WO2002095935A1 - Amplificateur de sortie audio - Google Patents

Amplificateur de sortie audio Download PDF

Info

Publication number
WO2002095935A1
WO2002095935A1 PCT/JP2002/004754 JP0204754W WO02095935A1 WO 2002095935 A1 WO2002095935 A1 WO 2002095935A1 JP 0204754 W JP0204754 W JP 0204754W WO 02095935 A1 WO02095935 A1 WO 02095935A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
audio
voltage
output
signal line
Prior art date
Application number
PCT/JP2002/004754
Other languages
English (en)
Japanese (ja)
Inventor
Mamoru Kitamura
Original Assignee
Niigata Seimitsu Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Niigata Seimitsu Co., Ltd. filed Critical Niigata Seimitsu Co., Ltd.
Publication of WO2002095935A1 publication Critical patent/WO2002095935A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H03F3/183—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
    • H03F3/187—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only in integrated circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics

Definitions

  • the present invention relates to an audio output amplifier, and is suitable for use as, for example, a headphone amplifier or the like provided in a portable electronic device capable of listening to sound by connecting a headphone.
  • portable players such as CD (Compact Disc), MD (Mini Disc) and DVD (Digital Video Disc), compression of MP3 (MPEG audio-Layer 3), ATRAC (Adaptive Transform Acoustic Coding), etc.
  • CD Compact Disc
  • MD Mini Disc
  • DVD Digital Video Disc
  • MP3 MPEG audio-Layer 3
  • ATRAC Adaptive Transform Acoustic Coding
  • Mobile audio devices, mobile phones, and mobile devices such as PDAs (Personal Digital Assistants) that support this method often output audio through headphones connected to these devices.
  • PDAs Personal Digital Assistants
  • a DA converter overnight and a headphone amplifier are used to convert the reproduced digital audio data into an analog signal and output it to a headphone.
  • FIG. 1 is a diagram showing a configuration example of a conventional DA converter and a headphone amplifier.
  • FIG. 1 shows a configuration for converting 1-bit digital audio data described below into an analog audio signal and outputting the analog audio signal.
  • the 1-bit method uses ⁇ modulation to control the distribution of quantization noise, thereby improving the resilience of digital data to the original analog signal compared to the widely used PCM method. This method has attracted particular attention recently.
  • a DA converter is provided with a digital interface (IZF) 1, a digital filter 2, and a ⁇ modulation processing unit 3.
  • a headphone amplifier is provided with the drivers 4 and 5, the coils LI and L3, the capacitors CI, C3, C4 and C5, and the resistors Rl and R3.
  • the DA converter generates a modulation signal based on digital audio data reproduced from a digital recording medium such as a CD.
  • the headphone amplifier connected after the DA converter is driven based on the modulated signal, and supplies an amount of current corresponding to the pulse width of the modulated signal, thereby converting the amplified analog audio signal. obtain.
  • the digital I / F 1 is for inputting a digital 1-bit signal reproduced from a digital recording medium (not shown).
  • the digital filter 2 performs a one-pass filter process on the 1-bit signal input by the digital I / F 1, and outputs the result to the ⁇ ⁇ modulation processing unit 3.
  • the ⁇ modulation processing unit 3 performs a conversion process based on ⁇ modulation on the signal output from the digital filter 2 to generate a modulated signal.
  • the drivers 4 and 5 are driven based on the modulation signal output from the ⁇ modulation processing unit 3 and output an amount of current corresponding to the pulse width of the modulation signal.
  • One driver 4 is in charge of the left (L) channel of the stereo sound
  • the other driver 5 is in charge of the right (R) channel of the stereo sound.
  • These drivers 4 and 5 are composed of switching amplifiers (inverting amplifiers) using pMOS transistors and nMOS transistors.
  • the power supply unit 6 supplies a power supply voltage to the above-described digital IZF 1, digital filter 2, ⁇ modulation processing unit 3, and drivers 4 and 5.
  • the digital I / F 1, digital filter 2, and ⁇ ⁇ ⁇ modulation processing unit 3 that constitute the DA converter are supplied with the digital power supply voltage (VDD, DG ND) and the analog power supply voltages (VCC, AGND) to the drivers 4 and 5 that constitute the headphone amplifier.
  • VDD, DG ND digital power supply voltage
  • VCC, AGND analog power supply voltages
  • the power supplied to these circuits from the power supply unit 6 is obtained from a battery (not shown).
  • Coil L 1 and capacitor C 1 constitute a single-pass filter for the L channel
  • coil L 3 and capacitor C 3 constitute a single-pass filter for the R channel
  • the resistor R1 forms a bias circuit for the L channel
  • the resistor R3 forms a bias circuit for the R channel.
  • the left and right analog audio signals generated by passing through these single-pass filters are output from output terminal 11 via capacitors C 4 and C 5, respectively.
  • Headphones that are widely used today have three signal lines (L channel, R channel, and ground).
  • the output terminal 11 also has three terminals 11a to l1c. ing.
  • the first terminal 11a is for the L channel
  • the second terminal lib is for the ground (GND)
  • the third terminal 11c is for the R channel.
  • the ground wire connected to the second terminal 1 lb is commonly used by the left headphone 12 and the right headphone 13.
  • the output voltage to the headphones 12 and 13 must be positively and negatively centered around the ground zero voltage.
  • the power supply is a single DC power supply that does not have plus or minus, such as a battery used in a portable device, the output voltage will swing in a form that is biased to one side, for example, only the plus side. In this case, the output sound does not produce bass sound, but becomes a kinky sound.
  • capacitors C 4 and C 5 are provided for DC cut.
  • the impedance of headphones used in portable electronic devices is generally as small as several tens to several tens of ohms. Therefore, in order to output an extremely low frequency sound such as an ⁇ wave to the headphone, the capacitance of the DC cutting capacitors C 4 and C 5 must be as large as several hundreds; F. In this case, the external shape of the DC cut capacitors C 4 and C 5 becomes very large.
  • the DC cut capacitor may be reduced in size, but it cannot be completely eliminated. Therefore, in portable electronic devices that require strong miniaturization and weight reduction, it is necessary to output extremely low frequency audio such as 0! Waves to headphones while keeping the size and weight of the device small. Is extremely difficult.
  • the present invention has been made in order to solve such a problem, and a sound having an extremely low frequency such as a wave is supplied to a headphone without hindering the reduction in size and weight of a portable device.
  • the purpose is to be able to output. Disclosure of the invention
  • the audio output amplifier of the present invention supplies a first signal line to which an audio signal including a low-frequency region is supplied, and a reference signal used to output the difference to the audio signal to an audio output unit. And a second signal line, An intermediate voltage generating circuit for generating an intermediate voltage of a power supply voltage used for amplifying the audio signal of the signal line and applying the intermediate voltage as the reference signal of the second signal line is provided.
  • a superimposing circuit for superimposing an audio signal having a higher frequency on a low-frequency signal, a first signal line to which an audio signal output from the superimposing circuit is supplied, A second signal line to which a reference signal used to output to an audio output unit by taking a difference from the audio signal supplied to the first signal line; and the audio of the first signal line
  • An intermediate voltage generating circuit for generating an intermediate voltage of a power supply voltage used for signal amplification and applying the intermediate voltage as the reference signal of the second signal line.
  • the first signal line includes two signal lines for supplying at least two channels of audio signals, and a reference signal supplied to the second signal line. Is commonly used for the audio signals of the two channels supplied to the two signal lines.
  • the intermediate voltage generating circuit includes a voltage dividing circuit that divides the power supply voltage into approximately 1Z2, and an operational amplifier that operates using the divided voltage as an input.
  • the difference between the audio signal output to the first signal line and the reference signal output to the second signal line is obtained, for example, the sound of a headphone or the like. Sound is emitted from the output unit.
  • the output from (one power supply voltage / 2) to (+ power supply voltage / 2) is seen from the audio output unit. It operates as if the voltage swings positively or negatively. Therefore, even if a DC cut capacitor is not provided on the first signal line to which the audio signal is supplied, the output voltage to the audio output section can be properly switched between positive and negative, and a sound with an extremely low frequency can be output. It becomes possible.
  • the impedance of the second signal line viewed from the audio output unit can be reduced to a negligible level. For this reason, it is possible to suppress the voltage fluctuation of the second signal line and always maintain the potential at the intermediate voltage.
  • FIG. 1 is a diagram showing a configuration of a conventional headphone amplifier.
  • FIG. 2 is a diagram showing a configuration example of a headphone amplifier according to the first embodiment in which the audio output amplifier of the present invention is implemented.
  • FIG. 3 is a diagram showing the behavior of the output voltage as viewed from the headphones in the present embodiment.
  • FIG. 4 is a diagram illustrating a configuration example of a headphone amplifier according to a second embodiment that implements the audio output amplifier of the present invention.
  • FIG. 5 is a diagram illustrating a configuration example of a headphone amplifier according to a third embodiment that implements the audio output amplifier of the present invention.
  • FIG. 2 is a diagram showing a configuration example of the headphone amplifier according to the first embodiment in which the audio output amplifier of the present invention is implemented.
  • the first embodiment is applicable to both the PCM system and the 1-bit system.
  • 12 V is used as the analog power supply voltage VCC.
  • R11 and R12 are resistors for voltage division and have the same resistance value.
  • the operational amplifier 21 operates using the intermediate voltage V CC / 2 generated by this voltage division as an input to the plus terminal.
  • the output of the operational amplifier 21 is fed back to its own negative terminal.
  • the L-channel audio signal and the R-channel audio signal input from the signal lines INL and INR are input to the positive terminals of the operational amplifiers 22 and 23 via the DC cut capacitors C11 and C12. You.
  • the input stages of the operational amplifiers 22 and 23 are provided with biasing resistors R 15 and R 16, respectively, to which the output signal of the operational amplifier 21 is supplied.
  • bias resistors R 15 and R 16 have a large resistance value (for example, 100 ⁇ ⁇ ⁇ ⁇ ).
  • the positive terminals of the operational amplifiers 22 and 23 are set to high impedance. In this way, it is possible to pass low-frequency audio signals (for example, low-frequency audio signals near 20 Hz) without increasing the capacitance of the DC cut capacitors C 11 and C 12. it can. That is, the capacitance of the capacitors C11 and C12 can be at most l ⁇ F (for example, 0.1iF).
  • a microcomputer (microcomputer) 28 is an extremely low frequency signal below 20 Hz, for example? A signal corresponding to a wave of about 13 Hz is generated. This very low frequency signal is generated, for example, as a PWM (Pulse Width Modulation) signal.
  • the PWM signal output from the microcomputer 28 is converted into an analog audio signal by a three-stage filter including resistors R24 to R26 and capacitors C14 to C16.
  • the means for generating an ultra-low frequency signal is not limited to the method using the microcomputer 28.
  • a digital signal processing circuit such as a DSP (Digital Signal Processor) generates an ultra-low frequency digital signal, and the digital signal is converted to an analog signal by a digital converter.
  • DSP Digital Signal Processor
  • the resistors R24 to R26 and the capacitors C14 to C16 in FIG. 2 can be used as a DZA comparator.
  • a CRZL C oscillator or the like can be used to generate data by analog processing.
  • This low-frequency analog audio signal is input to the plus terminal of the operational amplifier 24 via the DC cut capacitor C13.
  • the input stage of the operational amplifier 24 is also provided with a bias resistor R 17, to which the output signal of the operational amplifier 21 is supplied.
  • this bias resistor R17 for example, 100 ⁇
  • the ultra-low frequency of 20Hz or less can be achieved. Can be passed through.
  • the three operational amplifiers 22 to 24 function as a summing amplifier. That is, the audio signal of the L channel output from the operational amplifier 22 and passed through the resistor R18 and the very low frequency audio signal output from the operational amplifier 24 and passed through the resistor R20 are added.
  • the R-channel audio signal output from the operational amplifier 23 and passed through the resistor R 19 and the ultra-low-frequency audio signal output from the operational amplifier 24 and passed through the resistor R 21 are added. Note that the resistors R 18 to R 21 have the same resistance value (for example, 20 ⁇ ).
  • the L-channel and R-channel audio signals input from the signal lines INL and INR are superimposed on the very low-frequency ⁇ -wave generated by the microcomputer 28.
  • the audio signals of the L and R channels superimposed on the a-wave are input to the minus terminals of the operational amplifiers 25 and 27 at the next stage.
  • These operational amplifiers 25 and 27 operate as inverting amplifiers, and output the amplified signals to the first signal lines OUT L and OUTR.
  • the audio signal output from each of the operational amplifiers 25 and 27 varies between 0 and 12 V according to the power supply voltage VCC supplied to the control terminal of each of the operational amplifiers 25 and 27.
  • the audio signals of the L and R channels output to the first signal lines OUT L and OUTR are output to the left and right headphones via a mouth-pass filter and a headphone connection terminal (not shown).
  • the other operational amplifier 26 operates using the intermediate voltage V CCZ2 supplied from the operational amplifier 21 as an input to the plus terminal.
  • the output of this operational amplifier 26 is also fed back to its own negative terminal.
  • the intermediate voltage reference signal output to the second signal line COM is output to both left and right headphones via a headphone connection terminal (not shown).
  • the intermediate voltage VCCZ2 is always applied to the second signal line COM
  • the maximum voltage VCC is applied to the L channel
  • the output voltage has shifted to the positive side by + VC CZ 2 (-VCC-VCC / 2).
  • the operation when viewed from the left headphone, the operation is performed such that the output voltage varies between one VCCZ2 and ten VCCZ2.
  • the right headphone Therefore, according to the present embodiment, it is possible to provide a DC cut capacitor on the first signal lines OUT L and OUTR to which the audio signals of the L and R channels are supplied.
  • the output voltage to the left and right headphones can be positive or negative.
  • the intermediate voltage (VCC / 2) of the reference signal used when outputting to the left and right headphones based on the difference between the audio signals of the L and R channels is determined by the driver 4 shown in FIG. Instead of the same switching amplifiers as in Figs.
  • the operational amplifier is used in this way, the impedance of the second signal line C ⁇ M can be made negligibly small when viewed from the left and right headphones.
  • a method of generating an intermediate voltage (VCC / 2) by smoothing a 50% duty pulse output from the switching amplifier using an LC filter can be considered.
  • the second signal line C ⁇ M Since the impedance when looking at the headphone amplifier becomes large, the output voltage to the second signal line COM fluctuates greatly depending on the flowing current. For this reason, the separation between the L channel and the R channel is deteriorated, and there is a disadvantage that one of the L and R channel audio signals is mixed into the other.
  • a switching amplifier outputs a pulse, noise is generated to some extent, and SZN is deteriorated.
  • the voltage fluctuation of the second signal line COM is suppressed. 2 can be maintained.
  • the separation between the L channel and the R channel ⁇ SZN can be maintained well, and the output voltage to the left and right headphones can be positively and negatively. Can be shaken.
  • the configuration of the operational amplifiers 21 and 26 is simple and good, and the operational amplifiers 21 and 26 can be built in the IC chip without increasing the circuit area.
  • the output voltage to the left and right headphones is positive and negative in the range of VCCZ 2 to 10 VCC / 2, and the output power is lower than in the conventional case where the output voltage is changed in the range of 1 VCC to 10 VCC. Is declining.
  • the output power is as high as this embodiment. It is enough.
  • This second embodiment is also applicable to both the PCM system and the 1-bit system.
  • FIG. 4 is a diagram illustrating a configuration example of a headphone amplifier according to the second embodiment.
  • components having the same functions as the components shown in FIG. 2 are denoted by the same reference numerals, and overlapping description will be omitted.
  • a circuit for generating a wave and superimposing an audio signal thereon (microcomputer 28, It does not have three-stage filters R24 to R26, C14 to C16, operational amplifier 24, and resistors R18 to R21). Other circuits are the same as in FIG. In the case of the configuration shown in Fig. 4, an audio signal superimposed on a wave is input from the signal lines INL and INR, and is output to a headphone (not shown) via the operational amplifiers 22, 23, 25, and 27. Is done.
  • the intermediate voltage VCCZ2 is always applied to the second signal line C0M, if the headphone is used, the voltage between -VCC2 and + VCCZ2 is Operates as if the output voltage is positive or negative. Therefore, the output voltage to the left and right headphones can be changed to positive and negative without providing a DC cut capacitor on the first signal lines OUTL and OUTR to which the audio signals of the L and R channels are supplied. .
  • This third embodiment is also applicable to both the PCM method and the 1-bit method.
  • FIG. 5 is a diagram showing a configuration example of a headphone pump according to the third embodiment. Note that, in FIG. 5, components having the same functions as the components shown in FIG. 2 are given the same reference numerals, and overlapping descriptions will be omitted.
  • two operational amplifiers 31 and 32 are used instead of the operational amplifier 26 shown in FIG.
  • the operational amplifier 31 operates using the output signal of the L-channel operational amplifier 25 as an input to the minus terminal.
  • the operational amplifier 32 operates with the output signal of the R-channel operational amplifier 27 as an input to the minus terminal. That is, these operational amplifiers 31 and 32 also operate as inverting amplifiers.
  • the operational amplifier 25 outputs the L channel audio signal fluctuated between 0 and 12 V to the signal line OUT L—, and the operational amplifier 31 inverts the phase of the output signal to the signal line OUT L—
  • the L channel audio signal is output to the signal line 0 UTL +.
  • the difference between the audio signals output to these signal lines OUTL- and OUTL + is calculated and output to the left headphone.
  • the operational amplifier 27 outputs the audio signal of the R channel fluctuated between 0 and 12 V to the signal line OUT R—, and the operational amplifier 32 has the phase of the output signal to the signal line OU TR—.
  • the inverted R channel audio signal is output to the signal line OUT R +.
  • the difference between the audio signals output to these signal lines OUTR— and OUTR + is output to the right headphone.
  • the output of one of the L-channel signal lines OUT L— When the voltage is the maximum of 12 V, the output voltage of the other signal line OUT L + is 0 V, and the difference voltage applied to the left headphone is 12 V.
  • the output voltage of one signal line OUTL— is the minimum 0 V
  • the output voltage of the other signal line OUTL + is 12 V
  • the difference voltage applied to the left headphone is 112 V. Therefore, when viewed from the left headphone, it operates as if the output voltage is fluctuated between 11 V and +12 V (1 V C C to 10 V C C). This is the same for the right headphone.
  • the output terminal to the headphones is Although four devices are needed and lack versatility, they have the advantage that an output power about twice as large as that of the first embodiment can be obtained.
  • the voltage dividing resistors R 11 and R 12 are used as a configuration for generating the intermediate voltage of the power supply voltage VCC, but the present invention is not limited to this. Not something. That is, the present invention can be applied to any configuration capable of generating an intermediate voltage.
  • the voltage supplied to the second signal line COM is 1Z2 like the analog power supply voltage VCC, but it is not strictly 1Z2. Is also good. That is, as long as a desired maximum amplitude voltage or more can be obtained, the bias voltage may be slightly offset to the GND side or the VCC side.
  • the headphone for stereo sound having two channels of L and R channels has been described.
  • the present invention is similarly applied to a headphone or earphone for monaural. It is possible to apply Further, in the above-described embodiment, an example in which left and right headphones are provided has been described. However, the present invention can be applied to an earphone having only one audio output unit.
  • first to third embodiments are particularly preferable when applied to portable electronic devices which are desired to be small and light, but may be applied to stationary electronic devices. Needless to say.
  • the power supply is provided on the second signal line.
  • the audio output unit By applying an intermediate voltage, it is possible for the audio output unit to operate as if the output voltage is positive or negative between (one power supply voltage / 2) and (+ power supply voltage Z2). it can.
  • the output voltage to the audio output unit can be changed to positive or negative without providing a DC cut capacitor on the first signal line to which the audio signal is supplied. Therefore, it is possible to omit a very large capacitor, which is conventionally required for outputting low-frequency sound, without impeding the reduction in size and weight of the device, and to reduce the frequency of extremely low frequency such as a-wave. Audio can be output to the audio output unit.
  • the impedance of the second signal line can be made negligibly small as viewed from the audio output unit. it can. This makes it possible to suppress the voltage fluctuation of the second signal line and to always maintain the potential at the intermediate voltage. Therefore, when the present invention is applied to stereo sound having two channels of the left channel and the right channel, the separation ⁇ SN of the left and right channels can be maintained well, and the output voltages of the left and right channels can be properly adjusted. You can shake it.
  • the present invention is useful for outputting a sound of an extremely low frequency such as a 0! Wave to a headphone without hindering reduction in size and weight of a portable device.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Multimedia (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Amplifiers (AREA)

Abstract

L'invention concerne une tension intermédiaire d'une tension d'alimentation servant à l'amplification d'un signal audio d'une première ligne de signal OUTL et OUTR qui est générée. Cette tension intermédiaire s'applique comme tension de signal de référence à une seconde ligne de signal COM. Ainsi, on n'a pas besoin d'avoir recours à un condensateur pour couper le courant continu sur la première ligne de signal OUTL et OUTR à laquelle on fournit un signal audio. On peut faire fonctionner la tension de sortie afin de passer de VCC/2 à VCC2 visualisé depuis un écouteur. En fait, on peut omettre un très grand condensateur qui a été requis pour produire une basse fréquence audio.
PCT/JP2002/004754 2001-05-21 2002-05-16 Amplificateur de sortie audio WO2002095935A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001-150815 2001-05-21
JP2001150815A JP2002345078A (ja) 2001-05-21 2001-05-21 音声出力アンプ

Publications (1)

Publication Number Publication Date
WO2002095935A1 true WO2002095935A1 (fr) 2002-11-28

Family

ID=18995772

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2002/004754 WO2002095935A1 (fr) 2001-05-21 2002-05-16 Amplificateur de sortie audio

Country Status (2)

Country Link
JP (1) JP2002345078A (fr)
WO (1) WO2002095935A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8081785B2 (en) 2006-03-21 2011-12-20 Fairchild Semiconductor Corporation High efficiency converter providing switching amplifier bias
US8081777B2 (en) 2006-03-21 2011-12-20 Fairchild Semiconductor Corporation Volume-based adaptive biasing
JP7106052B2 (ja) * 2018-08-28 2022-07-26 日本精機株式会社 振動アクチュエータの駆動装置、駆動方法及び操作装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02137507A (ja) * 1988-11-18 1990-05-25 Sanyo Electric Co Ltd 増幅器
JPH0575362A (ja) * 1991-09-13 1993-03-26 Onkyo Corp 平衡増幅器
JPH1093365A (ja) * 1996-09-18 1998-04-10 Mitsubishi Electric Corp オーディオ用電力増幅回路
JPH11284450A (ja) * 1998-03-31 1999-10-15 Toshiba Corp 電力増幅回路
JP2001094366A (ja) * 1999-09-24 2001-04-06 Conisis Kenkyusho:Kk オーディオ電力増幅器の疑似接地回路

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02137507A (ja) * 1988-11-18 1990-05-25 Sanyo Electric Co Ltd 増幅器
JPH0575362A (ja) * 1991-09-13 1993-03-26 Onkyo Corp 平衡増幅器
JPH1093365A (ja) * 1996-09-18 1998-04-10 Mitsubishi Electric Corp オーディオ用電力増幅回路
JPH11284450A (ja) * 1998-03-31 1999-10-15 Toshiba Corp 電力増幅回路
JP2001094366A (ja) * 1999-09-24 2001-04-06 Conisis Kenkyusho:Kk オーディオ電力増幅器の疑似接地回路

Also Published As

Publication number Publication date
JP2002345078A (ja) 2002-11-29

Similar Documents

Publication Publication Date Title
TWI465034B (zh) 放大器電路及放大器電路中放大訊號之方法
US20070036367A1 (en) Apparatus and method of reducing noise of earphones, noise reducing earphones, and a portable audio reproducing apparatus having the same
JP2007531419A (ja) 単一電源直接駆動増幅器
US20050200405A1 (en) Audio signal amplification method and apparatus
US20070223718A1 (en) Headphone driver and methods for use therewith
US6529787B2 (en) Multimedia computer speaker system with bridge-coupled subwoofer
JP2008118248A (ja) Ｄ級アンプの駆動方法、ｄ級アンプの駆動回路、静電型トランスデューサ、超音波スピーカ、表示装置、および指向性音響システム
JPH04250710A (ja) オーディオ回路
WO2002095935A1 (fr) Amplificateur de sortie audio
WO2002095936A1 (fr) Amplificateur de sortie audio
JP5257288B2 (ja) 音声信号切り換えノイズ低減回路
JP2008148147A (ja) 増幅回路、それを用いたオーディオ再生装置ならびに電子機器
JP2007142996A (ja) オーディオミキシング装置
JP5514036B2 (ja) オーディオ用増幅器およびそれを用いた電子機器
US10461709B2 (en) Amplifier with auxiliary path for maximizing power supply rejection ratio
JP2004031998A (ja) 音響駆動回路
US20080088371A1 (en) Method, apparatus and system for reducing DC coupling capacitance at switching amplifier
KR101739087B1 (ko) 하이파이를 제공하는 오디오 신호 증폭 회로 및 방법
US8660276B2 (en) Driving circuit for a sound outputting apparatus
JPH08222976A (ja) オーディオ信号増幅装置
JP4861117B2 (ja) ミュート回路、それを用いたオーディオ信号増幅回路ならびに電子機器
JP4230332B2 (ja) オーディオ機器およびオーディオシステム
JP3929832B2 (ja) 入力信号処理回路
JP2007060510A (ja) デジタルアンプ
Mujawar et al. Stereo Audio Amplifier Board Using TDA2822

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CN KR US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase