KR100891483B1 - Piezoelectric element for small size of high voltage power driving circuit - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element driving circuit, and in particular, to provide a small high voltage power driving circuit for a piezoelectric element capable of generating a high voltage from a small and low voltage power source.

The present invention for achieving the above object, a radio wave controller for generating radio waves; A receiving module unit for receiving a radio wave signal from the radio wave controller using an RF radio transceiver, a power module unit for providing a driving voltage using a battery, and a pulse width modulation (PWM) control signal using a radio wave signal. It generates a microprocessor module unit, a buffer module unit for buffering electrical problems that may occur when the PWM control signal is transmitted from the microprocessor module unit to the full bridge drive module unit, and the PWM control signal to drive the piezoelectric element A piezo driver including a full bridge driving module unit converting the PWM signal and a high voltage switching driving module unit outputting a high voltage PWM using a PWM signal and a DC voltage; And a piezoelectric element actuator 300 for generating displacement by the high voltage PWM.

Piezoelectric element, PWM signal, Piezo driver, High voltage drive

Description

Small high voltage power driving circuit for piezoelectric element {PIEZOELECTRIC ELEMENT FOR SMALL SIZE OF HIGH VOLTAGE POWER DRIVING CIRCUIT}

1 is a block diagram showing a small high voltage power driving circuit for a piezoelectric element according to an embodiment of the present invention,

2 is a detailed configuration diagram illustrating a power module unit according to an embodiment of the present invention;

3 is a diagram illustrating a signal period received through an RF wireless transceiver according to an embodiment of the present invention;

4 is a detailed flowchart illustrating a voltage regulation module unit according to an embodiment of the present invention;

FIG. 5 is a detailed circuit diagram illustrating a full bridge configured only of N channels according to an embodiment of the present invention. FIG.

** Description of symbols for the main parts of the drawing **

100: radio wave controller 200: piezo drive unit

210: receiving module unit 220: power module unit

221: DC / DC conversion module unit 222: voltage control module unit

223: high voltage conversion module unit 230: microprocessor module unit

240: buffer module unit 250: full bridge drive module unit

260: high voltage switching drive module 300: piezoelectric element actuator

B: battery

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element driving circuit, and more particularly, to a small high voltage power driving circuit for a piezoelectric element capable of generating a high voltage from a small and low voltage power source.

Recently, due to the rapid development of not only home electronics, but also industrial electronics, quality according to performance is the top priority, but accordingly, it is a trend that requires miniaturization in appearance.

Conventional electric motors have excellent performance, but they have heavy weights, are difficult to miniaturize, and become smaller and less efficient. However, the piezoelectric element has an advantage that the device itself can act as an actuator, so the size can be made very small, the actuator can be directly included in the structure, and the weight is light. However, since a high voltage is required to drive the piezoelectric element, the volume of the power driving circuit increases, thereby automatically increasing the volume of the entire piezoelectric element driving system including the piezoelectric element. Cost increases with volume.

On the other hand, if the focus is placed on reducing the volume of electronic devices in accordance with the miniaturization trend, the electronic devices cannot be driven smoothly, and thus consumers do not achieve the desired effect.

That is, the electronic device is driven through the power consumption, and this power consumption is directly related to the energy efficiency of the electric device, and the energy efficiency is one factor indicating the quality of the electric device.

Accordingly, while the power supply is possible to smoothly drive the electronic devices, there is a problem that can be miniaturized according to the recent trend.

Piezoelectric elements, also called piezoelectric elements, have the advantage of being small, lightweight, and able to produce large forces effectively, limiting the range of application of the device due to the size and cost of the driving circuit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a small high voltage power driving circuit for a piezoelectric element capable of generating a high voltage from a small and low voltage power source.

Another object of the present invention is to provide a power source using a battery.

In addition, another object of the present invention is to connect a resistor in series to prevent the instantaneous large current is transmitted to the piezoelectric element to prevent the circuit from becoming unstable.

A small high voltage power drive circuit for a piezoelectric element of the present invention for achieving the above object, comprising: a radio wave controller (100) for generating radio waves; A reception module unit 210 for receiving a radio wave signal from the radio wave controller using an RF radio transceiver, a power module unit 220 for providing a driving voltage using a battery B provided separately, and the radio unit Microprocessor module unit 230 for generating a PWM (Pulse Width Modulation) control signal using a radio wave signal, and electrical that may occur when the PWM control signal is transmitted from the microprocessor module unit to the full bridge driving module unit The buffer module 240 buffers the problem, the full bridge driving module 250 converting the PWM control signal into a PWM signal to drive the piezoelectric element, and the high voltage PWM using the PWM signal and the DC voltage. Piezo driver 200 including a high voltage switching drive module unit 260 for outputting; And a piezoelectric element actuator 300 generating a displacement by the high voltage PWM.

Preferably, the power module unit 220 includes: a DC / DC conversion module unit 221 which receives a DC voltage from the battery and converts it into electric power having another DC voltage or another polarity; A voltage regulation module unit 222 which receives the DC voltage and adjusts the voltage accordingly; And a high voltage conversion module unit 223 which receives the DC voltage and converts the DC voltage into a high voltage. Characterized in that it comprises a.

Also preferably, the buffer module 240 buffers an electric problem so that the piezoelectric drive unit is not affected by any one of attenuating external noise, performing impedance matching, or driving a capacitive load. Characterized in that.

Preferably, the piezo driver 200 is configured to connect a resistor in series to prevent a momentary large current from being transmitted to the piezoelectric element, thereby preventing the circuit from becoming unstable.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. In the meantime, when it is determined that the detailed description of the known functions and configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, it should be noted that the detailed description is omitted.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

A small high voltage power driving circuit for a piezoelectric element according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

1 is a block diagram showing a small high voltage power driving circuit for a piezoelectric element according to an embodiment of the present invention, Figure 2 is a detailed block diagram showing a power module unit according to an embodiment of the present invention, Figure 3 is 4 is a view illustrating a signal cycle received through an RF wireless transceiver according to an embodiment of the present invention, FIG. 4 is a detailed flowchart illustrating a voltage regulation module unit according to an embodiment of the present invention, and FIG. 5 is an embodiment of the present invention. The detailed circuit diagram which shows the full bridge of the form which consists only of N channels according to this.

First, as shown in FIG. 1, a small high voltage power driving circuit for a piezoelectric element includes a radio wave controller 100 for generating radio waves, a piezo driver 200 for providing electric power for driving a small piezoelectric element, The piezoelectric element actuator 300 includes a configuration.

Specifically, referring to the piezo driver 200 with reference to FIG. 2, the reception module unit 210, the power module unit 220, the microprocessor module unit 230, the buffer module unit 240, and the full bridge driving module unit ( 250) and a high voltage switching drive module unit 260.

First, the reception module unit 210 receives a radio wave signal from the radio wave controller 100. As shown in FIG. 3, the minimum ON time is 1.1 ms and the maximum ON state is shown through the RF radio transceiver. Receive a radio wave signal with a time of 1.9 ms.

In this embodiment, although the radio wave signal of 72 MHz is set to be received, the present invention is not limited thereto.

On the other hand, the power module unit 220 performs a function of providing a driving voltage using a battery (B) provided separately, DC / DC conversion module unit 221, voltage control module unit 222 and high voltage conversion The module unit 223 is included.

The DC / DC conversion module unit 221 receives a DC voltage from the battery B separately provided and converts the DC voltage into another DC voltage. Specifically, the first DC / DC conversion module 2211 converts the input DC voltage of 7.4 V into power of another voltage or polarity of 12 V, and the input DC voltage of 7.4 V into power of other voltage or polarity of 3.3 V. It includes a second DC / DC conversion module 2212 to convert to.

Here, the converted DC voltage of 12V is transmitted to the voltage regulation module unit 222 and the full bridge driving module unit 250 to be described later.

In the present embodiment, the battery (B) is 7.4V / 1200mA of Skyholic's Sky-Holic Li-Poly Battery, which has an energy capacity by weight compared to Ni-CD or Ni-MH for RC. Although it is set to be 3 to 5 times higher than a conventional lithium polymer battery capable of discharging 10C (> 92%) or more, the present invention is not limited thereto.

The voltage adjusting module unit 222 receives a DC voltage from the first DC / DC conversion module 2211 and performs a function of adjusting the voltage accordingly. That is, the DC voltage of 12V is adjusted to the DC voltage of 5V.

For reference, referring to FIG. 4, the voltage regulation module unit 222 includes an input pin 1, a ground pin 5, and an output pin 3, and inputs a DC voltage of 12 V through the input pin 1. After receiving, outputs a DC voltage of 5V through the output pin (3). At this time, an output capacitor connected to the output pin 3 is provided with a bypass capacitor C35 to prevent internal oscillation when the power supply is unstable, and to improve the transient response of the stable output voltage. Capacitor C36 is provided.

The high voltage conversion module unit 223 receives a DC voltage from the second DC / DC conversion module 2212 and converts the DC voltage into a high voltage.

In other words, since the output voltage varies depending on the input voltage, when a DC voltage of 3.3V is input, a DC voltage of 200V can be output.

For reference, in driving a piezoelectric element, a DC voltage of about + 200V is required.

Intelligent devices have the advantage of requiring large currents for momentary large movements, but requiring very little current once they reach a steady state. Therefore, charge accumulators and capacitors can be used to construct the voltage source needed to drive intelligent devices.

Meanwhile, the microprocessor module unit 230 generates a pulse width modulation (PWM) control signal using a radio wave signal received through the receiving module unit 210.

In the present exemplary embodiment, the ATMEGA 128 of the dual 8BIT PWM channel is set to perform a function of generating a PWM control signal using the radio wave signal, but the present invention is not limited thereto.

Timer 3 configured in the microprocessor module unit 230 is used to generate the PWM control signal. Specifically, the reference clock of Timer 3 is set to use a 2 MHz clock by dividing the CPU clock, and when Timer 3 keeps counting up, the input signal goes from low to high level. The high level time of the pulse is obtained by measuring the time and again measuring the time as the input signal moves from the high level to the low level.

For example, a pulse clock according to 1.1 ms of minimum value is pulse clocks = (2E6) x (1.1E-3) = (2.2E3), and a pulse clock according to 1.9 ms of maximum value is pulse clocks = (2E6) × (1.9E-3) = (3.8E3).

For reference, the microprocessor module unit 230 has 0 to 255 according to the resolution of 8 bits, thereby outputting the minimum duty ratio when 0, and outputting the maximum duty ratio when 255.

That is, when the counter's pulse clock is 2.2E3, the minimum duty ratio 0 is output, and when the counter clock pulse is 3.8E3, the maximum duty ratio 255 is output.

Thus, if linear PWM = pulse_clocks / 6.3-349, the PWM value represents 0 to 255 when the pulse clock moves between 2.2E3 to 3.8E3. If you enter 0.2 at 0% duty ratio, it moves to 0. If you enter 254.17 at 100% duty ratio, it moves to 254.

In summary, when the signal rises, the time is read and the interrupt is read, and the interrupt is read. At the same time, it is timed again to interrupt the falling edge of the signal. Then, the falling edge of the signal is interrupted again. Subtracting the previously measured time value from the measured time value becomes the time occupied by the pulse width. Since the counter keeps counting up, overflow may occur. In this case, subtract the rising edge time from the maximum value the counter can have and add the measured time to the rising edge. The check for overflow is when the falling edge time is less than the rising edge time.

The buffer module 240 buffers an electrical problem that may occur when the PWM control signal received from the microprocessor module 230 is transmitted to the full bridge driving module 250.

That is, the buffer module unit 240 buffers electrical problems so that the piezo driver 200 is not affected when attenuating external noise, performing impedance matching, or driving a capacitive load.

At this time, the buffer module 240 receives a DC voltage of 5V from the first DC / DC conversion module 2211 and uses it as driving power.

Next, the full bridge driving module 250 converts the received PWM control signal into a PWM signal so as to drive the piezoelectric element.

Specifically, the full bridge driving module unit 250 drives a MOSFET and suppresses an oscillator (not shown) and an external operation function that can be internally adjusted with a low voltage level shift to drive the full bridge driving module unit 250. can do.

For reference, as shown in FIG. 5, four switching mode power supply metal oxide semiconductor field effect transistors (SMPS MOSFETs) are grouped diagonally with each other to be on the same group. When the on / off operation is performed evenly, the output is maintained at an average zero voltage.

In other words, when a large number of on operations are performed, a positive voltage is supplied, and when a large number of off operations are performed, a negative voltage is supplied on average.

In other words, the PWM driving circuit can change direction using a single power supply, which has the same effect as using two positive / negative power supplies.

On the other hand, by connecting the resistor in series to prevent the momentary large current is transmitted to the piezoelectric element to prevent the circuit from becoming unstable.

At this time, the MOSFET is a switching output circuit, consisting of only four N-channel.

Specifically, in the full bridge circuit, the load is connected between the output terminals of the half bridge circuit. When Tr2 and Tr3 are turned on, and Tr4 and Tr1 are turned off, current flows in the load in the IL + direction.

Conversely, when Tr4 and Tr1 are on and Tr2 and Tr3 are off, current flows in the IL- direction to the load.

In this way, the pair of switches Tr2, Tr3 or Tr4, Tr1 alternately conducts and operates repeatedly.

Therefore, since the voltage applied to both ends of the load is twice as large as the case where the load is driven in the half bridge circuit, the maximum power supplied to the load is four times that of the half bridge circuit. That is, the power supply voltage can be effectively used through the full bridge circuit.

The high voltage conversion driving module unit 260 receives the PWM signal capable of driving the piezoelectric element from the full bridge driving module unit 250 and then uses the DC voltage received from the second DC / DC conversion module 2212. It outputs high voltage PWM.

At this time, the high voltage conversion driving module unit 260 may output a DC voltage of up to + 250V using a DC voltage of 3.3V.

For reference, the analog input signal is amplified to high voltage by using like general operational amplifier. This op amp must be gained at least 10 to stabilize, and a compensation capacitor of at least 10 pF must be connected. If the output voltage is too high, it may cause damage to the piezo device, so a zener diode is connected to prevent instantaneous overvoltage, and the free wheeling diode is also connected to prevent the device from being destroyed by an inductive load.

Finally, the piezoelectric element actuator 300 performs a function of generating displacement by the high voltage PWM.

In this embodiment, the driving voltage is set to be driven using a DC voltage of approximately high voltage PWM ± 200V, but the present invention is not limited thereto.

According to the present invention described above, it can be manufactured in a form having a miniaturization and light weight through a small high voltage power drive circuit for a piezoelectric element capable of generating a high voltage with a small size and low power. For example, it can be manufactured in a very small and light form with a weight of 30g and a size of 5 * 10cm, and can be applied to various fields.

Therefore, PWM type digital input, wireless RC controller input or analog input can be directly received so that the user can give the necessary high voltage generation command by using microprocessor or RC controller and analog signal generator or command. Easy to do

In addition, since the power source can use a small low voltage external power source such as an external battery, the power source can be easily included in a high voltage system.

As described above and described with reference to a preferred embodiment for illustrating the technical idea of the present invention, the present invention is not limited to the configuration and operation as shown and described as described above, it is a deviation from the scope of the technical idea It will be understood by those skilled in the art that many modifications and variations can be made to the invention without departing from the scope of the invention. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (6)

In a small high voltage power drive circuit for a piezoelectric element, A radio wave controller 100 for generating radio waves; A piezo driver 200 which provides electric power for driving the small piezoelectric element; And A piezoelectric element actuator 300 generating a displacement by the high voltage PWM; Including but not limited to: The piezo drive unit 200, A reception module unit 210 for receiving a radio wave signal from the radio wave controller using an RF radio transceiver, a power module unit 220 for providing a driving voltage using a battery B provided separately, and the radio unit Microprocessor module unit 230 for generating a PWM (Pulse Width Modulation) control signal using a radio wave signal, and a full bridge driving module unit 250 for converting the PWM control signal into a PWM signal to drive a piezoelectric element A high voltage switching driving module unit 260 for outputting a high voltage PWM using a PWM signal and a DC voltage; Small high voltage power drive circuit for a piezoelectric element comprising a. delete The method according to claim 1, The power module unit 220, A DC / DC conversion module unit 221 which receives a DC voltage from the battery and converts the DC voltage into power of another DC voltage or another polarity; A voltage regulation module unit 222 which receives the DC voltage and adjusts the voltage accordingly; And A high voltage conversion module unit 223 which receives the DC voltage and converts the DC voltage into a high voltage; Small high voltage power drive circuit for a piezoelectric element comprising a. The method according to claim 1, A buffer module unit 240 for buffering an electrical problem that may occur when the PWM control signal is transmitted from the microprocessor module unit to the full bridge driving module unit; Small high voltage power drive circuit for a piezoelectric element comprising a. The method according to claim 4, The buffer module unit 240, Small high-voltage power for piezoelectric elements characterized in that the electrical problem is buffered so that the piezo driver is not affected by any of attenuating external noise, performing impedance matching, or driving a capacitive load. Driving circuit. The method according to claim 1, The piezo drive unit 200, A small high voltage power drive circuit for a piezoelectric element, characterized in that the resistor is connected in series to prevent a momentary large current from being transmitted to the piezoelectric element, thereby preventing the circuit from becoming unstable.

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