JPH05175840A - Reference voltage supply circuit for a/d converter - Google Patents
Reference voltage supply circuit for a/d converterInfo
- Publication number
- JPH05175840A JPH05175840A JP35626691A JP35626691A JPH05175840A JP H05175840 A JPH05175840 A JP H05175840A JP 35626691 A JP35626691 A JP 35626691A JP 35626691 A JP35626691 A JP 35626691A JP H05175840 A JPH05175840 A JP H05175840A
- Authority
- JP
- Japan
- Prior art keywords
- reference voltage
- converter
- supply circuit
- voltage
- supplied
- 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
Links
Landscapes
- Analogue/Digital Conversion (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、Ａ／Ｄコンバ−タを内
蔵する装置を複数台接続して構成されるシステムの各装
置のＡ／Ｄコンバータに基準電圧を供給するＡ／Ｄコン
バータの基準電圧供給回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an A / D converter for supplying a reference voltage to the A / D converter of each device of a system constituted by connecting a plurality of devices having an A / D converter. The present invention relates to a reference voltage supply circuit.
【０００２】[0002]
【従来技術】図２は従来の技術による複数のＡ／Ｄコン
バ−タを内蔵する装置の基準電圧供給回路を示す。この
ように構成されたシステムの各装置で基準電源を設けた
場合、その基準電圧の差で、各装置の変換結果にバラツ
キが生じ、その調整も煩雑となることから制御システム
用としては不適当である。2. Description of the Related Art FIG. 2 shows a reference voltage supply circuit for a device incorporating a plurality of A / D converters according to the prior art. When a reference power supply is provided in each device of the system configured as described above, the difference in the reference voltage causes variations in the conversion result of each device, and the adjustment is also complicated, and thus is unsuitable for a control system. Is.
【０００３】従って図２に示すように同一電源６からレ
ギュレータ８、抵抗器Ｒ１、基準電圧バス７を通して各
装置へ基準電圧を供給している。しかし図２の方法では
構造的に基準電圧バスが断線又は、接触不良等で電圧供
給不能になる危険がある。この場合のＡ／Ｄ変換値は、
非常に不安定となり制御システム用としては不向きであ
る。Therefore, as shown in FIG. 2, the same power supply 6 supplies a reference voltage to each device through a regulator 8, a resistor R1, and a reference voltage bus 7. However, in the method of FIG. 2, there is a risk that the reference voltage bus is structurally broken or the voltage cannot be supplied due to a contact failure or the like. The A / D conversion value in this case is
It is very unstable and not suitable for control systems.
【０００４】この欠点を直すため図３のように各装置の
内部電源から高抵抗Ｒ２（Ｒ１は充分に小さくＲ１＜＜
Ｒ２）を通して基準電圧バス７に接続する。これにより
正常時には、Ａ装置１の基準電圧Ｖcc1が抵抗器Ｒ１を
通して各装置へ供給され、その他のＢ装置２の電源Ｖcc
２は、基準電圧に殆ど影響を与えない。端子ＶＲＥＦ
１，ＶＲＥＦ２，・・・・，ＶＲＥＦｎの各電圧Ｖref
1，Ｖref2，・・・・，Ｖrefn，はＶref1＝Ｖref2＝・
・・・＝Ｖrefnとなる。基準電圧バス７が断線又は、接
触不良等の故障を起こした場合は、各装置の内部電源Ｖ
ccより基準電圧が供給されて、一応安定に動作する。In order to correct this drawback, a high resistance R2 (R1 is sufficiently small R1 <<
Connect to reference voltage bus 7 through R2). As a result, in a normal state, the reference voltage Vcc1 of the A device 1 is supplied to each device through the resistor R1 and the power source Vcc of the other B device 2 is supplied.
2 has almost no effect on the reference voltage. Terminal VREF
1, VREF2, ..., VREFn voltage Vref
1, Vref2, ..., Vrefn are Vref1 = Vref2 =.
... = Vrefn. When the reference voltage bus 7 has a disconnection or a failure such as a contact failure, the internal power supply V of each device
The reference voltage is supplied from cc and it operates stably.
【０００５】次に、スイッチ５のＯＮから端子ＶＲＥＦ
１，ＶＲＥＦ２の電圧Ｖref1，Ｖref2の変化を述べる。
Ａ装置１、Ｂ装置２のＲ３，Ｒ４，Ｃ１，Ｃ２は基準電
圧バスにノイズ等の電圧が発生した場合、端子ＶＲＥＦ
１，ＶＲＥＦ２への影響を削除するためのフィルタ回路
１０、１１の素子である。Ａ装置１、Ｂ装置２には、ス
イッチ５のＯＮによってレギュレ−タ８、９を通して同
時に基準電圧Ｖcc1，Ｖcc2が供給される。前述した通り
Ｒ１≪Ｒ２なので、基準電圧バスの電圧は主に、Ｒ１を
通して供給され、充分な時間経過後は、端子ＶＲＥＦ１
の電圧Ｖref1がＶref1＝Ｖcc1となる。図４に、スイッ
チ５がＯＮしてからのＶＲＥＦ１＝Ｖcc１となるまでの
端子ＶＲＥＦ１の電圧の変化を示す。時刻Ｔ0でスイッ
チ５をＯＮして、電圧Ｖref1が時定数Ｃ１・Ｒ３で立ち
上がって行き、Ａ／Ｄ変換開始時間Ｔ１までにＶref1＝
Ｖcc1となり支障はない。Next, from the ON state of the switch 5 to the terminal VREF
1, changes in the voltages Vref1 and Vref2 of VREF2 will be described.
R3, R4, C1 and C2 of the A device 1 and the B device 2 are connected to the terminal VREF when a voltage such as noise is generated on the reference voltage bus.
1, the elements of the filter circuits 10 and 11 for eliminating the influence on VREF2. When the switch 5 is turned on, the A device 1 and the B device 2 are simultaneously supplied with the reference voltages Vcc1 and Vcc2 through the regulators 8 and 9. As described above, since R1 << R2, the voltage of the reference voltage bus is mainly supplied through R1, and after a sufficient time elapses, the voltage of the terminal VREF1
Voltage Vref1 becomes Vref1 = Vcc1. FIG. 4 shows a change in the voltage of the terminal VREF1 after the switch 5 is turned on until VREF1 = Vcc1. At time T0, the switch 5 is turned on, the voltage Vref1 rises with the time constant C1 · R3, and Vref1 = by the A / D conversion start time T1.
It becomes Vcc1 and there is no problem.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上記構
成の基準電圧供給回路では、Ａ装置１とＢ装置２の間の
基準電圧バス７が何らかの原因により接地事故を起こし
てしまった場合、Ａ装置１、Ｂ装置２の両方共、端子Ｖ
ＲＥＦに電圧が供給されなくなり又、基準電圧バス７が
断線した状態でスイッチ５をＯＮした場合、Ｂ装置２の
端子ＶＲＥＦ２の電圧は図５のように時定数Ｃ２（Ｒ２
＋Ｒ４）で立上り、Ａ／Ｄ変換開始時間Ｔ１迄に間にあ
わない場合があるという欠点があった。However, in the reference voltage supply circuit having the above configuration, when the reference voltage bus 7 between the A device 1 and the B device 2 causes a grounding accident for some reason, the A device 1 , B device 2 both have terminals V
When the switch 5 is turned on in the state where the voltage is not supplied to REF and the reference voltage bus 7 is disconnected, the voltage of the terminal VREF2 of the B device 2 is time constant C2 (R2) as shown in FIG.
However, there is a drawback that it may start up at + R4) and may not be in time by the A / D conversion start time T1.
【０００７】本発明は上述の点に鑑みてなされたもの
で、上記問題点を除去するために、上記構成のシステム
において、基準電圧バス７が正常な場合は、基準電圧Ｖ
cc1の電圧がＡ装置，Ｂ装置の端子ＶＲＥＦ１，ＶＲＥ
Ｆ２に誤差なく供給され、基準電圧バス７が接地事故を
起こした場合や、断線又は、接触不良事故の場合でも、
それぞれの内部電源に速やかに切替ることによって信頼
性の高いＡ／Ｄコンバータの基準電圧供給回路を提供す
る。The present invention has been made in view of the above points, and in order to eliminate the above problems, in the system having the above configuration, when the reference voltage bus 7 is normal, the reference voltage V
The voltage of cc1 is VREF1, VRE of terminals A and B
Even if the reference voltage bus 7 is supplied to F2 without error and causes a grounding accident, a disconnection, or a contact failure accident,
A highly reliable reference voltage supply circuit for an A / D converter is provided by rapidly switching to each internal power supply.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するため
本発明は、図１に示すようにＡ／Ｄコンバ−タを内蔵し
ている複数装置のＡ／Ｄコンバータ３，４に外部から基
準電圧を供給している装置において、基準電圧バス７の
断線事故や接触不良又は接地事故等で基準電圧の供給が
停止した場合に、基準電圧を各装置の内部基準電源Ｖcc
1，Ｖcc2からダイオ−ドＤ１，Ｄ２を通して供給する手
段を設けたものである。In order to solve the above-mentioned problems, the present invention provides an external reference to A / D converters 3 and 4 of a plurality of devices having built-in A / D converters as shown in FIG. In the device which supplies the voltage, when the supply of the reference voltage is stopped due to a disconnection accident, a contact failure or a grounding accident of the reference voltage bus 7, the reference voltage is changed to the internal reference power supply Vcc of each device.
1, means for supplying from Vcc2 through diodes D1 and D2 is provided.
【０００９】[0009]
【作用】本発明では、基準電圧を外部から供給している
回路において、故障で外部からの基準電圧が供給されな
くなった場合でも、速やかに各装置の内部からの供給に
切り替わり又、図６に示すように電源スイッチ５をＯＮ
した起動時も、各端子ＶＲＥＦの電圧Ｖrefは速やかに
立上り、装置の誤動作が無くなり信頼性の高い装置が実
現できる。According to the present invention, even if the reference voltage from the outside is not supplied due to a failure in the circuit supplying the reference voltage from the outside, the supply is quickly switched to the supply from the inside of each device. Turn on the power switch 5 as shown
Even at the time of start-up, the voltage Vref of each terminal VREF rises quickly, the malfunction of the device is eliminated, and a highly reliable device can be realized.
【００１０】[0010]
【実施例】以下本発明の一実施例を図面に基づいて詳細
に説明する。図１は本発明によるＡ／Ｄコンバ−タの基
準電源供給回路を使用してＡ装置とＢ装置で同一入力信
号を変換する例である。Ａ装置１は、Ａ／Ｄコンバ−タ
３、フィルタ１０、電源６より基準電圧Ｖcc1を供給す
るレギュレ−タ８、基準電圧Ｖcc1より基準電圧バス７
に電圧を供給している抵抗器Ｒ１、本発明により挿入さ
れたダイオ−ドＤ１から構成される。Ｂ装置２は、Ａ／
Ｄコンバ−タ４、フィルタ１１、電源６より基準電圧Ｖ
cc2を供給するレギュレ−タ９、抵抗器Ｒ２、本発明に
より挿入されたダイオ−ドＤ２から構成される。各装置
の入力信号は可変抵抗器ＶＲ１から供給され、装置間は
基準電圧バス７で接続され、電源６からスイッチ５を通
して電源が供給されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example in which the same input signal is converted by the A and B devices using the reference power supply circuit of the A / D converter according to the present invention. The A device 1 includes an A / D converter 3, a filter 10, a regulator 8 which supplies a reference voltage Vcc1 from a power supply 6, and a reference voltage bus 7 based on the reference voltage Vcc1.
It is composed of a resistor R1 supplying a voltage to a diode and a diode D1 inserted according to the present invention. B device 2 is A /
Reference voltage V from D converter 4, filter 11 and power supply 6
It is composed of a regulator 9 for supplying cc2, a resistor R2, and a diode D2 inserted according to the present invention. The input signal of each device is supplied from a variable resistor VR1, the devices are connected by a reference voltage bus 7, and power is supplied from a power supply 6 through a switch 5.
【００１１】上記構成の基準電圧供給回路において、基
準電源電圧Ｖcc1とＶcc2の関係をＶcc1≒Ｖcc2でＶcc1
＞Ｖcc2に設定しておく。外部から供給される基準電圧
バス７の電圧がＶcc2−ダイオードＤ２の順方向降下電
圧（ダイオードの順方向へ電流が流れ始める時の電圧）
以上の場合は、ダイオ−ドＤ２はＯＮしないので、外部
から供給される基準電圧そのままの値が端子ＶＲＥＦ２
にかかる。In the reference voltage supply circuit having the above structure, the relationship between the reference power supply voltage Vcc1 and Vcc2 is Vcc1.apprxeq.Vcc2 and Vcc1.
Set to> Vcc2. The voltage of the reference voltage bus 7 supplied from the outside is Vcc2-the forward voltage drop of the diode D2 (the voltage at which the current starts to flow in the forward direction of the diode).
In the above case, since the diode D2 is not turned on, the value of the reference voltage supplied from the outside is the same as that of the terminal VREF2.
Take
【００１２】何らかの原因で外部から供給される基準電
圧バス７の電圧が基準電圧Ｖcc2−ダイオ−ドＤ２の順
方向降下電圧以下になった場合、速やかにＤ２ダイオ−
ドがＯＮしてＶＲＥＦ２の電圧をＶcc２−ダイオードＤ
２の順方向降下電圧値にくいとめる。電源スイッチ５を
ＯＮした時は、端子ＶＲＥＦの電圧は図６に示す様に立
上りＡ／Ｄ変換開始時間Ｔ２までに端子ＶＲＥＦ１は定
常電圧に落ち着く。この働きによって、端子ＶＲＥＦ２
に基準電圧が供給されなくなる事態は発生しないので、
装置が誤動作することを防止することが可能となる。If the voltage of the reference voltage bus 7 supplied from the outside falls below the reference voltage Vcc2-the forward drop voltage of the diode D2 for some reason, the D2 diode is immediately turned on.
Is turned on and the voltage of VREF2 is Vcc2-diode D
The forward voltage drop value of 2 is difficult. When the power switch 5 is turned on, the voltage of the terminal VREF rises to a steady voltage by the rising A / D conversion start time T2 as shown in FIG. By this function, the terminal VREF2
Since the situation where the reference voltage is not supplied to will not occur,
It is possible to prevent the device from malfunctioning.
【００１３】[0013]
【発明の効果】以上、詳細に説明したように本発明によ
れば、下記のような効果が期待される。 基準電圧を外
部から供給している回路において、断線事故や接触不良
や接地事故で基準電圧が供給されなくなった場合でも、
速やかに内部からの供給に切り替わるので、装置の誤動
作が無くなり、信頼性の高い装置が実現できる。As described in detail above, according to the present invention, the following effects are expected. In a circuit that supplies the reference voltage from the outside, even if the reference voltage is no longer supplied due to a disconnection accident, contact failure, or grounding accident,
Since the supply from the inside is switched promptly, malfunction of the device is eliminated, and a highly reliable device can be realized.
【図１】本発明によるＡ／Ｄコンバ−タの基準電圧供給
回路の使用例を示す図である。FIG. 1 is a diagram showing an example of use of a reference voltage supply circuit of an A / D converter according to the present invention.
【図２】従来技術による一台の装置から各装置へ基準電
圧を供給する回路を示す図である。FIG. 2 is a diagram showing a circuit for supplying a reference voltage from one device to each device according to the related art.
【図３】従来技術による各装置で非常用ロ−カル基準電
源を持つ回路図である。FIG. 3 is a circuit diagram having an emergency local reference power source in each device according to the prior art.
【図４】従来技術での正常時のＶＲＥＦ１の立上り時の
電圧変化図である。FIG. 4 is a voltage change diagram when VREF1 rises in a normal state according to a conventional technique.
【図５】図３で基準電圧バスが断線したときのＶＲＥＦ
２の立上りを示す図である。5 is VREF when the reference voltage bus is broken in FIG.
It is a figure which shows the rising of 2.
【図６】本発明による基準電圧供給回路でのＶＲＥＦの
立上りを示す図である。FIG. 6 is a diagram showing the rise of VREF in the reference voltage supply circuit according to the present invention.
１ Ａ装値 ２ Ｂ装値 ３ Ａ／Ｄコンバ−タ ４ Ａ／Ｄコンバ−タ ５ 電源スイッチ ６ 電源 ７ 基準電圧バス ８ レギュレ−タ ９ レギュレ−タ １０ フィルタ １１ フィルタ Ｒ１ 抵抗器 Ｄ１ ダイオ−ド Ｄ２ ダイオ−ド Ｒ２ 抵抗器 ＶＲ１ 可変抵抗器 1 A value 2 B value 3 A / D converter 4 A / D converter 5 Power switch 6 Power supply 7 Reference voltage bus 8 Regulator 9 Regulator 10 Filter 11 Filter R1 Resistor D1 Diode D2 diode R2 resistor VR1 variable resistor
Claims (1)
の装置に基準電圧供給バスを通して外部から基準電圧を
供給しているＡ／Ｄコンバータの基準電圧供給回路にお
いて、 前記基準電圧供給バスの基準電圧が零又は所定値以下に
降下した場合に、ダイオ−ドを通して各装置の内部電源
に速やかに切り替え、該内部電源から基準電圧を供給す
る手段を具備することを特徴とする基準電圧供給回路。1. A reference voltage supply circuit of an A / D converter which externally supplies a reference voltage to a plurality of devices each having a built-in A / D converter through a reference voltage supply bus. When the bus reference voltage drops to zero or a predetermined value or less, the reference voltage is characterized by including means for promptly switching to the internal power supply of each device through the diode and supplying the reference voltage from the internal power supply. Supply circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35626691A JPH05175840A (en) | 1991-12-24 | 1991-12-24 | Reference voltage supply circuit for a/d converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35626691A JPH05175840A (en) | 1991-12-24 | 1991-12-24 | Reference voltage supply circuit for a/d converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05175840A true JPH05175840A (en) | 1993-07-13 |
Family
ID=18448167
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35626691A Pending JPH05175840A (en) | 1991-12-24 | 1991-12-24 | Reference voltage supply circuit for a/d converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05175840A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007251323A (en) * | 2006-03-14 | 2007-09-27 | Renesas Technology Corp | Semiconductor integrated circuit |
| WO2017179301A1 (en) * | 2016-04-13 | 2017-10-19 | 株式会社ソシオネクスト | Reference voltage stabilizing circuit and integrated circuit provided with same |
| CN107742035A (en) * | 2017-10-25 | 2018-02-27 | 华自科技股份有限公司 | PCB layout method, apparatus, computer-readable recording medium and computer equipment |
-
1991
- 1991-12-24 JP JP35626691A patent/JPH05175840A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007251323A (en) * | 2006-03-14 | 2007-09-27 | Renesas Technology Corp | Semiconductor integrated circuit |
| WO2017179301A1 (en) * | 2016-04-13 | 2017-10-19 | 株式会社ソシオネクスト | Reference voltage stabilizing circuit and integrated circuit provided with same |
| CN107742035A (en) * | 2017-10-25 | 2018-02-27 | 华自科技股份有限公司 | PCB layout method, apparatus, computer-readable recording medium and computer equipment |
| CN107742035B (en) * | 2017-10-25 | 2021-02-05 | 华自科技股份有限公司 | PCB wiring method and device, computer readable storage medium and computer equipment |
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