Patent ID: 7049557

Claim:
A regulated flexible heater for using electrical power from a primary power supply to provide regulated heat, the regulated flexible heater comprising: a temperature dependent variable resistance pathway including at least one flexible temperature dependent variable resistance strand of material having a positive coefficient of temperature to resistance; a set point resistor; a comparator circuit element, wherein the comparator circuit element monitors the resistance of the flexible temperature dependent variable resistance pathway and the set point resistor, and wherein the comparator circuit element has a comparator output with a connect condition indicating when resistance of the temperature dependent variable resistance pathway is below a control value having a predetermined relationship to the set point resistance and a disconnect condition indicating when the resistance of the temperature dependent variable resistance pathway is above the predetermined control value; a heating circuit element including: heating connections for receiving the electrical power from the primary power supply; a conductive resistance pathway including at least one flexible conductive resistance strand of material; a control circuit element receiving the comparator output, wherein the control circuit element opens the heating circuit element when the comparator output is in the disconnect condition; wherein the flexible conductive resistance strand of material and flexible temperature dependent variable resistance strand of material are combined into a flexible planar body; and, wherein the flexible temperature dependent variable resistance strand of material and flexible conductive resistance strand of material run separate and distinct routes through the flexible body.