JPS59186411A - Variable gain amplifying circuit - Google Patents

Variable gain amplifying circuit

Info

Publication number
JPS59186411A
JPS59186411A JP58060759A JP6075983A JPS59186411A JP S59186411 A JPS59186411 A JP S59186411A JP 58060759 A JP58060759 A JP 58060759A JP 6075983 A JP6075983 A JP 6075983A JP S59186411 A JPS59186411 A JP S59186411A
Authority
JP
Japan
Prior art keywords
mosfets
well area
circuit
gain
variable gain
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
JP58060759A
Other languages
Japanese (ja)
Inventor
Hisahiro Moriuchi
久裕 森内
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP58060759A priority Critical patent/JPS59186411A/en
Publication of JPS59186411A publication Critical patent/JPS59186411A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03GCONTROL OF AMPLIFICATION
    • H03G3/00Gain control in amplifiers or frequency changers
    • H03G3/001Digital control of analog signals

Landscapes

  • Metal-Oxide And Bipolar Metal-Oxide Semiconductor Integrated Circuits (AREA)
  • Control Of Amplification And Gain Control (AREA)

Abstract

PURPOSE:To expand an operating voltage margin and to reduce a chip in size by using two transmission gate MOSFETs which are formed in a well area in series and have sources connected to the well area in common as a switch means which connects a feedback resistance selectively. CONSTITUTION:When only transmission gate MOSFETs Q1 and Q2 are turned on, the feedback resistance R1 is connected as shown in a figure, so its gain G is Ri/R1. When MOSFETs Q3 and Q4 or Q7 and Q8 are turned on, the gain is represented as a similar expression including resistances R2-R4. Sources and the well area are made common in the switching operation of said MOSFETs as shown in a sectinal figure, so threshold voltages of the MOSFETs Q1 and Q2 are not influenced by the substrate effect. Further, the potential of the well area is determined in the off-state immediately according to the source side, so no undesirable charge is accumulated in the parasitic capacity of the well area and a latch-up state due to a thyristor phenomenon does not occur.

Description

【発明の詳細な説明】 〔技術分野〕 この発明は、MOSFET (絶縁ゲート形電界効果ト
ランジスタ)を含む可変利得増幅回路に関するもので、
例えば、0MO3(相補型金属絶縁物半導体)集積回路
で構成されたものに有効な技術に関するものである。
[Detailed Description of the Invention] [Technical Field] The present invention relates to a variable gain amplifier circuit including a MOSFET (insulated gate field effect transistor).
For example, it relates to a technique that is effective for those configured with OMO3 (complementary metal-insulator-semiconductor) integrated circuits.

〔背景技術〕[Background technology]

従来より、例えばCQ出版社発行、長橋芳行著のrAD
/DA変換回路の設計Jにおいて、演算増幅器の利得を
設定する帰還抵抗を選択的に接続するスイッチ手段とし
て、CMO3伝送ゲート回路を用いたものが公知である
Conventionally, for example, rAD published by CQ Publishing and written by Yoshiyuki Nagahashi
/DA conversion circuit design J uses a CMO3 transmission gate circuit as a switch means for selectively connecting a feedback resistor for setting the gain of an operational amplifier.

CMO3伝送ゲート回路は、nチャンネルMO3FET
で構成された伝送ゲートMO3FETとpチャンネルM
O3FETで構成された伝送ゲートMO3FETとを並
列形態に接続して、両MO3FETを同時にオン/オフ
状態となるように制御するものである。
CMO3 transmission gate circuit is n-channel MO3FET
Transmission gate MO3FET and p-channel M
A transmission gate MO3FET composed of an O3FET is connected in parallel, and both MO3FETs are controlled to be turned on/off at the same time.

このような0M03回路を用いて中間レベルを伝達する
ものとすると、ウェル領域に、ソース電極に印加されて
いる電圧と異なった電圧が印加されるために、そのMO
SFETのしきい値電圧が他のMOSFETのしきい値
電圧よりも高くなるという公知の基板効果(サブストレ
ート効果)が生じてそのコンダクタンス特性が小さくな
るか又はオン状態にならないという問題が生じる。した
がって、上記コンダクタンス特性の悪化を補償するため
にそのサイズを大きく設定したり、動作電圧範囲が制限
されるという欠点が生じる。
If such a 0M03 circuit is used to transmit an intermediate level, a voltage different from the voltage applied to the source electrode is applied to the well region, so the MO
A known substrate effect occurs in which the threshold voltage of an SFET becomes higher than the threshold voltages of other MOSFETs, resulting in a problem that its conductance characteristics become small or it does not turn on. Therefore, there are disadvantages in that the size must be set large to compensate for the deterioration of the conductance characteristics, and the operating voltage range is limited.

〔発明の目的〕[Purpose of the invention]

この発明の目的は、動作電圧マージンの拡大を図った可
変利得増幅回路を折供することにある。
An object of the present invention is to provide a variable gain amplifier circuit with an expanded operating voltage margin.

この発明の他の目的は、チソプサイスの小型化を図った
可変利得増幅回路を提供することにある。
Another object of the present invention is to provide a variable gain amplification circuit that is smaller in size.

この発明の前記ならびにその他の目的と新規な特徴は、
この明細書の記述および添付図面から明らかになるであ
ろう。
The above and other objects and novel features of this invention include:
It will become clear from the description of this specification and the accompanying drawings.

〔発明の概要〕[Summary of the invention]

本願において開示される発明のうち代表的なものの概要
を簡単に説明すれば、下記の通りである。
A brief overview of typical inventions disclosed in this application is as follows.

すなわち、利得設定のための帰還抵抗を選択的に接続す
るスイッチ動作として、それぞれウェル領域に形成され
、直列形態とされるとともにそのソースとウェル領域と
を共通接続し、ゲートに共通に制御信号を印加した2つ
の伝送ゲー)MOSFETを用いることによって、基板
効果の影響を受けないスイッチ動作を実現するものであ
る。
That is, as a switch operation for selectively connecting feedback resistors for gain setting, resistors are formed in each well region, are connected in series, and their sources and well regions are commonly connected, and a control signal is commonly applied to the gates. By using a MOSFET (two transmission gates), a switching operation that is not affected by the substrate effect is realized.

以下、本発明を実施例とともに詳細に説明する。Hereinafter, the present invention will be explained in detail together with examples.

〔実施例1〕 第1図には、この発明の一実施例の回路図が示されてい
る。
[Embodiment 1] FIG. 1 shows a circuit diagram of an embodiment of the present invention.

この実施例の各回路素子は、特に制限されないが、公知
のCM OS 隻積回路の製造技術によって1個のンリ
コンのような半導体基板上において形成される。
Each circuit element of this embodiment is formed on a single semiconductor substrate such as a semiconductor by a known CMOS integrated circuit manufacturing technique, although this is not particularly limited.

演算増幅器OPは、公知の差動M OS F E T等
を含む差動増幅回路によって構成される。特に制限され
ないが、この演算増幅器oPの非反転入力端子(+)は
、回路の接地電位に接続される。また、反転入力端子(
=)には、入力抵抗Riを通して入力信号が印加される
。特に制限されないが、上記反転入力端子(−)と出力
端子との間には利得設定のための帰還抵抗を選択的に接
続する次の回路素子が設けられる。すなわち、上記演算
増幅器OPの出力端子にその一端が接続された直列抵抗
R1ないしR4が設けられる。これらの抵抗回路の各接
続点と上記演算増幅器opの反転入力端子(−)との間
に、直列形態の2つの伝送ゲートMO3FETQI、、
Q2ないし伝送ゲートMO5FETQ7.QBがそれぞ
れ設けられる。
The operational amplifier OP is constituted by a differential amplifier circuit including a known differential MOSFET or the like. Although not particularly limited, the non-inverting input terminal (+) of the operational amplifier oP is connected to the ground potential of the circuit. In addition, the inverting input terminal (
An input signal is applied to = ) through an input resistor Ri. Although not particularly limited, the following circuit element is provided between the inverting input terminal (-) and the output terminal to selectively connect a feedback resistor for gain setting. That is, series resistors R1 to R4 are provided, one end of which is connected to the output terminal of the operational amplifier OP. Between each connection point of these resistance circuits and the inverting input terminal (-) of the operational amplifier op, two transmission gates MO3FETQI in series are connected.
Q2 or transmission gate MO5FETQ7. A QB is provided for each.

特に制限されないが、これらの直列形態のMO3FET
QI、Q2ないしMO3FETQ7.Q8は、第2図の
構造断面図に代表として示されているMO3FETQI
、Q2のように、P型つェル領域Wl、W2にそれぞれ
形成される。上記ウェル領域Wl、W2内に形成された
P中領域cc1、CC2は、オーミック接触領域であり
、それぞれソースm域s1.S2と接続される。トレイ
ン領McD1.D2は共通に接続される。そして、ゲー
ト電極には共通に制御信号c1が印加されるものである
Although not particularly limited, these series MO3FETs
QI, Q2 or MO3FETQ7. Q8 is MO3FETQI, which is shown as a representative in the structural cross-sectional view of Fig. 2.
, Q2 are formed in P-type well regions Wl and W2, respectively. The P middle regions cc1 and CC2 formed in the well regions Wl and W2 are ohmic contact regions, and the source m regions s1. Connected to S2. Train territory McD1. D2 are commonly connected. A control signal c1 is commonly applied to the gate electrode.

この実施例回路の動作を次に説明する。The operation of this embodiment circuit will now be described.

いま、MO3FETQI、Q2のみをオン状態とすると
、演算増幅器opの反転入力端子(−)と出力端子との
間に帰還抵抗R1が接続されることになるので、その利
得Gは次式(1)より求められる。
Now, if only the MO3FETs QI and Q2 are turned on, the feedback resistor R1 will be connected between the inverting input terminal (-) and the output terminal of the operational amplifier op, so its gain G will be expressed by the following equation (1). More demanded.

G=Ri/R1・・・・・・・・・・・・(11以下、
同様にして、M OS F E T Q 3 、 Q 
4ないしMO3FETQ7.Q8をそれぞれオン状態と
すると、利得Gは次式(2)〜(4)のようになる。
G=Ri/R1・・・・・・・・・(11 or less,
Similarly, MOS FET Q 3 , Q
4 or MO3FETQ7. When each Q8 is turned on, the gain G becomes as shown in the following equations (2) to (4).

G=Rt/R1→−R2・・・・・・・・・(2)G=
Ri/R1+R2+R3・・・・・・(3)G=Ri/
R1+R2+R3+R4・・・(4)上述のようなMO
SFETのスイッチ動作において、この実施例では、第
2図に示すようにソースとウェル領域とが共通化されて
いるので、その基板効果によってMO3FETQI、Q
2のしきい値電圧が影響を受けない。また、そのオフ状
態において、ソース側の電位に従ってウェル領域の電位
が直ちに決まるので、ウェル領域の寄生容最に不所望の
チャージが蓄積されることもなく、サイリスタ現象によ
るランチアンプが生じない。
G=Rt/R1→−R2・・・・・・・・・(2) G=
Ri/R1+R2+R3...(3)G=Ri/
R1+R2+R3+R4...(4) MO as described above
In the switching operation of the SFET, in this embodiment, the source and well region are shared as shown in FIG.
2 threshold voltage is unaffected. Furthermore, in the off state, the potential of the well region is immediately determined according to the potential on the source side, so that no undesired charge is accumulated in the parasitic capacitance of the well region, and no launch amplifier occurs due to the thyristor phenomenon.

〔実施例2〕 第2図には、この発明をD/A変換器に適用した場合の
一実施例の回路図が示されている。
[Embodiment 2] FIG. 2 shows a circuit diagram of an embodiment in which the present invention is applied to a D/A converter.

このD/A変換方式は、直列スイッチによるアンプ・ゲ
イン可変方式と呼ばれるものであり、2進の重み(−1
げされた抵抗RないしR/8を演算増幅器OPの反転入
力端子(−)と出力端子との間に直列接続して、各抵抗
RないしR/8をそれぞれ短絡するスイッチ手段として
、上記第1図と同様な直列MO3FETQ1.Q2ない
しMO3FETQ7.QBをそれぞれ設けるものである
This D/A conversion method is called a variable amplifier gain method using series switches, and the binary weight (-1
The resistors R to R/8 are connected in series between the inverting input terminal (-) and the output terminal of the operational amplifier OP, and the resistors R to R/8 are connected in series to short-circuit each of the resistors R to R/8, respectively. Series MO3FETQ1 similar to the figure. Q2 or MO3FETQ7. A QB is provided for each.

そして、これらのMO3FETQI、Q2ないしQ7.
Q8のゲートには、2進の信号DoないしD3を印加す
るものである。この実施例では、上記2進信号DOない
しD3に従ってその帰還抵抗値が設定されるので、16
通りのD / A変換された出力電圧Voutが得られ
る。
And these MO3FETQI, Q2 to Q7.
Binary signals Do to D3 are applied to the gate of Q8. In this embodiment, the feedback resistance value is set according to the binary signals DO to D3, so 16
A normal D/A converted output voltage Vout is obtained.

〔効 果〕〔effect〕

(11そのソースとウェル領域とを接続した2つの伝送
ゲートMO3FETを直列形態とするものであるので、
そのしきい値電圧に基板効果の影響を受けることがなく
、設計条件に従ったスイッチ動作を行うことができると
いう効果が得られる。
(11 Since the two transmission gate MO3FETs with their sources and well regions connected are connected in series,
The advantage is that the threshold voltage is not affected by the substrate effect, and the switching operation can be performed in accordance with the design conditions.

(2)上記(1)により、しきい値電圧以上の制御信号
により確実にスイッチ手段としてのMOSFETをオン
状態とすることかできるから電源電圧のマージンの拡大
を図ることができるという効果が得られる。
(2) According to (1) above, since the MOSFET as a switching means can be reliably turned on by a control signal higher than the threshold voltage, the power supply voltage margin can be expanded. .

(3)上記(11により、基板効果を考慮してそのサイ
ズを大きくする必要がないから、MOSFETのサイズ
を小さく形成できることによって、アンプサイズの小型
化を図ることができるという効果が得られる。
(3) According to (11) above, there is no need to increase the size in consideration of the substrate effect, so the effect that the size of the MOSFET can be made small and the size of the amplifier can be reduced can be obtained.

(4)上記(2)により、低電圧でも動作する可変利得
増幅回路が得られるという効果が得られる。
(4) According to (2) above, it is possible to obtain a variable gain amplifier circuit that operates even at low voltage.

以上本発明者によってなされた発明を実施例に基づき具
体的に説明したか、この発明は上記実施例に限定される
ものではなく、その要旨を逸脱しない範囲で種々変更可
能であることばいうまでもない。例えば、上記利得設定
のための帰還抵抗を構成する複数の抵抗素子からなる抵
抗回路の構成は、並列形態の抵抗を選択的に短絡する等
のうように種々の変形を採ることができるものである。
Although the invention made by the present inventor has been specifically explained based on the examples above, it goes without saying that this invention is not limited to the above examples, and can be modified in various ways without departing from the gist thereof. do not have. For example, the configuration of a resistor circuit consisting of a plurality of resistor elements constituting the feedback resistor for setting the gain can be modified in various ways, such as selectively shorting resistors in parallel. be.

また、上記スイッチ手段としてのMO3’FETは、p
チャンネルMO3FETを用いるものであってもよい。
Furthermore, the MO3'FET as the switch means has p
A channel MO3FET may also be used.

この場合には、N型ウェル領域を用いるものとすればよ
く、これに応じて半導体基板はP型とすればよい。
In this case, an N-type well region may be used, and the semiconductor substrate may be of P-type accordingly.

また、演算増幅器の具体的回路構成は、何であってもよ
い。
Furthermore, the operational amplifier may have any specific circuit configuration.

〔利用分野〕[Application field]

この発明は、MOSFETで構成された可変利得増幅回
路として広く利用できるものである。
The present invention can be widely used as a variable gain amplifier circuit composed of MOSFETs.

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

第1図は、この発明の一実施例を示す回路図、第2図は
、そのスイッチ手段の一実施例を示す構造断面図、 第3図は、この発明をD/A変換器に適用した場合の一
実施例を示す回路図である。
Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a structural sectional view showing an embodiment of the switch means, and Fig. 3 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is a circuit diagram showing an example of the case.

Claims (1)

【特許請求の範囲】 1、演算増幅器の利得設定のための帰還抵抗を選択的に
接続するスイッチ手段として、それぞれウェル領域に形
成され、直列形態とされるとともにそのソースとウェル
領域とを共通接続し、ゲートに共通に制御信号を印加し
た2つの伝送ゲートMO3FETを用いることを特徴と
する可変利得増幅回路。 2、上記演算増幅器は、CMOS回路で構成され、上記
伝送ゲー)MOSFETは、P型ウェル領域に形成され
たnチャンネルMO3FETであることを特徴とする特
許請求の範囲第1項記載の可変利得増幅回路。
[Claims] 1. Switch means for selectively connecting feedback resistors for setting the gain of an operational amplifier are formed in respective well regions, connected in series, and having their sources and well regions commonly connected. A variable gain amplifier circuit characterized in that it uses two transmission gate MO3FETs whose gates are commonly applied with a control signal. 2. The variable gain amplifier according to claim 1, wherein the operational amplifier is constituted by a CMOS circuit, and the transmission MOSFET is an n-channel MO3FET formed in a P-type well region. circuit.
JP58060759A 1983-04-08 1983-04-08 Variable gain amplifying circuit Pending JPS59186411A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP58060759A JPS59186411A (en) 1983-04-08 1983-04-08 Variable gain amplifying circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP58060759A JPS59186411A (en) 1983-04-08 1983-04-08 Variable gain amplifying circuit

Publications (1)

Publication Number Publication Date
JPS59186411A true JPS59186411A (en) 1984-10-23

Family

ID=13151522

Family Applications (1)

Application Number Title Priority Date Filing Date
JP58060759A Pending JPS59186411A (en) 1983-04-08 1983-04-08 Variable gain amplifying circuit

Country Status (1)

Country Link
JP (1) JPS59186411A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02161769A (en) * 1988-12-15 1990-06-21 Toshiba Corp Transmission gate
EP1387493A2 (en) * 2002-08-02 2004-02-04 NEC Electronics Corporation Input protection circuit
US6696680B2 (en) 2000-03-02 2004-02-24 Sanyo Electric Co., Ltd. Variable resistance circuit, operational amplification circuit and semiconductor integrated circuit
JP2008123642A (en) * 2006-11-15 2008-05-29 Samsung Electronics Co Ltd Control circuit of negative potential monitor pad and nonvolatile memory equipped therewith
JP2012068265A (en) * 2011-12-21 2012-04-05 Seiko Npc Corp Infrared detector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02161769A (en) * 1988-12-15 1990-06-21 Toshiba Corp Transmission gate
US6696680B2 (en) 2000-03-02 2004-02-24 Sanyo Electric Co., Ltd. Variable resistance circuit, operational amplification circuit and semiconductor integrated circuit
EP1387493A2 (en) * 2002-08-02 2004-02-04 NEC Electronics Corporation Input protection circuit
EP1387493A3 (en) * 2002-08-02 2006-12-20 NEC Electronics Corporation Input protection circuit
US7233466B2 (en) 2002-08-02 2007-06-19 Nec Electronics Corporation Input protection circuit
JP2008123642A (en) * 2006-11-15 2008-05-29 Samsung Electronics Co Ltd Control circuit of negative potential monitor pad and nonvolatile memory equipped therewith
JP2012068265A (en) * 2011-12-21 2012-04-05 Seiko Npc Corp Infrared detector

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