JPS63104673A - Circuit of ultrasonic type atomizer - Google Patents

Abstract

PURPOSE:To prevent the breakdown of a piezo-electric oscillator or transistor for oscillation by detecting the abnormal heat generation of the piezo-electric oscillator or TR for oscillation with a positive characteristic thermistor provided in a bias circuit, thereby stopping the oscillation thereof. CONSTITUTION:An AC voltage is rectified and the rectified voltage is supplied in a power source circuit 12. The piezo-electric oscillator 11 for atomizing liquid is driven by a high frequency in an oscillation circuit 14. A bias voltage or bias current is supplied to the circuit 14 in a bias circuit 13. A function to stop the oscillation by detecting the abnormal heat generation of the piezo-electric oscillator 11 or the TR 10 for oscillation is provided to the positive characteristic thermistor 15 provided in the circuit 13. Namely, the abnormal heat generation of the piezo-electric oscillator or the TR for oscillation at the time of a non-water burning or abnormal operation is prevented by the positive characteristic thermistor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a circuit for an ultrasonic atomizer that drives a piezoelectric vibrator at high frequency and uses the ultrasonic energy to atomize liquid.

2. Description of the Related Art Conventionally, a circuit of this type of ultrasonic atomization device has a configuration as shown in FIG. In Fig. 4, 1 is an AC power supply;
2 is a diode bridge, 3,4°6.6 is a capacitor, 7 is a bias resistor, 8 is a resistor, 9 is a coil, 1o is a transistor, 11 is a piezoelectric vibrator, 12 is a power supply circuit, 13
is a bias circuit, 14 is an oscillation circuit, and AC power supply 1
is full-wave rectified by diode bridge 2, and bias resistor 7
The voltage divided by the resistor 8 and the resistor 8 is applied to the transistor 10 as a bias voltage. As a result, the piezoelectric vibrator 11
The device was constructed so that the liquid was atomized by being driven at a high frequency by a transistor 10.

Problems to be Solved by the Invention In such a conventional configuration, during dry cooking, where the circuit continues to operate even though there is no more liquid to atomize, or when the circuit operates abnormally due to an abnormal power supply voltage, etc. There was a problem that piezoelectric vibrators and transistors were destroyed due to abnormal heat generation.

The present invention solves these problems by using a positive characteristic thermistor (hereinafter referred to as a PTC thermistor) to detect abnormal heat generation of a piezoelectric vibrator or transistor during abnormal operation.
The purpose of this is to lower the bias voltage due to the increase in the resistance value of the PTC thermistor and stop the operation of the transistor, thereby preventing destruction of the piezoelectric vibrator and the transistor.

Means for Solving the Problem In order to solve this problem, the present invention provides a power supply circuit for rectifying an alternating current piezoelectric voltage and supplying the rectified voltage to the following circuits, and a power supply circuit for atomizing a liquid. An ultrasonic atomizer comprising an oscillation circuit for driving a piezoelectric vibrator at a high frequency and a bias circuit for supplying a bias voltage or bias current to the oscillation circuit, the bias circuit including a PTO
Equipped with a thermistor, the above PTC thermistor is warmed by abnormal heat generation of the piezoelectric vibrator or oscillation transistor during dry cooking or abnormal circuit operation, and the resistance value increases, lowering the bias voltage or bias current and stopping oscillation. This structure prevents the piezoelectric vibrator or oscillation transistor from being destroyed.

Effect With this configuration, during steady operation, the resistance value of the PTC thermistor is low, so a bias voltage or bias current is supplied to the oscillation circuit, and atomization occurs normally.However, when the heating is dry or when the circuit operates abnormally, piezoelectric vibration occurs. The PTC thermistor is warmed by abnormal heat generation of the transistor or transistor and self-heating of the PTC thermistor due to the abnormal current, which increases the resistance value of the PTC thermistor, lowers the bias voltage or bias current, and stops the operation of the transistor.
In this way, destruction of the piezoelectric vibrator and transistor can be prevented.

EXAMPLE An example of the present invention will be described below based on the drawings. In addition, FIG. 1, in which the same parts as in the conventional example are given the same reference numerals, is a diagram showing a circuit of an ultrasonic atomizer according to an embodiment of the present invention. This is a PTC thermistor that prevents the piezoelectric vibrator 11 and transistor 10 from being destroyed due to abnormal heat generation during dry cooking or abnormal operation.

Next, in FIG. 2, the PTC thermistor 16 is fixed on the transistor 10 of the oscillation circuit 14 with an adhesive or the like, and the PTC thermistor 16 is damaged due to abnormal heat generation and abnormal current of the transistor 1o during dry cooking or abnormal operation. The structure is such that the PTC thermistor 16 is warmed by self-heating, and the resistance value of the PTC thermistor 15 rises rapidly, thereby lowering the bias voltage and stopping the operation of the transistor 1o. Here, 16 is the heat sink of the transistor, 1
A is a printed circuit board.

Next, another embodiment shown in FIG. 3 will be described.

FIG. 3 shows a first embodiment in which the PTC thermistor 16 of FIG. 2 is fixed under the piezoelectric vibrator 11 with an adhesive or the like, and the operation is the same as that of the first embodiment. Here, 18 is a rubber gasket, and 19 is a main body of the atomizer.

In the embodiment of the present invention, the PTC thermistor 15 is mounted above the transistor 1o and below the piezoelectric vibrator 11;
Any place where you can take advantage of the abnormal heat generation is fine. Furthermore, the PTC thermistor 16 is connected between the bias circuit 13 and the oscillation circuit 14, and the p'rc thermistor 16
It may be connected anywhere as long as it can reduce the bias voltage or bias current and stop the operation of the transistor 1o by increasing the resistance value of the transistor 1o. Further, although the oscillation circuit 14 is a self-excited type emitter grounded, the excitation type may be either self-excited or externally excited, and the ground plane may be either collector grounded or emitter grounded.

Effects of the Invention As described above, according to the present invention, the PTC thermistor has the effect of preventing piezoelectric vibrators and transistors from being destroyed due to abnormal heat generation during idle cooking or abnormal operation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the circuit configuration of an ultrasonic atomizer according to an embodiment of the present invention, FIG. 2 is a perspective view showing a PTC thermistor according to the present invention attached to a heat sink of a transistor, and FIG. FIG.
The figure is a circuit diagram showing the circuit configuration of a conventional ultrasonic atomizer. 11... Piezoelectric vibrator, 12... Power supply circuit, 13... Bias circuit, 14...
Oscillation circuit, 16...PTC thermistor. Name of agent: Patent attorney Toshio Nakao (1 person)
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Claims (1)

[Claims] A power supply circuit for rectifying alternating current voltage and supplying the rectified voltage, an oscillation circuit for driving a piezoelectric vibrator at high frequency for atomizing liquid, and supplying a bias voltage or bias current to this oscillation circuit. An ultrasonic atomizer equipped with a bias circuit, which has a function of detecting abnormal heat generation of a piezoelectric vibrator or an oscillation transistor with a positive characteristic thermistor provided in the bias circuit and stopping the oscillation. Circuit of ultrasonic atomizer.