JPS63219211A - Switching amplifier - Google Patents

Switching amplifier

Info

Publication number
JPS63219211A
JPS63219211A JP24794186A JP24794186A JPS63219211A JP S63219211 A JPS63219211 A JP S63219211A JP 24794186 A JP24794186 A JP 24794186A JP 24794186 A JP24794186 A JP 24794186A JP S63219211 A JPS63219211 A JP S63219211A
Authority
JP
Japan
Prior art keywords
analog
signal
amplifier
amplifier circuit
switching
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
JP24794186A
Other languages
Japanese (ja)
Inventor
Masanori Fujisawa
雅憲 藤沢
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sanyo Electric Co Ltd
Original Assignee
Sanyo Electric 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 Sanyo Electric Co Ltd filed Critical Sanyo Electric Co Ltd
Priority to JP24794186A priority Critical patent/JPS63219211A/en
Publication of JPS63219211A publication Critical patent/JPS63219211A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To obtain a highly efficient amplifier characteristic while eliminating the effect of a pulse obstacle by using the amplifier at the AM radio reception while the amplifier is switched to an analog amplifier in a switching amplifier applying pulse width modulation to an analog signal. CONSTITUTION:When an input signal fed to an input terminal 11 is an analog signal such as an audio signal, a switch driving section 25 throws changeover switches (SW) 22, 23 to the switching amplifier circuit 13 to disconnect an analog amplifier circuit 26. Thus, the analog signal is amplified by an input stage 12 and subject to pulse width modolation at a modulator 15 by a carrier signal sent from a carrier signal generator 14, amplified by a pulse width amplifier 16 and on/off-control by a switch driving section 17. Moreover, when the input signal fed to the terminal 11 is an analog signal for AM radio, the switches SWs22, 23 are thrown to the position of the analog amplifier circuit 26. Thus, the radio interference at AM radio reception is excluded to amplify the analog signal such as audio signal with high efficiency.

Description

【発明の詳細な説明】 (イ)産業上の利用分野 本発明は、アナログ信号をパルス幅変調して増幅するス
イッチング増幅器に関するものて、特にオーディオ機器
等の駆動に用いて好適なスイッチング増幅器に関するも
のである。
DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a switching amplifier that amplifies an analog signal by pulse width modulating it, and particularly relates to a switching amplifier suitable for use in driving audio equipment, etc. It is.

(ロ)従来の技術 アナログ入力信号をパルス幅変調して増幅する、いわゆ
るPWM方式のスイッチング増幅器か知られている。前
記スイッチング増幅器は、第2図に示す如く、入力端子
(1)に印加されるオーディオ信号等のアナログ入力信
号を増幅する入力段(2)と、該入力段(2)の出力信
号を前記アナログ信号よりも十分に高いキャリア信号を
送出するキャリア信号発生器(3)からの信号を用いて
パルス幅変調する変調器(4)と、該変調器(4)の出
力を増幅するパルス増幅器(5)と、該パルス増幅器(
5)の出力でオン・オフさせるスイッチング素子(6)
と、該スイッチング素子(6)の出力を復調するローパ
スフィルタ(7)と、前記復調出力を負帰還する負帰還
回路(8)とから構成され、前記ローパスフィルタ(7
)の出力端子(9)に接続された負荷(10)に復調出
力か供給される。第2図(a)はキャリア信号発生器(
3)から送出される3角波等のキャリア信号、同図(b
)は入力端子(1)に印加されるオーディオ入力信号、
同図(c)は変調器(4)の出力、同図(d)はローパ
スフィルタ(7)の出力端子(9)に出力される復調出
力である。
(b) Prior Art A so-called PWM type switching amplifier is known, which amplifies an analog input signal by pulse width modulating it. As shown in FIG. 2, the switching amplifier includes an input stage (2) that amplifies an analog input signal such as an audio signal applied to an input terminal (1), and an output signal of the input stage (2) that amplifies the analog input signal such as an audio signal applied to an input terminal (1). A modulator (4) that performs pulse width modulation using a signal from a carrier signal generator (3) that sends out a carrier signal that is sufficiently higher than the carrier signal, and a pulse amplifier (5) that amplifies the output of the modulator (4). ) and the pulse amplifier (
Switching element (6) that is turned on and off by the output of 5)
, a low-pass filter (7) that demodulates the output of the switching element (6), and a negative feedback circuit (8) that negatively feeds back the demodulated output.
) is supplied with the demodulated output to a load (10) connected to the output terminal (9). Figure 2(a) shows the carrier signal generator (
3) A carrier signal such as a triangular wave transmitted from the same figure (b)
) is the audio input signal applied to input terminal (1),
(c) in the same figure shows the output of the modulator (4), and (d) in the same figure shows the demodulated output output to the output terminal (9) of the low-pass filter (7).

しかして、前記スイッチング増幅器は、スイッチング素
子(6)のオン抵抗か零であれば、原理的に損失か発生
しない為、高効率な特性が得られる。
Therefore, in the switching amplifier, if the on-resistance of the switching element (6) is zero, no loss occurs in principle, so that highly efficient characteristics can be obtained.

(ノリ発明か解決しようとする問題点 しかしながら、第2図の如き増幅器では、キャリア信号
発生器(3)の周波数か300 KH2から500KH
,程度のものであり、この周波数の信号かキャリア信号
発生器(3)、あるいはスイッチング素子(6)から輻
射されることがあった。その為、例えば、ラジオカセッ
ト等においてラジオモードて使用する場合には、前記キ
ャリア信号の周波数の高調波がAMラジオ受信器の受信
周波数帯である525KH,から1605KH,の中波
に近くなり、電波障害の影響を与える問題点かあった。
(Problem to be solved by this invention) However, in the amplifier as shown in Fig. 2, the frequency of the carrier signal generator (3) is 300KH2 to 500KH2.
, and a signal of this frequency was sometimes radiated from the carrier signal generator (3) or the switching element (6). Therefore, for example, when using a radio cassette or the like in radio mode, the harmonics of the frequency of the carrier signal become close to medium waves in the receiving frequency band of the AM radio receiver, 525KH to 1605KH, and the radio waves There were some problems that affected the disability.

(ニ)問題点を解決するだめの手段 本発明は、上述の点に鑑み成されたものて、アナログ入
力信号をパルス幅変調して増幅するスイッチング増幅回
路と、該アナログ入力信号な増幅するアナログ増幅回路
とを切換手段て、少なくともAMラジオ受信時にアナロ
グ増幅回路に切換える様にした点を特徴とする。
(d) Means for solving the problems The present invention has been made in view of the above points, and provides a switching amplifier circuit that amplifies an analog input signal by pulse width modulation, and an analog input signal that amplifies the analog input signal. The present invention is characterized in that the switching means is used to switch the amplifier circuit to the analog amplifier circuit at least when receiving AM radio.

(ホ)作用 本発明に依れば、AMラジオ受信時にのみアナログ増幅
回路に切換える為、パルス幅変調によるキャリア信号周
波数の電波障害の影響かなくなり、かつその他のアナロ
グ入力信号はスイッチング増幅回路を使用して損失の少
ない高効率な特性か得られる。
(e) Effects According to the present invention, since the switch is made to the analog amplifier circuit only when receiving AM radio, the influence of radio wave interference of the carrier signal frequency due to pulse width modulation is eliminated, and the switching amplifier circuit is used for other analog input signals. High efficiency characteristics with low loss can be obtained.

(へ)実施例 第1図は、本発明の一実施例を示す回路図て、(11)
は例えばオーディオ信号等のアナログ信号か入力信号と
して印加される入力端子、(12)は前記アナログ信号
を増幅する入力段、(す)は前記アナログ信号の周波数
よりも十分高い3角波等のキャリア信号を送出するキャ
リア信号発生器(14)と、前記キャリア信号によりア
ナログ信号をパルス幅変調する変調器(15)と、前記
変調器(15)の出力信号を増幅するパルス増幅器(1
5)と、前記パルス増幅器(16)の出力によりトラン
ジスタ等をオン・オフ駆動して出力を得るスイッチング
素子(17)とから成るスイッチング増幅回路、(18
)は低域周波数を通過させオーディオ出力信号に復調す
るローパスフィルタ、(19)は前記ローパスフィルタ
(18)の出力端を出力端子(20)と成し、該出力端
子(20)の出力信号を前記変調器(15)の入力端に
負帰還する負帰還回路、(旦)は前記入力段(12)と
変調器(15)との間、及び前記スイッチング素子(1
7)とローパスフィルタ(18)との間のそれぞれに設
けられた第1及び第2切換スイツチ(22)及び(23
)と、AMラジオのモードと他のテープあるいはコンパ
クト・ディスク等のモードとの切換を行う第3切換スイ
ツチ(24)と、前記第3切換スイツチ(24)の操作
により、前記第1及び第2切換スイツチ(22)及び(
23)を連動して前記ラジオモードとその他のモードに
切換えるスイッチ駆動部(25)とから成る切換手段、
及び(26)は前記ラジオモードの第1及び第2切換ス
イツチ(22)及び(23)間に接続されたアナログ増
幅回路である。そして前記出力端子(20)には、負荷
(27)か接続される。
(f) Embodiment FIG. 1 is a circuit diagram showing an embodiment of the present invention. (11)
is an input terminal to which an analog signal such as an audio signal is applied as an input signal, (12) is an input stage that amplifies the analog signal, and (su) is a carrier such as a triangular wave whose frequency is sufficiently higher than the frequency of the analog signal. A carrier signal generator (14) that sends out a signal, a modulator (15) that pulse width modulates an analog signal using the carrier signal, and a pulse amplifier (1) that amplifies the output signal of the modulator (15).
a switching amplifier circuit (18) comprising:
) is a low-pass filter that passes low frequencies and demodulates into an audio output signal; (19) is a low-pass filter that makes the output terminal of the low-pass filter (18) an output terminal (20), and outputs the output signal of the output terminal (20); A negative feedback circuit that provides negative feedback to the input terminal of the modulator (15) is provided between the input stage (12) and the modulator (15), and a
7) and the low-pass filter (18).
), a third changeover switch (24) for switching between the AM radio mode and another tape or compact disc mode, and by operating the third changeover switch (24), the first and second Changeover switch (22) and (
23) a switching means comprising a switch drive unit (25) that interlocks and switches between the radio mode and other modes;
and (26) are analog amplifier circuits connected between the first and second radio mode changeover switches (22) and (23). A load (27) is also connected to the output terminal (20).

しかして、入力端子(11)に印加される入力信号か、
テープあるいはコンパクト・ディスクからのオーディオ
信号等のアナログ信号である場合には、第3切換スイツ
チ(24)をテープあるいはコンパクト・ディスク側の
モードに切換えることにより、スイッチ駆動部(25)
か第1及び第2切換スイツチ(22)及び(23)をス
イッチング増幅回路(旦)側に切換え、アナログ増幅回
路(26)か切り離される。従って、アナログ入力信号
は入力段(12)て増幅され、キャリア信号発生器(1
4)から送出されるキャリア信号により変調器(15)
でパルス幅変調され、このパルス信号かパルス増幅器(
16)で増幅され、更に、該パルス増幅器(16)の出
力でスイッチング素子(17)かオン・オフ駆動される
。そして、前記スイッチング素子(17)の出力は、ロ
ーパスフィルタ(18)を通して復調され、出力端子(
20)から負荷(27)に供給される。従って、スイッ
チング増幅回路(貝)を使用することにより、高効率な
特性が得られる。
Therefore, the input signal applied to the input terminal (11)
If the signal is an analog signal such as an audio signal from a tape or compact disc, by switching the third changeover switch (24) to the tape or compact disc mode, the switch driver (25)
Then, the first and second changeover switches (22) and (23) are switched to the switching amplifier circuit (Dan) side, and the analog amplifier circuit (26) is disconnected. Therefore, the analog input signal is amplified at the input stage (12) and is amplified by the carrier signal generator (12).
Modulator (15) by the carrier signal sent from 4)
This pulse signal is pulse width modulated by a pulse amplifier (
16), and furthermore, the output of the pulse amplifier (16) drives a switching element (17) on and off. Then, the output of the switching element (17) is demodulated through a low-pass filter (18), and the output terminal (
20) to the load (27). Therefore, by using a switching amplifier circuit (shell), highly efficient characteristics can be obtained.

次に、入力端子(11)に印加される入力信号か、AM
ラジオのアナログ信号である場合には、第3切換スイツ
チ(24)をラジオ側のモードに切換えることにより、
スイッチ駆動部(25)が第1及び第2切換スイツチ(
22)及び(23)をアナログ増幅回路(26)側に切
換え、スイッチング増幅回路(13)か切り離される。
Next, the input signal applied to the input terminal (11) or the AM
If it is a radio analog signal, by switching the third switch (24) to the radio mode,
The switch drive section (25) operates the first and second changeover switches (
22) and (23) are switched to the analog amplifier circuit (26) side, and the switching amplifier circuit (13) is disconnected.

従って、アナログ信号は入力段(12)で増幅された後
、アナログ増幅回路(26)で増幅され、ローパスフィ
ルタ(18)を通して出力端子(20)から負荷(27
)に供給される。この場合、アナログ信号の増幅にスイ
ッチング増幅回路(す)を使用しない為、AM受信時に
影響を与えるキャリア信号の輻射による電波障害を排除
することが出来る。
Therefore, the analog signal is amplified at the input stage (12), then amplified by the analog amplifier circuit (26), passed through the low-pass filter (18), and then sent from the output terminal (20) to the load (27).
). In this case, since no switching amplifier circuit is used to amplify the analog signal, it is possible to eliminate radio wave interference due to carrier signal radiation that affects AM reception.

尚、前記実施例において、少なくともAM受信時に、ア
ナログ増幅回路(26)に切換え、その他のアナログ信
号増幅の場合にはスイ・ンチンク増幅回路(脛)に切換
え使用されればよく、その他の信号としては、テープ、
コンパクト・ディスク以外にレコードプレーヤ、FMラ
ジオ等によるアナログ信号でもよい。又、第1乃至第3
切換スイツチ(22)乃至(24)とスイッチ駆動部(
25)とは、スイッチング増幅回路(す)とアナログ増
幅回路(26)を選択的に切換えられる手段であるばよ
い。
In the above embodiment, at least when receiving AM, it is sufficient to switch to the analog amplifier circuit (26), and in the case of other analog signal amplification, switch to the switch amplifier circuit (26). is the tape,
In addition to compact discs, analog signals from record players, FM radio, etc. may also be used. Also, the first to third
Changeover switches (22) to (24) and switch drive unit (
25) may be any means that can selectively switch between the switching amplifier circuit (S) and the analog amplifier circuit (26).

(ト)発明の効果 以上述べた如く、本発明に依れば、AM受信時にのみス
イッチング増幅回路からアナログ増幅回路に切換えて使
用する様にしている為、スイッチング増幅回路を使用し
たときの電波障害を排除することか出来、かつその他の
アナログ信号増幅のときには、スイッチング増幅回路で
高効率の特性か得られる。
(G) Effects of the Invention As described above, according to the present invention, since the switching amplifier circuit is switched to the analog amplifier circuit only when receiving AM, radio wave interference occurs when the switching amplifier circuit is used. can be eliminated, and when amplifying other analog signals, high efficiency characteristics can be obtained with a switching amplifier circuit.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の一実施例を示す回路図、第2図は従来
のスイッチンク増幅器を示す回路図である。 (11)・・・入力端子、 (12)・・・入力段、 
(13)−・・スイッチング増幅回路、 (14)・・
・キャリア信号発生器、 (15)・・・変調器、 (
16)・・・パルス増幅器、(I7)・・・スイッチン
グ素子、 (18)・・・ローパスフィルタ、 (19
)・・・負帰還回路、 (20)・・・出力端子、(2
1)・・・切換手段、 (22)(23)(24)・・
・第1乃至第3切換スイツチ、 (25)・・・スイッ
チ駆動部、 (26)・・・アナログ増幅回路。
FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional switching amplifier. (11)...Input terminal, (12)...Input stage,
(13)--Switching amplifier circuit, (14)...
・Carrier signal generator, (15)...Modulator, (
16)...Pulse amplifier, (I7)...Switching element, (18)...Low pass filter, (19)...
)... Negative feedback circuit, (20)... Output terminal, (2
1)...Switching means, (22)(23)(24)...
・First to third changeover switches, (25)...Switch drive section, (26)...Analog amplifier circuit.

Claims (1)

【特許請求の範囲】[Claims] (1)アナログ入力信号をパルス幅変調して増幅するス
イッチング増幅回路と、前記アナログ入力信号を増幅す
るアナログ増幅回路と、前記スイッチング増幅回路とア
ナログ増幅回路とを切換える切換手段とを備え、前記ア
ナログ入力信号が少なくともAMラジオ受信時における
信号であるときに、前記アナログ増幅回路に切換えて使
用する様にしたことを特徴とするスイッチング増幅器。
(1) A switching amplifier circuit that pulse-width modulates and amplifies an analog input signal, an analog amplifier circuit that amplifies the analog input signal, and switching means that switches between the switching amplifier circuit and the analog amplifier circuit, A switching amplifier characterized in that when an input signal is at least a signal for AM radio reception, the switching amplifier is switched to the analog amplifier circuit for use.
JP24794186A 1986-10-17 1986-10-17 Switching amplifier Pending JPS63219211A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP24794186A JPS63219211A (en) 1986-10-17 1986-10-17 Switching amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP24794186A JPS63219211A (en) 1986-10-17 1986-10-17 Switching amplifier

Publications (1)

Publication Number Publication Date
JPS63219211A true JPS63219211A (en) 1988-09-12

Family

ID=17170828

Family Applications (1)

Application Number Title Priority Date Filing Date
JP24794186A Pending JPS63219211A (en) 1986-10-17 1986-10-17 Switching amplifier

Country Status (1)

Country Link
JP (1) JPS63219211A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002539660A (en) * 1999-03-09 2002-11-19 トリパス テクノロジー インコーポレイテッド Method and apparatus for noise shaping of mixed signal output
WO2003041269A1 (en) * 2001-11-05 2003-05-15 Motorola, Inc., A Corporation Of The State Of Delaware Variable frequency switching amplifier and method therefor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002539660A (en) * 1999-03-09 2002-11-19 トリパス テクノロジー インコーポレイテッド Method and apparatus for noise shaping of mixed signal output
WO2003041269A1 (en) * 2001-11-05 2003-05-15 Motorola, Inc., A Corporation Of The State Of Delaware Variable frequency switching amplifier and method therefor
US6819912B2 (en) 2001-11-05 2004-11-16 Freescale Semiconductor, Inc. Variable frequency switching amplifier and method therefor

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