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DESCRIPTION JP2012022537

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DESCRIPTION JP2012022537
PROBLEM TO BE SOLVED: To provide a piezoelectric actuator drive device for vibrating a
piezoelectric actuator, which is a piezoelectric device capable of optimizing electric power and
drive amplifier characteristics while corresponding to three functions of a haptic feedback
function, a receiver function for outputting voice, and a speaker function for generating music.
An actuator drive device is provided. SOLUTION: A piezoelectric actuator drive device 6
comprising a piezoelectric actuator drive amplifier unit A0 and a piezoelectric actuator drive
device power supply unit 100, which controls a power supply voltage VPP of the piezoelectric
actuator drive amplifier unit A0 and an amplifier bias voltage In the control signal 1) and the
signal (control signal 2) for controlling the driving force of the piezoelectric actuator drive
amplifier unit A0, the combination of the high / low signal level of the control signal 1 and the
control signal 2 is a haptic function, receiver function, speaker function Corresponding to each
function of [Selected figure] Figure 2
Piezoelectric actuator drive system
[0001]
The present invention relates to a piezoelectric actuator drive device having a haptic feedback
function, a receiver function for outputting sound, and a speaker function for reproducing music.
[0002]
As disclosed in Patent Document 1, in a touch panel type input device, a piezoelectric actuator
applies vibration to a fingertip of a user who operates to tactile feedback of sense of operation
and a touch panel on which a piezoelectric actuator or a piezoelectric actuator is attached. There
is an application that generates sound from
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[0003]
In addition, as disclosed in Patent Document 2, in a mobile terminal device including a mobile
telephone device, there are a receiver function for outputting sound and a speaker function for
generating music etc. as functions and functions for generating sound.
[0004]
JP, 2009-169612, A JP, 2006-54693, A
[0005]
As described above, a tactile feedback function (hereinafter referred to as a haptic function) for
giving vibration and feeding back the sense of operation as a tactile sense, a receiver function for
outputting sound, music, etc. are generated as an application for vibrating the piezoelectric
actuator. There are three functions of speaker function.
In each of these three functions, the frequency band required for the drive amplifier of the
piezoelectric actuator drive, the output voltage amplitude, the driving force, and the distortion
characteristics are different, so a piezoelectric actuator drive for vibrating the piezoelectric
actuator corresponding to these three functions must be provided. You must.
[0006]
However, in Patent Document 1, switching of drive amplifier characteristics corresponding to
these three functions is not taken into consideration.
[0007]
Further, in Patent Document 2, the haptic function is not considered as an application or function
to vibrate the piezoelectric actuator, and the drive power switching of the drive amplifier is
considered also with respect to the receiver function to output sound and the speaker function to
generate music. It has not been.
[0008]
In view of such circumstances, the object of the present invention is to optimize the power and
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drive amplifier characteristics of the piezoelectric actuator drive device corresponding to three
functions of a haptic function, a receiver function for outputting sound, and a speaker function
for generating music etc. To provide a piezoelectric actuator drive device.
[0009]
The outline of typical ones of the inventions disclosed in the present application will be briefly
described as follows.
[0010]
A piezoelectric actuator drive device for vibrating a piezoelectric actuator, comprising: an
amplifier bias voltage generation unit for controlling an amplifier bias voltage according to a first
control signal input; converting a single input signal into a differential output; A single
differential conversion unit that outputs a differential output signal, a high voltage amplifier unit
that amplifies the differential output signal, and a power supply unit that controls a power supply
voltage of the high voltage amplifier unit according to an input first control signal; And a current
source unit for controlling an amount of amplifier bias current of the high voltage amplifier unit
according to the second control signal to be input.
As a function to vibrate the piezoelectric actuator, it has a haptic feedback function, a receiver
function to output sound, and a speaker function to generate music, and the first control signal
and the first control signal to each of the haptic feedback function, the receiver function and the
speaker function The combination of the first signal level and the second signal level of each of
the second control signals is made to correspond to control the amplifier bias voltage, the power
supply voltage of the high voltage amplifier unit, and the amplifier bias current amount of the
high voltage amplifier unit.
[0011]
According to the present invention, it is possible to optimize the power and drive amplifier
characteristics of the piezoelectric actuator drive device corresponding to the haptic function, the
receiver function and the speaker function.
[0012]
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FIG. 1 is an example of a block diagram schematically showing a system configuration in a first
embodiment.
FIG. 2 is an example of a block diagram showing a configuration of a piezoelectric actuator drive
device in Embodiment 1.
FIG. 6 is an example of a block diagram showing a configuration of a single differential
conversion unit in Embodiment 1.
FIG. 6 is an example of a block diagram showing a configuration of a high voltage amplifier unit
in Embodiment 1.
FIG. 7 is an example of a block diagram showing a configuration of a piezoelectric actuator drive
device power supply unit in Embodiment 1.
FIG. 7 is an example of a diagram schematically showing an operation waveform of a
piezoelectric actuator drive device power supply unit in Embodiment 1.
FIG. 7 is an example of a diagram schematically showing an operation waveform of a
piezoelectric actuator drive device power supply unit in Embodiment 1.
FIG. 7 is an example of a block diagram showing a configuration of a gate control unit in
Embodiment 2. FIG. 13 is an example of a diagram schematically showing an operation waveform
of a piezoelectric actuator drive device power supply unit in Embodiment 2.
[0013]
Hereinafter, a first embodiment of the present invention will be described based on the attached
drawings.
[0014]
In the first embodiment of the present invention, the case where one piezoelectric actuator is
driven by one piezoelectric actuator driving device will be described below.
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[0015]
FIG. 1 is a block diagram schematically showing a system configuration in the first embodiment
of the present invention.
FIG. 2 is a block diagram showing the configuration of the piezoelectric actuator drive device
according to the first embodiment of the present invention corresponding to FIG.
[0016]
In FIG. 1, a piezoelectric actuator 4 is attached to a panel configured of a touch panel 1, a
vibration panel 2, and a liquid crystal panel 3, and one piezoelectric actuator driving device 6 is
disposed for each piezoelectric actuator 4.
The touch panel sensor unit 5 disposed on the touch panel generates a touch panel input signal
from the touch panel and transmits the touch panel input signal to the control device 7. The
touch panel circuit unit 701 of the control device 7 processes the touch panel input signal to
detect the position where the user's finger touches on the panel surface of the touch panel, and
generates a signal representing the position to the control circuit unit 702. Send.
[0017]
A control circuit unit 702 composed of an MCU (Micro Controller Unit) or the like outputs a
waveform generation control signal or an acoustic signal to the waveform generation circuit unit
703 in order to generate a predetermined tactile vibration or sound, an acoustic signal according
to a contact position. . For example, it is assumed that the acoustic signal is input from the host
control apparatus to the control circuit unit 702 via the communication interface 704. The
waveform generation circuit unit 703 outputs a haptic / acoustic signal to the piezoelectric
actuator driving device 6 with reference to the waveform data of the data storage device 8 based
on the waveform generation control signal and the acoustic signal.
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[0018]
The control circuit unit 702 operates to cause the piezoelectric actuator drive device 6 to
generate a predetermined control signal in order to correspond to the haptic function, the
receiver function, or the speaker function according to the touch position of the touch panel.
Alternatively, the controller 7 may be configured to transmit a touch panel input signal to the
host controller, and receive a control signal from the host controller to the piezoelectric actuator
driver 6 via the communication interface 704 and the control circuit unit 702. .
[0019]
In such a system configuration, the configuration of the piezoelectric actuator drive device 6 will
be described below with reference to FIG. FIG. 2 shows a case where a part of the piezoelectric
actuator driving device 6 is configured as a piezoelectric actuator driving IC 15. It is also possible
to configure all of the piezoelectric actuator drive device 6 as a module such as a piezoelectric
actuator drive IC or a SIP (System In Package).
[0020]
The piezoelectric actuator drive device 6 mainly includes a piezoelectric actuator drive amplifier
unit A 0 and a piezoelectric actuator drive device power supply unit 100.
[0021]
The piezoelectric actuator drive amplifier unit A0 mainly includes a single differential conversion
unit A1 and high voltage amplifier units A2 (A2a and A2b).
The piezoelectric actuator drive amplifier unit A0 amplifies the haptic / acoustic signal which is
an amplifier input signal, and applies a signal of opposite phase to both terminals of the
piezoelectric actuator 4 to obtain a BTL output with which an amplitude of about twice can be
obtained. The actuator 4 can be driven. The configuration and operation of the piezoelectric
actuator drive amplifier unit A0 will be described below with reference to FIGS.
[0022]
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The single differential conversion unit A1 converts a tactile / acoustic signal which is a single
input signal into a differential output by a circuit including the amplifiers A101 and A102 and
the resistance elements R4-R7 shown in FIG. The differential circuit outputs VOT and VOB
differentially. At this time, VOT is an in-phase signal with the input signal, and VOB is an inverted
signal. The input signal is input to the single differential conversion unit via a high pass filter
formed of a resistance element R4 and a capacitance element C2. The high pass filter cuts the DC
component of the input signal and plays a role in removing low frequency noise.
[0023]
The amplifier bias voltage generation unit A11 makes the amplifier bias voltage BIAS larger for
the VOT and VOB output signals at one of the High / Low levels in response to the High / Low
signal level of the control signal 1, and the control signal 1 is the other. At the level, set smaller.
[0024]
In FIG. 3, the amplifier bias voltage BIAS is generated by dividing the low voltage power supply
VDD using the resistors R8, R9 and R10, and the NMOS 14b is turned ON / OFF in response to
the Hi / Low level of the control signal 1. Thus, the division ratio is changed to change the output
voltage level of the amplifier bias voltage BIAS.
The capacitor C3 is provided as a bypass capacitor for the amplifier bias voltage BIAS.
[0025]
When the control signal 1 is input to the NMOS 14 b via the inverter 16, the amplifier bias
voltage BIAS is VDD × (R9 + R10) / (R8 + R9 + R10) when the control signal 1 is at the Hi level.
On the other hand, when the control signal 1 is at the low level, the amplifier bias voltage BIAS is
VDD × R9 / (R8 + R9).
[0026]
For example, assuming that VDD = 5 V, R8 = 200 k.OMEGA., R9 = 8 k.OMEGA., R10 = 125
k.OMEGA., BIAS = about 2.0 V when control signal 1 is at Hi level, and BIAS = about 0.2 V when
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Low level.
[0027]
The high voltage amplifier unit A2 amplifies the output signals VOT and VOB of the single
differential conversion unit A1 as input signals by the circuit including the gain amplifier A21
and the voltage follower A22 shown in FIG.
Note that both A2a and A2b shown in FIG. 2 have the same configuration as A2 shown in FIG.
The gain amplifier A21 amplifies the voltage amplitude to (R11 + R12) / R12 times by the
amplifier A103 and the resistance elements R11 and R12. In the case of the present embodiment,
the high voltage power supply VPP corresponds to the High / Low signal level of the control
signal 1, and in the case of this embodiment, the VPP voltage is increased when the High level
and VPP voltage when the Low level. Furthermore, by appropriately setting the amplifier bias
voltage generated by the amplifier bias generation unit A11 shown in FIG. 3, the maximum
output voltage amplitude of the piezoelectric actuator drive amplifier unit A0 is large when the
control signal 1 is at high level, Low It can be controlled small at the level.
[0028]
For example, the gain setting of the gain amplifier A21 is 50 times. When the control signal 1 of
the amplifier bias voltage BIAS described above is at the high level, the amplifier output of the
high voltage amplifier unit A2 can have a voltage amplitude centered on about 100V. Therefore,
by setting the high voltage power supply VPP to 200 V or more, the output of the high voltage
amplifier A2 can obtain an amplitude of ± 100 V with a center of 100 V. As the BTL output in
FIG. 2, a voltage amplitude of up to 400 V peak to peak can be obtained.
[0029]
On the other hand, when the control signal 1 is at the low level, if the gain setting of the gain
amplifier A21 is 50 times, the amplifier output of the high voltage amplifier unit A2 can have a
voltage amplitude centered on about 10V. Therefore, by setting the high voltage power supply
VPP to 20 V or more, the output of the high voltage amplifier A2 can obtain an amplitude of ±
10 V centered at 10 V. As a BTL output, a voltage swing of up to 20 V peak to peak can be
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obtained.
[0030]
Thus, the VPP voltage is increased and the amplifier bias voltage is increased corresponding to
the high level of the control signal 1, and the VPP voltage is reduced and the amplifier bias
voltage is reduced corresponding to the low level. That is, the maximum output voltage
amplitude of the drive amplifier unit is increased corresponding to the high level of the control
signal 1, and the maximum output voltage amplitude of the drive amplifier unit is reduced
corresponding to the low level. As a result, it is possible to optimize the power and drive
amplifier characteristics of the piezoelectric actuator drive device corresponding to each of the
haptic function, the receiver function, and the speaker function.
[0031]
Specifically, in the haptic function, it is necessary to increase the amplitude of the piezoelectric
actuator in order to sense sufficient vibration at the fingertip touching the panel. Therefore, in
the present embodiment, control is performed to increase the maximum output voltage
amplitude of the piezoelectric actuator drive amplifier by making the High signal level of the
control signal 1 correspond to the haptic function and raising the VPP power supply voltage and
simultaneously changing the amplifier bias voltage. Correspond to
[0032]
In addition, since a sufficient sound pressure from the panel is required also in the speaker
function, it is necessary to increase the amplitude of the piezoelectric actuator. Therefore, in the
present embodiment, control is performed to increase the maximum output voltage amplitude of
the piezoelectric actuator drive amplifier by making the High signal level of the control signal 1
correspond to the speaker function and raising the VPP power supply voltage and
simultaneously changing the amplifier bias voltage. Correspond to
[0033]
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On the other hand, since the receiver function is used for bringing the ear close to the panel and
listening to the sound, sound pressure is unnecessary as compared with the speaker function,
and the amplitude of the piezoelectric actuator may be smaller than other functions. Therefore, in
the present embodiment, control is performed to reduce the maximum output voltage amplitude
of the piezoelectric actuator drive amplifier by making the Low signal level of the control signal 1
correspond to the receiver function and reducing the VPP power supply voltage and
simultaneously changing the amplifier bias voltage. Correspond to By reducing the output
voltage amplitude of the drive amplifier, power can be reduced, and power optimization of the
piezoelectric actuator drive device becomes possible. In the present embodiment, the maximum
output voltage amplitude is made large corresponding to the high level of the control signal 1
Although the example has been described in which the size is made smaller corresponding to the
low level, it goes without saying that the maximum output voltage amplitude can be made
compatible by reversing the high / low level.
[0034]
The amplifier bias current input to the voltage follower A22 is generated by the current source
unit A3, and the amount of the current is controlled according to the High / Low signal level of
the control signal 2. As shown in FIG. 4, the current source portion A3 is composed of current
sources I1 and I2 having two different current amounts b, and the current amount is changed by
the selector 108 corresponding to the Hi / Low level of the control signal 2.
[0035]
For example, when the amplifier A104 is a class AB amplifier, if the amount of amplifier bias
current is large, the driving power of the high voltage amplifier unit A2 is increased, the cutoff
frequency can be increased, and the amplifier distortion characteristics can be improved. On the
other hand, current consumption and power consumption increase.
[0036]
When driving the haptic signal of the haptic function, the amplifier frequency band is sufficient
to be in the order of several hundred Hz from the balance with the tactile sense of the fingertip.
On the other hand, in the case of driving the acoustic signal of the receiver function and the
speaker function, the amplifier frequency band needs to be at least several kHz because the
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audible range is 20 Hz to 20 kHz.
[0037]
From this, for example, the Low signal level of the control signal 2 is made to correspond to the
receiver function and the speaker function, the amplifier bias current amount is increased, the
driving power of the high voltage amplifier section A2 is increased, and the cutoff frequency on
the high frequency side is By expanding, the distortion characteristic of the amplifier is improved
to improve the sound quality.
[0038]
On the other hand, the High signal level of control signal 2 corresponds to the haptic function to
reduce the amount of amplifier bias current, reduce the driving power of high-voltage amplifier
unit A2, reduce the cutoff frequency on the high frequency side, and reduce power. Do.
[0039]
This makes it possible to optimize the power of the piezoelectric actuator drive device compatible
with the three functions, and optimize the bandwidth of the drive amplifier and distortion
characteristics.
[0040]
In this embodiment, an example in which the amplifier bias current amount is increased
corresponding to the low level of the control signal 2 and reduced corresponding to the high
level is described. However, the high / low level is reversed to set the amplifier bias It goes
without saying that the amount of current can also be made to correspond.
[0041]
As shown in FIG. 2, the piezoelectric actuator drive device power supply unit 100 is based on the
battery 9 and is a VPP by a step-up DC-DC converter including an inductor element 10, a
MOSFET element 11, a diode element 12 and a capacitive element C1 Generate a voltage.
The VPP voltage is fed back to the gate control unit 101 as a voltage obtained by resistance
division using resistance elements R1, R2, and R3.
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The gate of the MOSFET element 11 is switched by the switching oscillation circuit unit 200, the
gate control unit 101, and the driver 13a.
[0042]
The configuration and operation of the piezoelectric actuator drive device power supply unit 100
will be described below with reference to FIGS.
First, it will be described below that the VPP voltage can be changed corresponding to the High /
Low signal level of the control signal 1.
[0043]
The step-up DC-DC converter control method is shown in FIG.
Here, even if the step-up ratio to be described later is large, the control system can be configured
only with the comparator 103, and therefore, a non-linear control system excellent in the
stability of the control system is used. When the control signal 1 is at the high level, the gate of
the NMOS 14a is turned on via the driver 13b. The voltage feedback signal input to the
comparator 103 of the gate control unit 101a is VPP × R2 / (R1 + R2). When Vref is set as the
reference voltage 104 at the other input of the comparator 103, VPP voltage when the control
signal 1 is High is referred to as VPPH from VPP × R2 / (R1 + R2) = Vref. VPPH = (R1 + R2) It
becomes / R2 × Vref.
[0044]
Similarly, when the control signal 1 is at the low level, the gate of the NMOS 14a is turned off.
Therefore, when the VPP voltage at this time is referred to as VPPL, VPPL = (R1 + R2 + R3) / (R2
+ R3) × Vref.
[0045]
For example, when R1 = 500 kΩ, R2 = 5 kΩ, R3 = 50 kΩ, and Vref = 2 V, VPPH = 202 V when
the control signal 1 is at the high level, and VPPL = about 20.2 V when the control signal 1 is at
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the low level.
[0046]
Thus, the VPP voltage can be controlled in response to the high / low signal level of the control
signal 1.
In this embodiment, the VPP voltage is controlled to be large at the high level and to be small at
the low level.
[0047]
Next, a method of improving distortion characteristics when the control signal 1 is switched from
the high level to the low level will be described.
[0048]
The ratio of output voltage fluctuation to the output voltage amplitude of the amplifier affects the
distortion characteristics.
That is, as the ratio of the output voltage fluctuation to the output voltage amplitude of the
amplifier is larger, the distortion characteristic is degraded.
As described above, when making the piezoelectric actuator drive device correspond to the
receiver function from the haptic function or the speaker function, the control signal 1 is
switched from the high level to the low level. At this time, the output voltage fluctuation is the
same whether the control signal 1 is high level or low level. Therefore, when the control signal 1
is low level, the distortion characteristic is deteriorated because the output voltage amplitude is
small.
[0049]
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Therefore, in the present embodiment, the switching frequency is controlled in accordance with
the signal level of the control signal 1. Specifically, it is characterized in that the frequency is
increased in response to the switching of the control signal 1 from the high level to the low level.
Thereby, the output voltage fluctuation is reduced, and the distortion characteristic can be
improved. The details will be described below with reference to FIGS. 5 to 7.
[0050]
In the switching oscillation circuit unit 200, the signal generated by the oscillation circuit unit
201 is divided by the frequency divider 202b to generate a switching signal of the frequency fsw.
[0051]
When the VPP voltage level falls below the above VPPH voltage level or VPPL voltage level, the
output signal of the comparator 103 becomes high level, and the output signal of the gate on
time generation circuit unit 102 is output from the gate control unit 101a via the AND circuit
105a. It is output.
At this time, the gate switching signal becomes high level via the driver 13a, and the gate of the
MOSFET element 11 is turned on.
[0052]
When the control signal 1 is at the high level, as shown in FIG. 6, the time Ton when the gate
switching signal is at the high level is generated by the gate on time generation circuit unit 102
based on the switching signal of the frequency fsw. It becomes Ton = Du / fsw using. Hereinafter,
Du will be referred to as a duty ratio of the switching signal.
[0053]
At this time, assuming that the voltage of the battery 9 constituting the step-up DC-DC converter
is VDD and the inductance of the inductor element 10 is L, the maximum current (hereinafter
referred to as Ip) flowing through the inductor element is Ip = VDD / L × Ton = (VDD x Du) / (L x
fsw).
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[0054]
In the present embodiment, as described above, when the control signal 1 is at the high level, the
VPP voltage is VPPH.
In addition, in portable terminal devices including a portable telephone device, considering that a
lithium ion battery is generally used as the battery voltage VDD, VDD is approximately 3.5 V.
Therefore, for example, when VPPH = 202 V, the boosting ratio is as large as 202 V / 3.5 V = 58,
and in order to boost, it is necessary to set Ip to a large value.
[0055]
On the other hand, when the control signal 1 is at the low level, the VPP voltage is approximately
VPPL. For example, when VPPL = 20.2 V, the boosting ratio is 20.2 V / 3.5 V = 5.8. The ripple
.DELTA.VPP of the VPP voltage can be expressed as .DELTA.VPP = Ip.times..alpha., Where .alpha.
Is the equivalent series resistance ESR (Equivalent Series Resistance) of C1 used as the output
smoothing capacitance of the step-up DC-DC converter. That is, even if the control signal 1
switches from High to Low level, the Ip value does not change, and the ripple of the VPP voltage
also becomes the same.
[0056]
In addition, power supply voltage fluctuation rejection ratio PSRR (Power Supply. When Rejection
Ratio) is β, the amplifier output voltage fluctuation of ΔVPP × β is involved. When the control
signal 1 is set to the low level, the ratio of the output voltage fluctuation to the output voltage
amplitude increases as the amplifier output voltage amplitude is smaller than the high level, and
the distortion characteristic of the amplifier output of the piezoelectric actuator drive amplifier
A0 is affected and deteriorated. Do.
[0057]
In order to avoid the above, as shown in FIG. 5, when the control signal 1 is at the high level, the
switching signal via the frequency divider 202b is selected by the selector 203, and the
frequency is fsw.
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[0058]
On the other hand, when the switching signal not via the frequency divider 202 b is selected by
the selector 203 in response to the low level of the control signal 1, for example, the switching
signal becomes 2 fsw in the example of FIG. 5.
As described above for Ip, Ip is reduced by half compared to when control signal 1 is at high
level, and as shown in FIG. 7, the ripple of VPP voltage is also reduced by half and the output
voltage fluctuation is also reduced by half. Strain characteristics can be improved. As described
above, by increasing the frequency fsw of the switching signal of the step-up DC-DC converter in
response to the switching from the high level to the low level of the control signal 1, the ripple of
the VPP voltage is reduced and the amplifier output Distortion characteristics can be improved.
[0059]
In the second embodiment of the present invention, another method of reducing the ripple of the
VPP voltage and improving the distortion characteristic of the amplifier output will be described
with reference to FIG. 8 and FIG.
[0060]
In the present embodiment, as shown in FIG. 8, a delay circuit 105 b, an AND circuit 106, and a
selector 107 are provided, and the duty ratio is controlled in accordance with the signal level of
the control signal 1.
Specifically, it is characterized in that the duty ratio is reduced in response to the switching of the
control signal 1 from the high level to the low level. As a result, by shortening the on time of the
gate switching signal and reducing the ripple of the VPP voltage, it is possible to improve the
distortion characteristics of the amplifier output.
[0061]
As shown in FIG. 8, in the gate control unit 101b, the output of the gate on time generation
circuit unit 102 corresponds to switching of the control signal 1 from high level to low level
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using the selector 107, and AND with the delay circuit 106. Control is performed such that a
signal through the circuit 105 b is input to the AND circuit 105 a.
[0062]
At this time, as shown in FIG. 9, the on time Ton ′ of the gate switching signal is an AND signal
of the signal Ton = Du / fsw generated by the gate on time generation circuit unit 102 and a
signal obtained by delaying this. , The gate on time can be shortened.
Assuming that the duty ratio in the present embodiment is Du ′, Ton ′ = Du ′ / fsw <Ton = Du
/ fsw. That is, while the frequency fsw is controlled in the first embodiment, this embodiment
corresponds to performing control to reduce the duty ratio Du of the switching signal. Thereby,
the ripple of the VPP voltage can be reduced, and the distortion characteristic of the amplifier
output can be improved.
[0063]
As described above, in the piezoelectric actuator drive device 6 including the piezoelectric
actuator drive amplifier unit A0 and the piezoelectric actuator drive device power supply unit
100, a signal (control signal for controlling the power supply voltage VPP of the piezoelectric
actuator drive amplifier A0 and the amplifier bias voltage 1) and the signal (control signal 2) for
controlling the driving force of the piezoelectric actuator drive amplifier A0, combining the high
/ low signal levels of control signal 1 and control signal 2 with each function of haptic function,
receiver function, speaker function By making it correspond, it becomes possible to realize a
piezoelectric actuator drive device capable of optimizing the power and drive amplifier
characteristics corresponding to these three functions.
[0064]
Further, in the above-described embodiment, although the supply source of the low voltage
power supply VDD is described as the battery 9, it is also possible to supply the VDD from the
battery 9 via a regulator or the like.
[0065]
In FIG. 1, the piezoelectric actuator driving device 6, the control device 7, and the data storage
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device 8 are separate devices, but the piezoelectric actuator driving device 6 and the control
device 7 may be one device or piezoelectric actuator driving It is also possible as a system
configuration that the device 6, the control device 7, and the data storage device 8 all be one
device.
At this time, it is not necessary to provide each of control signal 1 and control signal 2 as an
input signal of piezoelectric actuator drive device 6, and control signal corresponding to control
signal 1 and control signal 2 using serial communication etc. I wish I could receive
This makes it possible to reduce the mounting space.
[0066]
In the first embodiment of the invention, although the case where one piezoelectric actuator is
driven by one piezoelectric actuator driving device has been described, the case where a plurality
of piezoelectric actuators are driven by one piezoelectric actuator driving device, or one The case
where the piezoelectric actuator is driven by a plurality of piezoelectric actuator driving devices
is also possible as a system configuration.
[0067]
As mentioned above, although embodiment of this invention was described, this invention is not
limited to the said embodiment, A various deformation | transformation implementation is
possible, It is possible for the person skilled in the art to be able to combine suitably each
embodiment mentioned above. You will understand.
[0068]
Reference Signs List 1 touch panel 2 vibration panel 3 liquid crystal panel 4 piezoelectric
actuator 5 touch panel sensor unit 6 piezoelectric actuator driving device 7 control device 701
touch panel circuit unit 702 control circuit unit 703 waveform generation circuit unit 704
communication interface DESCRIPTION OF SYMBOLS 8 ... Data storage apparatus 9 ... Battery 10
... Inductor element 11 ... MOSFET element 12 ... Diode element 13 ... Driver 14a ... NMOS 15 ...
Piezoelectric actuator drive IC 16 ... Inverter 100 ... Piezoelectric actuator drive device power
supply part 101a, 101b ... Gate control Unit 102 ... Gate on time generation circuit unit 103 ...
Comparator 104 ... Reference power supply 105 a, 105 b ... AND circuit 106 ... Delay circuit 200
... Switching oscillator circuit unit 201 ... Oscillator circuit unit 202 ... Minute Devices 107, 108,
203: Selector R1-R10: Resistive element C1-C3: Capacitive element A0: Piezoelectric actuator
drive amplifier A1: Single differential converter A11: Amplifier bias voltage generator A2a, A2b:
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High voltage amplifier A21: Gain amplifier A22 Voltage follower A3 Current source A101-A104
Amp VPP High voltage power supply terminal VDD Low voltage power supply terminal VOT,
VOB Single differential conversion circuit output BIAS Amplifier bias voltage I1, I2 Current
source
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