JPH0510984B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to ultrasonic atomization devices such as ultrasonic inhalers that atomize liquid by vibrating an ultrasonic vibration horn by the vibration of an ultrasonic vibrator. Regarding equipment.

(b) Conventional technology Ultrasonic inhalers use a vibrating plate integrally formed at the tip of an ultrasonic vibrating horn, which is vibrated by the vibration of an ultrasonic vibrator to atomize liquid on the surface of the vibrating plate. There are some that are made to emit light. Conventionally, in this type of ultrasonic inhaler, as shown in Figure 2, a battery a is used as a power source, and the DC voltage of this battery a is DC-DC.
The converter b boosts the voltage and applies its output to the oscillation circuit c, which drives the ultrasonic vibrator e when the power switch d is turned on to perform atomization. The current flowing through the oscillation circuit c is detected by the current detection circuit f so that stable atomization can be achieved even if the load changes due to differences in the amount of atomized liquid dropped onto the diaphragm of the vibrating horn. , the control circuit g controls the output of the DC-DC converter b according to this current value, so that a constant current flows through the oscillation circuit c regardless of changes in the load.

(c) Problems to be Solved by the Invention Generally, the impedance of a vibrating horn increases as the amount of load increases. Therefore, when the amount of supplied liquid increases and the load increases, the current in the oscillation circuit decreases accordingly, but in the conventional device described above, the power from the DC-DC converter is increased by controlling a constant current to flow. , atomization is performed in response to overload. However, in reality, the Q of vibrating horns varies, and if the Q is low, the impedance will not become very large even under a large load, and with constant current drive, the oscillation circuit will receive enough power to atomize (spray). It may not be supplied.

In view of the above, the present invention provides an ultrasonic atomization device that can increase the power supply to the oscillation circuit even with a slight increase in load and achieve stable atomization even with a low-Q vibration horn. is intended to provide.

(d) Means and action for solving the problems The ultrasonic atomizer of the present invention comprises a DC power source, a DC booster circuit that boosts the DC voltage from the DC power source, and an output voltage of the DC booster circuit. An oscillation circuit that operates in response to the vibration, and an oscillation circuit that vibrates by this oscillation circuit
A first detection circuit that detects the current of the oscillation circuit and a second detection circuit that detects the output of the DC booster circuit, which includes an ultrasonic vibrator that atomizes liquid by driving an ultrasonic vibration horn. and a control circuit that controls the output of the DC booster circuit according to the detection outputs of the first and second detection circuits.

In this ultrasonic atomizer, when the load tends to increase, the output from the DC booster circuit is controlled to increase by current detection by the first detection circuit, and the output from the DC booster circuit is controlled to increase.
When an increase in the output of the DC booster circuit is detected by the detection circuit in Ru.

(E) Examples The present invention will be explained in more detail below with reference to Examples.

FIG. 1 is a circuit connection diagram of an ultrasonic inhaler in which the present invention is implemented. The circuit section of this ultrasonic inhaler includes a battery 1 as a DC power source, a power switch SW
1. Boost the DC voltage supplied from battery 1, etc.
A DC-DC converter 2, an oscillation circuit 3 that is activated by the power supply voltage supplied from the DC-DC converter 2 and vibrates the ultrasonic transducer 4, and a current detection circuit (first (detection circuit) 5, an output voltage detection circuit (second detection circuit) 6 that detects the output of the DC-DC converter 2,
It is comprised of a control circuit 7 for controlling the output of the CD-DC converter 2 according to the detection outputs of the current detection circuit 5 and output voltage detection circuit 6, a jack 8 for connecting an external DC voltage source, and the like.

The DC-DC converter 2 includes transistors Tr1,
It is composed of Tr2, Tr3, a charging/discharging circuit formed by a capacitor C2 and a resistor R4, a step-up transformer T1, a charging capacitor C3, and the like.

The oscillation circuit 3 includes a transistor Tr4 and a coil L.
3. This is a blotting oscillation circuit consisting of an oscillation transformer T2, resistors R5 and R6, and a capacitor 5C.
Note that d3, d4, and d5 are surge absorption diodes and Zener diodes. This oscillation circuit 3
A parallel connection of a resistor R7 and a variable resistor VR1 of the current detection circuit 5, and a parallel connection of a resistor R8 and a thermistor TH1 (temperature compensation circuit) are connected in series between the common terminal of the current detection circuit 5 and the common of the DC-DC converter 2. This circuit derives a voltage corresponding to the current flowing through the oscillation circuit 3, and inputs it to the base of the transistor Tr6 constituting the control circuit 7 via the resistor R9.

The output voltage detection circuit 6 is composed of a transistor Tr5 and resistors R10, R11, and R12, in which the resistors R10 and R11 are connected in series and connected between the output (high voltage side) of the DC-DC converter 2 and common, The connection point between and R11 is a transistor
Connected to the base of Tr5. Further, the emitter of the transistor Tr5 is connected to the common of the DC-DC converter 2, and the collector is connected to the common of the oscillation circuit 3 via the resistor R12. The feature of this circuit lies in the provision of this output voltage detection circuit 6. When the output of the DC-DC converter 2 increases, the potential at the connection point between resistors R10 and R11 increases accordingly, which helps turn on the transistor Tr5. It is becoming more and more common.

Next, the operation of the example circuit will be explained.

When the power switch SW1 is turned on, the positive voltage of the battery 1 is applied to the transistor Tr1 via the resistor R2.
The transistor Tr1 is turned on and the collector current of this transistor Tr1 starts to flow, and the transistor Tr2 is turned on and its collector current starts to flow. Here, transistor Tr6
is initially off. The above transistor
Due to the collector current of Tr2, transistor Tr3
turns on. As a result of this turning on, a charging current flows to the capacitor C2 through the resistor R4, the capacitor C2, and the base and collector of the transistor Tr3, the potential of the base of the transistor Tr3 decreases, and eventually the transistor Tr3 turns off. Transistor Tr
3 is turned off, the charge stored in the capacitor C2 is transferred to the resistor R4, the step-up transformer T1, and the diode d.
1, d2, capacitor C2, and the common path, the potential of the base of transistor Tr3 rises,
The base current of transistor Tr3 starts flowing again,
Transistor Tr3 turns on.

In this way, the transistor Tr3 is turned on/off.
The off state is repeated, and the current flowing through the secondary coil L2 of the step-up transformer T1 turns on and off, and the transistor
When Tr3 is off, the diodes d1 and d2 are made conductive by the back electromotive force of the secondary coil L2, the capacitor C3 is charged, and the battery voltage is boosted. The charge stored in the capacitor C3 is applied to the oscillation circuit 3, causing current to flow through the oscillation circuit 3.

In the oscillation circuit 3, when the current is supplied, the capacitor C5 is charged. As the charging progresses, the base potential of the transistor Tr4 rises, and a base current begins to flow, and likewise to the collector. This increase in collector current is caused by the oscillation transformer T
An electromotive force is induced in the secondary coil L5 of No. 2, and the base current is further increased to perform a so-called positive feedback operation.
Thereafter, the base current of the transistor Tr4 gradually decreases due to reverse charging of the capacitor C5, and the collector current stops increasing. This change in collector current induces a back electromotive force in the secondary coil L5, and in this case too, due to positive feedback operation, the transistor Tr
4 turns off instantly. In this way, the transistor Tr4 is repeatedly turned on and off to continue the oscillation operation. This oscillation causes the ultrasonic vibrator 4 to vibrate, driving an ultrasonic vibrating horn (not shown) to perform an atomizing action.

When the oscillation circuit 3 starts its oscillation operation, the current flowing through the oscillation circuit 3 reaches the resistance VR of the current detection circuit 5.
The voltage that flows through the 1st class and corresponds to the current of the oscillation circuit 3 is
Transistor Tr of control circuit 7 via resistor R9
It is input to the base of 6. This change in voltage results in a change in the voltage between the base and emitter of transistor Tr6, and this voltage value causes the transistor to
Tr6 is turned on. That is, the current detection circuit 5
When the current value detected at is large and the voltage value input from resistor R9 is large, transistor Tr6 is turned on. When transistor Tr6 turns on, the base current of transistor Tr1 decreases by that amount,
Transistor Tr1 becomes difficult to turn on. Therefore, the off period of transistor Tr3 is extended, and the DC
-The oscillation period of DC converter 2 becomes large, and the DC,
The output of DC converter 2 decreases.

Conversely, when the current value detected by the current detection circuit 5 becomes small and the voltage input to the base of the transistor Tr6 becomes small, the current flowing through the transistor Tr6 tends to decrease, and the degree of decrease in the base current of the transistor Tr1 decreases. becomes small and transistor
The off period of Tr3 is also shortened, and the output of the DC-DC converter 2 is controlled to be increased. By controlling in this manner, a constant current is supplied to the oscillation circuit 3.

In addition to the current detection circuit 5, this embodiment circuit includes:
An output voltage detection circuit 6 is also provided. Therefore, for example, when the load on the ultrasonic transducer 4 becomes large, resulting in a large impedance and the power supplied from the DC-DC converter 2 to the oscillation circuit 3 increases, the potential at the connection point between resistors R10 and R11 increases, The base current of transistor Tr5 increases,
Since the transistor Tr5 tends to turn on, the resistance
The current flowing through VR1 decreases and transistor Tr6
The base current of is also reduced. transistor according to
Increase the base current of Tr1 and reduce the transistor Tr
It operates to shorten the off period of 3, so
The output of the DC-DC converter 2 increases even more, and the power supply to the oscillation circuit 3 increases.

Conversely, the load on the ultrasonic transducer 4 becomes smaller and the DC
- When the power supplied from the DC converter 2 to the oscillation circuit 3 decreases, the base current of the transistor Tr5 becomes small, and the transistor Tr5 tends to turn off. Therefore, the transistor Tr6 tends to turn on relatively, and the base current of the transistor Tr1 decreases. Since the flow is made difficult, the output of the DC-DC converter 2 is further reduced.

In this way, the base-emitter voltage of the control circuit 7 is determined not only by the detection output of the current detection circuit 5, that is, the current of the oscillation circuit 3, but also by the detection output of the output voltage detection circuit 6, that is, the output of the DC-DC converter 2. Since it also changes depending on the voltage, compared to a constant current circuit operation, the
The output of the DC-DC converter 2 can be sensitively reacted.

(F) Effects of the Invention According to the present invention, the output power of the DC booster circuit is controlled by reacting more sensitively to load fluctuations than in conventional constant current circuits. Even if the impedance does not increase significantly despite the load increase, especially with a low Q load, more power than constant current operation is supplied, sufficient atomization is achieved, and stable atomization is achieved. I can do it. Further, when there is no load applied to the ultrasonic vibration horn, the power supplied to the oscillation circuit is extremely small, which has the advantage of extending battery life and making the vibration horn less likely to be destroyed.

[Brief explanation of the drawing]

FIG. 1 is a circuit connection diagram of an ultrasonic inhaler in which the present invention is implemented, and FIG. 2 is a schematic circuit diagram of an ultrasonic inhaler for explaining the prior art. 1: battery, 2: DC-DC converter, 3: oscillation circuit, 4: ultrasonic vibrator, 5: current detection circuit,
6: Output voltage detection circuit, 7: Control circuit.

Claims (1)

[Claims] 1. A DC power supply, a DC booster circuit that boosts the DC voltage from the DC power supply, an oscillation circuit that operates in response to the output voltage of the DC booster circuit, and An ultrasonic atomizer including an ultrasonic vibrator that atomizes liquid by driving a sonic vibration horn, comprising: a first detection circuit that detects the current of the oscillation circuit; and a first detection circuit that detects the output of the DC booster circuit. An ultrasonic atomization device comprising: two detection circuits; and a control circuit that controls the output of the DC booster circuit according to the detection outputs of the first and second detection circuits.