JPH03255373A - Insufficient voltage detecting circuit - Google Patents
Insufficient voltage detecting circuitInfo
- Publication number
- JPH03255373A JPH03255373A JP5405490A JP5405490A JPH03255373A JP H03255373 A JPH03255373 A JP H03255373A JP 5405490 A JP5405490 A JP 5405490A JP 5405490 A JP5405490 A JP 5405490A JP H03255373 A JPH03255373 A JP H03255373A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- output
- circuit
- output voltage
- 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
- 230000007423 decrease Effects 0.000 claims abstract description 6
- 238000001514 detection method Methods 0.000 claims description 20
- 230000003247 decreasing effect Effects 0.000 abstract description 2
- 238000012544 monitoring process Methods 0.000 abstract description 2
- 230000001276 controlling effect Effects 0.000 abstract 2
- 230000000875 corresponding effect Effects 0.000 abstract 1
- 238000000034 method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Dc-Dc Converters (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は不足電圧検出回路、特に、定電圧電源装置の不
足型圧検８回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an undervoltage detection circuit, and particularly to an undervoltage detection circuit of eight types for a constant voltage power supply device.
従来、この種の不足電圧検出回路は定電圧電源装置の出
力電圧そのものと、基準電圧を比較回路にて比較照合し
、不足電圧検出を実施している。Conventionally, this type of undervoltage detection circuit performs undervoltage detection by comparing and comparing the output voltage itself of a constant voltage power supply device with a reference voltage using a comparison circuit.
上述した従来の不足電圧検出回路は、定電圧電源装置の
出力電圧値そのものを基準電圧と比較回路にて比較する
ようになっているので、不足電圧検出値に相当する基準
電圧値は定電圧電源装置の出力電圧過渡応答特性、ある
いは出力電圧リモートコントロールの電圧変動分を考慮
し、比較的検出余裕があるように設定されている。この
ため、以下のような欠点がある。The conventional undervoltage detection circuit described above uses a comparator circuit to compare the output voltage value itself of the constant voltage power supply with the reference voltage, so the reference voltage value corresponding to the undervoltage detection value is determined from the constant voltage power supply. It is set to have a relatively large margin of detection, taking into account the output voltage transient response characteristics of the device or the voltage fluctuations of the output voltage remote control. For this reason, there are the following drawbacks.
■ 特に入力電圧モニタ回路がない場合、入力電圧があ
る範囲で低下し、その結果、出力電圧値がある範囲で低
下しても不足電圧検出しない。■ Especially when there is no input voltage monitor circuit, the input voltage drops within a certain range, and as a result, even if the output voltage drops within a certain range, no undervoltage is detected.
■ 過電流保護方式として、出力電圧垂下方式を有する
定電圧電源装置においては、出力電流がある範囲で定格
電流を越え、その結果、出力電圧がある範囲で低下して
も不足電圧を検出しない。■ In a constant voltage power supply that uses an output voltage droop method as an overcurrent protection method, undervoltage is not detected even if the output current exceeds the rated current within a certain range and as a result, the output voltage drops within a certain range.
本発明の不足電圧検出回路は、出力電圧を第一の基準電
圧と比較し、その誤差分を増幅して得られる制御信号に
レベルにより出力電圧の安定化制御する定電圧電源装置
の不足電圧検出回路において、出力電圧が低下した時の
信号レベルの電圧値を得る第二の基準電圧発生回路と、
制御信号レベルと第二の基準電圧発生回路の基準電圧を
比較することにより、出力電圧が低下した時に不足電圧
検出出力を発生する比較回路とを含んで構成される。The undervoltage detection circuit of the present invention compares the output voltage with a first reference voltage, amplifies the error, and uses the obtained control signal to control the output voltage stabilization based on the level. In the circuit, a second reference voltage generation circuit obtains a voltage value of a signal level when the output voltage decreases;
The device includes a comparison circuit that generates an undervoltage detection output when the output voltage decreases by comparing the control signal level with the reference voltage of the second reference voltage generation circuit.
次に本発明について、図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は、本発明の一実施例の要部を示すブロック図で
ある。FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention.
入力端子１１を介して入力される非安定電圧は、駆動口
！１８２により駆動制御されるＤＣ−ＤＣコンバータ１
を介して所定の安定化直流出力電圧Ｖ○に変換される。The unstable voltage input through the input terminal 11 is the drive port! DC-DC converter 1 driven and controlled by 182
is converted into a predetermined stabilized DC output voltage V○.
変換された安定化直流出力電圧Ｖｏは出力端チエ２を介
して出力されるとともに、一方の入力端子に第一の基準
電圧発生回路５から出力される第一の基準電圧ＶｒＩが
人力される誤差増幅器６の他方の入力端子に入力される
。The converted stabilized DC output voltage Vo is outputted via the output terminal 2, and the first reference voltage VrI outputted from the first reference voltage generation circuit 5 is manually input to one input terminal. It is input to the other input terminal of the amplifier 6.
誤差増幅器６においては、出力電圧Ｖｏと第一の基準電
圧Ｖｒｌとの差がとられ、Ｖ、、−Ｖｏに対応する誤差
電圧を増幅した制御用信号レベルＥを、第一の比較回路
４および第二の比較回路８に出力する。In the error amplifier 6, the difference between the output voltage Vo and the first reference voltage Vrl is calculated, and the control signal level E obtained by amplifying the error voltage corresponding to V, , -Vo is sent to the first comparator circuit 4 and It is output to the second comparison circuit 8.
第一の比較回路４においては、鋸歯状波発生回路３から
送られてくる所定周期の鋸歯状波信号Ｓが制御用信号レ
ベルＥのレベルに対応してパルス幅が制御されるスイッ
チングパルスが出力されて駆動回路２を介してＤＣ−Ｄ
Ｃコンバータ１に入力され、出力電圧の安定化制御を行
なう。In the first comparison circuit 4, a sawtooth wave signal S of a predetermined period sent from the sawtooth wave generation circuit 3 outputs a switching pulse whose pulse width is controlled in accordance with the level of the control signal level E. DC-D via the drive circuit 2
It is input to the C converter 1 and performs stabilization control of the output voltage.
一方、第二の比較回路８においては、第二の基準電圧発
生回路７から出力される第二の基準電圧Ｖｒ２と制御用
信号レベルＥと比較照合する。On the other hand, in the second comparison circuit 8, the second reference voltage Vr2 outputted from the second reference voltage generation circuit 7 is compared with the control signal level E.
ここで、第二の基準電圧Ｖ ｒ ２は、出力電圧Ｖ○が
正常値の時の制御用信号レベルＥの電圧値と比較照合し
た時に第二の比較回路８から不足電圧検出信号を出力せ
ず、又、出力電圧Ｖｏが低下した時の制御用信号レベル
Ｅの電圧値と比較照合した時に、第二の比較回路８から
不足電圧検出信号を出力するように選択されている。Here, the second reference voltage V r 2 causes the second comparison circuit 8 to output an undervoltage detection signal when it is compared with the voltage value of the control signal level E when the output voltage V○ is a normal value. First, the second comparison circuit 8 is selected to output an undervoltage detection signal when compared with the voltage value of the control signal level E when the output voltage Vo has decreased.
なお、本実施例では電源オフ時等に右いて、不足電圧検
出インヒビット回路９が設けられており、インヒビット
信号が入力端子１３を介し、不足電圧検出インヒビット
回路９に入力されている間は不足電圧検出インヒビット
回路９に不足電圧検出信号が入力されていても異常信号
を出力端子１４に出力しないように構成されている。In this embodiment, an undervoltage detection inhibit circuit 9 is provided when the power is turned off, and while an inhibit signal is input to the undervoltage detection inhibit circuit 9 via the input terminal 13, the undervoltage is not detected. Even if an undervoltage detection signal is input to the detection inhibit circuit 9, it is configured not to output an abnormal signal to the output terminal 14.
上記の構成において、入力電圧の低下あるいは過電流保
護として出力電圧垂下特性を有するスイッチングレギュ
レータにおいて、出力電流が定格値を越えた場合、あい
はその他の何んらかの障害により出力電圧Ｖｏが低下す
ると、誤差増幅器６において、出力電圧ＶＯと第一の基
準電圧Ｖｒ＋との差がとられ、Ｖｒｌ−Ｖｏに対応する
誤差電圧を増幅した制御用信号レベルＥを発生する。In the above configuration, in a switching regulator that has an output voltage drop characteristic for input voltage drop or overcurrent protection, if the output current exceeds the rated value, or due to some other failure, the output voltage Vo will drop. Then, in the error amplifier 6, the difference between the output voltage VO and the first reference voltage Vr+ is taken, and a control signal level E is generated by amplifying the error voltage corresponding to Vrl-Vo.
誤差増幅器６の増幅度はスイッチングレギュレータの出
力安定度のため、必要かつ十分大きな値に設定されてい
る。従って、出力電圧Ｖｏのわずかな低下でも制御用信
号レベルＥの電圧値は第二の基準電圧Ｖｒ２により設定
されるスレッシホールド電圧を越え、第二の比較回路８
からは不足電圧検出信号が出力される。The amplification degree of the error amplifier 6 is set to a necessary and sufficiently large value for output stability of the switching regulator. Therefore, even if the output voltage Vo slightly decreases, the voltage value of the control signal level E exceeds the threshold voltage set by the second reference voltage Vr2, and the second comparator circuit 8
An undervoltage detection signal is output from.
なお、スイッチングレギュレータの制御系回路の構成は
、上記の説明は一つの例として引用したものであり、他
の制御系回路を用いる場合についても、本発明が適用さ
れる。Note that the above description of the configuration of the control system circuit of the switching regulator is cited as an example, and the present invention is also applicable to cases where other control system circuits are used.
以上説明したように本発明は、定電圧電源装置の出力電
圧と基準電圧との誤差電圧を誤差増幅器により増幅した
制御用信号レベルを監視して不足電圧検出することによ
り、過渡応答時、あるいは出力電圧を低下させる出力電
圧リモートコントロール信号入力時等は確実に不足電圧
検出せず、入力電圧の低下、あるいは過電流保護方式と
しての出力電圧垂下特性を有するスイッチングレギュレ
ータの過電流によるわずかな出力電圧の低下も、不足電
圧検出出来るという効果がある。As explained above, the present invention detects an undervoltage by monitoring the control signal level obtained by amplifying the error voltage between the output voltage of a constant voltage power supply and a reference voltage using an error amplifier, thereby detecting a transient response or an output voltage. When inputting an output voltage remote control signal that lowers the voltage, the undervoltage is not reliably detected, and a slight drop in the output voltage due to a drop in the input voltage or an overcurrent of a switching regulator that has an output voltage droop characteristic as an overcurrent protection method. It also has the effect of being able to detect undervoltage.
第１図は、本発明の一実施例を示すブロック図である。
１・・・・・・ＤＣ−ＤＣコンバータ、２・・・・・・
駆動回路、３・・・・・・鋸歯状波発生回路、４・・・
・・・第一の比較回路、５・・・・・・第一の基準電圧
発生回路、６・・・・・・誤差増幅器、７・・・・・・
第二の基準電圧発生回路、訃・・・・・第二の比較回路
、９・・・・・・不足電圧検出インヒビット回路。FIG. 1 is a block diagram showing one embodiment of the present invention. 1...DC-DC converter, 2...
Drive circuit, 3... Sawtooth wave generation circuit, 4...
...First comparison circuit, 5...First reference voltage generation circuit, 6...Error amplifier, 7...
Second reference voltage generation circuit, 9...second comparison circuit, 9...undervoltage detection inhibit circuit.
Claims (1)
して得られる制御信号により出力電圧の安定化制御する
定電圧電源装置の不足電圧検出回路において、前記出力
電圧が低下し不足電圧検出値に達した時の前記制御信号
の電圧値を検出するための第二の基準電圧発生回路と、
前記前記信号と前記第二の基準電圧発生回路の基準電圧
を比較することにより、前記出力電圧が低下した時に不
足電圧検出出力を発生する比較回路とを含むことを特徴
とする不足電圧検出回路。In an undervoltage detection circuit of a constant voltage power supply device, the output voltage is compared with a first reference voltage and the output voltage is stabilized and controlled by a control signal obtained by amplifying the error. a second reference voltage generation circuit for detecting the voltage value of the control signal when the detected value is reached;
An undervoltage detection circuit comprising: a comparison circuit that generates an undervoltage detection output when the output voltage decreases by comparing the signal with a reference voltage of the second reference voltage generation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5405490A JPH03255373A (en) | 1990-03-05 | 1990-03-05 | Insufficient voltage detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5405490A JPH03255373A (en) | 1990-03-05 | 1990-03-05 | Insufficient voltage detecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03255373A true JPH03255373A (en) | 1991-11-14 |
Family
ID=12959903
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5405490A Pending JPH03255373A (en) | 1990-03-05 | 1990-03-05 | Insufficient voltage detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03255373A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5819320B2 (en) * | 1978-05-18 | 1983-04-18 | 松下電器産業株式会社 | electric clothes dryer |
| JPS59148560A (en) * | 1983-02-10 | 1984-08-25 | Hitachi Ltd | Voltage decrease prenotifying circuit |
| JPS6336405U (en) * | 1986-08-21 | 1988-03-09 | ||
| JPS63298168A (en) * | 1987-05-29 | 1988-12-05 | Mitsubishi Electric Corp | Current detector |
-
1990
- 1990-03-05 JP JP5405490A patent/JPH03255373A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5819320B2 (en) * | 1978-05-18 | 1983-04-18 | 松下電器産業株式会社 | electric clothes dryer |
| JPS59148560A (en) * | 1983-02-10 | 1984-08-25 | Hitachi Ltd | Voltage decrease prenotifying circuit |
| JPS6336405U (en) * | 1986-08-21 | 1988-03-09 | ||
| JPS63298168A (en) * | 1987-05-29 | 1988-12-05 | Mitsubishi Electric Corp | Current detector |
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