Electric heating temperature control apparatus and electric heating device

An electric heating device, comprising:

• an electric heating wire, comprising:
• a temperature sensing conductor,
• an insulating layer, and
• a heating conductor;
• and
• an electric heating temperature control apparatus connected to the electric heating wire, comprising:
• a temperature detecting circuit,
• a heating switching circuit, and
• a temperature parameter setting circuit;
• wherein
• the temperature sensing conductor is used for sensing a temperature of the heating conductor, the insulating layer is used for insulation between the temperature sensing conductor and the heating conductor, and the insulating layer changes its resistance or results in a short circuit between the temperature sensing conductor and the heating conductor when a local or overall temperature of the heating conductor changes, and the heating conductor is used for heating,
• the temperature detecting circuit comprises a temperature sensing voltage dividing and sampling unit, an AC voltage dividing and sampling unit and a differential signal processing unit;
• a first terminal of the temperature sensing voltage dividing and sampling unit is connected to a second terminal of the temperature sensing conductor, a first terminal of the temperature sensing conductor is connected to a live wire of an AC power supply, a second terminal of the temperature sensing voltage dividing and sampling unit is grounded, an output terminal of the temperature sensing voltage dividing and sampling unit is connected to the differential signal processing unit, and the temperature sensing voltage dividing and sampling unit is used for converting a signal flowing through the temperature sensing conductor into a temperature voltage signal and output it to the differential signal processing unit;
• a first terminal of the AC voltage dividing and sampling unit is connected to the live wire of the AC power supply, a second terminal of the AC voltage dividing and sampling unit is grounded, an output terminal of the AC voltage dividing and sampling unit is connected to the differential signal processing unit, and the AC voltage dividing and sampling unit is used for converting an input signal of the AC power supply into a reference voltage signal and output it to the differential signal processing unit;
• the differential signal processing unit is used for performing a differential comparison between the temperature voltage signal and the reference voltage signal and outputting a stop-heating signal or a heating signal according to the differential comparison between the temperature voltage signal and the reference voltage signal;
• the heating switching circuit is connected to the temperature detecting circuit and to the heating conductor, and is used for turning off a power supply circuit of the heating conductor when receiving the stop-heating signal, and turning on the power supply circuit of the heating conductor when receiving the heating signal, so as to control the heating conductor to heat or to stop heating;
• and
• the temperature parameter setting circuit is connected to the temperature detecting circuit for setting a temperature parameter.

The electric heating device according to claim 1314, wherein the safety protection circuit comprises a safety signal sampling unit and a safety signal processing unit;

• wherein a first terminal of the safety signal sampling unit is connected to a second terminal of the heating conductor, a second terminal of the safety signal sampling unit is grounded or connected to a voltage terminal of a power circuit, and the safety signal sampling unit is used for converting a current signal passing therethrough into a safety voltage signal and output it to the safety signal processing unit;
• the safety signal processing unit is connected to the heating switching circuit, and the safety signal processing unit performs abnormality analysis and judgment according to a received abnormality judgment sequence and the safety voltage signal, and outputs an abnormality signal to the heating switching circuit when an abnormality exists;
• and
• the heating switching circuit is also connected to the safety signal processing unit, and the heating switching circuit is also used for turning off the power supply circuit of the heating conductor when receiving the abnormality signal.