Digitalized driving method of piezoelectric ceramic transformer based on digital chip

Abstract

The present invention discloses a digitalized driving method for a piezoelectric ceramic transformer based on a digital chip, which includes the steps of: collecting an output voltage rectified by a piezoelectric ceramic transformer; comparing the collected output voltage with a predetermined voltage; adjusting the frequency of a driving signal if there is a difference; and adjusting the step-up ratio of the piezoelectric ceramic transformer according to the frequency of the driving signal, so that the piezoelectric ceramic transformer outputs a predetermined voltage. The present invention changes the step-up ratio of the piezoelectric ceramic transformer by changing the driving frequency in a digital manner, and finally stabilizes the output voltage. The output voltage of the piezoelectric ceramic transformer is stable, has high environmental compatibility, and is highly reliable.

Description

[Technical field]

[0001] The present invention relates to a digitalized driving method, and in particular to a digitalized driving method for a piezoelectric ceramic transformer based on a digital chip. [Background technology]

[0002] When high-voltage negative ions are generated using a piezoelectric ceramic transformer, they have the characteristics of being small in volume, high in operating frequency, and not easily destroyed by high voltage. The analog technology used in conventional piezoelectric ceramic transformer drive technology uses the resonance and output voltage of the piezoelectric ceramic transformer as the signal input of analog negative feedback. The analog piezoelectric ceramic drive method has the disadvantages of unstable output voltage, no oscillation, complex circuit, and large influence from environmental temperature. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE PRESENT DISCLOSURE In order to solve the above problems, the present invention aims to provide a digital driving method for a piezoelectric ceramic transformer based on a digital chip, so as to stabilize the output voltage of the piezoelectric ceramic transformer. [Means for solving the problem]

[0004] In order to achieve the above object, the present invention uses the following technical means: A digital driving method for a piezoelectric ceramic transformer based on a digital chip: collecting a rectified output voltage of the piezoelectric ceramic transformer; comparing the collected output voltage with a predetermined voltage and adjusting a frequency of the drive signal if there is a difference; and adjusting a step-up ratio of the piezoelectric ceramic transformer according to the frequency of the drive signal, so that the piezoelectric ceramic transformer outputs a predetermined voltage.

[0005] In addition, the rectified output voltage of the piezoelectric ceramic transformer is collected after the temperature and / or humidity are changed. comparing the collected output voltage with a predetermined voltage, and adjusting the frequency of the drive signal if there is a difference; The step-up ratio of the piezoelectric ceramic transformer is adjusted according to the frequency of the drive signal, so that the piezoelectric ceramic transformer outputs a predetermined voltage.

[0006] Furthermore, the current of the drive circuit of the piezoelectric ceramic transformer is collected, and when the current of the drive circuit exceeds a predetermined current, the drive circuit is turned off. Effect of the Invention

[0007] Compared with the prior art, the present invention has the following beneficial effects: The present invention changes the boost ratio of the piezoelectric ceramic transformer by changing the driving frequency in a digital manner, and finally stabilizes the output voltage, which makes the output voltage of the piezoelectric ceramic transformer stable, environmentally friendly, and reliable. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a principle diagram of a driving circuit in a digital driving method of a piezoelectric ceramic transformer based on a digital chip. [Diagram 2] FIG. 1 is a circuit diagram of a microcontroller DDS (Direct Digital Synthesis) generator and a reference voltage generation circuit. [Diagram 3] FIG. 2 is a circuit diagram of the temperature and humidity collection module. [Figure 4] FIG. 2 is a circuit diagram of a power supply module. [Diagram 5] This is a diagram of a boost boost circuit, a piezoelectric ceramic boost circuit, a voltage doubler rectifier circuit, a high-voltage sampling circuit, and a feedback voltage signal amplifier circuit. [Figure 6] FIG. 2 is a power supply voltage fluctuation collecting circuit diagram. [Figure 7] FIG. 2 is a clock generation circuit diagram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] For the circuit (negative ion generating circuit) according to the embodiment, refer to Fig. 1 to Fig. 7, and for the detailed description of the circuit, refer to Example 4. In addition, the digitized driving method of the piezoelectric ceramic transformer based on the digital chip includes, but is not limited to, the application to the above circuit. EXAMPLES

[0010] The digital driving method of the piezoelectric ceramic transformer based on the digital chip of this embodiment includes the steps of collecting the output voltage rectified by the piezoelectric ceramic transformer by a high-voltage sampling circuit; Sending the collected output voltage signal to a microcontroller DDS generator (sending the collected output voltage to the microcontroller DDS generator via a voltage signal amplifier circuit), and the microcontroller DDS generator comparing the collected output voltage with a predetermined voltage, and adjusting the frequency of the driving signal if there is a difference; adjusting a step-up ratio of the piezoelectric ceramic transformer according to a frequency of the drive signal, so that the piezoelectric ceramic transformer outputs a predetermined voltage; and collecting the current of the driving circuit of the piezoelectric ceramic transformer by a current sampling circuit, and turning off the driving circuit when the current of the driving circuit exceeds a predetermined current. For example, the driving circuit collects a current signal by a current sampling circuit and transmits it to a microcontroller DDS generator, and when the current of the driving circuit exceeds a predetermined current (for example, 500mA), the driving circuit (for example, a MOS transistor) is forcibly turned off to protect the circuit and ensure safety and reliability. EXAMPLES

[0011] The digital driving method of the piezoelectric ceramic transformer based on the digital chip of this embodiment includes the steps of collecting the rectified output voltage of the piezoelectric ceramic transformer by a high-voltage sampling circuit after the temperature and / or humidity change; Sending the collected output voltage signal to a microcontroller DDS generator (sending the collected output voltage to the microcontroller DDS generator via a voltage signal amplifier circuit), and the microcontroller DDS generator comparing the collected output voltage with a predetermined voltage, and adjusting the frequency of the driving signal if there is a difference; adjusting a step-up ratio of the piezoelectric ceramic transformer according to a frequency of the drive signal, so that the piezoelectric ceramic transformer outputs a predetermined voltage; and collecting the current of the driving circuit of the piezoelectric ceramic transformer by a current sampling circuit, and turning off the driving circuit when the current of the driving circuit exceeds a predetermined current. For example, the driving circuit collects a current signal by a current sampling circuit and transmits it to a microcontroller DDS generator, and when the current exceeds a predetermined current (e.g., 500mA), the driving circuit (MOS transistor) is forcibly turned off to protect the circuit and ensure safety and reliability. EXAMPLES

[0012] The basic means is the same as in the first or second embodiment, and similarly includes the steps of sending the collected output voltage signal to a microcontroller DDS generator (the collected output voltage is sent to the microcontroller DDS generator by a voltage signal amplifier circuit), and the microcontroller DDS generator compares the collected output voltage with a predetermined voltage, and if there is a difference, adjusts the frequency of the driving signal. When adjusting the frequency of the driving signal, the difference is that a DDS frequency generator is created by software using a microcontroller and an external reference crystal oscillator, and a method is used to adjust the frequency of the driving signal. That is, the microcontroller can adjust the output frequency over a wide range by a frequency divider, and can adjust the output frequency precisely by a software DDS, so that the output voltage can be precisely controlled. EXAMPLES

[0013] Referring to FIG. 1, the negative ion generating circuit of this embodiment includes a voltage doubler rectifier circuit 1 which is a diode voltage doubler rectifier part, a high voltage sampling circuit 2 which is a voltage dividing sampling circuit, a negative ion emitting carbon brush 3 which outputs a high voltage and is connected to a carbon brush to emit negative ions, a feedback voltage signal amplifier circuit 4 which is a sampling voltage amplification buffer circuit, a boost circuit 5 which is a driving circuit for a piezoelectric ceramic transformer, a piezoelectric ceramic boost circuit 6 which is a boost energy conversion module for the piezoelectric ceramic transformer, a current sampling circuit 7 which is an overcurrent sampling circuit for the piezoelectric ceramic driving circuit, a microcontroller DDS generator 8, a temperature and humidity collection module 9, a crystal clock source 10, a 5V stabilized power supply 11, and a 12V power supply voltage input circuit 12. The power supply module of the negative ion generating circuit is composed of the 5V stabilized power supply 11 and the 12V power supply voltage input circuit 12, and the power supply module supplies power to the entire negative ion generating circuit.

[0014] The negative ion generating circuit based on temperature and humidity adjustment takes a microcontroller DDS generator 8 as the main control unit. As can be seen from FIG. 1, the microcontroller DDS generator 8 is electrically connected to a power supply module, a crystal clock source 10 and a temperature and humidity collecting module 9, the negative ion emitting carbon brush 3 is electrically connected to the voltage doubler rectifier circuit 1, the voltage doubler rectifier circuit 1 is electrically connected to the piezoelectric ceramic boost circuit 6, the piezoelectric ceramic boost circuit 6 is electrically connected to the boost circuit 5, and the boost circuit 5 is electrically connected to the microcontroller DDS generator 8.

[0015] The control chip U2 used by the main control unit in this embodiment includes, but is not limited to, the STC8A8K64S4A12_LQFP44 chip shown in Figure 2. A reference voltage generating circuit is connected to the above-mentioned microcontroller DDS generator, and as can be seen from Figure 2, the reference voltage generating circuit includes a capacitor C16, a capacitor C13, an inductor L3 and a resistor R18 connected to pin 12 of the control chip U2, the other end of the capacitor C16 and the capacitor C25 is connected to analog ground AGND, the other end of the inductor L3 is connected to capacitor C17 and capacitor C18, the inductor L3 is connected to pin 14 of the control chip U2 and is connected to a 5V power supply, the other ends of the capacitor C17 and the capacitor C18 are connected to ground (GND), and resistors R21 and R22 are connected between the capacitor C17 and the capacitor C13, and the resistors R21 and R22 are connected to ground (EARTH). The other end of resistor R18 is connected to pin 2 of the voltage reference chip CJ431K, pin 1 of the voltage reference chip CJ431K and resistor R18 are connected to pin 11 of the control chip U2, a capacitor C19 is connected between pins 1 and 3 of the voltage reference chip CJ431K, and pin 3 of the voltage reference chip CJ431K is connected to analog ground (AGND).

[0016] A high voltage sampling circuit is connected to the voltage doubler rectifier circuit, and the high voltage sampling circuit is connected to a microcontroller DDS generator by a feedback voltage signal amplifier circuit. A current sampling circuit is connected to the boost circuit, and the current sampling circuit is electrically connected to the microcontroller DDS generator.

[0017] 3, the temperature and humidity collection module includes a control chip U1 (such as AHT20), pins 1 and 6 of the control chip U1 are vacant (no wire), pin 2 of the control chip U1 is connected to a 5V power supply, pins 3 and 4 of the control chip U1 are connected to a microcontroller DDS generator, pin 3 of the control chip U1 is connected to a 5V power supply by resistor R2, pin 4 of the control chip U1 is connected to a 5V power supply by resistor R1, a capacitor C1 is connected between pins 5 and 2 of the control chip U1, and pin 5 of the control chip U1 is connected to ground. After collecting temperature data and humidity data, the temperature and humidity collection module feeds back corresponding signals to the microcontroller DDS generator.

[0018] 2, as can be seen from the figure, a diode D6 is connected to pin 18 of the control chip U2, and the diode D6 is connected to the connector P2 (to prevent the programming current from flowing back into the microcontroller). A resistor R12 is connected to pin 20 of the control chip U2, and the connector CN4 is connected to the resistor R12 (CN4 is shorted to switch to USB program download mode).

[0019] Referring to FIG. 4, the power module uses a DCDC boost circuit, which includes a power management chip U4 (for example, a TLV61046ADBVRU4 chip), a capacitor C10, a capacitor C11, a diode D7, a resistor R13 and a resistor R16. An inductor L2 is connected between pin 1 and pin 6 of the power management chip U4. Pin 6 of the power management chip U4 is connected to the 5V power supply terminal. Pin 2 of the power management chip U4 is connected to ground. Pin 4 of the power management chip U4 is connected between resistors R13 and R16. The other end of resistor R16 is connected to ground, the other end of resistor R13 is connected to the 12V power supply terminal, diode D7 has one end connected to ground and the other end connected to resistor R13, capacitor C11 is connected in parallel to diode D7, capacitor C10 is connected in parallel to capacitor C11, resistor R7 is connected to pin 4 of power management chip U4, the other end of resistor R7 is connected to ground, the 12V power supply terminal is connected to pin 5 of power management chip U4, and capacitor C12, the other end of which is connected to ground, is connected to the 5V power supply terminal.

[0020] 5, as can be seen from the figure, the boost boost circuit 5 includes an inductor L1 and a capacitor C3 connected to a 12V power supply, the other end of the capacitor C3 is connected to a field effect transistor Q1, a capacitor C4 is connected in parallel to the field effect transistor Q1, and the inductor L1 is also connected to the field effect transistor Q1, the boost boost circuit 5 is connected to a piezoelectric ceramic boost circuit 6, the piezoelectric ceramic transformer PZT1 in the piezoelectric ceramic boost circuit 6 is connected to a voltage doubler rectifier circuit 1, the voltage doubler rectifier circuit 1 includes a diode D1 connected to pins 3 and 4 of the piezoelectric ceramic transformer PZT1, a diode D2 connected in parallel to the diode D1, a diode D3 connected in parallel to the diode D2, and a diode D4 connected in parallel to the diode D3, a capacitor C2 is connected between the diode D2 and the diode D3, and a capacitor C5 is connected between the diode D1 and the diode D2. The voltage doubler rectifier circuit 1 is connected to a negative ion emitting carbon brush 3. The high voltage sampling circuit 2 is connected to the voltage doubler rectifier circuit 1, and the high voltage sampling circuit 2 includes a resistor R5 connected between a diode D2 and a diode D3, and the resistor R5 is connected to a resistor R7, a capacitor C7 and a connector CN3 (used for product debugging, so that the microcontroller can omit the op-amp buffer and directly collect and test the negative high voltage). The diode D5 is connected in parallel to the capacitor C7, and one end of the capacitor C7 is connected to ground. The resistor R7 is connected to a resistor R6, and the resistor R6 is connected to a 12V power supply.A feedback voltage signal amplifier circuit 4 is connected to the high voltage sampling circuit 2, and the feedback voltage signal amplifier circuit 4 includes an operational amplifier U5 connected to the high voltage sampling circuit 2, a resistor R15 is connected between pins 3 and 4 of the operational amplifier U5, pin 5 of the operational amplifier U5 is connected to a 12V power supply (one end of a capacitor C15 is connected to the 12V power supply and the other end is connected to ground), pin 2 of the operational amplifier U5 is connected to ground, a resistor R19 is connected to pin 4 of the operational amplifier U5, the resistor R19 is connected to pin 2 of the control chip U2, a resistor R20 is connected in parallel to a capacitor C25, and one end of the capacitor C25 is connected to the resistor R19 and the other end is connected to ground.

[0021] Continuing with reference to FIG. 5, the negative ion generating circuit further includes a current sampling circuit 7, which includes an operational amplifier U3. Pin 1 of the operational amplifier U3 is connected to the boost circuit 5 and the piezoelectric ceramic boost circuit 6. Pin 2 of the operational amplifier U3 is connected to ground. Pin 4 of the operational amplifier U3 is connected to resistor R9 and pin 1 of the control chip U2. Pin 5 of the operational amplifier U3 is connected to the reference voltage generating circuit. A capacitor C9 is connected between pins 5 and 2 of the operational amplifier U3. The resistor R9 is connected to a capacitor C8, the other end of which is connected to ground. A resistor R8 is connected between pins 4 and 3 of the operational amplifier U3. A resistor R10 is connected to the resistor R8. The other end of the resistor R10 is connected to ground. The other end of the resistor R11 connected to pin 1 of the operational amplifier U3 is connected to ground.

[0022] 5, pin 1 of connector P1 connected to field effect transistor Q1 is connected to pin 27 of control chip U2, and pin 3 of connector P1 is connected to pin 23 of control chip U2. An ESD (Electro-Static Discharge) diode is integrated in field effect transistor Q1 to suppress damage to the device due to static electricity.

[0023] Referring to FIG. 6, the power supply voltage fluctuation collection circuit (collects power supply fluctuations of the input voltage) includes a connector CN1 (a connector for retaining a 12V independent power supply), pin 1 of the connector CN1 is connected to ground, pin 1 of the connector CN1 is connected to pin 4 of the control chip U2 by resistor R4, pin 2 of the connector CN1 is connected to a 12V power supply, and pin 2 of the connector CN1 is connected to pin 4 of the control chip U2 by resistor R3.

[0024] Referring to FIG. 7, the clock generation circuit (which generates a reference clock frequency) includes an external crystal oscillator Y1 connected to the control chip U2 (pins 8 and 9 of the control chip U2), with a capacitor C20 connected to pin 1 of the external crystal oscillator Y1 and a capacitor C21 connected to pin 2 of the external crystal oscillator Y1 and a capacitor C21 connected to ground. EXAMPLES

[0025] Table 1 shows test data on the relationship between temperature, humidity and negative ions. [Table 1] JPEG0007660940000002.jpg110167

[0026] The above is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiment, and any technical means that belong to the principle of the present invention are also within the scope of protection of the present invention. Those skilled in the art can make some improvements without departing from the principle of the present invention, and these improvements should also be considered as being within the scope of protection of the present invention.

Claims

1. Step 1: acquiring an output voltage rectified by a piezoelectric ceramic transformer using a high voltage sampling circuit; Step 2: sending the collected output voltage signal to a microcontroller DDS generator, which compares the collected output voltage with a predetermined voltage and adjusts the frequency of the drive signal if there is a difference; and step 3, in which the piezoelectric ceramic transformer outputs a predetermined voltage by adjusting a step-up ratio of the piezoelectric ceramic transformer according to a frequency of the drive signal; In step 1, after temperature and / or humidity changes, a high-voltage sampling circuit collects the rectified output voltage of a piezoelectric ceramic transformer; The present invention relates to a digital driving method for a piezoelectric ceramic transformer based on a digital chip.

2. The digital driving method for a piezoelectric ceramic transformer based on a digital chip as claimed in claim 1, characterized in that a current sampling circuit is used to collect the current of the driving circuit of the piezoelectric ceramic transformer, and when the current exceeds a predetermined current, the driving circuit is turned off.

Images