JPS63221225A - Temperature detector - Google Patents

Abstract

PURPOSE:To reduce variation in reference voltage and to facilitate adjusting operation by connecting both ends of the semifixed resistor for temperature setting of a reference voltage circuit to the semifixed resistors of a source voltage dividing circuit which are capable of independent voltage adjustment. CONSTITUTION:The series circuit of resistances 2 and 3 and a semifixed resistor 4 and the series circuit of resistances 5 and 6 and a semifixed resistor 7 are provided between power sources (a) and (b). Then a variable resistor 8 for temperature setting is connected between said semifixed resistors 4 and 7, and the output of this variable resistor 8 is applied as a reference voltage to a comparator 11. The comparator 11 compares a temperature information voltage obtained by a thermistor 10 and a resistance circuit 9 to said reference voltage to obtain a control output. Thus, both ends of the variable resistor 8 for temperature setting are connected to the independent semifixed resistors 4 and 7 for source voltage division potential output to reduce variation in output reference voltage, so the adjustment is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature detection device used in household electric appliances such as electric fans.

Conventional technology In recent years, the spread of air conditioners has significantly improved the comfort of living environments.However, air conditioners currently on the market produce less air than electric fans, and the user is exposed to the wind, which lowers the perceived temperature. It is not very effective, especially when heating the room, and the high temperature air ends up near the ceiling of the room. For this reason, it is necessary to stir the indoor air, and an electric fan is often used to stir the indoor air.

In this way, electric fans that are used in conjunction with air conditioners are equipped with temperature detectors that operate the fan when the temperature exceeds a predetermined temperature and stop the fan when the temperature drops below a predetermined temperature.

Since the temperature detector is used in a relatively low-priced product called an MK machine, it is not possible to use an expensive A/D converter such as a sequential comparison type VD converter. This will be useful. Figure 2 is a circuit diagram of a conventional temperature detector.
03 is a variable resistor whose both ends are connected to the semi-fixed resistors 101 and 102, and outputs a divided voltage of the stain source from the slider terminal, which is used as the reference voltage of the comparator 10.

A resistor 104 and a thermistor 106 are each connected in series between the power supplies, and a temperature-dependent power supply division voltage is obtained at the connection point P between the resistor 104 and the thermistor 105, and this is applied to the comparator 110 as a temperature information voltage. ing.

The comparator 110 compares the reference voltage with the temperature information voltage at the point P, outputs a uniquely determined output, and controls the control circuit (
(not shown) is used to control devices such as electric fans connected to the controller (not shown).

Here, by using a resistor 104 of an appropriate value for a teamister 106 of arbitrary performance, the potential of point P can be set as follows in a narrow temperature range (for example, 16°C to 35°C).
It changes almost linearly with temperature changes, and the P point potential at the upper and lower limits of detectable temperature determined by product specifications is uniquely determined.

The variable resistor 103 has its variable width set by setting the upper and lower limits of the potential at point P mentioned above with the semi-fixed resistors 102 and 103, and between which the resistance 11f changes linearly with respect to the slider movement KJJ. By ticking scales at equal intervals on a fixed surface along the slider lever and moving the saver lever in accordance with the scales, the comparator output changes at the temperature indicated by the slider lever.

Problems to be Solved by the Invention However, in the conventional configuration described above, the potential across the variable resistor 103 is controlled by the two semi-fixed resistors 101 and 102 connected in series to the variable resistor 103 in the reference voltage circuit. Therefore, there was a problem in that adjustments had to be made many times to reach predetermined upper and lower limit values. This is because the P point voltage change is very small compared to the power supply voltage, and is only about % in the temperature range mentioned above, and the practical temperature detection accuracy (±2 deg.
(within), it is necessary to set the potential with an accuracy of 3 effective digits, so the total resistance value accuracy of the variable resistor 103 is about ±10% to ±20%, except for special applications. It depends.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a temperature detection device that can easily adjust the potential of a variable resistor of a reference voltage circuit corresponding to a predetermined temperature.

Means for Solving the Problems In order to achieve this object, the temperature detection device of the present invention has two
A resistor and a semi-fixed resistor connected in series to these two resistors have two circuits that adjustably divide the power supply voltage, and the voltage divided by the two circuits is A reference voltage circuit that connects both ends of a variable resistor for temperature setting and outputs a reference voltage from its slider, and a resistor and thermistor that are connected in series between the power supplies, and the voltage at the connection point of both. The configuration of the temperature detection device includes a temperature information circuit that uses the temperature information voltage as a temperature information voltage, and a comparator that compares the temperature information voltage with the reference voltage.

Effect: With this configuration, when setting the potential at one end of the variable resistor in the reference voltage circuit using a semi-fixed resistor, it is possible to reduce potential fluctuations at the other end, making it easier to set the potential at both ends of the variable resistor. will be possible.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG.

As shown in the figure, the reference voltage circuit includes a semi-fixed resistor 4 and resistors 2 and 3 connected across the power supply.
a series circuit of another series circuit, and a series circuit of a resistor 6.6, also connected between the power supplies and a semi-fixed resistor element and a resistor 6.6 connected to both ends thereof, and an adjustable resistor of the semi-fixed resistor 4.7. Temperature setting variable resistor 8 with both ends connected to the voltage dividing point
Accordingly, a reference voltage is output from the sliding terminal of the temperature setting variable resistor 8.

The temperature information circuit consists of a resistor 9 and a thermistor 10 connected in series between power supplies, and a multi-temperature information voltage is obtained from a connection point P between the two. The comparator 11 compares these reference voltages with the temperature information voltage and outputs a control output.

The operation of the temperature detection device of this embodiment configured as described above will be explained below. The temperature of the temperature setting variable resistor 8 in the reference voltage circuit is set by moving its slider in accordance with a temperature scale shown on a fixed surface (not shown). Temperature setting variable resistor 8 is semi-fixed resistor 4 and 7
Since the voltage across both ends is fixed, a reference voltage that changes continuously and in series in proportion to the amount of slider movement is output to the slider terminal. The above-mentioned potentials at both ends are the upper and lower limit voltages of the temperature detection range determined by the specifications of the device among the temperature information voltage at point P obtained by dividing the stain source voltage by the thermistor 1o and resistor 9 forming the temperature information circuit. It will be set after adjustment. The comparator 11 is connected to the reference voltage of the slider terminal of the temperature setting variable resistor 8 and the P of the temperature information circuit.
The output is inverted when the potential matches the point potential.

Now, resistor 2.3 and semi-fixed resistor 4 of the reference voltage circuit
The series combined resistance value of the resistor 6.7 and the series combined resistance value of the semi-fixed resistor γ are each sufficiently smaller than the resistance value of the temperature setting variable resistor 8 (in practical terms, about 9). If you adjust the semi-fixed resistor 4 and change its slider potential, the change in the slider potential of the semi-fixed resistor 7 at the other end will be very small, compared to the conventional example. It is about 9% to 9%, and the adjustment can be completed with about 2 follow-up adjustments.

As described above, according to this embodiment, both ends of the temperature setting variable resistor 8 of the reference voltage circuit are connected to independent hand-turned constant resistors N4.7 for outputting the power supply voltage divided potential. , adjustments can be made easily.

Effects of the Invention As is clear from the above description of implementation, the present invention connects both ends of a temperature setting semi-fixed resistor of a reference voltage circuit to a semi-fixed resistor of a power supply voltage dividing circuit that can independently adjust the voltage. As a result, the change in the output reference voltage is extremely small, so that adjustment can be easily performed, and an excellent temperature detection device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a temperature detection device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional temperature detection device. 42.7...Semi-fixed resistor, 8...Variable resistor for temperature setting, 1o...Thermistor, 1
1...Comparator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] It has two circuits that divide the power supply voltage in an adjustable manner, consisting of two resistors and a semi-fixed resistor connected in series with the two resistors, and a circuit that divides the voltage of the two circuits. a reference voltage circuit that connects both ends of a variable resistor for temperature setting to each point and outputs a reference voltage from its slider;
A temperature detection device consisting of a temperature information circuit that is made up of a resistor and a thermistor connected in series between power supplies and uses the voltage at a connection point between the two as a temperature information voltage, and a comparator that compares the reference voltage and the temperature information voltage.