JPS58155424A - Temperature controlling device - Google Patents

Abstract

PURPOSE:To separate a detecting part and a control part, by constituting a temperature detecting part of a resonance circuit, and coupling the detecting part and the control part by capacity. CONSTITUTION:A variable capacitor 7 is set to a suitable value by operating it. A voltage controlling oscillator VCO 3 executes sweep oscillation. An oscillation output is applied to a resonance circuit 8 through floating capacity of electrode plates 4A, 4B. A detector 9 detects a resonance state of the resonance circuit 8. At the time of resonance, an output of a high level is obtained. This output signal becomes a trigger and a PUT 15 oscillates. Also, the VCO 3 is controlled simultaneously, is synchronized by resonance frequency of the resonance circuit 8, and the oscillation is continued. Oscillation frequency of the PUT 15 also synchronizes with its frequency. A current flowing to a heater 47 is controlled by controlling a triac switch 46 by an output of the PUT 15. In this way, it is possible to install a detecting part and a control part separately to a foot warmer plate and a wooden frame, of a foot warmer in a wooden frame.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes an operating section that sets a temperature by changing the resonant frequency of a resonant circuit, and a heating element that is provided separately from the operating section and that is operated to set the temperature of the operating section. The present invention relates to a temperature control device equipped with a control circuit that controls energization of a device and performs temperature control operations, and particularly relates to a temperature control device suitable for use when an operating section and a control circuit are provided separately.

Hereinafter, an embodiment of the temperature control device of the present invention will be described with reference to the drawings, regarding a case where the temperature control device of the present invention is implemented in a Yagura Kotatsu, in which an operating section is provided on a top plate and a control circuit is provided separately in the Yagura Kotatsu body.

In FIG. 1, 1 is the main body of the Yagura Kotatsu, 2 is a table plate having an operation part (not shown), etc., and a futon or the like is interposed between the two table plates and the main body of the Yagura Kotatsu. P with a 31d voltage controlled oscillator (hereinafter referred to as vCO)
Anode potential of U, T (programmable unijunction transistor) 15 (output of relaxation oscillation circuit Fig. 2)
The oscillation frequency changes depending on c)). 4A and 4B are electrodes for signal transmission and reception provided on the Yagura Kotatsu body l, 5
Reference numerals A to 5B are electrodes for transmitting and receiving signals provided on the table board 2, and are provided in pairs to face the electrodes 4A and 4B, respectively. 6 is an inductor, 7 is a variable capacitor, and the inductor 6 forms a resonant circuit 8, and the variable capacitor 7
By varying the capacitance value, the resonant frequency changes, which in turn changes the level of the control voltage of VCOA, and the level of the reference signal ((+) inputs) of the comparator 29 changes, causing the amount of current flowing through the load ( electricity) will change. Reference numeral 8 changes the resonance frequency fO in conjunction with a power adjustment operation section (not shown) provided on the table board 2. 9 is a detector, and the oscillation signal of the VCO 3 is supplied to the resonant circuit 8 of the table board 2 via the stray capacitance CA between the electrode plates 4A and 5A, and the signal is supplied via the stray capacitance cB between the electrode plates 5B and 4B. and is input to the detector 9. Then, a resonant state and a non-resonant state in the resonant circuit 8 are discriminated. An amplifier 10 amplifies the output signal of the detector 9 and outputs the amplified signal. A detector 11 converts the output of the amplifier 10 into a DC value. Reference numeral 12 denotes a comparator, and when the circuit is resonant, its output is ■ (low), and when it is not resonant, its output is ■ (high). 13 is a resistor, and 14 is a resistor, which form a relaxation oscillation circuit, the output of which is taken from the anode terminal of PLOT 5, and the output voltage is used as the control voltage of vco a, and also as the reference signal of comparator 290. It has become.

19 is a pulse transformer (19A is the primary side 19B is the secondary coil), 20 is a diode, 21 is an NPN transistor, 22.28 is a resistor, 24 is a capacitor, 25 is a resistor, 26 is a PNP) transistor, 27.28 is a resistance,
29 is a comparator, 30, 31, 32, and 33 are resistors, and 34 is a heat-sensitive element such as a thermistor (hereinafter explained as thermistor).
, 35° 36.37 is a resistor, 38 is a capacitor, 39 is an npn transistor, 40.41 is a resistor, 42 is an npn
) transistor, 43 and 44 are resistors, 45 is a diode, 46 is a control element such as a triac (hereinafter referred to as a triac), and 47 is a load (heater).

Then, the full-wave rectified signal of the AC power supply (omitted) is connected to the resistor 48,
44 and connected so as to be applied to the base of a transistor 420, and the transistor 42 is connected to a DC power supply (
+Vcc-ground) and the connecting end of the resistor 40, 41 connected to the ground. Also resistance 40.41
A connecting end of the transistor 390 is connected to a transistor 390, and the transistor 39 is connected through a resistor 37 between the connecting end of a resistor 36° capacitor 38 connected to a DC power supply and ground. The connecting end of the resistor 36 and capacitor 38 is also connected to the (→ input of the comparator 29 via the resistor 35. A thermistor 34 is also connected between the (→ input of the comparator 29 and the ground). and comparator 29
A resistor 30.3 connected to the DC power supply is connected to the (+) inputs of
The connecting ends of resistors 30 and 31 of 1.32 are connected, and the connecting ends of resistors 81 and 32 are connected to PTJTI5 through resistor 33.
is connected to the anode (output of the relaxation oscillator circuit).

Further, the output terminal of the comparator 29 is connected to the base of a transistor 260 via a resistor 28, the emitter of the transistor 26 is connected to the ■ side ("'cc") of the DC power supply, and a resistor is connected between the base and emitter of the transistor 26. 27 is connected.The collector of the transistor 26 is connected to the resistor 2.
A resistor 23 is connected in parallel to the resistor 25 via a capacitor 24. Further, a connection end between the resistor 23 and the capacitor 24 is connected to the base of the transistor 21 via the resistor 22. The emitter of the transistor 21 is connected to the ground side of the DC power supply, and the collector is connected to the - side of the DC power supply via the primary coil +9A of the pulse transformer 19.

Further, a diode 20 is connected in antiparallel to the coil +9A. The secondary coil 19B of the pulse transformer 19 is connected between the G and Tl terminals of the triac 46 via a diode 45.

In FIG. 2, (a) shows the full-wave rectified waveform of the AC power source to be applied to the base of the transistor 42, and (b) shows the waveform of the comparator 2.
The signal waveform from the serrated temperature sensor (thermistor) 34 to be applied to the ←) inputs of 9, (c) is the output of the relaxation oscillation circuit, that is, the anode potential of PUT + 5, and the solid line (A) is During resonance, the dashed line (B) indicates non-resonance, and at the lowest output, the VCO3 oscillates at the frequency f2, %vcoa, and at the highest output, the VCO3 oscillates (sweep oscillation) at the frequency f. Therefore, vcoa oscillates within the range of f1 to f2, and the resonant frequency fo can also be varied within that range (f, ≦fo≦f2).

) is the input (output) signal of the pulse transformer 19, (e)
is a waveform of energization of the load (heater) 47 (conduction of the triac 46), and is energized (conducted) at a conduction angle α.

(f) is the AC power waveform.

Next, to explain the operation mode of the temperature control circuit of the Yagura Kotatsu with the above configuration, first, the operation section of the table board 2 (
By operating the variable capacitor 7 (omitted), the variable capacitor 7 is set to an appropriate value, and a certain resonance frequency fO (however, f1≦f,≦
f2) is set. And the oscillation of VCO3 has a frequency f
1 to f2, and the signal is applied to the resonant circuit 8 via the stray capacitance CA between the electrode plates 4A and 5A.

The signal is also input to the detector 9 via the stray capacitance cB between the electrode plates 5B and 4B. It is assumed that the detector 9 detects that the resonant signal is higher in level than the non-resonant signal. Then, the signal is amplified by an amplifier 1O, and its vibration is compared with a DC signal by a detector 11.
The output of the comparator 12 at the time of resonance is ■ (high), and the output of the comparator 12 at resonance is ■ (low).

Since the output of the comparator 12 at the time of non-resonance is -, the capacitor 14 is charged via the resistor 13.

Therefore, as the anode potential of PTJT I 5 rises to some value (determined by resistor 17, 18, etc.), the charge on capacitor 14 discharges through PLIT I 5 and falls to a lower potential. By repeating this, PLIT1
The anode potential (potential of capacitor 14) of No. 5 is shown in Fig. 2 (
c) A sawtooth potential is obtained as shown by the dashed-dotted line in (B).

However, when the resonance signal is detected by the detector 9, the comparator 12
The output becomes ■, and charging of the capacitor 14 is stopped.

And since the control voltage of VCOA is also stopped, VCO8
The oscillation frequency of is temporarily fixed at the frequency at that time (resonant frequency fo). However, when the electric charge of capacitor r4 is discharged and the potential of capacitor 14 falls, the control voltage of vcoa also falls, and the oscillation of vcoa also deviates from the resonant frequency fO. As a result, the output of the comparator 12 becomes ■. Then, the capacitor I4 is charged, its potential rises, and stops again at a level corresponding to the resonant frequency fO (because it resonates and the output of the comparator 12 becomes ■). By repeating this, the potential of the capacitor 14, that is, the anode potential of PLIT15 ( The output of the relaxation oscillator circuit is kept almost constant as shown in FIGS. 2(c) and 2(a). Therefore, since the control voltage applied to C03 is constant, the oscillation frequency of vcoa is also constant (fo)
This state continues. Then, the output of the relaxation oscillator circuit is passed through the resistor 33, and the potential of the DC power supply is further increased by the resistors 30, 31.82, so that the comparator 29 (+
) is applied to the input as a reference signal. Since the transistor 42 turns on at approximately 0.7 volts or higher (turns OFF only when the AC power supply zero crosses), the transistor 39 turns ON only when the AC power supply zero crosses (only when the transistor 42 turns OFF). Therefore, the potential of the capacitor 38 is as shown in Figure 2 (
It becomes a sawtooth potential synchronized with the AC power supply as shown in (b). Since a thermistor 34 is connected to both ends of this capacitor 38 via a resistor 35, the potential of the thermistor 34 is of course a sawtooth potential (FIG. 2(b)). The maximum value of this sawtooth potential is determined by the resistance value of the thermistor 34, and is input to the (→ input of the comparator 29). b) When the (-) input is higher than ao' (the temperature is lower than the set value), (the set value and the thermistor 34
At a certain phase angle of the AC power supply (corresponding to the temperature (resistance value)), the output of the comparator 29 becomes - (low) and at that point the transistor 26 becomes conductive. Then, it is differentiated by a differentiating circuit consisting of resistors 25, 23, and a capacitor 24, and the transistor 21 is made conductive by the differentiated signal.

Therefore, a pulse-like signal as shown in FIG. 2 is input to and output from the pulse transformer 19. Therefore, the signal causes the triac 46 to conduct and the load (heater) 47 to be energized. However, in terms of timing, when the output of the comparator 29 becomes ■, the current is turned on at the conduction angle α. This conduction angle α changes the capacitance of the variable capacitor 7 of the resonant circuit 8, and the resonant frequency of the resonant circuit 8 spreads, thereby increasing the anode potential of the PLIT I 5 (level aO in Fig. 2 (C) and (A)). By being variable, it can be changed in response to the temperature.

In the above embodiments, the temperature control device of the present invention is applied to a kotatsu, but it can also be applied to other heating devices, and the present invention is not limited to the above embodiments. do not have.

Since the temperature control device of the present invention has the above configuration,
It is suitable for a temperature control device in which the operation part and control circuit are provided separately, and the temperature control can be performed reliably with a simple circuit configuration.Moreover, the temperature control is performed by phase control, so it is very easy to use.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the temperature control device of the present invention, and FIG. 2 is a signal waveform diagram of each main part of FIG. 1. In the drawing, 3 is a voltage controlled oscillator, 8 is a resonant circuit, 29 is a comparator, and 47 is a heater.

Claims (1)

[Claims] 1 An operating section that sets the temperature by changing the resonant frequency of a resonant circuit, and an operating section that is provided separately from the operating section and controls energization to the shift heater and performs temperature control operations by operating the operating section to set the temperature. In a temperature control device comprising a control circuit for performing The control circuit is configured such that the signal from the temperature detection circuit that detects the temperature is made into a sawtooth shape and is used as the other input of the comparator, and the output of the comparator controls the energization to the heater by phase control. Features temperature control device.