Thermally controlled circuit using planar resistive elements

摘要

A thermally controlled circuit board is provided. The circuit board includes a substrate, which carries a thermally controlled circuit. The thermally controlled circuit includes a heater, a logic unit and a thermostat. The heater includes planar resistive elements, which are embedded into the substrate. A power source is selectively coupled to the heater via control of the logic unit. The thermostat is programmed with a temperature set point, and outputs a control signal based on a measured temperature level relative to the temperature set point. The logic unit selectively couples the power source to the heater, based on the control signal output from the thermostat and selectively couples power to on-board components to control the temperature of the board and the components thereon to protect the components and insure reliable operation.