JP2844479B2 - Power supply fluctuation compensation circuit for switching amplifier - Google Patents
Power supply fluctuation compensation circuit for switching amplifierInfo
- Publication number
- JP2844479B2 JP2844479B2 JP1298957A JP29895789A JP2844479B2 JP 2844479 B2 JP2844479 B2 JP 2844479B2 JP 1298957 A JP1298957 A JP 1298957A JP 29895789 A JP29895789 A JP 29895789A JP 2844479 B2 JP2844479 B2 JP 2844479B2
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- Japan
- Prior art keywords
- power supply
- fluctuation
- correction rate
- pwm signal
- signal
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Description
【発明の詳細な説明】 〔概 要〕 PWM信号でスピーカを駆動するスイッチングアンプの
電源変動補償回路に関し、 電源電圧の変動によるスピーカ出力の変動を補償する
と共に、該補償によって最大出力レベルが低下しないよ
うにすることを目的とし、 オーディオ信号の振幅情報でパルス幅変調されたPWM
信号を入力とし、該PWM信号で駆動されるスイッチング
素子を通して変動のある電源電圧を間欠的にスピーカに
印加するスイッチングアンプの電源変動補償回路におい
て、前記電源電圧の変動を検出する電源変動検出回路
と、前記PWM信号のパルス幅を該電源電圧の変動幅に応
じて伸縮する補正率を算出する補正率算出部と、前記オ
ーディオ信号の振幅調整用ボリュームの作動量を検出す
るボリューム位置検出回路と、前記ボリューム位置検出
回路で検出されたボリュームの作動量から、前記補正率
に入力信号レベルに応じた重み付けを行う重み付け係数
を算出する重み付け算出部と、前記PWM信号のパルス幅
を前記補正率と重み付け係数を用いて補正する合成部を
備えるよう構成し、または オーディオ信号の振幅情報でパルス幅変調されたPWM
信号を入力とし、該PWM信号で駆動されるスイッチング
素子を通して変動のある電源電圧を間欠的にスピーカに
印加するスイッチングアンプの電源変動補償回路におい
て、前記電源電圧の変動を検出する電源変動検出回路
と、前記PWM信号のパルス幅を該電源電圧の変動幅に応
じて伸縮する補正率を算出する補正率算出部と、前記オ
ーディオ信号の振幅調整用ボリュームの出力レベルを検
出するレベル検出回路と、前記レベル検出回路で検出さ
れたボリュームの出力レベルから、前記補正率に入力信
号レベルに応じた重み付けを行う重み付け係数を算出す
る重み付け算出部と、前記PWM信号のパルス幅を前記補
正率と重み付け係数を用いて補正する合成部とを備える
よう構成する。DETAILED DESCRIPTION OF THE INVENTION [Summary] A power supply fluctuation compensation circuit for a switching amplifier that drives a speaker with a PWM signal compensates for fluctuations in speaker output due to fluctuations in power supply voltage and does not reduce the maximum output level due to the compensation. PWM with pulse width modulation with audio signal amplitude information
A power supply fluctuation compensation circuit for a switching amplifier that receives a signal as input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal; and a power supply fluctuation detection circuit that detects the fluctuation of the power supply voltage. A correction rate calculation unit that calculates a correction rate that expands and contracts the pulse width of the PWM signal in accordance with the fluctuation width of the power supply voltage, and a volume position detection circuit that detects an operation amount of the amplitude adjustment volume of the audio signal. A weighting calculation unit that calculates a weighting coefficient for weighting the correction rate according to an input signal level from the operation amount of the volume detected by the volume position detection circuit; and weighting the pulse width of the PWM signal with the correction rate. PWM that is configured to have a synthesis unit that corrects using coefficients or that is pulse width modulated with the amplitude information of the audio signal
A power supply fluctuation compensation circuit for a switching amplifier that receives a signal as input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal; and a power fluctuation detection circuit that detects the fluctuation of the power voltage. A correction rate calculation unit that calculates a correction rate that expands and contracts the pulse width of the PWM signal in accordance with the fluctuation width of the power supply voltage, a level detection circuit that detects an output level of an amplitude adjustment volume of the audio signal, From the output level of the volume detected by the level detection circuit, a weighting calculation unit that calculates a weighting coefficient that weights the correction rate according to the input signal level, and calculates the pulse width of the PWM signal by using the correction rate and the weighting coefficient. And a synthesizing unit for performing correction by using it.
本発明は、PWM信号でスピーカを駆動するスイッチン
グアンプの電源変動補償回路に関する。The present invention relates to a power supply fluctuation compensation circuit for a switching amplifier that drives a speaker using a PWM signal.
電源電圧の変動が出力に影響を与える回路では、電源
変動を抑制するか、その変動を検出して出力を補正する
ことが望ましい。ところが、車載用機器で電源をバッテ
リ直結とした場合には、電源電圧を安定化することはで
きない（負荷の増減等によって大きく変動する）ため、
電源変動を検出して機器出力を補正する方法が効果的で
ある。In a circuit in which a change in the power supply voltage affects the output, it is desirable to suppress the power supply change or to detect the change and correct the output. However, when the power supply is directly connected to the battery in the in-vehicle equipment, the power supply voltage cannot be stabilized (it fluctuates greatly due to the increase and decrease of the load, etc.).
A method of detecting a power supply fluctuation and correcting the device output is effective.
車載用オーディオ機器はソース（音源）のデジタル化
に伴ない各部もデジタル化される傾向にある。スピーカ
を駆動する電力増幅器もその一例で、ここにスイッチン
グアンプと呼ばれるデジタルアンプを使用すると大出力
を実現できる。In a vehicle-mounted audio device, each unit tends to be digitized with the digitization of a source (sound source). A power amplifier for driving a speaker is one example. If a digital amplifier called a switching amplifier is used here, a large output can be realized.
第４図はスイッチングアンプの説明図で、SPはスピー
カ、Q1〜Q4はスイッチング素子、Ａは制御信号、はそ
の反転信号、Vccは電源、GNDはアースである。素子Q1,Q
3は信号ＡがＨ（ハイ）のときにオンとなり、スピーカS
Pに実線矢印の極性で駆動電流を流す。これに対し素子Q
2,Q4は信号がＨのときにオンになり、スピーカSPに逆
極性の電流（破線矢印で示す）を流す。本例はBTL方式
としているため素子数が多いが、簡単にはスピーカSPの
一端を接地し、他端側の素子対Q1,Q2またはQ3,Q4を用い
るだけでよい。In illustration of FIG. 4 is a switching amplifier, SP speaker, Q 1 to Q 4 are the switching elements, A is the control signal, the inverted signal, Vcc is the power supply, GND is grounded. Element Q 1 , Q
3 turns on when the signal A is H (high), and the speaker S
A drive current is applied to P with the polarity of the solid arrow. On the other hand, element Q
2, Q 4 is turned on when the signal is H, the flow of the opposite polarity of the current (indicated by a dotted arrow) to the speaker SP. In this example, since the BTL method is used, the number of elements is large. However, simply, one end of the speaker SP is grounded, and only the element pair Q 1 , Q 2 or Q 3 , Q 4 on the other end may be used.
制御信号A,は一定周期のパルス列（キャリア）の各
パルスのデューティをオーディオ信号の振幅に応じて変
化させたPWM（パルス幅変調）信号である。このPWM信号
で素子Q1〜Q4を駆動すると、スピーカSPには電源電圧と
PWM信号のデューティに応じて積分された駆動電流が流
れ、これを平滑化すると元のアナログ値に復元されたオ
ーディオ信号がスピーカSPから再生される。The control signal A is a PWM (pulse width modulation) signal in which the duty of each pulse of a pulse train (carrier) having a constant period is changed according to the amplitude of the audio signal. Driving element Q 1 to Q 4 in this PWM signal, and the power supply voltage to the speaker SP
A drive current integrated in accordance with the duty of the PWM signal flows. When the drive current is smoothed, an audio signal restored to the original analog value is reproduced from the speaker SP.
第５図にはPWM信号のキャリアと、スピーカSPに印加
される電圧波形（PWM信号と相似）、および平滑化され
てスピーカSPに流れる駆動電流の波形を示してある。電
源電圧は、PWM信号の振幅を決定するものである。FIG. 5 shows the carrier of the PWM signal, the voltage waveform applied to the speaker SP (similar to the PWM signal), and the waveform of the drive current which is smoothed and flows through the speaker SP. The power supply voltage determines the amplitude of the PWM signal.
第４図の回路の電源Vccが車両のバッテリであると、
その電圧は負荷（例えばエアコンディショナ）の増減に
よって大きく変動する。この結果、スピーカSPの印加電
圧が例えば第５図のVccからVcc′に低下した場合、スピ
ーカ駆動電流も実線の（Vcc）から破線の（Vcc′）に減
少するため、スピーカSPで再生される音圧が低下する。If the power supply Vcc of the circuit of FIG. 4 is a vehicle battery,
The voltage fluctuates greatly according to the increase and decrease of the load (for example, the air conditioner). As a result, when the voltage applied to the speaker SP decreases from Vcc in FIG. 5 to Vcc ', for example, the speaker drive current also decreases from the solid line (Vcc) to the broken line (Vcc'), so that the speaker SP is reproduced. Sound pressure decreases.
この電源変動を補正するために安定化電源を用いる
と、スピーカ印加電圧は最初から低くなるので、デジタ
ルアンプの特長である高効率が実現できないだけでな
く、回路を小型化できない欠点がある。If a stabilized power supply is used to correct the power supply fluctuation, the voltage applied to the speaker is reduced from the beginning, so that not only high efficiency, which is a feature of the digital amplifier, cannot be realized, but also the circuit cannot be downsized.
本発明は、上述した電源変動をスイッチングアンプの
入力（PWM信号）に反映させることにより、その影響を
除去しようとするものである。The present invention is intended to eliminate the influence by reflecting the above-mentioned power supply fluctuation on the input (PWM signal) of the switching amplifier.
本発明は、オーディオ信号の振幅情報でパルス幅変調
されたPWM信号を入力とし、該PWM信号で駆動されるスイ
ッチング素子を通して変動のある電源電圧を間欠的にス
ピーカに印加するスイッチングアンプの電源変動補償回
路において、前記電源電圧の変動を検出する電源変動検
出回路と、前記PWM信号のパルス幅を該電源電圧の変動
幅に応じて伸縮する補正率を算出する補正率算出部と、
前記オーディオ信号の振幅調整用ボリュームの作動量を
検出するボリューム位置検出回路と、前記ボリューム位
置検出回路で検出されたボリュームの作動量から、前記
補正率に入力信号レベルに応じた重み付けを行う重み付
け係数を算出する重み付け算出部と、前記PWM信号のパ
ルス幅を前記補正率と重み付け係数を用いて補正する合
成部を備えることを特徴とし、または オーディオ信号の振幅情報でパルス幅変調されたPWM
信号を入力とし、該PWM信号で駆動されるスイッチング
素子を通して変動のある電源電圧を間欠的にスピーカに
印加するスイッチングアンプの電源変動補償回路におい
て、前記電源電圧の変動を検出する電源変動検出回路
と、前記PWM信号のパルス幅を該電源電圧の変動幅に応
じて伸縮する補正率を算出する補正率算出部と、前記オ
ーディオ信号の振幅調整用ボリュームの出力レベルを検
出するレベル検出回路と、前記レベル検出回路で検出さ
れたボリュームの出力レベルから、前記補正率に入力信
号レベルに応じた重み付けを行う重み付け係数を算出す
る重み付け算出部と、前記PWM信号のパルス幅を前記補
正率と重み付け係数を用いて補正する合成部とを備える
ことを特徴とする。The present invention relates to a power supply fluctuation compensation of a switching amplifier that receives a PWM signal pulse-width modulated with amplitude information of an audio signal as an input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal. In the circuit, a power supply fluctuation detection circuit that detects the fluctuation of the power supply voltage, a correction rate calculation unit that calculates a correction rate that expands and contracts the pulse width of the PWM signal according to the fluctuation width of the power supply voltage,
A volume position detection circuit that detects an operation amount of the amplitude adjustment volume of the audio signal; and a weighting coefficient that weights the correction rate according to an input signal level from the operation amount of the volume detected by the volume position detection circuit. And a synthesizing unit that corrects the pulse width of the PWM signal using the correction rate and the weighting coefficient, or a PWM that is pulse width modulated with amplitude information of an audio signal.
A power supply fluctuation compensation circuit for a switching amplifier that receives a signal as input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal; and a power supply fluctuation detection circuit that detects the fluctuation of the power supply voltage. A correction rate calculation unit that calculates a correction rate that expands and contracts the pulse width of the PWM signal in accordance with the fluctuation width of the power supply voltage, a level detection circuit that detects an output level of an amplitude adjustment volume of the audio signal, From the output level of the volume detected by the level detection circuit, a weighting calculation unit that calculates a weighting coefficient that weights the correction rate according to the input signal level, and calculates the pulse width of the PWM signal by using the correction rate and the weighting coefficient. And a synthesizing unit for performing correction by using the synthesizing unit.
第１図（ａ）に示すようにスピーカ印加電圧が電源変
動によってVccからVcc′に低下したとき、本発明では電
源変動検出回路によってこれを検出し、補正率算出部に
よってパルス幅ｔをｔ′に拡張するための補正率αを算
出する。この補正率αを用いると、振幅Vcc、幅ｔのパ
ルス（実線）の面積と振幅Vcc′、幅ｔ′のパルス（破
線）の面積が等しくなる。As shown in FIG. 1 (a), when the voltage applied to the loudspeaker drops from Vcc to Vcc 'due to power fluctuation, in the present invention, this is detected by the power fluctuation detecting circuit, and the pulse width t is changed to t' by the correction factor calculating section. The correction rate α is calculated to extend the correction to α. When this correction rate α is used, the area of the pulse (solid line) having the amplitude Vcc and the width t is equal to the area of the pulse (dashed line) having the amplitude Vcc ′ and the width t ′.
このようにパルス幅を補正すると、スピーカ印加電圧
がVcc′に低下してもスピーカ駆動電流は変らないの
で、スピーカ出力はVccのときと同じ音圧を保つことが
できる。When the pulse width is corrected in this manner, the speaker drive current does not change even if the speaker applied voltage drops to Vcc ', so that the speaker output can maintain the same sound pressure as at Vcc.
但し、このパルス幅の補正を大信号入力時にも可能と
するために、PWM信号の変化範囲を、予想される最大電
源変動率分だけ予め狭めておくことは、アンプの最大出
力を初めから制限してしまうため好ましくない。However, in order to enable this pulse width correction even when a large signal is input, narrowing the change range of the PWM signal by the expected maximum power supply fluctuation rate in advance limits the maximum output of the amplifier from the beginning. Is not preferred.
そこで本発明では第１図（ｃ）のような大信号入力時
には電源変動の補償を少なくしてアンプ出力の飽和を許
容し、同図（ｂ）のような小信号入力時に最大限電源変
動の補償を行うことで、最大出力の低下をきたさないよ
うにする。このような出力特性はアナログアンプに近い
ものとなる。Therefore, in the present invention, the compensation of the power supply fluctuation is reduced at the time of inputting a large signal as shown in FIG. 1 (c) to allow the saturation of the amplifier output, and at the time of inputting a small signal as shown in FIG. By performing compensation, the maximum output is not reduced. Such output characteristics are close to those of an analog amplifier.
このため本発明では、前述の補正率αに入力信号レベ
ルに応じた重み付けを行う。重み付け算出部はこのため
の係数βを算出する。For this reason, in the present invention, the correction rate α is weighted according to the input signal level. The weight calculation unit calculates a coefficient β for this.
本発明の第１の方式では入力信号レベルを調整するボ
リュームの作動量（機械式であれば位置、デジタル式で
あれば係数）をボリューム位置検出回路で検出し、その
出力を重み付け算出部に入力する。本発明の第２の方式
ではボリュームの出力レベルをレベル検出回路で検出
し、その出力を重み付け算出部に入力する。In the first method of the present invention, the operation amount (position in the case of a mechanical type, coefficient in the case of a digital type) of a volume for adjusting an input signal level is detected by a volume position detection circuit, and its output is input to a weighting calculation unit. I do. In the second method of the present invention, the output level of a volume is detected by a level detection circuit, and the output is input to a weight calculation unit.
第２図は本発明の第１実施例を示す構成図で、10はPC
M/PWM変換回路、21はスイッチングアンプのドライバ
段、22はその電力増幅段、SPはスピーカ、30は電源変動
検出回路、40はボリューム位置検出回路、51はボリュー
ム、52はソース切替スイッチ、53はA/D変換器である。FIG. 2 is a block diagram showing a first embodiment of the present invention.
M / PWM conversion circuit, 21 is a switching amplifier driver stage, 22 is its power amplification stage, SP is a speaker, 30 is a power supply fluctuation detection circuit, 40 is a volume position detection circuit, 51 is a volume, 52 is a source switch, 53 Is an A / D converter.
本装置の外部入力にはCD（コンパクトディスク）等の
デジタルソースからのＤ（デジタル）入力と、チューナ
等のアナログソースからのＡ（アナログ）入力があり、
後者はA/D変換器53でデジタル信号に変換される。従っ
て、ソース切替スイッチ52を通したボリューム51の入力
は全てＤ入力となる。このボリューム51と後段のPCM/PW
M変換回路10はDSP（デジタル信号処理器）にて実現でき
る。The external input of this device includes a D (digital) input from a digital source such as a CD (compact disk) and an A (analog) input from an analog source such as a tuner.
The latter is converted into a digital signal by the A / D converter 53. Therefore, all inputs of the volume 51 through the source changeover switch 52 become D inputs. This volume 51 and PCM / PW of the latter stage
The M conversion circuit 10 can be realized by a DSP (digital signal processor).
PCM/PWM変換器10は、ボリューム51の出力（PCM信号）
をPWM信号に変換するPWM変換部11と、電源変動検出回路
30で検出された電源Vccの変動分からパルス幅の補正率
αを算出する補正率算出部12と、ボリューム位置検出回
路40で検出されたボリューム51の係数から重み付け係数
βを算出する重み付け算出部13と、PWM変換部11で得ら
れたPWM信号のパルス幅を補正率αと重み付け係数βを
用いて補正する合成部14とを備える。PCM / PWM converter 10 outputs volume 51 (PCM signal)
Conversion unit 11 for converting the signal into a PWM signal, and power supply fluctuation detection circuit
A correction rate calculation unit 12 that calculates a correction rate α of the pulse width from the fluctuation amount of the power supply Vcc detected at 30, and a weight calculation unit 13 that calculates a weighting coefficient β from the coefficient of the volume 51 detected by the volume position detection circuit 40 And a synthesizing unit 14 for correcting the pulse width of the PWM signal obtained by the PWM conversion unit 11 using the correction rate α and the weighting coefficient β.
電源変動の補正率αは第１図（ａ）で説明した通りの
もので、Vccを最大値、Vcc′を現在値とすればVcc/Vc
c′に比例する。一方、重み付け係数βはボリューム51
の出力レベルが増大するにつれ小さくなる特性を有す
る。本例ではこのボリューム51の出力レベルをボリュー
ム51の係数から間接的に検出するため、構成は簡単であ
るが実際にはボリューム51の入力レベルがソースによっ
て異なるとその分が誤差になる。The power fluctuation correction rate α is as described in FIG. 1 (a). If Vcc is the maximum value and Vcc ′ is the current value, Vcc / Vc
It is proportional to c '. On the other hand, the weighting coefficient β is
Has a characteristic that it becomes smaller as the output level increases. In this example, since the output level of the volume 51 is indirectly detected from the coefficient of the volume 51, the configuration is simple. However, if the input level of the volume 51 differs depending on the source, an error will occur.
第３図に示す本発明の第２実施例はこの点を改善する
ものであり、レベル検出回路60でボリューム51の出力レ
ベル（平均値またはピーク値）を直接検出する。本例の
PCM/PWM変換回路10は第２図と同じ内部構成を有し、ま
た電力増幅部20は第２図のドライバ段21と電力増幅段22
を包含したものである。The second embodiment of the present invention shown in FIG. 3 improves this point, and the level detection circuit 60 directly detects the output level (average value or peak value) of the volume 51. In this example
The PCM / PWM conversion circuit 10 has the same internal configuration as that of FIG. 2, and the power amplification unit 20 includes a driver stage 21 and a power amplification stage 22 shown in FIG.
Is included.
電源変動検出回路30は、電源Vccで動作するA/D変換器
に定電圧を入力し、そのA/D変換出力を電源変動検出出
力とする構成、或いは定電圧で動作するA/D変換器に電
源Vccを分圧して入力し、そのA/D変換出力を電源変動検
出出力とする構成等で実現できる。The power supply fluctuation detection circuit 30 has a configuration in which a constant voltage is input to an A / D converter that operates on the power supply Vcc, and the A / D conversion output is used as a power supply fluctuation detection output, or an A / D converter that operates on a constant voltage. The power supply Vcc is divided and input, and the A / D conversion output is used as a power fluctuation detection output.
以上述べたように本発明によれば、PWM信号を入力と
するスイッチングアンプの電源変動を補償し、スピーカ
出力を常に安定に保つことができる。また、入力レベル
に制限を設けなくて良いので、最大出力を低下させずに
済む利点がある。As described above, according to the present invention, it is possible to compensate for fluctuations in the power supply of a switching amplifier that receives a PWM signal as input, and to always maintain a stable speaker output. Further, since there is no need to limit the input level, there is an advantage that the maximum output does not need to be reduced.
第１図は本発明の動作説明図、 第２図は本発明の第１実施例の構成図、 第３図は本発明の第２実施例の構成図、 第４図はスイッチングアンプの説明図、 第５図は第４図の動作波形図である。 図中、SPはスピーカ、20は電力増幅部、21はドライバ
段、22は電力増幅段、Q1〜Q4はスイッチング素子、12は
補正率算出部、13は重み付け算出部、30は電源変動検出
回路、40はボリューム位置検出回路、51はボリューム、
60はレベル検出回路である。FIG. 1 is a diagram for explaining the operation of the present invention, FIG. 2 is a block diagram of a first embodiment of the present invention, FIG. 3 is a block diagram of a second embodiment of the present invention, and FIG. FIG. 5 is an operation waveform diagram of FIG. In the figure, SP is a speaker, 20 a power amplifier section, 21 is a driver stage, power amplifier stage 22, Q 1 to Q 4 are the switching elements, 12 correction factor calculator, 13 weight calculating unit, 30 power supply variation Detection circuit, 40 is a volume position detection circuit, 51 is a volume,
60 is a level detection circuit.
フロントページの続き (72)発明者 上村 正継 兵庫県神戸市兵庫区御所通１丁目２番28 号 富士通テン株式会社内 (56)参考文献 特開 昭61−39708（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) H03F 3/217 H03F 1/30 H03G 3/02 - 3/18Continuation of the front page (72) Inventor Masatsugu Uemura 1-2-28 Goshodori, Hyogo-ku, Kobe-shi, Hyogo Inside Fujitsu Ten Co., Ltd. (56) References JP-A-61-39708 (JP, A) (58) Survey Field (Int.Cl. 6 , DB name) H03F 3/217 H03F 1/30 H03G 3/02-3/18
Claims (2)
されたPWM信号を入力とし、該PWM信号で駆動されるスイ
ッチング素子を通して変動のある電源電圧を間欠的にス
ピーカに印加するスイッチングアンプの電源変動補償回
路において、 前記電源電圧の変動を検出する電源変動検出回路（30）
と、 前記PWM信号のパルス幅を該電源電圧の変動幅に応じて
伸縮する補正率を算出する補正率算出部（12）と、 前記オーディオ信号の振幅調整用ボリュームの作動量を
検出するボリューム位置検出回路（40）と、 前記ボリューム位置検出回路で検出されたボリュームの
作動量から、前記補正率に入力信号レベルに応じた重み
付けを行う重み付け係数を算出する重み付け算出部（1
3）と、 前記PWM信号のパルス幅を前記補正率と重み付け係数を
用いて補正する合成部（14）を備えることを特徴とする
スイッチングアンプの電源変動補償回路。1. A power supply fluctuation of a switching amplifier which receives a PWM signal pulse-width modulated with amplitude information of an audio signal as an input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal. In a compensation circuit, a power supply fluctuation detection circuit for detecting a fluctuation of the power supply voltage (30)
A correction rate calculation unit (12) for calculating a correction rate for expanding and contracting the pulse width of the PWM signal in accordance with the fluctuation width of the power supply voltage; and a volume position for detecting an operation amount of the amplitude adjustment volume of the audio signal. A detection circuit (40), and a weight calculation unit (1) that calculates a weighting coefficient for weighting the correction rate according to an input signal level from the operation amount of the volume detected by the volume position detection circuit.
3) a power supply fluctuation compensation circuit for a switching amplifier, comprising: a synthesizing unit (14) for correcting the pulse width of the PWM signal using the correction rate and the weighting coefficient.
されたPWM信号を入力とし、該PWM信号で駆動されるスイ
ッチング素子を通して変動のある電源電圧を間欠的にス
ピーカに印加するスイッチングアンプの電源変動補償回
路において、 前記電源電圧の変動を検出する電源変動検出回路（30）
と、 前記PWM信号のパルス幅を該電源電圧の変動幅に応じて
伸縮する補正率を算出する補正率算出部（12）と、 前記オーディオ信号の振幅調整用ボリュームの出力レベ
ルを検出するレベル検出回路（60）と、 前記レベル検出回路で検出されたボリュームの出力レベ
ルから、前記補正率に入力信号レベルに応じた重み付け
を行う重み付け係数を算出する重み付け算出部（13）
と、 前記PWM信号のパルス幅を前記補正率と重み付け係数を
用いて補正する合成部（14）とを備えることを特徴とす
るスイッチングアンプの電源変動補償回路。2. A power supply fluctuation of a switching amplifier which receives a PWM signal pulse-width modulated with amplitude information of an audio signal as an input and intermittently applies a fluctuating power supply voltage to a speaker through a switching element driven by the PWM signal. In a compensation circuit, a power supply fluctuation detection circuit for detecting a fluctuation of the power supply voltage (30)
A correction rate calculating unit (12) for calculating a correction rate for expanding and contracting the pulse width of the PWM signal in accordance with the fluctuation width of the power supply voltage; and a level detection for detecting an output level of the amplitude adjustment volume of the audio signal. A circuit (60), and a weight calculation unit (13) for calculating a weighting coefficient for weighting the correction rate according to an input signal level from an output level of the volume detected by the level detection circuit.
And a synthesizing section (14) for correcting the pulse width of the PWM signal using the correction rate and the weighting coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1298957A JP2844479B2 (en) | 1989-11-17 | 1989-11-17 | Power supply fluctuation compensation circuit for switching amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1298957A JP2844479B2 (en) | 1989-11-17 | 1989-11-17 | Power supply fluctuation compensation circuit for switching amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03159409A JPH03159409A (en) | 1991-07-09 |
| JP2844479B2 true JP2844479B2 (en) | 1999-01-06 |
Family
ID=17866375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1298957A Expired - Fee Related JP2844479B2 (en) | 1989-11-17 | 1989-11-17 | Power supply fluctuation compensation circuit for switching amplifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2844479B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100433548C (en) * | 2002-11-15 | 2008-11-12 | 松下电器产业株式会社 | Power amplifier |
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|---|---|---|---|---|
| JP2002230905A (en) * | 2001-01-29 | 2002-08-16 | Niigata Seimitsu Kk | Device and method for reproducing voice |
| US6765436B1 (en) * | 2002-09-04 | 2004-07-20 | Cirrus Logic, Inc. | Power supply based audio compression for digital audio amplifier |
| EP1429454A1 (en) * | 2002-12-11 | 2004-06-16 | Dialog Semiconductor GmbH | Center of gravity compensation of class-D amplifier |
| EP1429455A1 (en) * | 2002-12-11 | 2004-06-16 | Dialog Semiconductor GmbH | Linearization of a PDM class-D amplifier |
| DE60317299T2 (en) | 2003-02-17 | 2008-08-28 | D&M Holdings, Inc., Sagamihara | Pulse width modulation amplifier |
| JP2005192067A (en) * | 2003-12-26 | 2005-07-14 | Matsushita Electric Ind Co Ltd | Audio amplifier |
| JP4445304B2 (en) | 2004-03-26 | 2010-04-07 | オンキヨー株式会社 | Switching amplifier |
| JP2006180199A (en) * | 2004-12-22 | 2006-07-06 | Alpine Electronics Inc | Digital amplifier mounting apparatus |
| JP2008047945A (en) * | 2005-03-28 | 2008-02-28 | Nec Saitama Ltd | Amplifier apparatus |
| JP4933583B2 (en) * | 2009-06-19 | 2012-05-16 | 株式会社デジタル | Alarm sound generation circuit |
| CN103500574B (en) * | 2012-08-16 | 2017-06-27 | 万喻 | A kind of intelligent electronic horn and its implementation |
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1989
- 1989-11-17 JP JP1298957A patent/JP2844479B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100433548C (en) * | 2002-11-15 | 2008-11-12 | 松下电器产业株式会社 | Power amplifier |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03159409A (en) | 1991-07-09 |
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