Patent ID: 8253079
Filing Date: 2012-08-28
Classification: H05B

Abstract:
1. A temperature-control circuit of a heating line, where the heating line comprises a heating wire, a sensing line, an insulation-and-meltable layer located between the heating wire and the sensing line, and a cladding layer covering the outer peripheries of the sensing line and the insulation-and-meltable layer; one end of the heating wire is coupled with one polarity of power while another end thereof is connected with a switch that is coupled with a reverse polarity of the power; the temperature-control circuit comprising: a first forward square-wave signal generation circuit, for outputting a first forward square-wave signal; a reverse square-wave signal output circuit, including a first RC circuit, a first voltage comparator, and a voltage adjustment circuit, where the RC circuit is in serial connection with the first forward square-wave signal generation circuit; a first node is provided between the first RC circuit and the first forward square-wave signal generation circuit while a second node is provided between the resistor and the capacitor of the first RC circuit; the non-inverting input end of the first voltage comparator is coupled with the voltage adjustment circuit for inputting an adjusted voltage; the inverting input end of the first voltage comparator is coupled with the second node for outputting reverse square-wave; a second forward square-wave signal generation circuit, including a capacitor and a second voltage comparator, where the capacitor is in serial connection with the sensing line; a third node is provided between the sensing line and the capacitor; and the non-inverting input end of the second voltage comparator is coupled with the third node for outputting second square-wave signal; an AND gate, provided with three input ends that are respectively connected with the output end of the first voltage comparator, the first node, and the output end of the second voltage comparator; and a trigger circuit, respectively connected with the output ends of the AND gate and the switch, so that when the three input ends of the AND gate have logic-high input simultaneously, the switch is triggered to be in conducting state to heat the heating wire; when the three input ends of the AND gate have logic-high input non-simultaneously, the switch is not triggered so as to stop the heating of the heating wire.