JPS62682B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a hair dryer.

FIG. 1 shows a temperature control circuit for a conventional hair dryer. A reference voltage generation circuit 1 that generates a reference voltage Vr, a temperature corresponding voltage generation circuit 8 that generates a temperature corresponding voltage V ₁ corresponding to the temperature generated by a temperature sensing element such as a thermistor, and the reference voltage generation circuit 1. Reference voltage Vr from and temperature corresponding voltage generation circuit 8
The output of the comparator ₃ is used to connect the thermoswitch 7, the heater 4, and the switching element 5 such as a triax via the trigger circuit 9. The switching element 5, which connects the series circuit to the AC power supply e, is controlled on and off. Furthermore, the reference voltage generation circuit 1
The comparator 3, the trigger circuit 9, and the temperature-corresponding voltage generation circuit 8 constitute a temperature control section 6'. Since the temperature is controlled by controlling the power higher than the power in actual use, a considerable temperature rise occurs instantaneously when the power supply e is turned on. Therefore, if a thermoswitch 7 is provided as a safety device in case the temperature control section 6' breaks down, the conventional temperature control section 6' will not operate until the temperature sensing element senses and controls the temperature when the power supply e is turned on. Because heat is not immediately transferred to the internal element itself due to the heat capacity of the hot element,
As shown in FIG. 2a, there is a delay in the temperature-corresponding voltage _V1 . On the other hand, the reference voltage Vr drops from a high voltage when the power supply e is turned on and settles at the reference voltage Vr. Therefore, t ₁ in the figure is the time until the reference voltage Vr is saturated, and t ₂ is the delay time until the air temperature setting value is reached by the temperature sensing element, and this temperature corresponding voltage V ₁
It takes time t ₂ for Vr to reach the reference voltage Vr,
Therefore, since temperature control is not performed within this time _t2 , the temperature of the heater 4 rises, causing an overshoot in the air temperature as shown in Fig. 2b (a). There was a problem that switch 7 would operate.

The present invention has been provided in view of the above-mentioned points, and is aimed at suppressing the overshoot of air temperature when the power is turned on when the temperature is controlled by a temperature sensing element such as a thermistor. It provides:

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 3 shows a block diagram similar to the conventional example shown in FIG.
is inserted. FIG. 4 shows a concrete circuit. 12 is the reference voltage generation circuit 1 shown in FIG.
This is an integrated circuit in which a comparator 3 and a trigger circuit 9 are integrated. For power supply e, temperature fuse 11, thermo switch 7, power supply switches SW ₁ , SW ₂ ,
Heater 4, switching element 5 such as triax
Connect a series circuit consisting of both switches SW ₁ ,
The series circuit of bridge rectifier D ₂ and voltage drop resistor R ₆ is grounded from the connection point of SW ₂ , and the noise prevention capacitor C ₂ is connected from the output terminal of bridge rectifier D ₂ .
and the air blowing motor M via the yoke _L1 and _L2 .
are connected. Also, connect the connection point of both switches SW ₁ and SW ₂ to the terminal of the integrated circuit 12 via a resistor R ₂ , and similarly connect a diode D ₁ and a resistor to the terminal.
Connected via _R3 . The reference voltage Vr of the reference voltage generating circuit 1 is outputted to the terminal of the integrated circuit 12, and the terminal is the input terminal of the comparator 3. That is, a delay circuit 10 consisting of a resistor R and a capacitor C is inserted between these terminals. Furthermore, a variable resistor is connected between the terminals of the integrated circuit 12.
A temperature-sensitive voltage generating circuit 8 consisting of R ₅ and a temperature-sensitive element 2 such as a thermistor is connected, and a smoothing capacitor C ₁ is connected, and a temperature-sensitive voltage is connected to the terminal.
Entering V ₁ . The terminal is connected to the gate of the switching element 5 via a resistor _R1 .
Here, when only switch SW ₁ is turned on, the motor M rotates and only blows air, and when switch SW ₂ is also turned on, the switching element 5 is turned on by the signal from the integrated circuit 12, and the heater 4 is energized to send hot air. It is.

When the power source e is turned on, the reference voltage Vr input to the terminal of the comparator 3, that is, the integrated circuit 12.
For the delay circuit 10, as shown in FIG. 5a,
It decreases once and then increases until it is saturated with the time constant of the delay circuit 10. On the other hand, the rise of the temperature sensing element 2 itself is slow, and therefore control is performed using the reference voltage Vr which is lowered once in the delay circuit ₁₀ and then gradually increased from a low rise of the temperature corresponding voltage V1. Therefore, since the wind temperature is gradually controlled and raised from a low temperature to the set value, overshoot does not occur as shown in FIG. 5b.

As described above, the present invention provides a hair dryer with a delay circuit that delays the rise of the reference voltage between the reference voltage generation circuit and the comparator.
The reference voltage does not immediately reach the air temperature set value when the power is turned on, but gradually rises from a low temperature, so the temperature corresponding voltage from the temperature sensing element is controlled from a low voltage to reach the air temperature set value as before. Therefore, the temperature can be controlled reliably without causing the thermoswitch to operate first.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the conventional example, Fig. 2a is a characteristic diagram of the reference voltage and temperature corresponding voltage, Fig. 2b is a characteristic diagram of air temperature, and Fig. 3 is a block diagram of the embodiment of the present invention. FIG. 4 is a specific circuit diagram of the same as above, FIG. is a temperature sensing element, 3 is a comparator, 4 is a heater, 5 is a switching element, 6 is a temperature control section, 7
is a thermoswitch, 10 is a delay circuit, Vr reference voltage, and V ₁ is a temperature corresponding voltage.

Claims (1)

[Claims] 1 A comparator compares and determines the reference voltage generated by the reference voltage generation circuit and the temperature-corresponding voltage generated by detecting the wind temperature with the temperature sensing element, and the output of this comparator is used to connect the heater in series. In the hair dryer, the hair dryer is equipped with a temperature control section for controlling on/off of an element, and a thermoswitch connected in series with the heater, and a delay circuit for delaying the rise of the reference voltage is provided between the reference voltage generation circuit and the comparator. A hair dryer characterized by: