JP2001306165A - Voltage detecting circuit - Google Patents
Voltage detecting circuitInfo
- Publication number
- JP2001306165A JP2001306165A JP2000116557A JP2000116557A JP2001306165A JP 2001306165 A JP2001306165 A JP 2001306165A JP 2000116557 A JP2000116557 A JP 2000116557A JP 2000116557 A JP2000116557 A JP 2000116557A JP 2001306165 A JP2001306165 A JP 2001306165A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- circuit
- power supply
- charge pump
- reference 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
Links
Landscapes
- Measurement Of Current Or Voltage (AREA)
- Control Of Electrical Variables (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電圧検出回路に関
する。[0001] The present invention relates to a voltage detection circuit.
【０００２】[0002]
【従来の技術】従来の電圧検出回路は図２に示すよう
に、電源電圧を印加するために設けられた端子ＶＤＤと
ＶＳＳの間に直列に接続されている抵抗２０２、抵抗２
０３、からなる分圧回路と一定電圧を発生することので
きる基準電圧発生回路２０１と電圧比較回路２０４で構
成される。電圧比較回路２０４は、複数のＭＯＳＦＥＴ
からなり、該分圧回路によって分圧された分圧電圧と基
準電圧発生回路２０１から発生された基準電圧を比較し
て、該分圧電圧が該基準電圧よりも高い場合はＨｉが、
逆に低い場合はＬｏが出力される。2. Description of the Related Art As shown in FIG. 2, a conventional voltage detection circuit includes a resistor 202 and a resistor 2 connected in series between terminals VDD and VSS provided for applying a power supply voltage.
, A reference voltage generating circuit 201 capable of generating a constant voltage, and a voltage comparing circuit 204. The voltage comparison circuit 204 includes a plurality of MOSFETs.
Comparing the divided voltage divided by the voltage dividing circuit with the reference voltage generated from the reference voltage generating circuit 201, when the divided voltage is higher than the reference voltage, Hi is
On the other hand, when it is low, Lo is output.
【０００３】動作は、まず入力電圧を該分圧回路にて分
圧された分圧電圧と基準電圧回路２０１の基準電圧を電
圧比較回路２０４で比較し、比較された信号は外部端子
ＶＯＵＴより出力される。例えば、分圧電圧が基準電圧
より高い場合は電圧比較回路２０４の出力電圧はＶＤＤ
となり、外部端子ＶＯＵＴからＶＤＤが出力される。ま
た、逆に該分圧電圧が基準電圧より低い場合は、ＶＳＳ
が外部端子ＶＯＵＴから出力される。In operation, first, a divided voltage obtained by dividing an input voltage by the voltage dividing circuit and a reference voltage of a reference voltage circuit 201 are compared by a voltage comparing circuit 204, and the compared signal is output from an external terminal VOUT. Is done. For example, when the divided voltage is higher than the reference voltage, the output voltage of the voltage comparison circuit 204 is VDD.
, And VDD is output from the external terminal VOUT. On the other hand, when the divided voltage is lower than the reference voltage, VSS
Is output from the external terminal VOUT.
【０００４】[0004]
【発明が解決しようとする課題】従来の電圧検出回路に
おいて、電圧比較回路を構成しているＭＯＳＦＥＴの閾
値を十分に超えるような電圧が入力されなくなると電圧
比較回路は正常に動作をすることができなくなる。その
結果、電圧検出回路の出力が不定となり、ＨｉかＬｏか
不確定になる。図３は不確定な状態を示す図で、領域Ａ
が出力において不定になる領域である。ここで、ＶＤＤ
は入力電圧、ＶＯＵＴは出力電圧である。In the conventional voltage detection circuit, if a voltage that exceeds the threshold value of the MOSFET constituting the voltage comparison circuit is no longer input, the voltage comparison circuit may operate normally. become unable. As a result, the output of the voltage detection circuit becomes indefinite, and Hi or Lo becomes indefinite. FIG. 3 is a diagram showing an indeterminate state.
Is an area where output is undefined. Here, VDD
Is an input voltage, and VOUT is an output voltage.
【０００５】[0005]
【課題を解決するための手段】上記の課題を解決するた
めに、本願発明では電源端子ＶＤＤとＶＳＳとの間にチ
ャージポンプ回路を設け、その昇圧出力を電圧比較回路
に供給する構成とした。In order to solve the above-mentioned problems, a charge pump circuit is provided between the power supply terminals VDD and VSS in the present invention, and the boosted output is supplied to a voltage comparison circuit.
【０００６】[0006]
【発明の実施の形態】以下、本発明の実施例を図面を用
いて説明する。図１は本発明である電圧検出回路の回路
図である。外部端子ＶＤＤとＶＳＳの間に直列に接続さ
れている抵抗１０２、抵抗１０３とがあり、入力された
電源電圧を所定の比率で分割することができる分圧回路
で構成されている。抵抗１０２と抵抗１０３との接合部
は、電圧比較回路１０４の−入力端子と接続されてい
る。一方、電源電圧の大きさに関係なく一定の基準電圧
を発生することのできる基準電圧回路１０１は電圧比較
回路１０４の＋入力端子と接続されている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a voltage detection circuit according to the present invention. There are a resistor 102 and a resistor 103 connected in series between the external terminals VDD and VSS, and is constituted by a voltage dividing circuit that can divide an input power supply voltage at a predetermined ratio. The junction between the resistor 102 and the resistor 103 is connected to the negative input terminal of the voltage comparison circuit 104. On the other hand, a reference voltage circuit 101 capable of generating a constant reference voltage regardless of the magnitude of the power supply voltage is connected to the + input terminal of the voltage comparison circuit 104.
【０００７】また、チャージポンプ回路１０５をＶＤＤ
とＶＳＳの間に付加して、その出力を電圧比較回路１０
４に入力するようにしてある。Further, the charge pump circuit 105 is connected to VDD
, And the output of the voltage comparison circuit 10
4 is input.
【０００８】動作は、外部端子ＶＳＳをＧＮＤとして、
外部端子ＶＤＤから入力された電圧は抵抗１０２、抵抗
１０３からなる該分圧回路で分圧される。この分圧され
た電圧は、電圧比較回路１０４において基準電圧発生回
路１０１で発生される基準電圧と比較される。この電圧
比較回路１０４には、チャージポンプ回路１０５によっ
て、図４のＶＤＤupのようにチャージポンプの作用によ
り電源電圧より高い昇圧した出力電圧が入力される。電
圧比較回路１０４で該基準電圧と該分圧電圧を比較した
結果入力電圧の方が高い場合は外部端子ＶＯＵＴからＶ
ＤＤが出力される。また、その逆に、該分圧電圧が該基
準電圧より低い場合は、ＶＳＳが外部端子ＶＯＵＴから
出力される。The operation is performed by setting the external terminal VSS to GND.
The voltage input from the external terminal VDD is divided by the voltage dividing circuit including the resistors 102 and 103. The divided voltage is compared with the reference voltage generated by the reference voltage generation circuit 101 in the voltage comparison circuit 104. To the voltage comparison circuit 104, a boosted output voltage higher than the power supply voltage due to the action of the charge pump, such as VDD up in FIG. As a result of comparing the reference voltage and the divided voltage by the voltage comparison circuit 104, if the input voltage is higher than the external terminal VOUT,
DD is output. Conversely, when the divided voltage is lower than the reference voltage, VSS is output from the external terminal VOUT.
【０００９】以上のように、電圧比較回路１０４が正常
に動作することができないような低い電圧であっても、
チャージポンプ回路１０５によって昇圧された電圧が電
圧比較回路１０４に供給される構成としたことで、図４
のように電圧比較回路１０４が正常に動作をすることが
できる。As described above, even if the voltage is low enough that the voltage comparison circuit 104 cannot operate normally,
Since the voltage boosted by the charge pump circuit 105 is supplied to the voltage comparison circuit 104,
As described above, the voltage comparison circuit 104 can operate normally.
【００１０】[0010]
【発明の効果】本発明の電圧検出回路はたとえ入力電圧
が、電圧検出回路が正常に動作できないような低い電圧
であっても、チャージポンプ回路で昇圧させた電圧を電
圧比較回路に入力することによって、電圧比較回路の動
作が正しく行われるという効果を有する。According to the voltage detection circuit of the present invention, the voltage boosted by the charge pump circuit is input to the voltage comparison circuit even if the input voltage is such a low voltage that the voltage detection circuit cannot operate normally. Thereby, the operation of the voltage comparison circuit is performed correctly.
【図１】本発明の電圧検出回路図FIG. 1 is a diagram of a voltage detection circuit according to the present invention.
【図２】従来の電源検出回路の一例FIG. 2 shows an example of a conventional power supply detection circuit.
【図３】電圧検出回路の動作を示す図FIG. 3 illustrates an operation of a voltage detection circuit.
【図４】本発明の電圧検出回路の動作を示す図FIG. 4 is a diagram showing the operation of the voltage detection circuit of the present invention.
１０１ 基準電圧回路 １０２ 抵抗 １０３ 抵抗 １０４ 電圧比較回路 １０５ チャージポンプ回路 ２０１ 基準電圧回路 ２０２ 抵抗 ２０３ 抵抗 ２０４ 電圧比較回路 DESCRIPTION OF SYMBOLS 101 Reference voltage circuit 102 Resistance 103 Resistance 104 Voltage comparison circuit 105 Charge pump circuit 201 Reference voltage circuit 202 Resistance 203 Resistance 204 Voltage comparison circuit
Claims (2)
できる電源電圧分割回路と、電源電圧の大きさに関係な
く一定の基準電圧を発生することのできる基準電圧発生
回路と、入力された該基準電圧と分圧回路にて分圧され
た電源電圧との大きさを比較して出力信号を切り替える
ことができる電圧比較回路とからなり、特定の電圧を検
出することのできる電圧検出回路において、電源間にチ
ャージポンプ回路を付加し、該チャージポンプ回路の昇
圧出力電圧を電圧比較回路に供給することを特徴とする
電圧検出回路。1. A power supply voltage dividing circuit capable of dividing a power supply voltage at a predetermined ratio, a reference voltage generating circuit capable of generating a constant reference voltage irrespective of the magnitude of the power supply voltage, and A voltage comparing circuit that can compare the magnitude of the reference voltage and the power supply voltage divided by the voltage dividing circuit and switch an output signal, and that can detect a specific voltage. And a charge pump circuit added between the power supplies, and a boosted output voltage of the charge pump circuit is supplied to a voltage comparison circuit.
電圧比較回路からなる電圧検出回路において、電源間に
接続され、昇圧出力電圧が前記電圧比較回路に接続され
たチャージポンプ回路を有する電圧検出回路。2. A voltage detecting circuit comprising a power supply voltage dividing circuit, a reference voltage generating circuit, and a voltage comparing circuit, comprising a charge pump circuit connected between power supplies and having a boosted output voltage connected to the voltage comparing circuit. circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000116557A JP2001306165A (en) | 2000-04-18 | 2000-04-18 | Voltage detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000116557A JP2001306165A (en) | 2000-04-18 | 2000-04-18 | Voltage detecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001306165A true JP2001306165A (en) | 2001-11-02 |
Family
ID=18628005
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000116557A Pending JP2001306165A (en) | 2000-04-18 | 2000-04-18 | Voltage detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001306165A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6483155A (en) * | 1987-09-25 | 1989-03-28 | Sony Corp | Detecting circuit of fluctuation of external power supply voltage for semiconductor device |
| JPH08508600A (en) * | 1993-04-05 | 1996-09-10 | ナショナル・セミコンダクター・コーポレイション | Device and method for adjusting threshold voltage of MOS transistor |
-
2000
- 2000-04-18 JP JP2000116557A patent/JP2001306165A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6483155A (en) * | 1987-09-25 | 1989-03-28 | Sony Corp | Detecting circuit of fluctuation of external power supply voltage for semiconductor device |
| JPH08508600A (en) * | 1993-04-05 | 1996-09-10 | ナショナル・セミコンダクター・コーポレイション | Device and method for adjusting threshold voltage of MOS transistor |
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