close

Вход

Забыли?

вход по аккаунту

?

JP2010098712

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2010098712
A method and electronic device for driving a capacitor-type electro-acoustic transducer is
provided to save power using physical properties of low power consumption of the capacitortype electro-acoustic transducer. An electronic device is coupled to a capacitor type electroacoustic transducer and a capacitor type electro-acoustic transducer, includes a high voltage
amplifier, receives an input voice signal and converts it into an output voice signal, thereby using
the capacitor type. And an audio driver for driving the electroacoustic transducer. The absolute
value of the voltage of the input audio signal is smaller than the absolute value of the voltage of
the output audio signal. The capacitor type electroacoustic transducer is an electret speaker or an
electret earphone. The capacitor type electroacoustic transducer includes an electret diaphragm
and a perforated electrode plate. [Selected figure] Figure 1
Method and electronic apparatus for driving a capacitor type electroacoustic transducer
[0001]
The present invention relates to a method and an electronic device for driving a capacitor type
electroacoustic transducer, and more particularly to a method and an electronic device for
driving a capacitor type electroacoustic transducer by high voltage / low current method and
controlling its bandwidth and power consumption. .
[0002]
With the spread of multimedia applications, portable music players and portable devices with
music playback capabilities have become commonplace.
04-05-2019
1
Power consumption is a major issue for portable devices. In the example of a portable
multimedia device with a built-in speaker, the power consumption required for the speaker
accounts for 20% to 70% of the total power consumption. The conventional dynamic speaker is
driven by a high current / low voltage amplifier, and requires 1.5 to 2 W of power consumption
to output a stereo sound of 93 to 100 dB at a distance of 10 cm. This is too high a power
consumption for portable multimedia devices.
[0003]
Therefore, reducing the power consumption of the speaker and extending the use time of the
portable multimedia device are important design issues.
[0004]
One of the objects of the present invention is to provide a method and an electronic device for
driving a capacitor type electroacoustic transducer, and save power by utilizing the physical
characteristics of low power consumption of the capacitor type electroacoustic transducer. .
[0005]
The present invention discloses an electronic device.
The electronic device is coupled to a capacitor-type electro-acoustic transducer and a capacitortype electro-acoustic transducer, includes a high voltage amplifier, receives an input voice signal
and converts it into an output voice signal, thereby converting the capacitor-type electro-acoustic
transducer And an audio driver for driving the device.
The absolute value of the voltage of the input audio signal is smaller than the absolute value of
the voltage of the output audio signal. The capacitor type electroacoustic transducer is an
electret speaker or an electret earphone. The capacitor type electroacoustic transducer includes
an electret diaphragm and a perforated electrode plate.
[0006]
04-05-2019
2
The present invention discloses a method of driving a capacitor type electro-acoustic transducer.
The method receives the input voice signal by the high voltage amplifier and converts it into an
output voice signal, and the step of absolute voltage value of the input voice signal is smaller
than the absolute value of voltage of the output voice signal, Driving a capacitive electro-acoustic
transducer.
[0007]
FIG. 1 is an explanatory view showing a first embodiment of an electronic device for driving a
capacitor type electroacoustic transducer according to the present invention. FIG. 7 is an
explanatory view showing a second embodiment of an electronic device for driving a capacitor
type electroacoustic transducer according to the present invention. It is explanatory drawing
showing the capacitor | condenser type electroacoustic transducer shown in FIG. 5 is a flow chart
illustrating an example of operation of a method of driving a capacitor type electro-acoustic
transducer according to the present invention. 7 is a flowchart illustrating another operation
example of a method of driving a capacitor type electroacoustic transducer according to the
present invention.
[0008]
Please refer to FIG. FIG. 1 is an explanatory view showing a first embodiment of an electronic
device 100 for driving a capacitor type electroacoustic transducer according to the present
invention. As shown in FIG. 1, the electronic device 100 includes an audio signal source 110, an
AC-DC / DC-DC (AC-DC / DC-DC) power converter 120, an audio driver 130, and a capacitor type
electric audio converter. And 170, although not limited thereto. The audio signal source 110
provides an input audio signal SIN, and is a portable multimedia device providing an audio signal
such as an MP3 player, a CD player, or a smartphone. The audio driver 130 is coupled to the
audio signal source 130, the AC-DC / DC-DC power converter 120, and the capacitor type
electro-acoustic transducer 170 to receive the input audio signal SIN and convert it to the output
audio signal SOUT And a high voltage amplifier OP1 for driving the capacitor type
electroacoustic transducer 170. Generally, the voltage of the input voice signal SIN is about 0 to
3 Vpp (peak-to-peak voltage), and the voltage of the output voice signal SOUT is 84 Vpp or more.
The AC-DC / DC-DC power converter 120 is coupled to the high voltage amplifier OP1 and
generates an AC commercial power VAC of 110V to 220V or a first DC voltage VDC1 to a second
DC voltage VDC2 larger than the first DC voltage VDC1. Convert to In general, the first DC
voltage VDC1 is about 2.5V to 5V, and the second DC voltage VDC2 is about 80V to 100V.
04-05-2019
3
[0009]
It should be noted that the electronic device 100 is a mobile phone, a game console or a PDA
(Personal Digital Assistant). However, the present invention is not limited thereto, and other
multimedia electronic devices may be used as the electronic device 100. The capacitor type
electroacoustic transducer 170 is an electret speaker or an electret earphone. However, the
present invention is not limited thereto, and other capacitor type electroacoustic transducers can
also be used. Please refer to FIG. The capacitor type electroacoustic transducer 170 includes a
perforated electrode plate 180 and an electret diaphragm 190. The perforated electrode plate
180 includes a plurality of holes 182, and the electret diaphragm 190 includes a plate 192 and
an electrode layer 194. Plate 192 carries a charge (not shown) and is composed of
polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene (FEP) (although the invention is
not limited thereto). The electrode layer 194 is made of aluminum, chromium, or another
conductive material.
[0010]
In this embodiment, the input voice signal SIN is a single end signal, and the output voice signal
SOUT is a pair of differential signals, and includes a first signal SOUT1 and a second signal
SOUT2. However, the present invention is not limited thereto, and a single end signal or a pair of
differential signals can be used as the input audio signal SIN, or a single end signal or a pair of
differential signals can be used as the output audio signal SOUT. When the output audio signal
SOUT is a pair of differential signals, the perforated electrode plate 180 of the capacitor type
electro-acoustic transducer 170 receives the first signal SOUT1 of the pair of differential signals,
and the electret diaphragm 190 receives the second signal SOUT2 of the pair of differential
signals (shown in FIG. 1). When the output audio signal SOUT is a single end signal, the electret
diaphragm 190 of the capacitor type electro-acoustic transducer 170 receives the single end
signal, and the perforated electrode plate 180 is grounded (not shown).
[0011]
Simply stated, the audio signal source 110 of the electronic device 100 provides the input audio
signal SIN (e.g. 1.68 Vpp) to the high voltage amplifier OP1 of the audio driver 130, and the ACDC / DC-DC power converter 120 has 110V ~ A 220 V AC commercial power VAC or a first DC
04-05-2019
4
voltage VDC1 is converted to a second DC voltage VDC2 (for example, 84 V), and the second DC
voltage VDC2 is applied to the high voltage amplifier OP1 as an operation power supply. Finally,
the high voltage amplifier OP1 converts the input audio signal SIN into an output audio signal
SOUT (for example, the first signal SOUT1 is +84 Vp and the second signal SOUT2 is -84 Vp) to
drive the capacitor type electro-acoustic transducer 170 Do. In the present embodiment, the high
voltage amplifier OP1 drives the capacitor type electro-acoustic transducer 170 in a high voltage
/ low current system.
[0012]
Please refer to FIG. FIG. 2 is an explanatory view showing a second embodiment of an electronic
device 200 for driving a capacitor type electroacoustic transducer according to the present
invention. The electronic device 200 shown in FIG. 2 has the same structure as the electronic
device 100 shown in FIG. The difference between the two is that the electronic device 200
includes a first low pass filter (LPF), an automatic gain controller (AGC) 220, and a second LPF
250. The first LPF 210 and the AGC 220 are provided in the audio driver 230, and the second
LPF 250 is coupled between the high voltage amplifier OP 1 and the capacitor type electroacoustic transducer 170. The first LPF 210 is coupled to the audio signal source 110 and filters
the input audio signal SIN to generate an input audio signal SIN1. The first LPF 210 controls the
bandwidth of the capacitor type electro-acoustic transducer 170. For example, the bandwidth
required for voice calls on mobile phones is only 4 KHz and 10 KHz for multimedia audio
playback. The AGC 220 is coupled between the first LPF 210 and the high voltage amplifier OP1
and adjusts the gain of the input speech signal SIN1 to generate the input speech signal SIN2.
[0013]
It should be noted that the high voltage amplifier OP1 is implemented by a class AB amplifier or
a class D amplifier, but the present invention is not limited thereto. The second LPF 250 is
coupled to a class D amplifier (that is, the high voltage amplifier OP1) to filter and remove high
frequency signal components of the output audio signal SOUT2.
[0014]
Please refer to FIG. FIG. 3 is an explanatory view showing the capacitor type electro-acoustic
transducer 170 shown in FIG. The capacitor type electro-acoustic transducer 170 can be
04-05-2019
5
regarded as a capacitor (whose capacitance value is C), so the force (F) received by the electret
diaphragm 190 of the capacitor type electro-acoustic transducer 170 is expressed by the
following equation be able to.
[0015]
The above C indicates a capacitance value, E indicates an electrostatic field consisting of
electrostatic charges of the electret diaphragm 190, and ΔV indicates a potential difference
between both ends of the capacitor (ie, the signals SOUT1 and SOUT2 received by the electret
diaphragm 190 and the perforated electrode plate 180). Voltage difference). The capacitance
value C and the electrostatic field E can be expressed by the following equations.
[0016]
[0017]
The above ε r indicates the dielectric constant of vacuum, ε 0 indicates the relative dielectric
constant, A indicates the area of the capacitor (area of the electret diaphragm 190 and the
perforated electrode plate 180), d indicates the distance between both ends of the capacitor (ie
electret vibration) V static represents the electrostatic potential of the electrostatic charge on the
electret diaphragm 190. In FIG.
By substituting Equations 2 and 3 into Equation 1, it can be understood that the force F received
by the electret diaphragm 190 is in direct proportion to the potential difference ΔV.
[0018]
In addition, since the capacitor type electro-acoustic transducer 170 can be regarded as a
capacitor, the capacitance value C of the capacitor type electro-acoustic transducer 170 can
generally be defined by the following equation.
[0019]
04-05-2019
6
The above Q indicates the charge amount of the capacitor, ΔV indicates the potential difference
between both ends of the capacitor (ie, the voltage difference between the signals SOUT1 and
SOUT2 received by the electret diaphragm 190 and the perforated electrode plate 180), I
indicates the current value, t indicates time, and f indicates bandwidth (ie, bandwidth of the
capacitor type electroacoustic transducer 170).
Since the charge amount Q of the capacitor is I × t and t = I / f, the relationship between the
bandwidth f and the current value I can be derived from the above equation (4).
[0020]
As shown in the equation 5, when the capacitance value C and the potential difference ΔV
between both ends of the capacitor are constant, the bandwidth f and the current value I are in
direct proportion. In other words, the current value I can be controlled using the first LPF 210,
and the bandwidth f of the capacitor type electro-acoustic transducer 170 can be determined. For
example, if the current value I is 2 mA, the bandwidth f is about 10 KHz, and if the current value I
is 1 mA, the bandwidth f is about 4 KHz. The frequency range that can be received by the human
ear is 20 Hz to 20 KHz, of which the ratio occupied by 10 KHz to 20 KHz is small (about 1% to
5%), so the current value I is reduced and the band of capacitor type electroacoustic transducer
170 The width f can be 10 KHz, which can reduce the power consumption of the capacitor type
electro-acoustic transducer 170. However, the above 10 KHz example is only given to illustrate
the present invention, and does not limit the present invention. As is known to those skilled in
the art, the bandwidth f of the capacitor type electro-acoustic transducer 170 can be designed
according to the actual requirements.
[0021]
Further, the power consumption of the capacitor type electroacoustic transducer 170 can be
expressed by the following equation.
[0022]
Since the potential difference ΔV is considerably large (for example, 168 Vpp) and the
capacitance value C is extremely small (usually 20 pF to 20 nF), the power consumption of the
capacitor type electroacoustic transducer 170 is extremely small in the μW class.
04-05-2019
7
For example, in the case of stereo sound with an output volume of 93 to 100 dB, the total power
consumption required for the AC-DC / DC-DC power converter 120, the audio driver 130, and the
capacitor type electroacoustic converter 170 is only 420 mW, Much less than the power
consumption of 1.5-2 W of conventional dynamic speakers driven by high current / low voltage
amplifiers. Thus, the mechanism for driving the capacitor type electro-acoustic transducer 170
with the high voltage / low current high voltage amplifier according to the present invention can
reduce power consumption by 3 to 4 times compared to the prior art.
[0023]
Since the magnitude of the current value I input to the capacitor type electro-acoustic transducer
170 affects the power consumption of the entire system, either the current is limited by the first
LPF 210 or the current limiting function of the high voltage amplifier OP1 is used. Power
consumption can be reduced. FIG. 4 is a flowchart showing an operation example of a method of
driving a capacitor type electroacoustic transducer according to the present invention. The
method includes the following steps (the following steps are not limited to being performed in
the order shown in FIG. 4 but may be adjusted as appropriate to obtain the desired result): Step
402: Start. Step 404: Provide an input audio signal. Step 406: A high voltage amplifier receives
the input speech signal and converts it into an output speech signal. The absolute value of the
voltage of the input audio signal is smaller than the absolute value of the voltage of the output
audio signal. Step 408: Drive a capacitor type electroacoustic transducer based on the output
voice signal. Step 410: Convert AC commercial power or a first DC voltage into a second DC
voltage. The second DC voltage is greater than the first DC voltage. Step 412: Use the second DC
voltage as an operation power supply of the high voltage amplifier. The operation of each
element can be understood by referring to each step shown in FIG. 4 together with each element
shown in FIG. 1, so that the detailed description of the steps shown in FIG. 4 is omitted for the
sake of simplicity. It should be noted that the above flow is only an example and does not limit
the present invention. Other steps may be inserted or a plurality of steps may be merged into one
without departing from the spirit of the present invention.
[0024]
Please refer to FIG. FIG. 5 is a flow chart showing another operation example of a method of
driving a capacitor type electro-acoustic transducer according to the present invention. The
method includes (but is not limited to) the following steps: Step 402: Start. Step 404: Provide an
input audio signal. Step 510: A filtering operation is performed on the input audio signal in the
04-05-2019
8
first LPF. Step 520: Adjust the gain of the input speech signal. Step 406: A high voltage amplifier
receives the input speech signal and converts it into an output speech signal. The absolute value
of the voltage of the input audio signal is smaller than the absolute value of the voltage of the
output audio signal. Step 408: Drive a capacitor type electroacoustic transducer based on the
output voice signal. Step 530: The second LPF filters out signal components higher than a
specific frequency of the output audio signal. Step 410: Convert AC commercial power or a first
DC voltage into a second DC voltage. The second DC voltage is greater than the first DC voltage.
Step 412: Use the second DC voltage as an operation power supply of the high voltage amplifier.
It should be noted that the steps shown in FIG. 5 are similar to the steps shown in FIG. 4, and FIG.
5 is a variation of FIG. The difference between the two is that the filter operation (step 510), the
gain adjustment (step 520), and the high frequency signal component removal (step 530) are
added to the steps of FIG. 4 in FIG. The operation of each element can be understood by referring
to each step shown in FIG. 5 together with each element shown in FIG. 2, so that the detailed
description of the steps shown in FIG. Step 510 is performed by the first LPF 210, step 520 is
performed by the AGC 220, and step 530 is performed by the second LPF 250.
[0025]
The above embodiments merely illustrate the technical features of the present invention, and are
not intended to limit the present invention. As described above, the present invention provides a
method and an electronic device for driving a capacitor type electroacoustic transducer by a high
voltage / low current method. Compared with the conventional method of driving a dynamic
speaker with a high current / low voltage amplifier, the capacitor with the high voltage / low
current high voltage amplifier according to the present invention when the output volume is the
same (for example, 93 to 100 dB stereo sound) The mechanism for driving the digital electroacoustic transducer 170 can reduce power consumption by 3 to 4 times, and the output sound of
the capacitive electro-acoustic transducer 170 is a plane wave, and a spherical surface like the
output sound of a conventional dynamic speaker Because it differs from waves, it can effectively
reduce the echo and improve the call quality in the speaker mode of the mobile phone. Since the
capacitor type electro-acoustic transducer 170 can be regarded as a capacitor, the bandwidth f is
in direct proportion to the current value I when the capacitance value C and the potential
difference ΔV across the capacitor are constant. Therefore, the bandwidth f of the capacitor type
electro-acoustic transducer 170 can be determined by controlling the current value I with the
first LPF. By reducing the current value I, the bandwidth f of the capacitor type electro-acoustic
transducer 170 can be reduced to 4 kHz bandwidth suitable for voice communication of a mobile
phone, and the power of the voice driver 130 and the capacitor type electro-acoustic transducer
170 Consumption can be reduced. If the current value I is increased, the bandwidth f of the
capacitor type electro-acoustic transducer 170 can be increased to 10 kHz bandwidth suitable
for multimedia audio reproduction, and the sound quality can be optimized. It should be noted
04-05-2019
9
that the above flow is only an example and does not limit the present invention. Other steps may
be inserted or a plurality of steps may be merged into one without departing from the spirit of
the present invention.
[0026]
The above is a preferred embodiment of the present invention, and does not limit the scope of
implementation of the present invention. Therefore, any modifications or alterations which can
be made by those skilled in the art, which are made within the spirit of the present invention and
which have equivalent effects on the present invention, shall fall within the scope of the claims of
the present invention. Do.
[0027]
DESCRIPTION OF SYMBOLS 100, 200 Electronic device 110 Audio signal source 120 AC-DC /
DC-DC power converter 130, 230 Audio driver 170 Capacitor type electroacoustic transducer
180 Perforated electrode plate 182 hole 190 Electret diaphragm 192 Plate body 194 Electrode
layer 210 1st LPF 220 AGC 250 2nd LPF d distance OP1 High voltage amplifier SIN, SIN1, SIN2
input voice signal SOUT output voice signal SOUT1 first signal SOUT2 second signal VAC AC
commercial power VDC1 first DC voltage VDC2 second DC voltage Vstatic electrostatic potential
ΔV potential difference
04-05-2019
10
Документ
Категория
Без категории
Просмотров
0
Размер файла
20 Кб
Теги
jp2010098712
1/--страниц
Пожаловаться на содержимое документа