| 摘要 |
PURPOSE: A temperature controller for an electric heater mat is provided to achieve improved accuracy of temperature control and shield EMI by minimizing changes of voltage and current. CONSTITUTION: A temperature controller comprises an AC power unit(10) for supplying power to the temperature controller; a heating unit(20) including heater wires(H1,H2) for receiving AC power and generating heat, sensor wires(S1,S2) for sensing specific temperature by sensing the AC power and a temperature sensor layer deposited between the heater wires and sensor wires; a temperature detection unit(30) including a resistor(R1) and a capacitor(C1), and which detects negative sensor voltage by the AC power and the resistor; a DC power unit(40) including diodes(D2,D3), an electrolytic capacitor(C3) and a Zener diode(ZD1), and which converts the input AC power into smoothed DC power; a temperature set unit(50) including resistors(R4,R5,R7) and a variable resistor(R6), and which sets a reference temperature by the temperature setting of the variable resistor; a reference voltage generating unit(60) including resistors(R8,R9), a diode(D4) and a capacitor(C4), and which generates a reference voltage by moving the temperature point of the reference temperature voltage; a temperature comparing unit(70) including a comparator(U1A) for comparing a GND voltage(negative) and a result voltage(positive) which is obtained by performing compensation between the voltage detected by the temperature detection unit and the reference voltage output from the temperature set unit, a capacitor(C5) for storing signals output from the comparator, and a resistor(R10); an output unit(80) including a transistor(Q1) and a SCR(TH1); a zero voltage detection unit(90) including resistors(R13 to R16), a diode(D6) and a comparator(U1B); and a safety circuit breaker unit(100) for automatically breaking circuit upon occurrence of erroneous operation of circuit.
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