrumentation, small environmental enclosures, and electronic equipment cooling applications.
-Edited by Peter Welander, process industries editor, PWelander@cfemedia.com
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