JPH04125470A - Battery voltage monitoring circuit - Google Patents

Battery voltage monitoring circuit

Info

Publication number
JPH04125470A
JPH04125470A JP2246813A JP24681390A JPH04125470A JP H04125470 A JPH04125470 A JP H04125470A JP 2246813 A JP2246813 A JP 2246813A JP 24681390 A JP24681390 A JP 24681390A JP H04125470 A JPH04125470 A JP H04125470A
Authority
JP
Japan
Prior art keywords
terminal
voltage
comparator
battery voltage
output
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
JP2246813A
Other languages
Japanese (ja)
Inventor
Toru Otsu
徹 大津
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP2246813A priority Critical patent/JPH04125470A/en
Publication of JPH04125470A publication Critical patent/JPH04125470A/en
Pending legal-status Critical Current

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  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Tests Of Electric Status Of Batteries (AREA)

Abstract

PURPOSE:To enable output when a power supply is turned on to be stable by tentatively reducing + side input voltage of a reference voltage input of a comparator as compared with - side voltage of a battery voltage input of a guarantee circuit. CONSTITUTION:A guarantee circuit 20 is provided in this circuit. A battery voltage Vcc which is fed to a terminal 30 is divided by resistors R1 and R2 and is fed to - side terminal 10a of a comparator 10 and at the same time charge current flows to a capacitor C tentatively, thus enabling a transistor Tr to be turned on. Thus, + side terminal 10b of the comparator 10 is ground through a collector and an emitter of the transistor Tr, thus enabling voltage at the terminal 10b to be at a lower grounding potential then voltage at the terminal 10a and L to be output to an output terminal 40. Thus, even if the voltage Vcc which is applied to the terminal 30 is at the middle point of operation level of hysteresis characteristics of a circuit, output of the comparator 10 is always set to L when the power supply is turned on, a device can be operated, and a battery can be used without any waste.

Description

【発明の詳細な説明】 [概要] オープンコレクタタイプの比較器を使用してヒステレシ
ス特性を持たせたバッテリー電圧監視回路に関し、 電源パワーオン時の出力の安定化を目的とし、電源パワ
ーオン時に比較器の+側入力電圧を一時的に一側電圧よ
りも低くして“L”が出力されるように構成する。
[Detailed Description of the Invention] [Summary] Regarding a battery voltage monitoring circuit that uses an open collector type comparator and has hysteresis characteristics, the purpose of stabilizing the output when the power source is turned on is to compare the voltage when the power source is turned on. The + side input voltage of the device is temporarily lowered than the one side voltage so that "L" is output.

[産業上の利用分野] 本発明は、オープンコレクタタイプの比較器を使用して
ヒステレシス特性を持たせたバッテリー電圧監視回路に
関する。
[Industrial Application Field] The present invention relates to a battery voltage monitoring circuit that uses an open collector type comparator to provide hysteresis characteristics.

[従来の技術] 従来、この種のバッテリー電圧監視回路は、第3図に示
すように、比較器CO’MPの一側入力端子に、バッテ
リー電圧Vccを抵抗R1およびR2で分割した電圧を
入力し、+側入力端子には抵抗R5を介して基準電圧V
refを入力するとともに、比較器COMPの出力Vo
utを抵抗R4を介して帰還させた電圧を入力させてい
た。
[Prior Art] Conventionally, this type of battery voltage monitoring circuit inputs a voltage obtained by dividing the battery voltage Vcc by resistors R1 and R2 to one side input terminal of the comparator CO'MP, as shown in FIG. The reference voltage V is applied to the + side input terminal via the resistor R5.
ref is input, and the output Vo of the comparator COMP is input.
A voltage fed back from ut via resistor R4 was input.

比較器COMPは、その−個入力端子に入力されるバッ
テリー電圧VCCが、→−一側入力端子入力される基準
電圧V refよりも大きいと、出力Voutとして“
L”を出力し、反対に小さいと“HI+を出力して、バ
ッテリー電圧が低下したことを知らせるパワーアラーム
を発する。
The comparator COMP outputs "Vout" as the output Vout when the battery voltage VCC input to its - input terminal is larger than the reference voltage V ref input to the - input terminal.
If the battery voltage is low, it will output "HI+" and a power alarm will be issued to notify you that the battery voltage has dropped.

第4図はこのようなバッテリー電圧監視回路における入
出力特性を示している。バッテリー電圧Vccが低下し
て動作レベルVaに下がると出力VOutは“H”にな
り、バッテリー電圧Vccが高くなって動作レベルvb
に上がると出力Voutは“L”になる。このように、
バッテリー電圧Vccの減少時と増加時とで動作レベル
を変化させてヒステリシス特性を持たせるのは、入力信
号のノイズによる影響を避けるためである。
FIG. 4 shows the input/output characteristics of such a battery voltage monitoring circuit. When the battery voltage Vcc decreases to the operating level Va, the output VOut becomes "H", and the battery voltage Vcc increases to the operating level Vb.
, the output Vout becomes "L". in this way,
The reason why the operating level is changed when the battery voltage Vcc decreases and when it increases to provide a hysteresis characteristic is to avoid the influence of input signal noise.

[発明が解決しようとする課題] しかしながら、このような従来のバッテリー電圧監視回
路では、そのヒステリシス特性のために、動作レベルに
Vaからvbの範囲で幅があり、電源パワーオン時にバ
ッテリー電圧Vccが動作レベルVaとvbの中間にあ
ると、ヒステリシス特性における電圧減少時か増加時か
不明のため、出力voutが“l(”になるか“′L”
になるか−律に定まらない問題点があった。すなわち、
バッテリー電圧VCCが動作レベルVa以上あれば出力
Voutに“L”が出力されて回路の動作が可能である
にも拘らず、“ト■”が出力されてパワーアラームが発
せられることがあり、バッテリーが無駄になってしまう
問題点があった。
[Problem to be Solved by the Invention] However, in such a conventional battery voltage monitoring circuit, due to its hysteresis characteristic, the operating level varies from Va to Vb, and when the power source is turned on, the battery voltage Vcc is If the operating level is between Va and Vb, it is unclear whether the voltage is decreasing or increasing due to the hysteresis characteristic, so the output vout will be “L(” or “’L”)
- There was a problem that was not determined by law. That is,
If the battery voltage VCC is equal to or higher than the operating level Va, "L" is output to the output Vout and the circuit can operate, but "G" may be output and a power alarm is issued, and the battery There was a problem that it was wasted.

本発明は、このような従来の問題点を解決するものであ
り、電源パワーオン時の出力の安定化を図ったバッテリ
ー電圧監視回路を提供することを目r1勺とする。
The present invention is intended to solve these conventional problems, and its primary purpose is to provide a battery voltage monitoring circuit that stabilizes the output when the power source is turned on.

[課題を解決するための手段] 本発明は、上記目的を達成するために、第1図の原理ブ
ロック図に示すように、電源パワーオン時に基準電圧V
 refが入力される比較器1の+側入力電圧を、バッ
テリー電圧が入力される一側入力電圧よりも一時的に低
くして出力Voutを“L”に保証する保証回路2を備
えたものである。
[Means for Solving the Problems] In order to achieve the above object, the present invention, as shown in the principle block diagram of FIG.
It is equipped with a guarantee circuit 2 that guarantees the output Vout to be "L" by temporarily lowering the + side input voltage of the comparator 1 to which ref is inputted than the one side input voltage to which the battery voltage is inputted. be.

し作用コ バッテリー電圧Vccが回路のヒステリシス特性におけ
る動作レベルの中間にあっても、電源パワーオン時には
、比較器の出力Voutは必ず“L”になるので、装置
は動作可能になり、バッテリーを無駄なく使用すること
ができる。
Even if the operating voltage Vcc of the battery is in the middle of the operating level in the hysteresis characteristic of the circuit, the output Vout of the comparator will always be "L" when the power is turned on, so the device will be able to operate and the battery will not be wasted. can be used.

[実施例] 第2図は本発明の一実施例の構成を示しており、第3図
に示した従来例に保証回路を付加した構成になっている
。第2図において、10は比較器であり、20は保証回
路である。R1−R6は抵抗であり、Cはコンデンサ、
Trはトランジスタ、Vrefは基準電圧である。保証
回路20は、コンデンサC1抵抗R6およびトランジス
タ1’ rにより構成されている。30はVCC端子、
40は出力端子である。
[Embodiment] FIG. 2 shows the configuration of an embodiment of the present invention, which has a configuration in which a guarantee circuit is added to the conventional example shown in FIG. 3. In FIG. 2, 10 is a comparator and 20 is a guarantee circuit. R1-R6 are resistors, C is a capacitor,
Tr is a transistor, and Vref is a reference voltage. The guarantee circuit 20 is composed of a capacitor C1, a resistor R6, and a transistor 1'r. 30 is the VCC terminal,
40 is an output terminal.

抵抗R1はVCC端子30と比較器10の一側端子10
aとの間に接続され、抵抗R2は比較器10の一側端子
10aとグランドとの間に接続されている。抵抗R3は
Vcc端子30と比較器10の出力端子10cとの間に
接続され、抵抗R4は比較器10の出力端子10Cと比
較器10の+側端子10bとの間に接続されている。抵
抗R5は比較器1oの+側端子10bと基準電圧V r
efとの間に接続されている。コンデンサCはVcc端
子30とトランジスタTrのベースとの間に接続され、
抵抗R6はトランジスタ′1゛rのベースとグランドと
の間に接続されている。トランジスタTrのコレクタは
比較器10の+側端子10bに接続され、エミッタはグ
ランドに接続されている。
Resistor R1 connects VCC terminal 30 and one side terminal 10 of comparator 10.
a, and the resistor R2 is connected between the one side terminal 10a of the comparator 10 and the ground. The resistor R3 is connected between the Vcc terminal 30 and the output terminal 10c of the comparator 10, and the resistor R4 is connected between the output terminal 10C of the comparator 10 and the + side terminal 10b of the comparator 10. The resistor R5 connects the + side terminal 10b of the comparator 1o and the reference voltage V r
ef. A capacitor C is connected between the Vcc terminal 30 and the base of the transistor Tr,
A resistor R6 is connected between the base of the transistor '1'r and ground. The collector of the transistor Tr is connected to the + side terminal 10b of the comparator 10, and the emitter is connected to ground.

次に上記実施例の動作について説明する。Vcc端子3
0に加えられたバッテリー電圧は、抵抗R1およびR2
に分圧されて比較器10の一側端子10aに入力される
とともに、コンデンサCに一時的に充電電流が流れてト
ランジスタTrをオンさせるので、比較器10の+側端
子10bはトランジスタTrのコレクタおよびエミッタ
を通して接地される。このため、比較器10の+側端子
IQbの電圧は、−側端子10aの電圧よりも低い接地
電位になるので、出力端子40には“L”が出力される
。したがって、Vcc@子30に加えられるバッテリー
電圧が、第4図に示すヒステリシス特性における減少時
の動作レベルVaと増加時の動作レベルvbとの中間に
あっても、出力端子40には必ず“L”が出力されるの
で、装置がパワーアラームを出力することがなく、バッ
テリーを無駄な(使用することができる。
Next, the operation of the above embodiment will be explained. Vcc terminal 3
The battery voltage applied to 0 is applied to resistors R1 and R2
At the same time, a charging current temporarily flows through the capacitor C and turns on the transistor Tr, so that the + side terminal 10b of the comparator 10 is connected to the collector of the transistor Tr. and grounded through the emitter. Therefore, since the voltage at the + side terminal IQb of the comparator 10 becomes a ground potential lower than the voltage at the - side terminal 10a, "L" is output to the output terminal 40. Therefore, even if the battery voltage applied to the Vcc@ terminal 30 is between the operating level Va when decreasing and the operating level Vb when increasing in the hysteresis characteristic shown in FIG. 4, the output terminal 40 is always "L". is output, so the device does not output a power alarm and the battery can be used unnecessarily.

[発明の効果] 以上説明したように、本発明によれば、電源パワーオン
時に基準電圧が入力される比較器の+側入力電圧を、バ
ッテリー電圧が入力される一側電圧よりも一時的に低く
して出力を“L I+に保証する保証回路を備えたもの
であり、バッテリー電圧が回路のヒステリシス特性にお
ける動作レベルの中間にあっても、電源パワーオン時に
は比較器の出力が必ず“L”になるので、装置は動作可
能になり、バッテリーを無駄なく使うことができる。
[Effects of the Invention] As explained above, according to the present invention, the + side input voltage of the comparator to which the reference voltage is input when the power source is turned on is temporarily set higher than the one side voltage to which the battery voltage is input. It is equipped with a guarantee circuit that guarantees the output to be "L" when the power is turned on, even if the battery voltage is in the middle of the operating level according to the circuit's hysteresis characteristics. As a result, the device becomes operational and the battery can be used efficiently.

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

第1図は本発明の詳細な説明する原理ブロック図、第2
図は本発明の一実施例を示すバッテリー電圧監視回路の
回路図、第3図は従来のバッチリー電圧監視回路の回路
図、第4図は第3図に示すバッテリー電圧監視回路の人
出力特性図である。 10・・・比較器、10a・・・−側端子、10b・・
・、ト側端子、10c・・・出力端子、20・・・保証
回路、30・・・Vcc端子、40・・・出力端子、R
1−R6・・・抵抗、C・・・コンデンサ、Tr・・・
トランジスタ、Vref・・・基準電圧。 全8月の旅理口 第1図 Vout 従来例の凹踏図 第3図 従来例の入出力性・比図 第4図
Fig. 1 is a principle block diagram explaining the present invention in detail;
The figure is a circuit diagram of a battery voltage monitoring circuit showing an embodiment of the present invention, FIG. 3 is a circuit diagram of a conventional battery voltage monitoring circuit, and FIG. 4 is a human output characteristic diagram of the battery voltage monitoring circuit shown in FIG. 3. It is. 10...Comparator, 10a...- side terminal, 10b...
・, G side terminal, 10c... Output terminal, 20... Guarantee circuit, 30... Vcc terminal, 40... Output terminal, R
1-R6...Resistor, C...Capacitor, Tr...
Transistor, Vref...Reference voltage. Figure 1: Vout for the entire month of August Figure 3: Concave diagram of the conventional example Figure 4: Input/output performance/ratio diagram of the conventional example

Claims (1)

【特許請求の範囲】 1)オープンコレクタタイプの比較器(1)を使用して
ヒステレシス特性を持たせたバッテリー電圧監視回路に
おいて、電源パワーオン時に基準電圧(Vref)が入
力される比較器(1)の+側入力電圧を、バッテリー電
圧(Vcc)が入力される−側電圧よりも一時的に低く
して出力(Vout)を“L”に保証する保証回路(2
)を備えたバッテリー電圧監視回路。 2)保証回路(2)は比較器(2)の+側端子に接続さ
れ、この比較器(2)の基準電圧を可変制御することを
特徴とする請求項1記載のバッテリー電圧監視回路。 3)保証回路(2)は、バッテリー電圧(Vcc)入力
端子に接続されたコンデンサCと、ベースがコンデンサ
Cの他端に接続されたトランジスタ(Tr)と、トラン
ジスタ(Tr)のベースとグランドとの間に接続された
抵抗R6とにより構成され、前記トランジスタ(Tr)
は、コレクタが比較器(1)の+側端子に接続され、エ
ミッタがグランドに接続されることにより、電源パワー
オン時の+側入力電圧を−側入力電圧よりも一時的に低
くすることを特徴とする請求項2記載のバッテリー電圧
監視回路。
[Claims] 1) In a battery voltage monitoring circuit that uses an open collector type comparator (1) and has a hysteresis characteristic, the comparator (1) to which a reference voltage (Vref) is input when the power source is turned on. ) is a guarantee circuit (2) that guarantees the output (Vout) to be "L" by temporarily lowering the + side input voltage of the battery voltage (Vcc) than the - side voltage that is inputted.
) battery voltage monitoring circuit. 2) The battery voltage monitoring circuit according to claim 1, wherein the guarantee circuit (2) is connected to the + side terminal of the comparator (2) and variably controls the reference voltage of the comparator (2). 3) The guarantee circuit (2) consists of a capacitor C connected to the battery voltage (Vcc) input terminal, a transistor (Tr) whose base is connected to the other end of the capacitor C, and a connection between the base of the transistor (Tr) and the ground. and a resistor R6 connected between the transistor (Tr)
The collector is connected to the + side terminal of the comparator (1), and the emitter is connected to the ground, so that the + side input voltage is temporarily lower than the - side input voltage when the power supply is turned on. The battery voltage monitoring circuit according to claim 2.
JP2246813A 1990-09-17 1990-09-17 Battery voltage monitoring circuit Pending JPH04125470A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2246813A JPH04125470A (en) 1990-09-17 1990-09-17 Battery voltage monitoring circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2246813A JPH04125470A (en) 1990-09-17 1990-09-17 Battery voltage monitoring circuit

Publications (1)

Publication Number Publication Date
JPH04125470A true JPH04125470A (en) 1992-04-24

Family

ID=17154072

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2246813A Pending JPH04125470A (en) 1990-09-17 1990-09-17 Battery voltage monitoring circuit

Country Status (1)

Country Link
JP (1) JPH04125470A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0902294A1 (en) * 1997-09-09 1999-03-17 Texas Instruments Deutschland Gmbh A voltage monitoring circuit
JP2014023316A (en) * 2012-07-19 2014-02-03 Hioki Ee Corp Overdischarge prevention circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0902294A1 (en) * 1997-09-09 1999-03-17 Texas Instruments Deutschland Gmbh A voltage monitoring circuit
JP2014023316A (en) * 2012-07-19 2014-02-03 Hioki Ee Corp Overdischarge prevention circuit

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