JPH0389173A - Voltage drop detection circuit - Google Patents

Voltage drop detection circuit

Info

Publication number
JPH0389173A
JPH0389173A JP1225886A JP22588689A JPH0389173A JP H0389173 A JPH0389173 A JP H0389173A JP 1225886 A JP1225886 A JP 1225886A JP 22588689 A JP22588689 A JP 22588689A JP H0389173 A JPH0389173 A JP H0389173A
Authority
JP
Japan
Prior art keywords
voltage
comparator
output
voltage drop
charging
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
JP1225886A
Other languages
Japanese (ja)
Inventor
Taku Mikami
卓 三上
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 JP1225886A priority Critical patent/JPH0389173A/en
Publication of JPH0389173A publication Critical patent/JPH0389173A/en
Pending legal-status Critical Current

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  • Measurement Of Current Or Voltage (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

PURPOSE:To obtain a pulse having width only corresponding to a time constant by providing a charging and discharging part for charging and discharging the output of a comparator detecting whether input voltage drops to send out the output to a voltage drop detector so as to delay the same by the time constant thereof. CONSTITUTION:A charging and discharging part 3 charged from the output of a comparator 1 with a predetermined time constant and instantaneously performing discharge is provided between the comparator 1 and a voltage drop detection circuit 2. By this constitution, even when voltage is simultaneously applied to the comparator 1 and the detector 2, the output voltage of the charging the discharging part 3 applied to the detector 2 is applied so as to be delayed from the above-mentioned applied voltage by the time constant of the charging and discharging part 3. By this method, a pulse having width only corresponding to the time constant is obtained and, since the width of the output pulse of the voltage drop detection circuit does not becomes extremely narrow, for example, the voltage drop detection circuit used on the side of the moving station of automobile telephone system is improved.

Description

【発明の詳細な説明】 〔概要〕 例えば、自動車電話システムの移動局側において使用す
る電圧低下検出回路に関し、 この回路の出力パルスの幅が極端に狭くならない様にす
ることを目的とし、 入力電圧が規定電圧よりも低下しているか否かを検出す
る比較器と1人力信号を用いて電圧低下時間が規定時間
よりも長い時、規定時間以上の時間に対応する幅のパル
スを送出する電圧低下検出器とを有する電圧低下検出回
路において、該比較器の出力を充放電して得た信号を該
電圧低下検出器に送出する充放電部分を有する様に構成
するヵ〔産業上の利用分野〕 本発明は9例えば自動車電話システムの移動局側で使用
する電圧低下検出回路に関するものである。
[Detailed Description of the Invention] [Summary] For example, regarding a voltage drop detection circuit used on the mobile station side of a car telephone system, the purpose of this circuit is to prevent the output pulse width of this circuit from becoming extremely narrow. When the voltage drop time is longer than the specified time, a voltage drop that sends out a pulse with a width corresponding to the time longer than the specified time using a comparator and a manual signal to detect whether the voltage has fallen below the specified voltage. A voltage drop detection circuit having a detector is configured to have a charging/discharging portion that sends a signal obtained by charging and discharging the output of the comparator to the voltage drop detector. [Industrial application field] The present invention relates to a voltage drop detection circuit used, for example, on the mobile station side of a car telephone system.

自動車電話システムの移動局側機器で使用する電力は電
池から供給されているが、電池の負荷が変動すると機器
に供給される電源電圧が変動することがある。
The power used by mobile station equipment in a car telephone system is supplied from a battery, but if the load on the battery fluctuates, the power supply voltage supplied to the equipment may fluctuate.

そこで、この回路を用いて電源電圧が規定時間以上、規
定電圧より低下したか否かを電源電圧が復旧した時に検
出しているが、この回路から出力される検出パルスは自
局の動作制御に使用しているので、誤制御の可能性を少
なくする為にパルス幅が極端に狭くならない様にするこ
とが必要である。
Therefore, this circuit is used to detect whether the power supply voltage has fallen below the specified voltage for more than a specified time when the power supply voltage is restored, but the detection pulse output from this circuit is used to control the operation of the own station. In order to reduce the possibility of erroneous control, it is necessary to prevent the pulse width from becoming extremely narrow.

〔従来の技術〕[Conventional technology]

第4図は従来例の回路図、第5図は第4図の動作説明図
を示す。尚、第5図中の左側の符号は第4図中の同じ符
号の部分の波形を示す。以下、第5図を参照して第4図
の動作を説明する。
FIG. 4 is a circuit diagram of a conventional example, and FIG. 5 is an explanatory diagram of the operation of FIG. 4. Note that the symbols on the left side of FIG. 5 indicate the waveforms of the portions with the same symbols in FIG. The operation shown in FIG. 4 will be explained below with reference to FIG.

先ず、電源スィッチSW、をオンにすると規定の電源電
圧(例えば、約+14v)が抵抗R,,R,で分圧され
2例えば、+8vが比較器11に加えられる。
First, when the power switch SW is turned on, a specified power supply voltage (for example, approximately +14V) is divided by the resistors R, , R, and 2, for example, +8V is applied to the comparator 11.

ここには1例えば+5vが抵抗R1を介してしきい値電
圧として加えられているので2つの電圧が比較されて電
圧v2が出力される。比較器11の出力は抵抗R4+ 
インバータ21.抵抗R8を介して電圧v。
Since 1, for example, +5V is applied here as a threshold voltage via the resistor R1, the two voltages are compared and a voltage v2 is output. The output of comparator 11 is resistor R4+
Inverter 21. Voltage v across resistor R8.

(vz >vl)に変換されてトランジスタ22のベー
スに加えられるので、このトランジスタはオン状態にな
る。
(vz > vl) and is applied to the base of transistor 22, which turns on the transistor.

この為、+5vがオン状態になったトランジスタ22.
ダイオードD、を介してコンデンサC1を充電し、充電
電圧が比較器23の一端子に、子端子に+5vが 抵抗
R□R1で分圧された電圧が印加されるので比較器23
から電圧v、が出力される(第5図−■〜■のAの部分
参照)。
For this reason, transistor 22.+5v is turned on.
The capacitor C1 is charged via the diode D, and the charging voltage is applied to one terminal of the comparator 23, and the voltage obtained by dividing +5V by the resistor R□R1 is applied to the child terminal of the comparator 23.
A voltage v is output from the circuit (see parts A in FIG. 5--).

次に、電源電圧が1.時間だけ規定電圧よりも低下した
とすると、比較器11の出力はり、になるが。
Next, the power supply voltage is 1. If the voltage drops below the specified voltage by a certain amount of time, the output of the comparator 11 will be .

インバータ21で反転されてトランジスタ22のベース
に加えられるので、このトランジスタがオフになる。
The signal is inverted by an inverter 21 and applied to the base of a transistor 22, turning this transistor off.

これにより、コンデンサC4に蓄えられた電荷は抵抗R
7を介して放電を開始するが、C+Rt <t、の為に
完全に放電する。一方、比較器23は子端子に印加され
る電圧が一端子に印加される電圧より高くなった時点で
電圧v2が出力される(第5図−■〜■のBの部分参照
)。
As a result, the charge stored in capacitor C4 is transferred to resistor R
7, but it is completely discharged because C+Rt <t. On the other hand, the comparator 23 outputs the voltage v2 when the voltage applied to the child terminal becomes higher than the voltage applied to one terminal (see portions B in ■ to ■ in FIG. 5).

そして9時間tI経過後に電源電圧が第5図−■〜■の
Cの部分の様に規定電圧に復帰すると第5図−■〜■の
Aの部分と同様に各部が動作する。
After 9 hours tI have elapsed, when the power supply voltage returns to the specified voltage as shown in section C of FIG.

その後、電源電圧が再び第5図のDの部分の様に規定電
圧以下になるが、規定電圧以下の時間がCIR,の時定
数よりも短いので、第5図−■の右側に示す様にコンデ
ンサに蓄えられた電荷は一部。
After that, the power supply voltage becomes lower than the specified voltage again as shown in part D in Fig. 5, but the time when the voltage is below the specified voltage is shorter than the time constant of CIR, so as shown on the right side of Fig. 5-■. A portion of the charge is stored in the capacitor.

放電しただけで、再び充電される。これにより。Just discharge it and it will be charged again. Due to this.

比較器23の出力は第5図−■の右側に示す様に電圧V
、の出力がそのまま送出される。
The output of the comparator 23 is a voltage V as shown on the right side of Figure 5-■.
, is sent out as is.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

ここで、約+14Vの電源電圧と+5vが共に時間t1
以上断になっている時は比較器23の出力電圧はOにな
っている。
Here, the power supply voltage of approximately +14V and +5V are both at time t1.
When the power is off, the output voltage of the comparator 23 is O.

しかし、電源電圧と+5vが同時に印加されると比較器
23の子端子には抵抗R1+ R9で分圧された電圧が
印加される。一方、トランジスタ22は電圧印加から時
間Δt1まではオフの状態にあるので(+5vが抵抗R
3を介してベースに加えられるが、インバータ21の出
力が定常状態にならない為)、比較器23から電圧vz
が出力される。
However, when the power supply voltage and +5V are applied simultaneously, the voltage divided by the resistors R1+R9 is applied to the child terminal of the comparator 23. On the other hand, since the transistor 22 is in an off state from the voltage application until the time Δt1 (+5V is the resistance R
3, but since the output of the inverter 21 does not reach a steady state), the voltage vz from the comparator 23
is output.

そして1時間Δt8以降はインバータ21から電圧Vg
が送出されるのでトランジスタ22はオンになり。
After 1 hour Δt8, the voltage Vg from the inverter 21
is sent out, so transistor 22 is turned on.

比較器23から電圧v、が出力されるが、第5図−■に
示す様に極端に幅(Δ1+)の狭いパルスが出力される
と云う問題がある。
A voltage v is output from the comparator 23, but there is a problem in that a pulse with an extremely narrow width (Δ1+) is output as shown in FIG.

〔課題を解決する為の手段〕[Means to solve problems]

第1図は本発明の原理ブロック図を示す。 FIG. 1 shows a block diagram of the principle of the present invention.

図中、3は該比較器の出力を充放電して得た信号を該電
圧低下検出器に送出する充放電部分である。
In the figure, numeral 3 is a charging/discharging portion that charges and discharges the output of the comparator and sends a signal obtained to the voltage drop detector.

〔作用〕[Effect]

本発明は比較器lと電圧低下検出器2との間に。 The present invention is applied between the comparator 1 and the voltage drop detector 2.

該比較器の出力より所定の時定数で充電され、瞬時に放
電が行われる充放電部分3を設ける。
A charging/discharging section 3 is provided which is charged with a predetermined time constant from the output of the comparator and discharged instantaneously.

これにより比較器lおよび電圧低下検出器2への電圧印
加が同時に行われても、電圧低下検出器に加えられる充
放電部分の出力電圧は上記の印加電圧よりも充放電部分
の時定数だけ遅れて加えられる。これにより9時定数分
だけの幅を有するパルスが得られ、電圧低下検出回路の
出力パルスの幅が極端に狭くなることはなくなる。
As a result, even if voltage is applied to comparator l and voltage drop detector 2 at the same time, the output voltage of the charging and discharging section applied to the voltage drop detector lags behind the above applied voltage by the time constant of the charging and discharging section. can be added. As a result, a pulse having a width of 9 time constants is obtained, and the width of the output pulse of the voltage drop detection circuit does not become extremely narrow.

〔実施例〕〔Example〕

第2図は本発明の実施例の回路図、第3図は第2図の動
作説明図を示す。尚、第3図の左側の符号は第2図中の
同じ符号の部分の波形図を示す。
FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of FIG. 2. Note that the symbols on the left side of FIG. 3 indicate waveform diagrams of the portions with the same symbols in FIG.

以下、第3図を参照して第2図の動作を説明する。The operation shown in FIG. 2 will be explained below with reference to FIG.

先ず、電圧低下検出回路は動作状態にあり、スイッチS
−1をオンにすると比較器11から電圧Vgが抵抗R5
゜、インバータ21.抵抗R4を介してトランジスタ2
20ベースに加えられるので、このトランジスタはオン
になるが1時定数C,Rl。でコンデンサC2に電荷が
蓄えられる。
First, the voltage drop detection circuit is in the operating state, and the switch S
-1 is turned on, the voltage Vg from the comparator 11 is applied to the resistor R5.
゜, inverter 21. Transistor 2 via resistor R4
20 is applied to the base, so this transistor is turned on but with a 1 time constant C, Rl. Electric charge is stored in capacitor C2.

そして、オンになったトランジスタ22を介してコンデ
ンサC3に電荷が蓄えられ、このコンデンサの端子電圧
が比較器23の一端子に印加される。そこで、この比較
器23から電圧v1が出力される(第3図−■〜■のA
の部分参照)。
Charge is then stored in the capacitor C3 via the turned-on transistor 22, and the terminal voltage of this capacitor is applied to one terminal of the comparator 23. Therefore, voltage v1 is output from this comparator 23 (A of
).

しかし、電源電圧が時間t8以上、規定電圧以下になる
と比較器11の出力はV+(Vz >vl)となるので
コンデンサC2に蓄えられた電荷はダイオードD8を介
して急速に放電される。このコンデンサC2の端子電圧
はインバータ21を介してトランジスタ22のベースに
加えられているので、トランジスタはオフとなり、コン
デンサCIに蓄えられた電荷はR1を介して放電される
が、一端子の電圧が90以下になると、比較器23から
電圧v2が送出される(第3図−■〜■のBの部分参照
)。
However, when the power supply voltage becomes equal to or greater than time t8 and equal to or less than the specified voltage, the output of comparator 11 becomes V+ (Vz > vl), so that the charge stored in capacitor C2 is rapidly discharged via diode D8. Since the terminal voltage of this capacitor C2 is applied to the base of the transistor 22 via the inverter 21, the transistor is turned off and the charge stored in the capacitor CI is discharged via R1, but the voltage at one terminal is When the voltage falls below 90, the voltage v2 is sent out from the comparator 23 (see portions B in Figure 3--).

そして2時間1.経過後に電源電圧が規定電圧に復旧す
るとコンデンサC2は時定数C,R,。で充電されるの
で第3図−■に示す様にインバータ21から出力される
電圧v2の継続時間が従来例の1.よりもt2だけ伸び
、この間、トランジスタ22はオフになっている。しか
し、インバータの出力電圧がvlになるとトランジスタ
がオンとなり、コンデンサC1に電荷が蓄えられ、比較
器23から電圧V、が送出され、結局第3図−■に示す
様に従来例よりも幅がt2だけ伸びたパルスが送出され
る。
And 2 hours 1. When the power supply voltage returns to the specified voltage after a period of time, the capacitor C2 has a time constant C, R, and so on. As shown in FIG. 3-2, the duration of the voltage v2 output from the inverter 21 is longer than that of the conventional example. During this period, the transistor 22 is turned off. However, when the output voltage of the inverter reaches vl, the transistor turns on, charge is stored in the capacitor C1, and the voltage V is sent out from the comparator 23. As shown in Figure 3-■, the width is wider than that of the conventional example. A pulse extended by t2 is sent out.

次に、電源電圧、+5Vなどが時間t1以上断になって
いて、これらの電圧が印加されると、先ず比較器23の
子端子に電圧が印加されるので第3図−■に示す様に電
圧v2が送出される。その後1時定数CzR+oだけ経
過してトランジスタ22がオンになり、比較器の出力は
電圧Vlが送出される。
Next, when the power supply voltage, +5V, etc. is cut off for more than time t1 and these voltages are applied, the voltage is first applied to the child terminal of the comparator 23, so as shown in Fig. 3-■. Voltage v2 is delivered. After one time constant CzR+o has elapsed, the transistor 22 is turned on, and the voltage Vl is sent out as the output of the comparator.

これにより、従来例で生じた極端に狭い幅のパルスでな
く1時間幅t2のパルスが送出される。
As a result, a pulse with a width of 1 time t2 is sent out, instead of a pulse with an extremely narrow width that occurs in the conventional example.

〔発明の効果〕〔Effect of the invention〕

以上詳細に説明した様にこの回路から出力されるパルス
の幅は極端に狭くならないと云う効果がある。
As explained in detail above, there is an effect that the width of the pulse output from this circuit does not become extremely narrow.

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

第1図は本発明の原理ブロック図、 第2図は本発明の実施例の回路図、 第3図は第2図の動作説明図、 第4図は従来例の回路図、 第5図は第4図の動作説明図を示す。 図において、 1は比較器、 2は電圧低下検出器、 3は充放電部分を示す。 本発明0層理アロツク稠 第1回 木f!−明f)穴殊例の回路図 第2面 第2囮の動fj説明図 FIG. 1 is a block diagram of the principle of the present invention. FIG. 2 is a circuit diagram of an embodiment of the present invention, Figure 3 is an explanatory diagram of the operation of Figure 2; Figure 4 is a circuit diagram of a conventional example. FIG. 5 shows an explanatory diagram of the operation of FIG. 4. In the figure, 1 is a comparator, 2 is a voltage drop detector; 3 indicates a charging/discharging part. Inventive zero-layer structure 1st Tree f! - Clear f) Hole special circuit diagram 2nd side 2nd decoy movement fj explanatory diagram

Claims (1)

【特許請求の範囲】[Claims] 入力電圧が規定電圧よりも低下しているか否かを検出す
る比較器(1)と、入力信号を用いて電圧低下時間が規
定時間よりも長い時、規定時間以上の時間に対応する幅
のパルスを送出する電圧低下検出器(2)とを有する電
圧低下検出回路において、該比較器の出力を充放電して
得た信号を該電圧低下検出器に送出する充放電部分(3
)を有することを特徴とする電圧低下検出回路。
A comparator (1) detects whether the input voltage is lower than the specified voltage, and when the voltage drop time is longer than the specified time using the input signal, a pulse with a width corresponding to the time longer than the specified time is generated. In a voltage drop detection circuit that has a voltage drop detector (2) that sends out a voltage drop detector, a charging/discharging part (3) that sends a signal obtained by charging and discharging the output of the comparator to the voltage drop detector.
) A voltage drop detection circuit characterized by having:
JP1225886A 1989-08-31 1989-08-31 Voltage drop detection circuit Pending JPH0389173A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1225886A JPH0389173A (en) 1989-08-31 1989-08-31 Voltage drop detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1225886A JPH0389173A (en) 1989-08-31 1989-08-31 Voltage drop detection circuit

Publications (1)

Publication Number Publication Date
JPH0389173A true JPH0389173A (en) 1991-04-15

Family

ID=16836410

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1225886A Pending JPH0389173A (en) 1989-08-31 1989-08-31 Voltage drop detection circuit

Country Status (1)

Country Link
JP (1) JPH0389173A (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5290046A (en) * 1976-01-22 1977-07-28 Nippon Denso Co Ltd Voltage monitor circuit
JPS6121977B2 (en) * 1982-11-05 1986-05-29 Kusumoto Kasei Kk
JPS63197114A (en) * 1987-02-10 1988-08-16 Fujitsu Ltd Reset signal circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5290046A (en) * 1976-01-22 1977-07-28 Nippon Denso Co Ltd Voltage monitor circuit
JPS6121977B2 (en) * 1982-11-05 1986-05-29 Kusumoto Kasei Kk
JPS63197114A (en) * 1987-02-10 1988-08-16 Fujitsu Ltd Reset signal circuit

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