WO2017020563A1

WO2017020563A1 - High-precision frequency sweeping circuit and frequency sweeping method for ultrasonic atomization piece

Info

Publication number: WO2017020563A1
Application number: PCT/CN2016/072453
Authority: WO
Inventors: 郑瑶; 郭耀波
Original assignee: 深圳市尚进电子科技有限公司
Priority date: 2015-08-06
Filing date: 2016-01-28
Publication date: 2017-02-09
Also published as: CN105049024A; CN105049024B

Abstract

A high-precision frequency sweeping circuit for an ultrasonic atomization piece comprises a booster circuit and a frequency sweeping circuit. The booster circuit is electrically connected to the frequency sweeping circuit. Also provided is a frequency sweeping method based on a frequency sweeping circuit, comprising: inputting a fixed DC voltage and a fixed frequency to a booster circuit; inputting a frequency drive to the frequency sweeping circuit; recording a voltage value of a voltage feedback point of the booster circuit; additionally inputting a frequency to the frequency sweeping circuit; and recording a voltage value of the voltage feedback point of the booster circuit, determining whether the frequency input to the frequency sweeping circuit reaches a rated value, if so, stopping scanning and analyzing the recorded voltage value to find a central frequency of an atomization piece, otherwise, returning to the previous step. The high-precision frequency sweeping circuit for an ultrasonic atomization piece is applicable to frequency measurement and drive of various ultrasonic atomization pieces. Measurement does not need to be carried out on the basis of peaks of pulse signals, and therefore MHz-level frequency scanning can be performed for ultrasonic atomization pieces. It is unnecessary to perform discriminative compensation for different models of atomization pieces, and any ultrasonic atomization piece can be driven.

Description

Ultrasonic atomizing sheet high-precision frequency sweeping circuit and frequency sweeping method

Technical field

The invention relates to the field of atomizing sheets, in particular to a high-precision frequency sweeping circuit and a frequency sweeping method for an ultrasonic atomizing sheet.

Background technique

Ultrasonic nebulizer utilizes electronic high frequency oscillation (oscillation frequency is 1.7MHz or 2.4MHz Exceeding the human hearing range, the electronic oscillation does not harm the human body and the animal) Through the high-frequency resonance of the ceramic atomized sheet, the liquid water molecular structure is broken up to produce a natural and elegant water mist, and then the mist is blown from the bottom to the outlet through a small fan, so that the air is humid and accompanied by abundant negative oxygen ions, Clean air, improve health and create a comfortable environment.

Due to the uneven manufacturing technology, different manufacturers and batches of ultrasonic atomizers have different resonance frequencies at the center. When driving it, if the driving frequency is not its central resonance frequency, it will cause atomization. The conversion efficiency of the sheet is low and the amount of atomization is extremely small.

Summary of the invention

The invention provides a high-precision frequency sweeping circuit and a frequency sweeping method for an ultrasonic atomizing sheet, which can determine the central resonant frequency of the atomizing sheet, thereby determining the driving frequency for driving the atomizing sheet, thereby improving the transducing efficiency of the atomizing sheet and Atomization amount.

The technical solution of the present invention is realized as follows: a high-precision frequency sweeping circuit of an ultrasonic atomizing sheet, comprising a boosting circuit and a frequency sweeping circuit, wherein the boosting circuit is electrically connected with the frequency sweeping circuit, and the boosting circuit comprises a fourth capacitor and a diode a second inductor, a second transistor, a first resistor and a second resistor; the fourth capacitor and the diode are both connected in parallel with the DC power source, and the anode pin of the diode is connected to the anode of the DC power source and connected to one end of the second inductor The other end of the second inductor is connected to the drain of the second transistor and the first resistor. The first resistor and the second resistor are connected in series, and the source of the second transistor and the second resistor are connected to the cathode of the DC power source.

Further, the frequency sweeping circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a first transistor, and an atomizing sheet; the second capacitor is connected in parallel with the first resistor and the second resistor, and the second capacitor The positive pole is connected to the first inductor, and the other end of the first inductor is connected to the drain of the first triode and the first capacitor; the first capacitor, the atomizing sheet and the third capacitor are connected in series, and the third capacitor is respectively connected with the second capacitor and the second capacitor The source of a triode is connected. The gate of the first transistor is a frequency receiving point whose frequency duty ratio is greater than or equal to 50%.

Further, the series connection point of the first resistor and the second resistor is a voltage feedback point, and the voltage feedback point is used to record the change of the voltage value when the frequency is swept, and the voltage feedback point is used to adjust the second triode during normal operation. The input frequency of the gate, the duty cycle of the input frequency is 20%-60%.

Further, the first triode and the second triode are both N-channel FETs.

The invention provides a high-precision frequency sweeping method for an ultrasonic atomizing sheet, which can be frequency-swept according to an ultrasonic atomizing sheet high-precision frequency sweeping circuit, wherein the frequency sweeping process comprises the following steps:

(1) inputting a fixed DC voltage and a fixed frequency to the booster circuit during frequency sweeping;

(2) inputting a frequency drive to the frequency sweeping circuit;

(3) recording the voltage value of the voltage feedback point of the booster circuit;

(4) increasing the frequency drive input to the frequency sweep circuit;

(5 Recording the voltage value of the voltage feedback point of the booster circuit, and determining whether the frequency input to the frequency sweep circuit reaches the rated value. If yes, end the scan and analyze the recorded voltage value to find the center frequency of the atomizer, otherwise enter the step ( 4 ).

Further, the specificity of step (1) is:

(101) connecting the booster circuit to a fixed DC power source;

(102) When sweeping, input a fixed frequency to the gate of the second transistor, and the duty ratio of the fixed frequency ranges from 20% to 60%.

Further, the step (2) specifically drives the 90KHz frequency input to the gate of the first transistor. Frequency driven duty cycle is greater than or equal to 50%.

Further, step (4) may specifically increase the input frequency of the frequency sweep circuit by 1 KHz.

The beneficial effects of the invention are:

1. Improved the accuracy of the ultrasonic atomizing chip circuit sweeping frequency, and can be widely applied to the measurement and driving of various ultrasonic atomizing chip frequencies;

2, because the highest point measurement based on the pulse signal is not required, it is possible to perform the ultrasonic atomizing chip frequency scanning at the megahertz level;

3, there is no need to distinguish the different types of atomizers, so it can drive any ultrasonic atomizer in the true sense.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a circuit diagram of a high-precision frequency sweeping circuit of an ultrasonic atomizing sheet in the prior art;

2 is a flow chart of a high-precision frequency sweeping method of an ultrasonic atomizing sheet in the prior art;

3 is a circuit diagram of a high-precision frequency sweeping circuit of an ultrasonic atomizing sheet according to the present invention;

4 is a flow chart of a method for high-precision frequency sweeping of an ultrasonic atomizing sheet according to the present invention;

Figure 5 is a graph showing the voltage variation of the voltage feedback point measured by the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in Figure 1, W1 in the figure Indicates the ultrasonic atomizing sheet, because the characteristics of the ultrasonic atomizing sheet can be expressed by a capacitor. The ultrasonic atomizing sheet is equivalent to a capacitor at a specific frequency. In the figure, C1 and C3 are in the circuit. In the case of an AC signal, it is equivalent to a resistor. There are two functions in this circuit. One is to prevent the DC voltage from being applied to both ends of the atomizer, and the protection atomizer will not burn. The second is equivalent to 2 in the AC circuit. The resistance can be adjusted by adjusting the size of the atomizer. Input a frequency of 90-130KHz to the gate of the transistor in the circuit, and start at 1KHz from 90KHz For the unit to increment, the circuit works as follows:

1. In the first cycle, the Q1 MOS transistor is turned on, the current passes through L1, Q1, and RS1, and at this time, L1 starts to store energy;

2. In the second cycle, the Q1 MOS tube is turned off, the energy stored in L1 is released, the current flows into W1, and W1 begins to store energy;

3. The third cycle, Q1 The MOS transistor is turned on, the current passes through L1, Q1, and RS1, and at this time, L1 starts to store energy, and the energy stored in W1 starts to reverse through Q1 and RS1, and the energy is released. At this time, a higher than normal switch is generated at the FB position of the resistor RS1. The higher voltage peak, using the voltage division principle of the resistor, the voltage peak at the FB position is generated by the current common to the L1 energy storage and the W1 release energy;

4. In the fourth cycle and the second cycle, the Q1 MOS transistor is turned off, the energy stored in L1 is released, and the current flows into W1, and W1 starts to store energy again.

figure 2 For the flow chart of the high-precision frequency sweeping method of the ultrasonic atomizing sheet in the prior art, the figure shows a complete working cycle, in which we continuously adjust the PWM The frequency, the ultrasonic atomizing sheet has a characteristic that when the atomizing sheet is at the center frequency, it stores the maximum energy, so when we adjust the PWM frequency, it will be at the center point of the atomizing sheet. The voltage is at the highest point. Using this principle, the PWM frequency at the highest point of the FB is the center frequency of the atomizer. The atomizing sheet is then driven at this frequency.

However, the frequency of the maximum point of energy storage of the atomized sheet produced by some manufacturers is not the center frequency of the atomizing sheet, and the deviation is about 2-5KHz. Left and right, therefore, it is necessary to perform frequency compensation for products from different manufacturers, which results in the inability to perform large-scale trial installation, and at the same time, it can only be at 200KHz due to the speed of collecting FB point voltage. Scanning within, it is not possible to perform automatic sweeping of the atomizer at 2MHz frequency.

In view of the shortcomings of the prior art, the present invention improves the circuit, as shown in FIG. 3, since the driving voltage of the ultrasonic atomizing sheet needs to reach 60V. Above, the actual supply voltage is generally only 5-12V. If the circuit of the 'DRIVE' part is used directly, it can form a booster circuit, but the driving voltage is far less than 60V. . Therefore, high voltage driving is generally used, so the input voltage of the 'HIDC-VIN' part of the original method is usually about 24V, and this voltage is achieved by the boosting IC; D1 in the figure, L2 and Q2 form a complete DC-DC boost circuit, which only needs to be boosted by the frequency of 100KHz for the 'DC-PWM' port, and R1 and R2. The partial voltage feedback constitutes a feedback circuit that adjusts the 'DC-PWM' by feedback to achieve voltage stability.

When the input voltage is 5V, the booster circuit gets a voltage point of 20V, at this time 'DRIVE 'The circuit part starts to sweep. When the frequency of the sweep slowly starts to approach the center point of the frequency of the atomizer, the power consumption of the 'DRIVE' part of the circuit starts to increase, in order to keep the DC-DC boost stable' DC-PWM 'gradually increase the duty cycle until the maximum duty cycle is 60% (DC-DC boost maximum duty cycle is generally only 60%, see the relevant DC-DC at home and abroad for details) The data of the boost control circuit); when the frequency of the atomization chip starts to approach the center frequency, the power of the boost circuit portion has been increased to the maximum, that is, the boost circuit is already in saturation, so when the frequency is closer to the fog When the center point of the film is not enough due to the power of the booster circuit, ' C2 'The voltage of the positive pole of the capacitor begins to decrease, and the voltage signal fed back by 'DC-FB' also begins to decrease until the frequency reaches the center of the frequency of the atomizer. 'DC-FB The voltage fed back is already at the lowest point, and then deviates from the center frequency of the atomizer again as the frequency of the sweep progresses, and the voltage at 'DC-FB' rises again.

Based on the above findings, as shown in Figure 3 As shown, the present invention provides a practical and low-cost ultrasonic atomizing sheet high-precision frequency sweeping circuit, including a boosting circuit and a frequency sweeping circuit. The boosting circuit is electrically connected to the frequency sweeping circuit, and the boosting circuit includes a fourth a capacitor, a diode, a second inductor, a second transistor, a first resistor, and a second resistor; the fourth capacitor and the diode are both connected in parallel with the DC power source, and the anode pin of the diode is connected to the anode of the DC power source, and the second inductor One end of the second inductor is connected to the drain of the second transistor and the first resistor, the first resistor and the second resistor are connected in series, and the source of the second transistor and the second resistor are connected to the DC power source. negative electrode. The frequency sweeping circuit includes a first capacitor, a second capacitor, a third capacitor, a first inductor, a first transistor, and an atomizing sheet; the second capacitor is connected in parallel with the first resistor and the second resistor, and the anode of the second capacitor is connected An inductor, the other end of the first inductor is connected to the drain of the first transistor and the first capacitor; the first capacitor, the atomizer and the third capacitor are connected in series, and the third capacitor is respectively connected to the second capacitor and the first three poles The source of the tube is connected. The gate of the first transistor is a frequency receiving point whose frequency duty ratio is greater than or equal to 50% . The series connection point of the first resistor and the second resistor is a voltage feedback point, and the voltage feedback point is used to record the change of the voltage value during the frequency sweep, and the voltage feedback point is used to adjust the gate of the second triode during normal operation. Input frequency, the duty cycle of the input frequency is 20%-60%. The first triode and the second triode are both N-channel FETs. Known that the input voltage is 5V, in 'DC-PWM The power supplied by the boost circuit is constant when the duty cycle is constant and the frequency is constant. At this time, the power consumption of the 'DRIVE' circuit is higher. The lower the voltage fed back at the DC-FB' is when ' DRIVE 'When the circuit starts to sweep, we constantly monitor the voltage at 'DC-FB'. When the voltage at 'DC-FB' is at the lowest point, the corresponding frequency is the center frequency of the atomizer.

Figure 4 As shown, an ultrasonic atomizing sheet high-precision frequency sweeping method is based on an ultrasonic atomizing sheet high-precision frequency sweeping circuit for sweeping, and the frequency sweeping process comprises the following steps:

(1) inputting a fixed DC voltage and a fixed frequency to the boosting circuit;

The specificity of step (1) is:

(101) connecting the booster circuit to a fixed DC power source; the voltage value of the DC power source can be set to 5V in this embodiment;

(102) input a fixed frequency to the gate of the second transistor, such as 100KHz, step (1) The fixed duty cycle of the input frequency of the medium boost circuit is 20%-60%. The duty cycle is the ratio of the time that the high level takes up in one cycle, such as the square wave duty cycle is 50% and the duty cycle is 0.5. , indicating that the positive level takes 0.5 cycles.

(2) input a 90KHz frequency drive to the frequency sweep circuit; step (2) specifically inputs 90KHz to the gate of the first transistor Frequency drive, in different embodiments, the input frequency is different, and the specific can be set according to requirements. The frequency driven duty cycle is greater than or equal to 50%.

(4) increasing the input frequency to the frequency sweeping circuit; step (4) specifically increasing the input frequency of the frequency sweeping circuit by 1 KHz; setting the added value as 1KHz, which guarantees accuracy and precision.

(5 Recording the voltage value of the voltage feedback point of the booster circuit, and determining whether the frequency input to the frequency sweep circuit reaches the rated value, where the rated value is set to 130 KHz in this embodiment. When the voltage value reaches the lowest point, the corresponding frequency input to the frequency sweeping circuit is the center frequency of the atomizing sheet; if yes, the scanning ends, otherwise the step (4) is entered.

By integrating DC-DC boost function and DC-DC The boost mode has been changed so that we can measure the power to measure the frequency of the ultrasonic atomizer without increasing the cost of the circuit, as opposed to the external boost IC. Controlled circuits can also save some of the cost.

As shown in Figure 5, it is the voltage change curve of the measured voltage feedback point DC-FB; the unit of the vertical axis of the graph is V.

The ultrasonic atomization sheet used in the above example has a resonance frequency of 115 kHz. The following is a detailed description of the example:

In the example, the DC input voltage is 5.0 volts.

In the example, the partial pressure ratio of ' R1 '' R2 ' is 10 : 1

In the example, the 'DC-PWM' input has a frequency of 100KHz and a duty cycle of 45%.

In the example, the 'PWM' input frequency is 90KHz and is accumulated in 1KHz with a duty cycle of 50%.

The Y axis is the voltage value collected at 'DC-FB' in the chart, the unit is V;

The X axis in the graph is the corresponding frequency input to 'PWM'.

According to the actual test, we can get from the chart only when the 'PWM' frequency is closest to the resonant frequency of the ultrasonic atomizer. 'The overall power consumption of the circuit is the largest. In this example, the power supplied by the 'DC-DC' circuit is constant, so as the power consumption of the 'DRIVE' circuit increases' DC-FB The voltage at 'will decrease.

The invention improves the precision of the frequency sweeping of the ultrasonic atomizing sheet circuit, and can be widely applied to the measurement and driving of various ultrasonic atomizing sheet frequencies; since the highest point measurement based on the pulse signal is not required, the megahertz level can be performed. Ultrasonic atomization film frequency scanning; no need to distinguish the different types of atomization film, so it can drive any ultrasonic atomization piece in a real sense.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are within the spirit and scope of the present invention, should be included in the scope of the present invention. within.

Claims

An ultrasonic atomizing sheet high-precision frequency sweeping circuit comprises a boosting circuit and a frequency sweeping circuit, wherein the boosting circuit is electrically connected to the frequency sweeping circuit, and the boosting circuit comprises a fourth capacitor and a diode a second inductor, a second transistor, a first resistor, and a second resistor; the fourth capacitor and the diode are both connected in parallel with a DC power source, and a cathode pin of the diode is connected to a positive pole of the DC power source, and One end of the second inductor is connected, the other end of the second inductor is connected to the drain of the second transistor and the first resistor, the first resistor and the second resistor are connected in series, and the second transistor The source and the second resistor are connected to the negative pole of the DC power source.
The ultrasonic atomizing sheet high-precision frequency sweeping circuit according to claim 1, wherein the frequency sweeping circuit comprises a first capacitor, a second capacitor, a third capacitor, a first inductor, and a first triode And the atomizing sheet; the second capacitor is connected in parallel with the first resistor and the second resistor, the anode of the second capacitor is connected to the first inductor, and the other end of the first inductor is connected to the drain of the first transistor and a first capacitor; the first capacitor, the atomizing sheet and the third capacitor are connected in series, and the third capacitor is respectively connected to the second capacitor and a source of the first transistor.
The ultrasonic atomizing sheet high-precision frequency sweeping circuit according to claim 1, wherein the series connection point of the first resistor and the second resistor is a voltage feedback point, and the voltage feedback point is in a frequency sweeping It is used to record the change of the voltage value, which is used to adjust the input frequency of the gate of the second transistor during normal operation, and the duty ratio of the input frequency is 20%-60%.
The ultrasonic atomizing sheet high-precision frequency sweeping circuit according to claim 2, wherein the gate of the first transistor is a frequency receiving point, and the frequency duty ratio is greater than or equal to 50%.
The ultrasonic atomizing sheet high-precision frequency sweeping circuit according to any one of claims 1 to 4, wherein the first triode and the second three-stage tube are both N-channel field effect transistors .
A high-precision frequency sweeping method for an ultrasonic atomizing sheet, which can perform frequency sweeping according to an ultrasonic atomizing sheet high-precision frequency sweeping circuit according to any one of claims 1 to 4, wherein the frequency sweeping process comprises the following steps :

(1) input a fixed DC voltage and a fixed frequency to the booster circuit during frequency sweeping;

(2) input a frequency drive to the frequency sweep circuit;

(3) recording the voltage value of the voltage feedback point of the boosting circuit;

(4) increasing the frequency drive input to the frequency sweep circuit;
The method of high-precision frequency sweeping of an ultrasonic atomizing sheet according to claim 6, wherein the step (1) is as follows:

(101) connecting the booster circuit to a fixed DC power source;

(102) A fixed frequency is input to the gate of the second transistor when sweeping, and the duty ratio of the fixed frequency ranges from 20% to 60%.
The method of claim 6, wherein the step (2) is specifically to input a 90 KHz frequency drive to the gate of the first transistor.
A high-precision frequency sweeping method for an ultrasonic atomizing sheet according to claim 8, wherein: The frequency driven duty cycle is greater than or equal to 50%.
The method of high-precision frequency sweeping of an ultrasonic atomizing sheet according to claim 6, wherein the step (4) is specifically increasing the input frequency of the frequency sweeping circuit by 1 kHz.