JPH0369213B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a temperature control device that controls temperature using duty control.

Prior Art A conventional temperature control device is shown in FIG. As shown in the figure, there is a half-wave rectifier circuit 1 that converts AC power source AC into DC, a pulse generator 2 that generates pulses with a constant period, and two different operating times that are synchronized with the pulses of this pulse generator 2. a timer 3 having
The output signal of this timer 3 controls the opening and closing of the switch S connected to the AC power source AC, and outputs a high signal to the load controller 5 which controls the drive of the load 1 and the timer 3 when the temperature is below a predetermined temperature. , and a signal generator 4 that outputs a low signal to the timer 3 when the temperature is above a predetermined temperature.

Pulse generator 2 includes resistor R3 and capacitor C2,
It consists of resistors R4, R5, comparator I _c1, etc., and the voltage at the connection point between resistor R3 and capacitor C2
V _c2 has a waveform as shown in Figure 2, and this voltage V _c2
and resistors R4, R5 or resistors R4, R5, R6
A pulse with a constant period, V _T shown in FIG. 2, is generated.

Timer 3 consists of resistor R8, capacitor C3, resistors R9 and R10, and comparator _Ic2 .
The voltage V _c3 at the connection point between the resistor R8 and the capacitor C3, which are connected to the output of the pulse generator 2, changes as shown in FIG. When the signal generator 4 is a high signal, the voltage V _c3 and the divided voltage of the resistors R9, R10 are compared by the comparator I _c2 , and when the signal generator 4 is a low signal, the voltage V _c3 and the voltage divided by the resistors R9, R10, R14 are compared. The divided voltages are compared, and an output signal of V ₀ as shown in FIG. 2 is obtained. When this output V ₀ is a low signal, the coil L
1 is energized and the switch S is closed.

The signal generator 4 is a thermistor R15 for temperature detection.
and resistor R11, resistor R12, R13, comparator I _c3
It consists of a thermistor R15 and a resistor R
Connection point voltage V _A with 11, resistor R12 and resistor R1
3 and outputs the output voltage V _D shown in FIG. 2 to the timer 3.

Problems to be Solved by the Invention However, in the conventional configuration, the output of the signal generator 4
If V _D repeats high and low changes, the comparison voltage reference of timer 3 is changed, the output V ₀ of timer 3 also changes high and low, and load controller 5
has a repetitive on/off action. For this reason, when the load controller 5 operates a mechanical contact like the switch S, there is a problem in that the life of the contact is significantly reduced. Furthermore, if the load controller 5 is a semiconductor switching element such as a triac,
The problem was that flicker noise was generated.

The present invention solves the above problems by eliminating the repetitive operation of the load controller that turns on and off in short cycles,
The purpose of the present invention is to provide a temperature control device that improves contact life and prevents flickering.

Means for Solving the Problems In order to achieve the above object, the present invention provides a pulse generator that generates pulses with a constant period, and a pulse generator that operates for a time that is synchronized with the pulses generated by the pulse generator and that is less than or equal to the pulse period. a signal generator that outputs a signal according to the temperature detected by the temperature detector; a load controller that drives the load during the operating time of the timer; a switching device, the switching device selects one timer operation from a plurality of timer operation times of the timer at a timing synchronized with the pulse according to a signal from the signal generator, and switches the timer operation time. It is something.

Effect According to the above configuration, since the switching device inputs the signal from the signal generator in synchronization with the pulses from the pulse generator, the operation time from the signal generator to the timer is required between the pulses generated from the pulse generator. Even if a repetitive operation occurs in which a signal for switching is repeatedly output, the switch will not change the operating time of the timer with this repetitive signal.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

First, the configuration of the present invention will be explained with reference to FIG.
As shown in the figure, there is a pulse generator 2 that generates pulses with a constant period, and a pulse generator 2 that is synchronized with the pulse generator 2.
It also includes a timer 3 that operates for a time equal to or less than this pulse period. This timer 3 has a plurality of different operating times, and selection and switching of these operating times is performed by the output of a switch 6. During the operating time of the timer 3, the load controller 5 is driven. The switch 6 inputs the pulses from the pulse generator 2 and switches the signal generator 4 in synchronization with the pulses.
Input the signal. The signal generator 4 outputs a signal according to the detected temperature.

Figure 4 is the circuit diagram of the conventional half-wave rectifier circuit 1.
, pulse generation circuit 2, timer 3, and signal generator 4
is also adopted in this embodiment. To explain the non-conventional switch 6, a differentiating circuit consisting of a capacitor C4 and resistors R16 and R17 is connected to the clock input terminal of the D-type flip-flop _Ic4 .
Clock the signal at the rising edge of V _T to the input terminal T
Output to. That is, a signal synchronized with the pulses of the pulse generator 2 is output to the clock input terminal, and the D-type flip-flop _Ic4 inputs the high or low signal of the signal generator 4 to the D terminal at the timing of inputting the output signal of the differential circuit. , the high or low signal inputted to the D terminal is outputted to the Q terminal, and continues to be outputted until the next signal is inputted to the clock input terminal T.

Next, the operation of this embodiment will be explained with reference to FIGS. 4 and 5. In the pulse generator 2, the voltage V _c2 at the connection point between the resistor R3 and the capacitor C2 changes as shown in Figure 5, and the comparator I _c1 inputting this voltage V _c2 generates the pulse waveform of V _T shown in Figure 5. Output. The period of this pulse is T. Due to the pulse V _T , the voltage at the connection point between the resistor R9 and the capacitor C3 of the timer 3 has a waveform of V _c3 as shown in FIG. The switching device 6 also has Q due to the pulse V _T shown in Fig. 5 and the output V _D of the signal generator 4.
Outputs a high or low signal. That is,
Output of signal generator 4 at the rising edge of pulse V _T
V _D is input, and the high or low signal of this output V _D is output as output Q. The operating time of the timer 3 is switched by the output Q of the switch 6. When output Q is a low signal, comparator I _c2 of timer 3
The comparison voltage becomes the voltage V1 determined by the resistors R9, R10, and R14, and the high signal output operation time of the timer 3 at this voltage V1 becomes T1. When the output Q is a high signal, the comparison voltage of the comparator I _c2 of the timer 3 becomes the voltage V2 determined by the resistors R9 and R10, and at this voltage V2, the high signal operation time of the timer 3 becomes T2, and the output Q becomes The operating time of the timer 3 becomes longer than when the signal is low.

As described above, the output _V0 of the timer 3 can be switched to T1 or T2 for the timer operation time by the switch 6 which outputs a high or low signal in synchronization with the pulse of the pulse generator 2.
Even if the output of the signal generator 4 performs a repetitive operation of repeating high and low signals in a short period shorter than the pulse period, this repetitive operation can be prevented from being output as the output V ₀ of the timer 3.

Effects of the Invention As is clear from the above embodiments, according to the present invention, the temperature is controlled by switching the operation time of the timer in synchronization with pulses of a constant cycle, so that the temperature changes in a short period of time shorter than the pulse cycle. Even if the signal generator repeatedly outputs a signal to switch the timer operation time, the load controller driven by the output of the timer synchronized with the pulse does not perform the repetitive operation. It is possible to prevent shortening of contact life and occurrence of flicker.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a conventional example, Fig. 2 is an operation waveform diagram showing the operation of the conventional example, Fig. 3 is a block diagram showing the configuration of the present invention, and Fig. 4 shows an embodiment of the present invention. The circuit diagram and FIG. 5 are operational waveform diagrams showing the operation of the same embodiment. 2... Pulse generator, 3... Timer, 4...
Signal generator, 5...load controller, 6...switcher.

Claims (1)

[Claims] 1. A pulse generator that generates pulses with a constant period, a timer that is synchronized with the pulses generated by this pulse generator and operates for a time shorter than this pulse period, and a signal that outputs a signal according to the temperature detected by the temperature detector. The switch includes a signal generator, a load controller that drives the load during the operating time of the timer, and a switch that switches the operating time of the timer at a timing synchronized with the pulse, and the switch is configured to control the load from the signal generator. A temperature control device characterized in that one timer operation is selected from a plurality of timer operation times of the timer at a timing synchronized with the pulse according to a signal, and the operation time of the timer is switched.