JPH06284599A - Power supply switching circuit - Google Patents
Power supply switching circuitInfo
- Publication number
- JPH06284599A JPH06284599A JP5074384A JP7438493A JPH06284599A JP H06284599 A JPH06284599 A JP H06284599A JP 5074384 A JP5074384 A JP 5074384A JP 7438493 A JP7438493 A JP 7438493A JP H06284599 A JPH06284599 A JP H06284599A
- Authority
- JP
- Japan
- Prior art keywords
- battery
- power supply
- external
- voltage
- effect transistor
- 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
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/20—End-user application control systems
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、外部直流電源からバッ
テリに充電し且つ外部直流電源又はバッテリ電源から選
択的に負荷に電流を流すべくこれら各切り替えを自動的
に行う電源切替回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply switching circuit for charging a battery from an external DC power supply and automatically switching between the external DC power supply and the battery power supply so as to selectively supply a current to a load. is there.
【０００２】[0002]
【従来の技術】携帯用機器等においては、外部供給電源
に基づいて直流を供給する外部直流電源から内蔵バッテ
リに充電し外部直流電源と内蔵バッテリとを自動的に切
り替えて使用することにより内蔵バッテリの消耗を低減
する方法が取られている。このような外部直流電源と内
蔵バッテリ電源とを自動的に切り替える電源切替回路に
関して、本出願と同一出願人による特願平４−２１４９
３２号の出願がある。2. Description of the Related Art In portable equipment and the like, a built-in battery is used by charging the built-in battery from an external DC power supply that supplies DC based on an external power supply and automatically switching between the external DC power supply and the built-in battery. Methods have been taken to reduce the consumption of the. Regarding a power supply switching circuit that automatically switches between the external DC power supply and the built-in battery power supply, Japanese Patent Application No. 4-2149 filed by the same applicant as the present application
There is an application for No. 32.
【０００３】図２は該出願に示す回路に考慮し得るバッ
テリ充電回路を付加してなる電源切替回路の回路図であ
り、外部直流電源から内蔵バッテリへの充電と外部直流
電源使用と内蔵バッテリ使用とを自動的に切り替えるよ
うにしたものである。FIG. 2 is a circuit diagram of a power supply switching circuit in which a battery charging circuit which can be considered in the circuit shown in the application is added, and charging from an external DC power supply to an internal battery, use of the external DC power supply and use of the internal battery. It is designed so that and are automatically switched.
【０００４】同図において、１は商用電源等による外部
供給電源に基づいて直流を供給する外部直流電源、２は
負荷回路、３はバッテリ、４は負荷接続電源切替制御
部、５はバッテリ充電切替制御部である。In the figure, 1 is an external DC power supply for supplying DC based on an external power supply such as a commercial power supply, 2 is a load circuit, 3 is a battery, 4 is a load connection power supply switching control section, and 5 is battery charge switching. It is a control unit.
【０００５】外部直流電源１及びバッテリ３の正極は、
負荷接続電源切替制御部４の入力端子ＩＮ１，ＩＮ２に
接続され、負極は接地端子Ｇに接続されている。また、
負荷回路２の電源入力端子は負荷接続電源切替制御部４
の出力端子ＯＵＴに接続されている。The external DC power supply 1 and the positive electrode of the battery 3 are
The load connection power supply switching control unit 4 is connected to the input terminals IN1 and IN2, and the negative electrode is connected to the ground terminal G. Also,
The power supply input terminal of the load circuit 2 is the load connection power supply switching control unit 4
Of the output terminal OUT.
【０００６】負荷接続電源切替制御部４は、ＭＯＳ型Ｐ
チャネルの電界効果トランジスタ（以下、ＦＥＴと称す
る）Ｑ１，Ｑ２と、差動スイッチング回路４１とにより
構成されている。ＦＥＴＱ１は、そのドレインが第１の
入力端子ＩＮ１を介して外部直流電源１の正極端子に接
続され、ソースは出力端子ＯＵＴを介して負荷回路２の
正極入力端子に接続されている。また、ＦＥＴＱ２は、
そのドレインが第２の入力端子ＩＮ２を介してバッテリ
３の正極端子に接続され、ソースは出力端子ＯＵＴに接
続されている。上記のＦＥＴＱ１とＦＥＴＱ２は本発明
の第１と第２の電界効果トランジスタをなす。The load connection power supply switching control unit 4 is a MOS type P
It is composed of field effect transistors (hereinafter, referred to as FETs) Q1 and Q2 of the channel and a differential switching circuit 41. The drain of the FET Q1 is connected to the positive electrode terminal of the external DC power supply 1 via the first input terminal IN1, and the source is connected to the positive electrode input terminal of the load circuit 2 via the output terminal OUT. Further, the FET Q2 is
The drain is connected to the positive terminal of the battery 3 via the second input terminal IN2, and the source is connected to the output terminal OUT. The above-mentioned FETQ1 and FETQ2 form the first and second field effect transistors of the present invention.
【０００７】差動スイッチング回路４１は、接合型Ｎチ
ャネルの電界効果トランジスタ（以下、ＦＥＴと称す
る）Ｑ３，Ｑ４，Ｑ５と、ＰＮＰ型のトランジスタＱ
６，Ｑ８と、ＮＰＮ型のトランジスタＱ７，Ｑ９と、Ｍ
ＯＳ型Ｎチャネルの電界効果トランジスタ（以下、ＦＥ
Ｔと称する）Ｑ１０，Ｑ１１と、抵抗Ｒ１〜Ｒ６等によ
り構成され、抵抗Ｒ１とＲ３と、抵抗Ｒ２とＲ４と、抵
抗Ｒ５とＲ６とはそれぞれ互いに同一抵抗値のものが使
用されている。ＦＥＴＱ１とＦＥＴＱ２のゲートは、Ｆ
ＥＴＱ１０とＱ１１の各ドレインにそれぞれ接続され、
ＦＥＴＱ３とＱ４は、ＦＥＴＱ１とＦＥＴＱ２のゲート
に出力端子ＯＵＴからそれぞれ定電流を供給する。そし
てＦＥＴＱ５は各トランジスタＱ６，Ｑ８のエミッタに
同様に定電流を供給する。トランジスタＱ６は、ベース
に第２の入力端子ＩＮ２の電圧を抵抗Ｒ３，Ｒ４で分圧
して受け、コレクタが、トランジスタＱ９のコレクタと
ＦＥＴＱ１０のゲートに接続されると共に抵抗Ｒ５を介
してトランジスタＱ７のベースに接続されている。そし
てトランジスタＱ８は、ベースに第１の入力端子ＩＮ１
の電圧を抵抗Ｒ１，Ｒ２で分圧して受け、コレクタが、
トランジスタＱ７のコレクタとＦＥＴＱ１１のゲートに
接続されると共に抵抗Ｒ６を介してトランジスタＱ９の
ベースに接続されている。また、各トランジスタＱ７，
Ｑ９のエミッタとＦＥＴＱ１０，Ｑ１１の各ドレインは
接地されている。The differential switching circuit 41 includes a junction type N-channel field effect transistor (hereinafter referred to as FET) Q3, Q4, Q5 and a PNP type transistor Q.
6, Q8, NPN type transistors Q7, Q9, and M
OS type N-channel field effect transistor (hereinafter referred to as FE
(Referred to as T) Q10 and Q11, resistors R1 to R6, etc., and resistors R1 and R3, resistors R2 and R4, and resistors R5 and R6 having the same resistance value are used. The gates of FETQ1 and FETQ2 are F
Connected to each drain of ETQ10 and Q11,
The FETs Q3 and Q4 supply constant currents from the output terminal OUT to the gates of the FETs Q1 and Q2, respectively. The FET Q5 similarly supplies a constant current to the emitters of the transistors Q6 and Q8. The transistor Q6 receives at its base the voltage of the second input terminal IN2 by being divided by the resistors R3 and R4, its collector is connected to the collector of the transistor Q9 and the gate of the FET Q10, and the base of the transistor Q7 via the resistor R5. It is connected to the. The transistor Q8 has a base connected to the first input terminal IN1.
Is divided by resistors R1 and R2, and the collector receives
It is connected to the collector of the transistor Q7 and the gate of the FET Q11, and is also connected to the base of the transistor Q9 via the resistor R6. In addition, each transistor Q7,
The emitter of Q9 and the drains of the FETs Q10 and Q11 are grounded.
【０００８】バッテリ充電切替制御部５は、抵抗Ｒ７，
Ｒ８と、ＭＯＳ型Ｎチャネルの電界効果トランジスタ
（以下、ＦＥＴと称する）Ｑ１２，Ｑ１３と、接合型Ｎ
チャネルの電界効果トランジスタ（以下、ＦＥＴと称す
る）Ｑ１４と、抵抗Ｒ９，Ｒ１０，Ｒ１１と、ＩＣ化さ
れたシャントレギュレータＳＲ等よりなる。抵抗Ｒ７，
Ｒ８はバッテリ電圧検出回路をなし、バッテリ３の端子
間に接続されていてその分電圧を取り出す。ＦＥＴＱ１
２は該分電圧をゲートに受けドレインが外部直流電源１
に接続されソースが抵抗Ｒ９を介して接地されていて、
該分電圧に応じてそのドレイン電流が調節される。ＦＥ
ＴＱ１４は抵抗Ｒ１０，Ｒ１１に対する定電流回路を形
成し、抵抗Ｒ１０，Ｒ１１はシャントレギュレータＳＲ
のトリップ電圧を設定している。ＦＥＴＱ１３はシャン
トレギュレータＳＲの該設定電圧をゲートに受けドレイ
ンがＦＥＴＱ２のゲートに接続されソースが抵抗Ｒ９を
介して接地されていて、ＦＥＴＱ１１がオフのときに、
ＦＥＴＱ１２のドレイン電流に応じて抵抗Ｒ９による電
圧降下が該設定電圧以下になると抵抗Ｒ９を介してＦＥ
ＴＱ２のゲートを接地させる。The battery charge switching controller 5 includes a resistor R7,
R8, a MOS type N-channel field effect transistor (hereinafter referred to as FET) Q12 and Q13, and a junction type N
It is composed of a field effect transistor (hereinafter referred to as FET) Q14 of a channel, resistors R9, R10 and R11, and an IC-shaped shunt regulator SR. Resistance R7,
R8 constitutes a battery voltage detection circuit, which is connected between the terminals of the battery 3 and extracts the voltage correspondingly. FET Q1
2 is the external DC power supply 1 whose drain receives the corresponding voltage at its gate
And the source is grounded through a resistor R9,
The drain current is adjusted according to the divided voltage. FE
TQ14 forms a constant current circuit for the resistors R10 and R11, and the resistors R10 and R11 are the shunt regulator SR.
The trip voltage of is set. The FET Q13 receives the set voltage of the shunt regulator SR at the gate, the drain is connected to the gate of the FET Q2, the source is grounded through the resistor R9, and the FET Q11 is off,
When the voltage drop by the resistor R9 becomes equal to or lower than the set voltage according to the drain current of the FET Q12, the FE is passed through the resistor R9.
The gate of TQ2 is grounded.
【０００９】上記の図２の構成において例えば、バッテ
リ３の電圧Ｖｂが外部直流電源１の電圧Ｖａよりも高い
とき、或いはバッテリ３が接続され、外部直流電源１が
接続されていないときは、トランジスタＱ６のベース電
圧は、トランジスタＱ８のベース電圧より高くなる。一
般にＭＯＳ型のＦＥＴＱ１，Ｑ２にはドレイン・ソース
間に寄生ダイオードが形成されており、更に、トランジ
スタＱ６，Ｑ８のそれぞれのエミッタ電圧は同一である
ので、トランジスタＱ６のベース・エミッタ間電圧は、
トランジスタＱ８のベース・エミッタ間電圧よりも高く
なってトランジスタＱ８がオンになり、バッテリ３から
ＦＥＴＱ２の寄生ダイオード及びＦＥＴＱ５を介して流
れる電流がトランジスタＱ８を介してＱ９をオンにす
る。これによりトランジスタＱ８のコレクタが高レベル
になって、ＦＥＴＱ１１がオンになり、ＦＥＴＱ２のゲ
ートが接地され、ＦＥＴＱ２のゲート・ソース間に逆バ
イアス電圧が印加されてＦＥＴＱ２はオンになり、バッ
テリ３からＦＥＴＱ２を介して負荷回路２に通電され
る。一方、トランジスタＱ６はオフになっていて、トラ
ンジスタＱ９がオンになっているのでＦＥＴＱ１０はオ
フとなる。これにより、ＦＥＴＱ１はオフとなり、外部
直流電源１（第１の入力端子ＩＮ１）と出力端子ＯＵＴ
との間は遮断される。In the configuration of FIG. 2 described above, for example, when the voltage Vb of the battery 3 is higher than the voltage Va of the external DC power supply 1, or when the battery 3 is connected and the external DC power supply 1 is not connected, the transistor The base voltage of Q6 will be higher than the base voltage of transistor Q8. Generally, in the MOS type FETs Q1 and Q2, a parasitic diode is formed between the drain and the source, and since the respective emitter voltages of the transistors Q6 and Q8 are the same, the base-emitter voltage of the transistor Q6 is
When the voltage becomes higher than the base-emitter voltage of the transistor Q8 and the transistor Q8 is turned on, the current flowing from the battery 3 through the parasitic diode of the FET Q2 and the FET Q5 turns on the transistor Q9 through the transistor Q8. As a result, the collector of the transistor Q8 becomes high level, the FET Q11 is turned on, the gate of the FET Q2 is grounded, the reverse bias voltage is applied between the gate and source of the FET Q2, the FET Q2 is turned on, and the battery 3 causes the FET Q2 to turn on. The load circuit 2 is energized via. On the other hand, since the transistor Q6 is off and the transistor Q9 is on, the FET Q10 is off. As a result, the FET Q1 is turned off, and the external DC power supply 1 (first input terminal IN1) and the output terminal OUT
Is cut off between and.
【００１０】また、バッテリ３の電圧Ｖｂが外部直流電
源１の電圧Ｖａよりも低いとき、或いは外部直流電源１
が接続され、バッテリ３が接続されていないときは、前
述とは対称的な状態になる。即ち、トランジスタＱ８の
ベースに印加される電圧は、トランジスタＱ６のベース
に印加される電圧より高くなってトランジスタＱ６がオ
ンになり、外部直流電源１からＦＥＴＱ１の寄生ダイオ
ード及びＦＥＴＱ５を介して流れる電流がトランジスタ
Ｑ６を介してＱ７をオンにする。これによりトランジス
タＱ６のエミッタが高レベルになって、ＦＥＴＱ１０が
オンになりＦＥＴＱ１のゲートが接地され、ＦＥＴＱ１
のゲート・ソース間に逆バイアス電圧が印加されてＦＥ
ＴＱ１はオンになり、外部直流電源１からＦＥＴＱ１を
介して負荷回路２に通電される。一方、トランジスタＱ
８はオフになっていて、トランジスタＱ７がオンになっ
ているのでＦＥＴＱ１１はオフとなる。これにより、Ｆ
ＥＴＱ２はオフとなり、バッテリ３（第２の入力端子Ｉ
Ｎ２）と出力端子ＯＵＴとの間は遮断される。When the voltage Vb of the battery 3 is lower than the voltage Va of the external DC power supply 1, or when the external DC power supply 1
Is connected and the battery 3 is not connected, the state is symmetrical to the above. That is, the voltage applied to the base of the transistor Q8 becomes higher than the voltage applied to the base of the transistor Q6, the transistor Q6 is turned on, and the current flowing from the external DC power supply 1 through the parasitic diode of the FET Q1 and the FET Q5 is generated. Turn on Q7 through transistor Q6. As a result, the emitter of the transistor Q6 becomes high level, the FET Q10 is turned on, the gate of the FET Q1 is grounded, and the FET Q1 is turned on.
Reverse bias voltage is applied between the gate and source of
The TQ1 is turned on, and the load circuit 2 is energized from the external DC power supply 1 through the FET Q1. On the other hand, transistor Q
8 is off and the transistor Q7 is on, so the FET Q11 is off. This gives F
The ETQ2 is turned off, and the battery 3 (second input terminal I
The connection between N2) and the output terminal OUT is cut off.
【００１１】バッテリ３の電圧Ｖｂが外部直流電源１の
電圧Ｖａよりも低いときは、このときバッテリ３の電圧
Ｖｂが所定電圧以上になっていると、ＦＥＴＱ１２はオ
ンして外部直流電源１から電流供給されて抵抗Ｒ９の電
位が上昇し、ＦＥＴＱ１３はオフになる。よってＦＥＴ
Ｑ２は、上記のバッテリ３の電圧Ｖｂが外部直流電源１
の電圧Ｖａよりも高いとき、の条件に従う。また、バッ
テリ３の電圧Ｖｂが外部直流電源１の電圧Ｖａよりも低
く且つ所定電圧以下のときは、ＦＥＴＱ１２はオフして
抵抗Ｒ９の電位が下降する。このときＦＥＴＱ１１がオ
フならば、ＦＥＴＱ１３はオンになる。よってＦＥＴＱ
２は、ＦＥＴＱ１１の作動に優先してＦＥＴＱ１３に従
って作動してオンになり、バッテリ３が充電される。When the voltage Vb of the battery 3 is lower than the voltage Va of the external DC power supply 1, if the voltage Vb of the battery 3 is equal to or higher than a predetermined voltage at this time, the FET Q12 is turned on and a current is supplied from the external DC power supply 1. When supplied, the potential of the resistor R9 rises and the FET Q13 is turned off. Therefore FET
Q2 indicates that the voltage Vb of the battery 3 is the external DC power source 1
When the voltage is higher than the voltage Va of, the condition of is followed. Further, when the voltage Vb of the battery 3 is lower than the voltage Va of the external DC power supply 1 and equal to or lower than the predetermined voltage, the FET Q12 is turned off and the potential of the resistor R9 drops. At this time, if the FET Q11 is off, the FET Q13 is on. Therefore FETQ
2 operates in accordance with the FET Q13 in preference to the operation of the FET Q11 to be turned on, and the battery 3 is charged.
【００１２】[0012]
【発明が解決しようとする課題】しかしながら上記の電
源切替回路においては、バッテリ３は抵抗Ｒ７，Ｒ８を
介して常に放電されているので、充放電頻度が大になっ
てバッテリ３の寿命が低減するという問題点があった。However, in the above power supply switching circuit, the battery 3 is constantly discharged through the resistors R7 and R8, so that the charging / discharging frequency is increased and the life of the battery 3 is shortened. There was a problem.
【００１３】本発明の目的は、バッテリの不用の放電を
極力少なくした電源切替回路を提供することにある。An object of the present invention is to provide a power supply switching circuit in which unnecessary discharge of a battery is minimized.
【００１４】[0014]
【課題を解決するための手段】本発明は上記の目的を達
成するために、外部供給電源に基づいて直流を供給する
外部直流電源からバッテリに充電し且つ外部直流電源又
はバッテリ電源から選択的に負荷に電流を流すべくこれ
ら各切り替えを行う電源切替回路において、外部直流電
源と負荷との間に接続された第１の電界効果トランジス
タと、バッテリ電源と負荷との間に接続された第２の電
界効果トランジスタと、バッテリ電源の電圧が外部直流
電源の電圧よりも低いときに第１の電界効果トランジス
タをオンに且つ第２の電界効果トランジスタをオフに制
御し高いときに第２の電界効果トランジスタをオンに且
つ第１の電界効果トランジスタをオフに制御する差動ス
イッチング回路と、バッテリ電源の端子間に接続されて
いてバッテリ電圧を検出するバッテリ電圧検出回路を含
んでなり該バッテリ電圧検出回路によるバッテリ電圧が
外部直流電源の電圧よりも所定の水準値をもって低いと
き前記差動スイッチング回路に優先させて第２の電界効
果トランジスタをオンに制御するバッテリ充電切替制御
回路と、差動スイッチング回路が第１の電界効果トラン
ジスタをオンに制御すべく作動したときバッテリ電圧検
出回路をバッテリ電源から切り離しオフに制御すべく作
動したときこれを接続する電圧検出回路開閉手段とを設
けた。In order to achieve the above-mentioned object, the present invention charges a battery from an external DC power supply which supplies DC based on an external power supply and selectively from the external DC power supply or the battery power supply. In a power supply switching circuit that performs each of these switching operations so that a current flows through a load, a first field effect transistor connected between an external DC power supply and the load and a second field effect transistor connected between the battery power supply and the load. A field effect transistor, and a second field effect transistor when the voltage of the battery power supply is lower than the voltage of the external DC power supply, the first field effect transistor is turned on and the second field effect transistor is turned off, and when the voltage is high, the second field effect transistor Connected between the terminals of the battery power supply and the differential switching circuit for controlling the on-state and the first field-effect transistor to turn off the battery voltage. When the battery voltage detected by the battery voltage detection circuit is lower than the voltage of the external DC power supply by a predetermined level value, the differential switching circuit is prioritized to turn on the second field effect transistor. Connect the battery charge switching control circuit that controls the power supply to the battery and the differential switching circuit that operates to control the first field-effect transistor to turn on when the battery voltage detection circuit disconnects from the battery power supply and controls to turn off. And a voltage detection circuit opening / closing means for operating the voltage detection circuit.
【００１５】[0015]
【作用】本発明によれば、バッテリ電圧が外部直流電源
電圧よりも高いとき、或いはバッテリが接続され外部直
流電源が接続ていないときは、差動スイッチング回路に
より、第２の電界効果トランジスタがオンに且つ第１の
電界効果トランジスタがオフになる。よって外部直流電
源が遮断された上でバッテリから負荷回路に通電され
る。また、バッテリ電圧が外部直流電源電圧よりも低い
とき、或いは外部直流電源が接続され、バッテリが接続
されていないときは、差動スイッチング回路により、第
１の電界効果トランジスタがオンに且つ第２の電界効果
トランジスタがオフになる。よってバッテリが遮断され
た上で外部直流電源から負荷回路に通電される。そして
また、バッテリ電圧が外部直流電源電圧よりも低く且つ
所定電圧以下のときは、バッテリ充電切替制御回路のバ
ッテリ電圧検出回路によりこれが検出されて、差動スイ
ッチング回路に優先させて第２の電界効果トランジスタ
がオンに制御されて、バッテリが充電される。上記の差
動スイッチング回路が第１の電界効果トランジスタをオ
ンに制御すべく作動したときには、電圧検出回路開閉手
段により、バッテリ電圧検出回路がバッテリ電源から切
り離される。According to the present invention, when the battery voltage is higher than the external DC power supply voltage, or when the battery is connected and the external DC power supply is not connected, the second field effect transistor is turned on by the differential switching circuit. In addition, the first field effect transistor is turned off. Therefore, the load circuit is energized after the external DC power supply is cut off. Further, when the battery voltage is lower than the external DC power supply voltage, or when the external DC power supply is connected and the battery is not connected, the differential switching circuit turns on the first field effect transistor and turns on the second field effect transistor. The field effect transistor is turned off. Therefore, the battery is shut off and then the load circuit is energized from the external DC power supply. When the battery voltage is lower than the external DC power supply voltage and equal to or lower than the predetermined voltage, this is detected by the battery voltage detection circuit of the battery charge switching control circuit, and the second field effect is given priority over the differential switching circuit. The transistor is controlled to turn on and the battery is charged. When the differential switching circuit operates to control the first field effect transistor to be turned on, the voltage detection circuit opening / closing means disconnects the battery voltage detection circuit from the battery power supply.
【００１６】[0016]
【実施例】図１は本発明の一実施例を示す電源切替回路
の回路図である。同図において、図２と同等の部分には
同一の符号を付して示し、以下に異なる部分について説
明する。1 is a circuit diagram of a power supply switching circuit showing an embodiment of the present invention. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals, and different parts will be described below.
【００１７】Ｑ１５は電圧検出回路開閉手段としてのＭ
ＯＳ型Ｎチャネルの電界効果トランジスタ（以下、ＦＥ
Ｔと称する）で、抵抗Ｒ７と直列にしてドレインが抵抗
Ｒ７に接続され、ソースが接地され、ゲートがＦＥＴＱ
１２のゲートに接続されている。Q15 is an M as a voltage detecting circuit opening / closing means.
OS type N-channel field effect transistor (hereinafter referred to as FE
T), the drain is connected to the resistor R7 in series with the resistor R7, the source is grounded, and the gate is FETQ.
It is connected to 12 gates.
【００１８】以上の図１の構成において例えば、バッテ
リ３の電圧Ｖｂが外部直流電源１の電圧Ｖａよりも低い
とき、或いは外部直流電源１が接続され、バッテリ３が
接続されていないときは、トランジスタＱ６がオンにな
り、ＦＥＴＱ１０とＦＥＴＱ１５はそれぞれゲートが高
レベルとなってオンになる。よって図２の電源切替回路
におけると同等な回路が形成されて、外部直流電源１か
らＦＥＴＱ１を介して負荷回路２に通電され、そしてＦ
ＥＴＱ１５がオンになったことによりバッテリ充電切替
制御部５は正常に作動して、ＦＥＴＱ２を介して適時に
バッテリ３に充電される。尚、該充電時にはＦＥＴＱ１
５はオンになるが、このときの抵抗Ｒ７，Ｒ８を介する
電流は外部直流電源１から供給されるのでこのときバッ
テリ３から放電されることはない。In the configuration of FIG. 1 described above, for example, when the voltage Vb of the battery 3 is lower than the voltage Va of the external DC power supply 1, or when the external DC power supply 1 is connected and the battery 3 is not connected, the transistor Q6 is turned on, and the gates of the FETs Q10 and Q15 are turned to high level and turned on. Therefore, a circuit equivalent to that in the power supply switching circuit of FIG. 2 is formed, the load circuit 2 is energized from the external DC power supply 1 through the FET Q1, and F
Since the ETQ 15 is turned on, the battery charge switching control unit 5 operates normally, and the battery 3 is charged in a timely manner via the FET Q2. In addition, at the time of the charging, FETQ1
5 is turned on, but the current flowing through the resistors R7 and R8 at this time is supplied from the external DC power supply 1 and therefore is not discharged from the battery 3 at this time.
【００１９】バッテリ３の電圧Ｖｂが外部直流電源１の
電圧Ｖａよりも高いとき、或いはバッテリ３が接続され
ていて外部直流電源１が接続されていないときは、トラ
ンジスタＱ８がオンになり、ＦＥＴＱ１０とＦＥＴＱ１
５はそれぞれゲートが低レベルとなってオフになる。よ
ってバッテリ３からＦＥＴＱ２を介して負荷回路２に通
電され、同時に抵抗Ｒ７と接地間が遮断されて抵抗Ｒ
７，Ｒ８を介する電流がなくなってバッテリ３の消費電
力が低減される。When the voltage Vb of the battery 3 is higher than the voltage Va of the external DC power supply 1, or when the battery 3 is connected and the external DC power supply 1 is not connected, the transistor Q8 is turned on and the FET Q10 is connected. FET Q1
In each of the gates 5, the gate becomes low level and is turned off. Therefore, the load circuit 2 is energized from the battery 3 through the FET Q2, and at the same time, the resistor R7 is disconnected from the ground, and the resistor R
7, the current flowing through R8 is eliminated, and the power consumption of the battery 3 is reduced.
【００２０】[0020]
【発明の効果】以上説明したように本発明によれば、負
荷回路にバッテリが接続されていて外部直流電源が接続
されていないときは、電圧検出回路開閉手段により、バ
ッテリ電圧検出回路がバッテリ電源から切り離されるよ
うにしたので、バッテリが負荷回路に放電中において、
バッテリ電圧検出回路を介するバッテリ放電回路が遮断
されて、バッテリ３の消費電力が低減される。As described above, according to the present invention, when the battery is connected to the load circuit and the external DC power supply is not connected, the battery voltage detection circuit is switched to the battery power supply by the voltage detection circuit opening / closing means. Since the battery is being discharged to the load circuit,
The battery discharge circuit via the battery voltage detection circuit is cut off, and the power consumption of the battery 3 is reduced.
【図１】本発明の一実施例を示す電源切替回路の回路図FIG. 1 is a circuit diagram of a power supply switching circuit showing an embodiment of the present invention.
【図２】従来の電源切替回路の回路図FIG. 2 is a circuit diagram of a conventional power supply switching circuit.
１…外部直流電源、２…負荷回路、３…バッテリ、４…
負荷接続電源切替制御部、４１…差動スイッチング回
路、５…バッテリ充電切替制御部、Ｑ１，Ｑ２…Ｐチャ
ネルの電界効果トランジスタ、Ｑ１０〜Ｑ１３，Ｑ１５
…Ｎチャネルの電界効果トランジスタ、Ｑ６，Ｑ８…Ｐ
ＮＰ型のトランジスタ、Ｑ７，Ｑ９…ＮＰＮ型のトラン
ジスタ、Ｒ１〜Ｒ８…抵抗、ＩＮ１，ＩＮ２…入力端
子、ＯＵＴ…出力端子、Ｇ…接地端子。1 ... External DC power supply, 2 ... Load circuit, 3 ... Battery, 4 ...
Load connection power supply switching control unit, 41 ... Differential switching circuit, 5 ... Battery charge switching control unit, Q1, Q2 ... P-channel field effect transistor, Q10-Q13, Q15
... N-channel field effect transistors, Q6, Q8 ... P
NP type transistors, Q7, Q9 ... NPN type transistors, R1 to R8 ... Resistors, IN1, IN2 ... Input terminals, OUT ... Output terminals, G ... Ground terminals.
Claims (1)
外部直流電源からバッテリに充電し且つ外部直流電源又
はバッテリ電源から選択的に負荷に電流を流すべくこれ
ら各切り替えを行う電源切替回路において、 外部直流電源と負荷との間に接続された第１の電界効果
トランジスタと、 バッテリ電源と負荷との間に接続された第２の電界効果
トランジスタと、 バッテリ電源の電圧が外部直流電源の電圧よりも低いと
きに第１の電界効果トランジスタをオンに且つ第２の電
界効果トランジスタをオフに制御し高いときに第２の電
界効果トランジスタをオンに且つ第１の電界効果トラン
ジスタをオフに制御する差動スイッチング回路と、 バッテリ電源の端子間に接続されていてバッテリ電圧を
検出するバッテリ電圧検出回路を含んでなり該バッテリ
電圧検出回路によるバッテリ電圧が外部直流電源の電圧
よりも所定の水準値をもって低いとき前記差動スイッチ
ング回路に優先させて第２の電界効果トランジスタをオ
ンに制御するバッテリ充電切替制御回路と、 差動スイッチング回路が第１の電界効果トランジスタを
オンに制御すべく作動したときバッテリ電圧検出回路を
バッテリ電源から切り離しオフに制御すべく作動したと
きこれを接続する電圧検出回路開閉手段とを設けた、 ことを特徴とする電源切替回路。1. A power supply switching circuit that charges a battery from an external DC power supply that supplies DC based on an external power supply and performs each of these switching operations so that a current flows selectively from an external DC power supply or a battery power supply, A first field-effect transistor connected between the external DC power supply and the load; a second field-effect transistor connected between the battery power supply and the load; Is low, the first field effect transistor is turned on and the second field effect transistor is turned off, and when high, the second field effect transistor is turned on and the first field effect transistor is turned off. Dynamic switching circuit and a battery voltage detection circuit connected between the terminals of the battery power source to detect the battery voltage. A battery charge switching control circuit for controlling the second field effect transistor to be turned on by giving priority to the differential switching circuit when the battery voltage by the revoltage detection circuit is lower than the voltage of the external DC power source by a predetermined level value; And a voltage detection circuit opening / closing means for connecting the dynamic voltage switching circuit when the dynamic switching circuit operates to control the first field effect transistor to be turned on and to disconnect the battery voltage detection circuit from the battery power source to operate to control to the off state. A power supply switching circuit characterized by the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5074384A JPH06284599A (en) | 1993-03-31 | 1993-03-31 | Power supply switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5074384A JPH06284599A (en) | 1993-03-31 | 1993-03-31 | Power supply switching circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06284599A true JPH06284599A (en) | 1994-10-07 |
Family
ID=13545625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5074384A Pending JPH06284599A (en) | 1993-03-31 | 1993-03-31 | Power supply switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06284599A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT505417B1 (en) * | 2007-11-27 | 2009-01-15 | Poetzelberger Ulrich Dipl Ing | DEVICE FOR UNLOCKING VOLTAGE SOURCES |
| JP2011101586A (en) * | 2009-11-03 | 2011-05-19 | Samsung Sdi Co Ltd | Battery pack |
-
1993
- 1993-03-31 JP JP5074384A patent/JPH06284599A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT505417B1 (en) * | 2007-11-27 | 2009-01-15 | Poetzelberger Ulrich Dipl Ing | DEVICE FOR UNLOCKING VOLTAGE SOURCES |
| JP2011101586A (en) * | 2009-11-03 | 2011-05-19 | Samsung Sdi Co Ltd | Battery pack |
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