JPH06308171A - Power supply-voltage detecting circuit - Google Patents

Power supply-voltage detecting circuit

Info

Publication number
JPH06308171A
JPH06308171A JP5097963A JP9796393A JPH06308171A JP H06308171 A JPH06308171 A JP H06308171A JP 5097963 A JP5097963 A JP 5097963A JP 9796393 A JP9796393 A JP 9796393A JP H06308171 A JPH06308171 A JP H06308171A
Authority
JP
Japan
Prior art keywords
power supply
circuit
signal
comparator
voltage
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
JP5097963A
Other languages
Japanese (ja)
Inventor
Kazuo Kimura
和生 木村
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.)
Sharp Corp
Original Assignee
Sharp Corp
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 Sharp Corp filed Critical Sharp Corp
Priority to JP5097963A priority Critical patent/JPH06308171A/en
Publication of JPH06308171A publication Critical patent/JPH06308171A/en
Pending legal-status Critical Current

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  • Measurement Of Current Or Voltage (AREA)
  • Manipulation Of Pulses (AREA)
  • Logic Circuits (AREA)
  • Dram (AREA)

Abstract

PURPOSE:To detect the drop of a power supply voltage with a single power supply by outputting the first signal corresponding to a varying resistance value from the first circuit, which is connected to the power supply, outputting the second signal corresponding to the specified resistance value from the second circuit, and comparing the first and second signals with respect to the voltage with a comparing circuit. CONSTITUTION:Diffused resistors R1, R2 and R3 are formed on one transistor resistor RT and the fluctuation of a power supply voltage. An output terminal Y, a +input terminal and a -input terminal are provided in the comparator 1. The result of the detection of the power supply voltage is outputted from the output terminal Y. The gate of the resistor RT is connected to GND. The source is connected to VDD. The drain is connected to the diffused resistor R1 and the +input terminal of the comparator 1. The opposite-side terminal of the resistor R1 is connected to GND. The -input of the comparator 1 is connected to the resistors R2 and R3. When the difference between the first signal and the second signal becomes the specified value, the signal corresponding to the specified value is outputted. Therefore, the drop of the power supply voltage can be detected with a single power supply.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は電源電圧検出回路に係
り、詳細には半導体集積回路からなりコンパレータとト
ランジスタ抵抗、半導体集積回路上トランジスタ抵抗よ
り安定した抵抗値の得られる抵抗(ここでは例として拡
散抵抗)を1つの半導体チップ上に形成した電源電圧検
出回路に係る。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply voltage detecting circuit, and more particularly, to a comparator and a transistor resistance which are composed of a semiconductor integrated circuit, and a resistance which can obtain a stable resistance value than the transistor resistance on the semiconductor integrated circuit (here, as an example. The present invention relates to a power supply voltage detection circuit in which a diffusion resistance) is formed on one semiconductor chip.

【0002】[0002]

【従来の技術】図2は従来の半導体集積回路(以下IC
という)の回路構成を示すブロック図であって、電源電
圧VDD1を有する第1電源、コンパレータ2とICの
外部に安定した電圧を供給することができる基準電圧V
DD2を有する第2電源と抵抗r1、r2で構成されて
いる。コンパレータ2には+入力端子、−入力端子とコ
ンパレータ2の出力端子Yが設けられておりY出力には
電源電圧VDD1の検出結果が出力される。このコンパ
レータ2の+側入力は、ICの第1電源に接続され、コ
ンパレータ2の−側入力は、IC外部の抵抗r1、r2
により、第2電源の基準電圧VDD2の抵抗分割された
入力電圧が印加される。したがって、ICの電源電圧で
あるVDD1が電圧降下し、コンパレータ2の−側入力
の電圧より小さくなったときは、コンパレータ2の出力
レベルが反転し、VDD1が電圧降下していたことを検
出していた。すなわち、従来のICに供給される単一の
電源電圧だけでは、電圧効果の検出が困難であったた
め、ICにコンパレータ2を内蔵するのは勿論のこと、
ICに比較電圧用の−入力端子をコンパレータ2に設け
第1電源を+入力端子に接続して、ICに供給される第
1電源の電圧VDD1の電圧降下が生じても、常にある
一定の電圧を供給することのできる第2電源をこの入力
端子に接続していた。
2. Description of the Related Art FIG. 2 shows a conventional semiconductor integrated circuit (hereinafter referred to as IC
Is a block diagram showing the circuit configuration of the reference voltage V which can supply a stable voltage to the first power supply having the power supply voltage VDD1, the comparator 2 and the outside of the IC.
It is composed of a second power supply having a DD2 and resistors r1 and r2. The comparator 2 is provided with a + input terminal, a − input terminal and an output terminal Y of the comparator 2, and the detection result of the power supply voltage VDD1 is output to the Y output. The + side input of the comparator 2 is connected to the first power source of the IC, and the − side input of the comparator 2 is connected to the resistors r1 and r2 outside the IC.
Thus, the resistance-divided input voltage of the reference voltage VDD2 of the second power supply is applied. Therefore, when VDD1 which is the power supply voltage of the IC drops and becomes lower than the voltage of the-side input of the comparator 2, the output level of the comparator 2 is inverted and it is detected that VDD1 has dropped. It was That is, since it is difficult to detect the voltage effect with only a single power supply voltage supplied to the conventional IC, it goes without saying that the comparator 2 is built in the IC.
Even if a voltage drop of the voltage VDD1 of the first power supply supplied to the IC occurs, the negative input terminal for the comparison voltage is provided in the comparator 2 in the comparator 2 and the first power supply is connected to the + input terminal. Was connected to this input terminal.

【0003】[0003]

【発明が解決しようとする課題】しかしながら、第2電
源にて永久に安定した電圧を供給することは困難であ
り、また、第2電源を搭載するための領域確保や電源交
換の手間が生じていた。
However, it is difficult to permanently supply a stable voltage with the second power source, and it is necessary to secure an area for mounting the second power source and replace the power source. It was

【0004】本発明の目的は第2電源を不要としIC外
部の外付け部品点数を減らすと同時にICの端子数の削
減が可能な半導体集積回路における電源電圧検出回路を
提供することにある。
It is an object of the present invention to provide a power supply voltage detection circuit in a semiconductor integrated circuit which does not require a second power supply and can reduce the number of external parts outside the IC and at the same time reduce the number of terminals of the IC.

【0005】[0005]

【課題を解決するための手段】電源と接続されており電
源電圧の変動に応じて抵抗値が変化し該変化する抵抗値
に対応する第1信号を出力する第1回路と、電源と接続
されており所定の抵抗値を有し所定の抵抗値に対応する
第2信号を出力する第2回路と、第1回路から供給され
る第1信号と第2回路から供給される第2信号とを電圧
に関して比較し、第1信号および第2信号の電圧の差異
が所定の値になったとき該所定の値に応じた信号を出力
する比較回路とを含むことを特徴とする。
A first circuit connected to a power supply and having a resistance value that changes in response to a change in the power supply voltage and outputting a first signal corresponding to the changing resistance value is connected to the power supply. A second circuit having a predetermined resistance value and outputting a second signal corresponding to the predetermined resistance value, a first signal supplied from the first circuit, and a second signal supplied from the second circuit. And a comparator circuit that compares the voltages and outputs a signal according to the predetermined value when the difference between the voltages of the first signal and the second signal reaches a predetermined value.

【0006】[0006]

【作用】電源と接続された第1回路が電源電圧の変動に
応じて抵抗値が変化し該変化する抵抗値に対応する第1
信号を出力し、電源と接続された第2回路が所定の抵抗
値を有し所定の抵抗値に対応する第2信号を出力し、比
較回路が第1回路から供給される第1信号と第2回路か
ら供給される第2信号とを電圧に関して比較して第1信
号および第2信号の電圧の差異が所定の値になったとき
該所定の値に応じた信号を出力するので、単一の電源に
より電源電圧の降下を検出し得る。
The resistance value of the first circuit connected to the power supply changes in response to the fluctuation of the power supply voltage, and the first circuit corresponding to the changing resistance value.
The second circuit, which outputs a signal, has a predetermined resistance value and has a predetermined resistance value, outputs a second signal corresponding to the predetermined resistance value, and the comparison circuit outputs the first signal and the first signal supplied from the first circuit. The second signal supplied from the two circuits is compared with respect to the voltage, and when the difference between the voltages of the first signal and the second signal reaches a predetermined value, a signal corresponding to the predetermined value is output. Can detect a drop in the power supply voltage.

【0007】[0007]

【実施例】図1は本発明の半導体集積回路からなる電源
電圧検出回路の実施例のブロック図である。同図におい
て、1はコンパレータ、VDDは電源の電源電圧、GN
Dはアース、R1、R2、R3は抵抗値の変動の少ない
抵抗、例えば拡散抵抗、RTはPチャネル型トランジス
タ抵抗、VMはコンパレータの+入力端子の入力電圧、
VREFはコンパレータ1の−入力電圧を示す。
1 is a block diagram of an embodiment of a power supply voltage detecting circuit comprising a semiconductor integrated circuit according to the present invention. In the figure, 1 is a comparator, VDD is a power supply voltage of a power supply, GN
D is ground, R1, R2, and R3 are resistors whose resistance values do not fluctuate much, such as diffusion resistors, RT is a P-channel transistor resistor, VM is the input voltage of the + input terminal of the comparator,
VREF indicates the negative input voltage of the comparator 1.

【0008】この回路はコンパレータ1とPチャネル型
トランジスタ抵抗RT(Nチャネル型トランジスタ抵抗
でもよい)並びに電源電圧の変動に対し、拡散抵抗R
1、R2、R3を1つの半導体チップ上に形成したIC
であって、コンパレータ1にはコンパレータ1の出力端
子Y、+入力端子、−入力端子が設けられておりY出力
端子からは電源電圧検出結果が出力される。
This circuit includes a diffusion resistance R for the comparator 1, a P-channel type transistor resistance RT (or an N-channel type transistor resistance may be used), and a variation in the power supply voltage.
IC in which 1, R2 and R3 are formed on one semiconductor chip
Therefore, the comparator 1 is provided with the output terminal Y, the + input terminal, and the − input terminal of the comparator 1, and the power supply voltage detection result is output from the Y output terminal.

【0009】Pチャネル型トランジスタ抵抗RTのゲー
トはGNDに接続され、ソースはVDDに、ドレインは
拡散抵抗R1とコンパレータ1の+入力端子に接続さ
れ、拡散抵抗R1の反対側端子はGNDに接続されてい
る。また、コンパレータ1の−入力は、拡散抵抗R2、
R3の接続点に接続され、拡散抵抗R2、R3の反対側
端子はVDD、GNDに接続されている。
The gate of the P-channel transistor resistance RT is connected to GND, the source is connected to VDD, the drain is connected to the diffusion resistor R1 and the + input terminal of the comparator 1, and the opposite terminal of the diffusion resistor R1 is connected to GND. ing. Further, the minus input of the comparator 1 is a diffusion resistor R2,
It is connected to the connection point of R3, and the opposite terminals of the diffused resistors R2 and R3 are connected to VDD and GND.

【0010】RT<R1、R2=R3としたとき、 VM=R1・VDD/(RT+R1) > VDD/2 VREF=R3・VDD/(R2+R3)= VDD/
2 したがって、 コンパレータ+側電圧 > コンパレータ−側電圧とな
り、 Y=”ハイ(HIGH)”レベル が出力される。
When RT <R1 and R2 = R3, VM = R1.VDD / (RT + R1)> VDD / 2 VREF = R3.VDD / (R2 + R3) = VDD /
2 Therefore, the comparator + side voltage> the comparator-side voltage, and the Y = “high (HIGH)” level is output.

【0011】上記状態により、電源電圧VDDが電圧降
下するにつれ、Pチャネル型トランジスタ抵抗RTは次
第に大きくなる。このPチャネル型トランジスタ抵抗R
Tの特性を利用し、 RT > R1となつたとき、 VM=R1・VDD/(RT+R1) < VDD/2 したがって、 コンパレータ+側電圧 < コンパレータ−側電圧とな
り、 Y=”ロ−(LOW)”レベル が出力される。すなわち、電圧レベルがある基準(ここ
ではVDD/2)以下に電圧降下したことを示す。これ
により電源電圧がVDD/2より小さいことが検出でき
る。
In the above state, the P-channel type transistor resistance RT gradually increases as the power supply voltage VDD drops. This P-channel type transistor resistance R
Using the characteristics of T, when RT> R1, VM = R1.VDD / (RT + R1) <VDD / 2 Therefore, comparator + side voltage <comparator−side voltage, and Y = “low (LOW)” The level is output. That is, it indicates that the voltage level drops below a certain reference (VDD / 2 in this case). This makes it possible to detect that the power supply voltage is lower than VDD / 2.

【0012】本実施例では、IC外部の外付け抵抗まで
もIC内部に取り組むことによりICの端子数を削減す
ることができる。
In the present embodiment, the number of terminals of the IC can be reduced by tackling even the external resistance outside the IC inside the IC.

【0013】[0013]

【発明の効果】電源と接続された第1回路が電源電圧の
変動に応じて抵抗値が変化し該変化する抵抗値に対応す
る第1信号を出力し、電源と接続された第2回路が所定
の抵抗値を有し所定の抵抗値に対応する第2信号を出力
し、比較回路が第1回路から供給される第1信号と第2
回路から供給される第2信号とを電圧に関して比較して
第1信号および第2信号の電圧の差異が所定の値になっ
たとき該所定の値に応じた信号を出力するので、単一の
電源により電源電圧の降下を検出し得る。
The first circuit connected to the power supply changes the resistance value according to the fluctuation of the power supply voltage, outputs the first signal corresponding to the changing resistance value, and the second circuit connected to the power supply operates. A second signal having a predetermined resistance value and corresponding to the predetermined resistance value is output, and the comparison circuit supplies a first signal and a second signal supplied from the first circuit.
The second signal supplied from the circuit is compared with respect to the voltage, and when the difference between the voltages of the first signal and the second signal reaches a predetermined value, a signal corresponding to the predetermined value is output, so that a single signal is output. The power supply can detect a drop in the power supply voltage.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の半導体集積回路からなる電源電圧検出
回路の実施例のブロック図である。
FIG. 1 is a block diagram of an embodiment of a power supply voltage detection circuit including a semiconductor integrated circuit according to the present invention.

【図2】従来の半導体集積回路の回路構成を示すブロッ
ク図である。
FIG. 2 is a block diagram showing a circuit configuration of a conventional semiconductor integrated circuit.

【符号の説明】[Explanation of symbols]

1 コンパレータ RT Pチャネル型トランジスタ抵抗 R1、R2、R3 拡散抵抗 1 Comparator RT P-channel transistor resistance R1, R2, R3 Diffusion resistance

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 電源と接続されており電源電圧の変動に
応じて抵抗値が変化し該変化する抵抗値に対応する第1
信号を出力する第1回路と、前記電源と接続されており
所定の抵抗値を有し前記所定の抵抗値に対応する第2信
号を出力する第2回路と、前記第1回路から供給される
第1信号と前記第2回路から供給される第2信号とを電
圧に関して比較し、第1信号および第2信号の電圧の差
異が所定の値になったとき該所定の値に応じた信号を出
力する比較回路とを含むことを特徴とする電源電圧検出
回路。
1. A first value which is connected to a power supply and whose resistance value changes in response to fluctuations in the power supply voltage and which corresponds to the changing resistance value.
A first circuit that outputs a signal, a second circuit that is connected to the power supply, that outputs a second signal that has a predetermined resistance value and that corresponds to the predetermined resistance value, and that is supplied from the first circuit The first signal and the second signal supplied from the second circuit are compared with respect to voltage, and when the difference between the voltages of the first signal and the second signal reaches a predetermined value, a signal corresponding to the predetermined value is detected. A power supply voltage detection circuit including a comparison circuit for outputting.
JP5097963A 1993-04-23 1993-04-23 Power supply-voltage detecting circuit Pending JPH06308171A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5097963A JPH06308171A (en) 1993-04-23 1993-04-23 Power supply-voltage detecting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5097963A JPH06308171A (en) 1993-04-23 1993-04-23 Power supply-voltage detecting circuit

Publications (1)

Publication Number Publication Date
JPH06308171A true JPH06308171A (en) 1994-11-04

Family

ID=14206335

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5097963A Pending JPH06308171A (en) 1993-04-23 1993-04-23 Power supply-voltage detecting circuit

Country Status (1)

Country Link
JP (1) JPH06308171A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7026855B2 (en) * 2004-03-02 2006-04-11 Kabushiki Kaisha Toshiba Semiconductor device to prevent a circuit from being inadvertently active
JP2011135329A (en) * 2009-12-24 2011-07-07 Mitsubishi Electric Corp Electric circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7026855B2 (en) * 2004-03-02 2006-04-11 Kabushiki Kaisha Toshiba Semiconductor device to prevent a circuit from being inadvertently active
JP2011135329A (en) * 2009-12-24 2011-07-07 Mitsubishi Electric Corp Electric circuit

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