JP2003092843A - Charging circuit of secondary battery - Google Patents
Charging circuit of secondary batteryInfo
- Publication number
- JP2003092843A JP2003092843A JP2001287039A JP2001287039A JP2003092843A JP 2003092843 A JP2003092843 A JP 2003092843A JP 2001287039 A JP2001287039 A JP 2001287039A JP 2001287039 A JP2001287039 A JP 2001287039A JP 2003092843 A JP2003092843 A JP 2003092843A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- charging
- current
- circuit unit
- constant
- 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.)
- Granted
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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、携帯電話等に用い
られる二次電池の充電回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery charging circuit used in a mobile phone or the like.
【０００２】[0002]
【従来の技術】一般に、携帯電話等の移動無線通信機で
は、電源として二次電池が使用される。特に、リチウム
イオン電池は、単位体積当たりのエネルギー密度および
単位質量当たりのエネルギー密度が大きく、それを搭載
する機器の小型軽量化を可能にする。リチウムイオン電
池を充電する場合、電池の電圧を一定に保って充電電流
を供給する定電圧充電方式や、定電流充電の後に定電圧
充電を行う定電流・定電圧充電方式が採用される。いず
れの方式を実現する充電回路も、定電圧充電時に充電電
流があらかじめ決められた満充電電流以下になったこと
を検出して、充電を完了する。2. Description of the Related Art Generally, a mobile radio communication device such as a mobile phone uses a secondary battery as a power source. In particular, a lithium ion battery has a large energy density per unit volume and a large energy density per unit mass, and enables downsizing and weight reduction of a device equipped with the same. When charging a lithium-ion battery, a constant voltage charging method that keeps the battery voltage constant to supply a charging current or a constant current / constant voltage charging method that performs constant voltage charging after constant current charging is adopted. The charging circuit that realizes either method detects that the charging current has become equal to or less than a predetermined full charging current during constant voltage charging, and completes charging.
【０００３】以下に、従来の二次電池の充電回路につい
て説明する。図７は、従来の二次電池の充電回路を示す
図である。図７において、充電回路は、充電電流を供給
するＡＣアダプタ１１０、ＡＣアダプタ１１０が接続さ
れたことを検出するアダプタ検出回路１１２、被充電二
次電池（以下、「二次電池」という。）１１４の電圧を
検出する電池電圧検出回路１１６、二次電池１１４に対
して定電圧充電を行う定電圧回路１１８、二次電池１１
４に流れる充電電流を検出する充電電流検出回路１２
２、充電電流を電圧に変換する抵抗Ｒ１、二次電池１１
４からＡＣアダプタ１１０へ流れる電流を阻止するダイ
オードＤ１、および、定電圧回路１１８の駆動制御を行
う充電制御回路１２４から成る。ここで、ＡＣアダプタ
１１０は端子１３０に接続される。定電圧回路１１８
は、基準電圧Ｅ１を発生する定電圧発生回路１４０と制
御トランジスタＭ１とオペアンプＡ１とから構成され
る。また、充電電流検出回路１２２は、基準電圧Ｅ２を
発生する定電圧発生回路１４２とオペアンプＡ２とから
構成される。また、アダプタ検出回路１１２は、基準電
圧Ｅ３を発生する定電圧発生回路１４４とオペアンプＡ
３とから構成される。抵抗Ｒ１は、ＡＣアダプタ１１０
と制御トランジスタＭ１との間に接続され、ダイオード
Ｄ１は、制御トランジスタＭ１と二次電池１１４との間
に接続される。A conventional charging circuit for a secondary battery will be described below. FIG. 7 is a diagram showing a conventional charging circuit for a secondary battery. In FIG. 7, the charging circuit includes an AC adapter 110 that supplies a charging current, an adapter detection circuit 112 that detects that the AC adapter 110 is connected, and a secondary battery to be charged (hereinafter referred to as “secondary battery”) 114. Voltage detection circuit 116 for detecting the voltage of the secondary battery, a constant voltage circuit 118 for constant voltage charging of the secondary battery 114, the secondary battery 11
Charge current detection circuit 12 for detecting the charge current flowing through
2. Resistor R1 for converting charging current into voltage, secondary battery 11
4 includes a diode D1 that blocks a current flowing from the AC adapter 110 to the AC adapter 110, and a charge control circuit 124 that controls driving of the constant voltage circuit 118. Here, the AC adapter 110 is connected to the terminal 130. Constant voltage circuit 118
Is composed of a constant voltage generating circuit 140 for generating a reference voltage E1, a control transistor M1 and an operational amplifier A1. The charging current detection circuit 122 is composed of a constant voltage generation circuit 142 that generates a reference voltage E2 and an operational amplifier A2. The adapter detection circuit 112 also includes a constant voltage generation circuit 144 that generates a reference voltage E3 and an operational amplifier A.
3 and 3. The resistor R1 is the AC adapter 110.
Is connected between the control transistor M1 and the control transistor M1, and the diode D1 is connected between the control transistor M1 and the secondary battery 114.
【０００４】以下に、この充電回路の動作を説明する。
ＡＣアダプタ１１０が端子１３０で回路に接続され、か
つ、ＡＣアダプタ１１０の電圧が所定値以上になると、
アダプタ検出回路１１２は、充電制御回路１２４に所定
の信号Ｓｇ１を出力する。また、電池電圧検出回路１１
６は、二次電池１１４の電圧を検出して電池電圧信号Ｓ
ｇ２を出力する。充電制御回路１２４は、アダプタ検出
回路１１２から信号が入力されると動作を始め、定電圧
回路１１８に所定の充電制御信号Ｓｇ５を出力する。定
電圧回路１１８は、充電制御信号Ｓｇ５が入力される
と、二次電池１１４に対して定電圧充電を始める。充電
中、ダイオードＤ１は、二次電池１１４から制御トラン
ジスタＭ１および抵抗Ｒ１を介してＡＣアダプタ１１０
に電流が逆流することを防止する。充電電流は、抵抗Ｒ
１により電圧に変換され、その電圧は、充電電流検出回
路１２２に入力される。充電電流検出回路１２２は、そ
の入力された電圧から、充電電流が所定値を下回ったこ
とを検知すると、充電制御回路１２４に、所定の充電完
了信号Ｓｇ６を送る。充電制御回路１２４は、充電完了
信号Ｓｇ６が入力されると、充電制御信号Ｓｇ５を出力
して、定電圧回路１１８の動作を停止させる。The operation of this charging circuit will be described below.
When the AC adapter 110 is connected to the circuit at the terminal 130 and the voltage of the AC adapter 110 becomes a predetermined value or more,
The adapter detection circuit 112 outputs a predetermined signal Sg1 to the charge control circuit 124. In addition, the battery voltage detection circuit 11
6 detects the voltage of the secondary battery 114 to detect the battery voltage signal S
Output g2. The charging control circuit 124 starts operation when a signal is input from the adapter detection circuit 112, and outputs a predetermined charging control signal Sg5 to the constant voltage circuit 118. When the charging control signal Sg5 is input, the constant voltage circuit 118 starts constant voltage charging of the secondary battery 114. During charging, the diode D1 is connected to the AC adapter 110 from the secondary battery 114 via the control transistor M1 and the resistor R1.
Prevents current from flowing backwards. The charging current is the resistance R
The voltage is converted into a voltage by 1, and the voltage is input to the charging current detection circuit 122. When the charging current detection circuit 122 detects from the input voltage that the charging current falls below a predetermined value, it sends a predetermined charging completion signal Sg6 to the charging control circuit 124. When the charging completion signal Sg6 is input, the charging control circuit 124 outputs the charging control signal Sg5 to stop the operation of the constant voltage circuit 118.
【０００５】[0005]
【発明が解決しようとする課題】上述のように従来の充
電回路は、充電電流を検出するために抵抗Ｒ１を用いて
いる。しかし、充電開始時において、充電電流は大電流
であり、大きな電圧降下を伴うことから、抵抗Ｒ１の発
熱が非常に大きくなる。また、これによる電力損失も大
きい。このような発熱や電力の無駄を少なくするため
に、抵抗Ｒ１の抵抗値を小さくすることも考えられる
が、定電圧充電を行うことにより、充電完了を検出する
時の電流が小さく、抵抗Ｒ１の両端に発生する電圧が小
さくなるので、その電圧を検出するオペアンプＡ１の入
力オフセット電圧などが無視できなくなる、すなわち、
充電電流の電流検出精度が低下するという問題があっ
た。また、オフセット電圧の小さいオペアンプは高価で
あり、それらを用いると、製造コストが高くなるという
問題があった。As described above, the conventional charging circuit uses the resistor R1 to detect the charging current. However, at the start of charging, the charging current is a large current and a large voltage drop occurs, so that the heat generation of the resistor R1 becomes extremely large. In addition, the power loss due to this is large. In order to reduce such heat generation and waste of electric power, it is conceivable to reduce the resistance value of the resistor R1; Since the voltage generated at both ends becomes small, the input offset voltage of the operational amplifier A1 that detects the voltage cannot be ignored, that is,
There is a problem that the current detection accuracy of the charging current is reduced. Further, operational amplifiers having a small offset voltage are expensive, and using them causes a problem of high manufacturing cost.
【０００６】さらに、充電開始時に二次電池に対して大
電流が供給されると、二次電池が過放電状態である場合
は、不具合が生じる。よって、このような充電回路で
は、過放電状態にある二次電池を充電することができな
かった。Further, if a large current is supplied to the secondary battery at the start of charging, a problem occurs if the secondary battery is in an over-discharged state. Therefore, such a charging circuit cannot charge the secondary battery in the over-discharged state.
【０００７】本発明の目的は、発熱や電力損失が小さ
く、高精度に二次電池の満充電状態を検出することがで
きる充電回路を提供することである。また、本発明の更
なる目的は、製造コストの低減を図ることができる充電
回路を提供することである。また、本発明の更なる目的
は、過放電状態にある二次電池に対しても充電を行うこ
とができる充電回路を提供することである。An object of the present invention is to provide a charging circuit which generates little heat and power loss and can detect a fully charged state of a secondary battery with high accuracy. A further object of the present invention is to provide a charging circuit that can reduce the manufacturing cost. A further object of the present invention is to provide a charging circuit that can charge a secondary battery that is in an overdischarged state.
【０００８】[0008]
【課題を解決するための手段】本発明に係る第１の充電
回路は、二次電池の充電を行う充電回路であり、所定の
直流電源と前記の二次電池との間に直列に接続され、入
力された制御信号に応じて、あらかじめ設定された２つ
の定電流のうち一方を、前記の二次電池に出力する定電
流回路部と、前記の定電流回路部に並列に接続され、前
記の二次電池に所定の定電圧を印加して充電を行う定電
圧回路部と、前記の二次電池の電圧を検出して出力する
電池電圧検出回路部と、前記の定電圧回路部からの電流
出力が停止すると所定の充電完了信号を出力する充電電
流検出回路部と、前記の充電完了信号が入力されると、
前記の定電流回路部および前記の定電圧回路部の動作を
停止させる充電制御回路部とを備える。また、前記の充
電制御回路部は、定電流回路部に対して、前記の二次電
池の電圧が所定電圧未満の場合は、所定の第１の定電流
を出力させる制御信号を出力し、前記の二次電池の電圧
が所定電圧以上の場合は、前記の第１の定電流よりも大
きい所定の第２の定電流を出力させる制御信号を出力す
る。A first charging circuit according to the present invention is a charging circuit for charging a secondary battery, which is connected in series between a predetermined DC power source and the secondary battery. A constant current circuit unit that outputs one of two preset constant currents to the secondary battery according to an input control signal, and the constant current circuit unit that is connected in parallel to the constant current circuit unit. The constant voltage circuit unit for applying a predetermined constant voltage to the secondary battery for charging, the battery voltage detection circuit unit for detecting and outputting the voltage of the secondary battery, and the constant voltage circuit unit When the charging current detection circuit unit that outputs a predetermined charging completion signal when the current output is stopped and the charging completion signal is input,
And a charge control circuit section for stopping the operations of the constant current circuit section and the constant voltage circuit section. The charge control circuit unit outputs to the constant current circuit unit a control signal for outputting a predetermined first constant current when the voltage of the secondary battery is less than a predetermined voltage, When the voltage of the secondary battery is equal to or higher than the predetermined voltage, the control signal for outputting the predetermined second constant current larger than the first constant current is output.
【０００９】好ましくは、前記の充電回路は、さらに、
前記の二次電池に充電電流を供給する直流電源を備え
る。Preferably, the charging circuit further comprises:
A DC power supply for supplying a charging current to the secondary battery is provided.
【００１０】好ましくは、前記の充電回路は、さらに、
前記の定電圧回路部から出力される電流の制御を行う充
電電流制御回路部を備える。また、前記の充電電流制御
回路部は、定電圧回路部に対して、定電圧回路部の出力
電流の最大値が所定値になるように動作制御を行う。ま
た、前記の充電制御回路部は、前記の充電完了信号が入
力されると、さらに、前記の充電電流制御回路部の動作
を停止させるPreferably, the charging circuit further comprises:
The charging current control circuit unit is provided for controlling the current output from the constant voltage circuit unit. Further, the charging current control circuit unit controls the constant voltage circuit unit so that the maximum value of the output current of the constant voltage circuit unit becomes a predetermined value. Further, the charge control circuit unit further stops the operation of the charge current control circuit unit when the charge completion signal is input.
【００１１】好ましくは、前記の定電圧回路部は、所定
の定電圧を生成して出力する定電圧発生回路と、前記の
二次電池の電圧とその定電圧とを比較し、その比較結果
を示す信号を出力する電圧比較器と、前記の比較結果を
示す信号に応じた電流を、所定の直流電源から前記の二
次電池に出力する制御トランジスタとを備える。Preferably, the constant voltage circuit section compares the voltage of the secondary battery and the constant voltage with a constant voltage generating circuit for generating and outputting a predetermined constant voltage, and comparing the comparison result. A voltage comparator that outputs a signal indicating the above, and a control transistor that outputs a current corresponding to the signal indicating the comparison result to the secondary battery from a predetermined DC power source are provided.
【００１２】好ましくは、前記の定電圧回路部は、さら
に、前記の電圧比較器へ流れる電流を阻止するダイオー
ドを備える。[0012] Preferably, the constant voltage circuit section further includes a diode that blocks a current flowing to the voltage comparator.
【００１３】好ましくは、前記の充電電流制御回路部
は、所定の第２定電圧を生成して出力する第２の定電圧
発生回路と、前記の制御トランジスタの制御端子に印加
される電圧と前記の第２定電圧とを比較し、その比較結
果を示す信号を出力する第２の電圧比較器と、前記の制
御端子から前記の第２の電圧比較器に流れる電流を阻止
する第２のダイオードとを備える。Preferably, the charging current control circuit section includes a second constant voltage generating circuit for generating and outputting a predetermined second constant voltage, the voltage applied to the control terminal of the control transistor, and the voltage applied to the control terminal of the control transistor. And a second diode for blocking a current flowing from the control terminal to the second voltage comparator. With.
【００１４】好ましくは、前記の充電電流検出回路部
は、前記の電圧比較器から出力される信号を検出し、そ
の検出した信号から前記の定電圧回路部の出力電流が停
止したことを検知する。Preferably, the charging current detection circuit section detects a signal output from the voltage comparator and detects from the detected signal that the output current of the constant voltage circuit section has stopped. .
【００１５】好ましくは、前記の充電電流検出回路部
は、所定の第３定電圧を生成して出力する第３の定電圧
発生回路と、前記の制御トランジスタの制御端子に印加
される電圧と前記の第３定電圧とを比較し、その制御端
子に印加される電圧と前記の第３定電圧が等しい場合
に、充電完了信号を出力する第３の電圧比較器とを備え
る。また、前記の第３定電圧は、前記の制御トランジス
タがカットオフするように前記の制御端子に印加される
電圧である。Preferably, the charging current detection circuit section includes a third constant voltage generating circuit for generating and outputting a predetermined third constant voltage, a voltage applied to a control terminal of the control transistor, and the voltage applied to the control terminal of the control transistor. And a third voltage comparator which outputs a charging completion signal when the voltage applied to its control terminal is equal to the third constant voltage. Further, the third constant voltage is a voltage applied to the control terminal so that the control transistor is cut off.
【００１６】本発明に係る第２の充電回路は、二次電池
の充電を行う充電回路であり、所定の直流電源と前記の
二次電池との間に直列に接続され、前記の二次電池に所
定の定電圧を印加して充電を行う定電圧回路部と、前記
の二次電池の電圧を検出して出力する電池電圧検出回路
部と、前記の定電圧回路部からの出力電流が所定値にな
ると、所定の充電完了信号を出力する充電電流検出回路
部と、前記の充電完了信号が入力されると、前記の定電
圧回路部の動作を停止させる充電制御回路部とを備え
る。また、前記の定電圧回路部は、所定の定電圧を生成
して出力する定電圧発生回路と、前記の二次電池の電圧
とその定電圧とを比較し、その比較結果を示す信号を出
力する電圧比較器と、前記の比較結果を示す信号に応じ
た電流を、所定の直流電源から前記の二次電池に出力す
る制御トランジスタとを備える。また、前記の充電電流
検出回路部は、前記の電圧比較器から出力される信号を
検出し、その検出した信号から前記の制御トランジスタ
の出力電流が所定値であることを検知して、充電完了信
号を出力する。The second charging circuit according to the present invention is a charging circuit for charging the secondary battery, which is connected in series between a predetermined DC power source and the secondary battery, and is connected to the secondary battery. A constant voltage circuit section that applies a predetermined constant voltage to charge the battery, a battery voltage detection circuit section that detects and outputs the voltage of the secondary battery, and an output current from the constant voltage circuit section that is a predetermined value. A charging current detection circuit unit that outputs a predetermined charging completion signal when the value reaches a value, and a charging control circuit unit that stops the operation of the constant voltage circuit unit when the charging completion signal is input. The constant voltage circuit section compares a constant voltage generating circuit that generates and outputs a predetermined constant voltage with the voltage of the secondary battery and the constant voltage, and outputs a signal indicating the comparison result. And a control transistor that outputs a current corresponding to the signal indicating the comparison result from a predetermined DC power supply to the secondary battery. Further, the charging current detection circuit unit detects a signal output from the voltage comparator, detects from the detected signal that the output current of the control transistor is a predetermined value, and completes charging. Output a signal.
【００１７】好ましくは、前記の第２の充電回路は、さ
らに、前記の二次電池に充電電流を供給する直流電源を
備える。Preferably, the second charging circuit further includes a DC power supply for supplying a charging current to the secondary battery.
【００１８】好ましくは、前記の充電電流検出回路部
は、所定の第２定電圧を生成して出力する第２の定電圧
発生回路と、制御トランジスタの制御端子に印加される
電圧と前記の第２定電圧とを比較し、その制御端子に印
加される電圧と前記の第２定電圧が等しい場合に、充電
完了信号を出力する第２の電圧比較器とを備える。ま
た、前記の第２定電圧は、前記の制御トランジスタの出
力電流が所定値であるように前記の制御端子に印加され
る電圧である。Preferably, the charging current detection circuit section includes a second constant voltage generation circuit for generating and outputting a predetermined second constant voltage, a voltage applied to a control terminal of a control transistor, and the first constant voltage generation circuit. A second voltage comparator that compares the two constant voltages and outputs a charging completion signal when the voltage applied to the control terminal is equal to the second constant voltage. The second constant voltage is a voltage applied to the control terminal so that the output current of the control transistor has a predetermined value.
【００１９】好ましくは、前記の定電圧回路部は、さら
に、前記の電圧比較器へ流れる電流を阻止するダイオー
ドを備える。Preferably, the constant voltage circuit section further includes a diode that blocks a current flowing to the voltage comparator.
【００２０】好ましくは、前記の充電回路は、さらに、
前記の定電圧回路部から出力される電流の制御を行う充
電電流制御回路部を備える。また、前記の充電電流制御
回路部は、定電圧回路部に対して、定電圧回路部の出力
電流の最大値が所定値になるように動作制御を行う。ま
た、前記の充電制御回路部は、前記の充電完了信号が入
力されると、さらに、前記の充電電流制御回路部の動作
を停止させる。Preferably, the charging circuit further comprises:
The charging current control circuit unit is provided for controlling the current output from the constant voltage circuit unit. Further, the charging current control circuit unit controls the constant voltage circuit unit so that the maximum value of the output current of the constant voltage circuit unit becomes a predetermined value. Further, when the charge completion signal is input, the charge control circuit unit further stops the operation of the charge current control circuit unit.
【００２１】好ましくは、前記の充電電流制御回路部
は、所定の第３定電圧を生成して出力する第３の定電圧
発生回路と、制御トランジスタの制御端子に印加される
電圧と前記の第３定電圧とを比較し、その比較結果を示
す信号を出力する第３の電圧比較器と、前記の制御端子
から前記の第３の電圧比較器に流れる電流を阻止する第
２のダイオードとを備える。Preferably, the charging current control circuit section includes a third constant voltage generating circuit for generating and outputting a predetermined third constant voltage, a voltage applied to a control terminal of a control transistor, and the third constant voltage generating circuit. A third voltage comparator that compares the three constant voltages and outputs a signal indicating the comparison result, and a second diode that blocks a current flowing from the control terminal to the third voltage comparator. Prepare
【００２２】好ましくは、前記の充電回路は、さらに、
前記の定電圧回路部に並列に接続され、あらかじめ設定
された定電流を、前記の二次電池に出力する定電流回路
部を備える。また、前記の充電制御回路部は、前記の定
電流回路部に対して、前記の二次電池の電圧が所定電圧
未満の場合は、前記の定電流回路部を駆動させ、前記の
二次電池の電圧が所定電圧以上の場合は、前記の定電流
回路部を停止させる。Preferably, the charging circuit further comprises:
A constant current circuit unit that is connected in parallel to the constant voltage circuit unit and outputs a preset constant current to the secondary battery is provided. In addition, the charge control circuit unit drives the constant current circuit unit to drive the constant current circuit unit when the voltage of the secondary battery is less than a predetermined voltage with respect to the constant current circuit unit. If the voltage is higher than the predetermined voltage, the constant current circuit section is stopped.
【００２３】好ましくは、前記の定電圧回路部は、さら
に、前記の二次電池から前記の制御トランジスタを介し
て前記の直流電源へ流れる電流を阻止する第３のダイオ
ードを備える。Preferably, the constant voltage circuit section further includes a third diode that blocks a current flowing from the secondary battery to the DC power source via the control transistor.
【００２４】好ましくは、前記の制御トランジスタは、
ｐチャネル型金属酸化膜半導体電界効果トランジスタで
ある。Preferably, the control transistor is
It is a p-channel type metal oxide semiconductor field effect transistor.
【００２５】好ましくは、前記の制御トランジスタは、
ＰＮＰバイポーラトランジスタである。Preferably, the control transistor is
It is a PNP bipolar transistor.
【００２６】[0026]
【発明の実施の形態】以下、添付の図面を参照して、本
発明の実施の形態について説明する。
（第１の実施の形態）図１は、本発明の第１の実施の形
態による充電回路を示す図である。図１において、充電
回路は、充電電流を供給するＡＣアダプタ１０、ＡＣア
ダプタ１０が接続されたことを検出するアダプタ検出回
路１２、二次電池１４の電圧を検出する電池電圧検出回
路１６、二次電池１４に対して定電圧充電を行う定電圧
回路１８、二次電池１４に定電流を供給する定電流回路
２０、制御トランジスタＭ１の制御端子の電圧を検出す
る制御端子電圧検出回路２２、二次電池１４からＡＣア
ダプタ１０へ流れる電流を阻止するダイオードＤ１、お
よび、定電圧回路１８と定電流回路２０の駆動制御を行
う充電制御回路２４から成る。ＡＣアダプタ１０は、端
子３０に接続される。定電圧回路１８は、基準電圧Ｅ１
を発生する定電圧発生回路４０と制御トランジスタＭ１
とオペアンプＡ１とから構成され、制御端子電圧検出回
路２２は、基準電圧Ｅ２を発生する定電圧発生回路４２
とオペアンプＡ２とから構成され、アダプタ検出回路１
２は、基準電圧Ｅ３を発生する定電圧発生回路４４とオ
ペアンプＡ３とから構成される。また、ダイオードＤ１
は、制御トランジスタＭ１と二次電池１４との間に接続
され、二次電池１４から制御トランジスタＭ１および抵
抗Ｒ１を介してＡＣアダプタ１０に電流が逆流すること
を防止する。なお、図１では、制御トランジスタＭ１
は、ｐチャネル型金属酸化膜半導体電界効果トランジス
タ（以下、「ｐＭＯＳトランジスタ」という。）として
示される。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) FIG. 1 is a diagram showing a charging circuit according to a first embodiment of the present invention. In FIG. 1, the charging circuit includes an AC adapter 10 that supplies a charging current, an adapter detection circuit 12 that detects that the AC adapter 10 is connected, a battery voltage detection circuit 16 that detects the voltage of the secondary battery 14, and a secondary battery. A constant voltage circuit 18 for performing constant voltage charging on the battery 14, a constant current circuit 20 for supplying a constant current to the secondary battery 14, a control terminal voltage detection circuit 22 for detecting the voltage of the control terminal of the control transistor M1, a secondary It is composed of a diode D1 that blocks a current flowing from the battery 14 to the AC adapter 10, and a charge control circuit 24 that controls driving of the constant voltage circuit 18 and the constant current circuit 20. The AC adapter 10 is connected to the terminal 30. The constant voltage circuit 18 has a reference voltage E1.
Voltage generating circuit 40 for generating a voltage and control transistor M1
The control terminal voltage detection circuit 22 includes a constant voltage generation circuit 42 that generates a reference voltage E2.
And an operational amplifier A2, the adapter detection circuit 1
Reference numeral 2 is composed of a constant voltage generating circuit 44 for generating a reference voltage E3 and an operational amplifier A3. Also, the diode D1
Is connected between the control transistor M1 and the secondary battery 14 and prevents current from flowing backward from the secondary battery 14 to the AC adapter 10 via the control transistor M1 and the resistor R1. In FIG. 1, the control transistor M1
Are shown as p-channel metal oxide semiconductor field effect transistors (hereinafter referred to as “pMOS transistors”).
【００２７】以下に、この充電回路の動作を説明する。
充電回路の電源であるＡＣアダプタ１０が端子３０で回
路に接続され、端子３０に接続されたオペアンプＡ３の
一方の入力端電圧が所定の基準電圧Ｅ３以上になると、
アダプタ検出回路１２は、充電制御回路２４に所定の信
号Ｓｇ１を送る。また、電池電圧検出回路１６は、二次
電池１４の電圧を検出し、電池電圧信号Ｓｇ２を生成し
て充電制御回路２４に出力する。充電制御回路２４は、
信号Ｓｇ１が入力されると起動し、電池電圧信号Ｓｇ２
が入力されると、定電流回路２０に定電流制御信号Ｓｇ
３を出力する。定電流回路２０は、定電流制御信号Ｓｇ
３が入力されると起動する。ここで、定電流回路２０
は、その内部に２つの電流源を備え、電流値の異なる２
種類の電流のうち一方を、ＩＢによって示される向きに
出力することができる。充電制御回路２４は、入力され
た電池電圧信号Ｓｇ２から二次電池１４の電圧が所定の
電圧Ｖ１より小さいことを検出すると、定電流回路２０
に対し、定電流制御信号Ｓｇ３と共に、定電流値切替信
号Ｓｇ４を出力する。これは、二次電池１４の電圧がＶ
１より小さい場合、つまり、二次電圧１４が過放電状態
にある場合は、いきなり大電流で充電すると不具合が生
じるので、充電電流を絞るために行う。これにより、定
電流回路２０は、定電流値切替信号Ｓｇ４が入力される
と、電流値Ｉ１の電流を出力する。リチウムイオン電池
の場合、電圧Ｖ１は、約２．５Ｖに設定され、電流値Ｉ
１は、通常、数ｍＡ〜数十ｍＡ程度である。以上のよう
に、定電流回路２０に定電流制御信号Ｓｇ３が出力され
ると、二次電池１４の充電が始まる。The operation of this charging circuit will be described below.
When the AC adapter 10 which is the power supply of the charging circuit is connected to the circuit at the terminal 30 and the one input terminal voltage of the operational amplifier A3 connected to the terminal 30 becomes equal to or higher than the predetermined reference voltage E3,
The adapter detection circuit 12 sends a predetermined signal Sg1 to the charge control circuit 24. Further, the battery voltage detection circuit 16 detects the voltage of the secondary battery 14, generates a battery voltage signal Sg2, and outputs it to the charging control circuit 24. The charge control circuit 24 is
It starts when the signal Sg1 is input, and the battery voltage signal Sg2
Is input to the constant current circuit 20, the constant current control signal Sg
3 is output. The constant current circuit 20 has a constant current control signal Sg.
It starts when 3 is input. Here, the constant current circuit 20
Is equipped with two current sources inside and two with different current values.
One of the types of current can be output in the direction indicated by I B. When the charge control circuit 24 detects from the input battery voltage signal Sg2 that the voltage of the secondary battery 14 is lower than the predetermined voltage V1, the constant current circuit 20.
On the other hand, the constant current control signal Sg3 and the constant current value switching signal Sg4 are output. This is because the voltage of the secondary battery 14 is V
If it is smaller than 1, that is, if the secondary voltage 14 is in the over-discharged state, a problem will occur if the battery is suddenly charged with a large current. Therefore, the charging current is reduced. Accordingly, the constant current circuit 20 outputs the current having the current value I1 when the constant current value switching signal Sg4 is input. In the case of a lithium ion battery, the voltage V1 is set to about 2.5V and the current value I
1 is usually about several mA to several tens of mA. As described above, when the constant current control signal Sg3 is output to the constant current circuit 20, charging of the secondary battery 14 starts.
【００２８】充電制御回路２４は、二次電池１４が電流
値Ｉ１の電流で充電され、電池電圧検出回路１６からの
電池電圧信号Ｓｇ２によって、二次電池１４の電圧が所
定の電圧Ｖ１に到達したことを検知すると、二次電池１
４が正常な電池であると判断して、定電流回路２０に定
電流値切替信号Ｓｇ４を出力する。これにより、定電流
回路２０は、電流値Ｉ１よりも大きい電流値Ｉ２を二次
電池１４に出力する。ここで、電流値Ｉ２は、定電圧充
電が完了したときに二次電池１４に流れる満充電電流と
同じ値である。さらに、充電制御回路２４は、定電圧回
路１８に充電制御信号Ｓｇ５を出力し、定電圧回路１８
を起動させる。定電圧回路１８は、二次電池１４に対
し、Ｉcによって示される向きに充電電流を出力する。
以降、二次電池１４は、定電圧回路１８と定電流回路２
０の両方から出力される電流で充電される。In the charge control circuit 24, the secondary battery 14 is charged with the current of the current value I1, and the battery voltage signal Sg2 from the battery voltage detection circuit 16 causes the voltage of the secondary battery 14 to reach the predetermined voltage V1. When this is detected, the secondary battery 1
4 is a normal battery, and a constant current value switching signal Sg4 is output to the constant current circuit 20. As a result, the constant current circuit 20 outputs a current value I2 larger than the current value I1 to the secondary battery 14. Here, the current value I2 is the same value as the full charge current flowing through the secondary battery 14 when the constant voltage charging is completed. Further, the charging control circuit 24 outputs the charging control signal Sg5 to the constant voltage circuit 18, and the constant voltage circuit 18
To start. The constant voltage circuit 18 outputs the charging current to the secondary battery 14 in the direction indicated by I c .
After that, the secondary battery 14 includes the constant voltage circuit 18 and the constant current circuit 2
It is charged by the current output from both 0s.
【００２９】その後、二次電池１４の電圧がさらに上昇
して、定電圧回路１８の基準電圧Ｅ１にほぼ等しい電圧
Ｖ２に到達すると、二次電池１４の電圧はそれ以上上昇
せずに一定に保持され、充電電流だけが徐々に減少する
ようになる。このとき、オペアンプＡ１は、二次電池１
４の電圧と基準電圧Ｅ１とを比較し、その差に応じてｐ
ＭＯＳトランジスタＭ１のゲート（制御端子）に正のゲ
ート電圧（制御電圧）を印加している。二次電池１４の
電圧が大きくなると、印加されるゲート電圧も大きくな
るので、ドレイン電流が徐々に制限される。つまり、二
次電池１４に供給される充電電流が除々に減少する。リ
チウムイオン電池の場合、この電圧Ｖ２は、約４．２Ｖ
に設定される。それ以上電圧を上げると、二次電池内部
に金属リチウムが析出して不具合が生じる。従来の定電
流・定電圧充電回路であっても、二次電池１４の電圧が
電圧Ｖ２に到達すると、定電流充電から定電圧充電に移
行する。なお、理想的には、二次電池１４がＶ２に到達
すると同時に全充電電流が減少し始めるが、電池内部の
化学反応の進行状態により、多少の時間差がある。After that, when the voltage of the secondary battery 14 further rises and reaches the voltage V2 which is almost equal to the reference voltage E1 of the constant voltage circuit 18, the voltage of the secondary battery 14 is kept constant without further increasing. Therefore, only the charging current gradually decreases. At this time, the operational amplifier A1 is connected to the secondary battery 1
4 and the reference voltage E1 are compared, and p is determined according to the difference.
A positive gate voltage (control voltage) is applied to the gate (control terminal) of the MOS transistor M1. As the voltage of the secondary battery 14 increases, the applied gate voltage also increases, so the drain current is gradually limited. That is, the charging current supplied to the secondary battery 14 gradually decreases. In the case of a lithium ion battery, this voltage V2 is about 4.2V.
Is set to. When the voltage is further increased, metallic lithium is deposited inside the secondary battery, which causes a problem. Even in the conventional constant current / constant voltage charging circuit, when the voltage of the secondary battery 14 reaches the voltage V2, the constant current charging shifts to the constant voltage charging. Ideally, the total charging current starts to decrease at the same time when the secondary battery 14 reaches V2, but there is a slight time difference depending on the progress state of the chemical reaction inside the battery.
【００３０】図２は、以上の動作を図式的に示すグラフ
である。図２の（１）は、充電時間の経過による二次電
池２４の電圧の変化を示すグラフであり、図２の（２）
は、充電時間の経過による充電電流の変化を示すグラフ
である。また、図２の（３）は、充電時間の経過による
ｐＭＯＳトランジスタＭ１のゲート電圧の変化を示すグ
ラフである。図２の（２）には、定電流回路２０から出
力される電流（ａ）（太線で示される。）、定電圧回路
１８から出力される充電電流（ｂ）、および、その定電
圧回路１８から出力される電流に定電流回路２０から出
力される電流を加えた全充電電流（ｃ）の変化が示され
る。図２の（１）および図２の（２）を参照すると、二
次電池１４は、その電圧がＶ１に到達するまで（充電時
間ｔ１まで）は、定電流回路２０から出力される電流値
Ｉ１の電流で充電される。二次電池１４の電圧がＶ１に
到達すると、定電流回路２０から電流値Ｉ２の充電電流
が出力され、定電圧回路１８も充電電流を出力し始め
る。定電圧回路１８から出力される充電電流は、最初、
ＡＣアダプタ１０の電流容量とｐＭＯＳトランジスタＭ
１の容量のいずれか小さい容量によって制限される電流
である。図２の（２）では、例として、ＡＣアダプタ１
０の電流容量がより小さい場合の充電電流が示される。
二次電池１４は、定電圧回路１８と定電流回路２０の両
方から出力される電流で充電され、二次電池１４の電圧
が上昇して所定の電圧Ｖ２に到達する。FIG. 2 is a graph schematically showing the above operation. (1) of FIG. 2 is a graph showing a change in voltage of the secondary battery 24 with the passage of charging time, and (1) of FIG.
[Fig. 4] is a graph showing changes in charging current with the passage of charging time. Further, (3) of FIG. 2 is a graph showing changes in the gate voltage of the pMOS transistor M1 with the elapse of the charging time. In (2) of FIG. 2, the current (a) output from the constant current circuit 20 (shown by a thick line), the charging current (b) output from the constant voltage circuit 18, and the constant voltage circuit 18 thereof. The change in the total charging current (c) obtained by adding the current output from the constant current circuit 20 to the current output from Referring to (1) of FIG. 2 and (2) of FIG. 2, the secondary battery 14 has a current value I1 output from the constant current circuit 20 until the voltage thereof reaches V1 (up to the charging time t1). Is charged with the current of. When the voltage of the secondary battery 14 reaches V1, the constant current circuit 20 outputs the charging current having the current value I2, and the constant voltage circuit 18 also starts to output the charging current. The charging current output from the constant voltage circuit 18 is initially
Current capacity of AC adapter 10 and pMOS transistor M
The current is limited by the smaller one of the capacities of 1. In (2) of FIG. 2, as an example, the AC adapter 1
The charging current is shown when the current capacity of 0 is smaller.
The secondary battery 14 is charged with a current output from both the constant voltage circuit 18 and the constant current circuit 20, and the voltage of the secondary battery 14 rises to reach a predetermined voltage V2.
【００３１】二次電池１４が所定の電圧Ｖ２に到達して
からある程度の時間が経過すると、ｐＭＯＳトランジス
タＭ１のゲート電圧は、徐々に上昇し始め、それに応じ
て、定電圧回路１８から出力される電流は徐々に減少し
始める。そして、充電時間ｔ２において、ｐＭＯＳトラ
ンジスタＭ１のゲート電圧は、図２の（３）に示される
ように、ほぼＡＣアダプタ電圧近くまで上昇する。この
とき、定電圧回路１８のｐＭＯＳトランジスタＭ１はカ
ットオフし、定電圧回路１８から出力される充電電流は
停止する。つまり、全充電電流は、定電流回路２０から
出力される電流値Ｉ２の電流のみである。When a certain amount of time has passed since the secondary battery 14 reached the predetermined voltage V2, the gate voltage of the pMOS transistor M1 begins to gradually rise, and accordingly, the constant voltage circuit 18 outputs it. The current gradually begins to decrease. Then, at the charging time t2, the gate voltage of the pMOS transistor M1 rises to almost the AC adapter voltage as shown in (3) of FIG. At this time, the pMOS transistor M1 of the constant voltage circuit 18 is cut off, and the charging current output from the constant voltage circuit 18 is stopped. That is, the total charging current is only the current having the current value I2 output from the constant current circuit 20.
【００３２】本実施の形態による充電回路において、電
流値Ｉ２は満充電電流の値に等しく設定されているた
め、定電圧回路１８のｐＭＯＳトランジスタＭ１がカッ
トオフして、二次電池１４に、定電流回路２０から出力
される電流値Ｉ２の電流だけしか流れなくなったとき
は、充電完了時とみなすことができる。In the charging circuit according to the present embodiment, the current value I2 is set equal to the value of the full charging current, so that the pMOS transistor M1 of the constant voltage circuit 18 is cut off, and the secondary battery 14 is charged with a constant voltage. When only the current of the current value I2 output from the current circuit 20 flows, it can be considered that the charging is completed.
【００３３】よって、制御端子電圧検出回路２２の基準
電圧Ｅ２を、ＡＣアダプタ１０の電圧から基準電圧Ｅ２
だけ低下した電圧が、ｐＭＯＳトランジスタＭ１がカッ
トオフするゲート電圧に等しくなるように設定すると、
制御端子電圧検出回路２２は、制御トランジスタＭ１が
カットオフしたとき、すなわち、オペアンプＡ２の一方
の入力端に入力されるｐＭＯＳトランジスタＭ１のゲー
ト電圧がＡＣアダプタ１０の電圧から基準電圧Ｅ２だけ
低下した電圧に等しくなったとき、充電制御回路２４に
充電完了信号Ｓｇ６を出力する。以上のように、制御端
子電圧検出回路２２は、ｐＭＯＳトランジスタＭ１のゲ
ート電圧を検出するすることによって、二次電池１４に
所定の電流が流れていることを検知するので、充電電流
検出回路ともいえる。充電制御回路２４は、充電完了信
号Ｓｇ６が入力されると、定電圧回路１８および定電流
回路２０に、それぞれ、充電制御信号Ｓｇ５および定電
流制御信号Ｓｇ３を出力し、その動作を停止させる。Therefore, the reference voltage E2 of the control terminal voltage detection circuit 22 is changed from the voltage of the AC adapter 10 to the reference voltage E2.
If the voltage lowered by just the same as the gate voltage at which the pMOS transistor M1 is cut off is set,
The control terminal voltage detection circuit 22 is a voltage obtained when the control transistor M1 is cut off, that is, the gate voltage of the pMOS transistor M1 input to one input terminal of the operational amplifier A2 is lower than the voltage of the AC adapter 10 by the reference voltage E2. When it becomes equal to, the charging completion signal Sg6 is output to the charging control circuit 24. As described above, the control terminal voltage detection circuit 22 detects that a predetermined current is flowing in the secondary battery 14 by detecting the gate voltage of the pMOS transistor M1. . When the charging completion signal Sg6 is input, the charging control circuit 24 outputs the charging control signal Sg5 and the constant current control signal Sg3 to the constant voltage circuit 18 and the constant current circuit 20, respectively, and stops the operation.
【００３４】本実施の形態による充電回路においては、
充電電流検出用の抵抗が不要であり、抵抗による発熱や
電力損失がなく、高精度に満充電状態を検出することが
できる。また、定電流回路２０から出力される電流の電
流値を、それぞれ大きさの異なる電流値のなかから選択
することができるので、新たに回路を追加することなく
過放電電池等に対しても充電を行うことができる。In the charging circuit according to this embodiment,
Since a resistor for detecting the charging current is unnecessary, there is no heat generation or power loss due to the resistor, and the fully charged state can be detected with high accuracy. In addition, since the current value of the current output from the constant current circuit 20 can be selected from the current values having different magnitudes, it is possible to charge an over-discharged battery without adding a new circuit. It can be performed.
【００３５】なお、本実施の形態による充電回路では、
制御端子電圧検出回路２２において、基準電圧Ｅ２を発
生する定電圧発生回路４２を利用し、その基準電圧Ｅ２
を、ＡＣアダプタ１０の電圧から基準電圧Ｅ２だけ低下
した電圧が、ｐＭＯＳトランジスタＭ１がカットオフす
るゲート電圧に等しくなるように設定する。しかし、こ
れは、充電完了電圧を発生する定電圧発生回路を利用
し、その充電完了電圧を、ｐＭＯＳトランジスタＭ１が
カットオフするゲート電圧に等しくなるように設定する
ことと同じことである。In the charging circuit according to this embodiment,
In the control terminal voltage detection circuit 22, a constant voltage generation circuit 42 that generates the reference voltage E2 is used, and the reference voltage E2
Is set so that the voltage obtained by lowering the voltage of the AC adapter 10 by the reference voltage E2 is equal to the gate voltage at which the pMOS transistor M1 is cut off. However, this is the same as using a constant voltage generation circuit that generates a charge completion voltage and setting the charge completion voltage to be equal to the gate voltage at which the pMOS transistor M1 is cut off.
【００３６】なお、図１において、制御トランジスタＭ
１はｐＭＯＳトランジスタであるが、図３に示すよう
に、バイポーラＰＮＰトランジスタであっても同様の効
果が得られる。この場合、制御端子電圧検出回路２２の
基準電圧Ｅ２は、ＡＣアダプタ１０の電圧から基準電圧
Ｅ２だけ低下した電圧が、バイポーラＰＮＰトランジス
タがカットオフするベース電圧に等しくなるように設定
するとよい。In FIG. 1, the control transistor M
Although 1 is a pMOS transistor, a similar effect can be obtained with a bipolar PNP transistor as shown in FIG. In this case, the reference voltage E2 of the control terminal voltage detection circuit 22 may be set so that the voltage reduced by the reference voltage E2 from the voltage of the AC adapter 10 becomes equal to the base voltage at which the bipolar PNP transistor is cut off.
【００３７】（第２の実施の形態）図４は、本発明の第
２の実施の形態による二次電池１４の充電回路を示す図
である。図４において、図１の回路と同じ構成要素には
同じ番号が付されている。これらの構成要素については
説明を省略する。本実施の形態による充電回路は、図１
の充電回路に、ｐＭＯＳトランジスタＭ１から出力され
る充電電流の制御を行う充電電流制御回路５０、およ
び、負荷抵抗Ｒ２が追加される。また、定電圧回路１８
のオペアンプＡ１とｐＭＯＳトランジスタＭ１との間に
ダイオードＤ３が接続される。充電電流制御回路５０
は、基準電圧Ｅ４を発生する定電圧発生回路４６とオペ
アンプＡ２とダイオードＤ２とから構成される。負荷抵
抗Ｒ２は、その一端が接地され、他端がｐＭＯＳトラン
ジスタＭ１のゲート端子に接続される。(Second Embodiment) FIG. 4 is a diagram showing a charging circuit for a secondary battery 14 according to a second embodiment of the present invention. 4, the same components as those of the circuit of FIG. 1 are given the same numbers. Descriptions of these components will be omitted. The charging circuit according to the present embodiment is shown in FIG.
A charging current control circuit 50 for controlling the charging current output from the pMOS transistor M1 and a load resistor R2 are added to the charging circuit of FIG. In addition, the constant voltage circuit 18
A diode D3 is connected between the operational amplifier A1 and the pMOS transistor M1. Charging current control circuit 50
Is composed of a constant voltage generating circuit 46 for generating a reference voltage E4, an operational amplifier A2 and a diode D2. The load resistor R2 has one end grounded and the other end connected to the gate terminal of the pMOS transistor M1.
【００３８】図５の（１）、図５の（２）および図５の
（３）は、それぞれ、充電時間の経過による二次電池１
４の電圧の変化、充電電流の変化およびｐＭＯＳトラン
ジスタＭ１のゲート電圧の変化を示す。図５の（２）に
は、定電流回路２０から出力される電流（ａ）（太線で
示される。）、定電圧回路１８から出力される充電電流
（ｂ）、および、その定電圧回路１８から出力される電
流に定電流回路２０から出力される電流を加えた全充電
電流（ｃ）の変化が示される。本実施の形態による充電
回路は、二次電池１４の電圧が所定の電圧Ｖ１に到達す
るまで（充電時間がｔ１になるまで）は、第１の実施の
形態による回路と同様の動作をする。充電制御回路２４
は、電池電圧検出回路１６からの電池電圧信号Ｓｇ２に
よって、二次電池１４の電圧が所定の電圧Ｖ１に到達し
たことを検知すると、定電流回路２０に定電流値切替信
号Ｓｇ４を出力する。これにより、定電流回路２０は、
電流値Ｉ１よりも大きい電流値Ｉ２を二次電池１４に出
力する。さらに、充電制御回路２４は、定電圧回路１８
と充電電流制御回路５０に充電制御信号Ｓｇ５を出力
し、定電圧回路１８と充電電流制御回路５０とを起動さ
せる。5 (1), FIG. 5 (2) and FIG. 5 (3) respectively show the secondary battery 1 according to the lapse of charging time.
4 shows changes in the voltage of No. 4, changes in the charging current, and changes in the gate voltage of the pMOS transistor M1. In (2) of FIG. 5, a current (a) output from the constant current circuit 20 (shown by a thick line), a charging current (b) output from the constant voltage circuit 18, and the constant voltage circuit 18 thereof. The change in the total charging current (c) obtained by adding the current output from the constant current circuit 20 to the current output from The charging circuit according to the present embodiment operates similarly to the circuit according to the first embodiment until the voltage of the secondary battery 14 reaches a predetermined voltage V1 (until the charging time reaches t1). Charge control circuit 24
When the battery voltage signal Sg2 from the battery voltage detection circuit 16 detects that the voltage of the secondary battery 14 has reached the predetermined voltage V1, it outputs the constant current value switching signal Sg4 to the constant current circuit 20. As a result, the constant current circuit 20
A current value I2 larger than the current value I1 is output to the secondary battery 14. Further, the charging control circuit 24 is configured to operate the constant voltage circuit 18
And the charging control signal Sg5 is output to the charging current control circuit 50 to activate the constant voltage circuit 18 and the charging current control circuit 50.
【００３９】最初は二次電池１４の電圧がまだ低いの
で、定電圧回路１８のオペアンプＡ１の出力は、ほぼ０
Ｖである。一方、充電電流制御回路５０のオペアンプＡ
４は、ｐＭＯＳトランジスタＭ１のゲート電圧と、ＡＣ
アダプタ１０の電圧（端子３０の電圧）から基準電圧Ｅ
４だけ低下した電圧とを比較し、ｐＭＯＳトランジスタ
Ｍ１のゲート電圧がＡＣアダプタ１０の電圧から基準電
圧Ｅ４だけ低下した電圧に一定に保持されるように、電
圧を出力する。このとき、定電圧回路１８のダイオード
Ｄ３は、ｐＭＯＳトランジスタＭ１のゲート端子からオ
ペアンプＡ１に流れる電流を阻止する。結局、ｐＭＯＳ
トランジスタＭ１のゲート電圧が一定に保たれ、ｐＭＯ
ＳトランジスタＭ１のドレイン電流、つまり、定電圧回
路１８から出力される充電電流は電流値Ｉ３で一定とな
る。At first, since the voltage of the secondary battery 14 is still low, the output of the operational amplifier A1 of the constant voltage circuit 18 is almost zero.
V. On the other hand, the operational amplifier A of the charging current control circuit 50
4 is the gate voltage of the pMOS transistor M1 and AC
From the voltage of the adapter 10 (voltage of terminal 30) to the reference voltage E
The voltage is output so that the gate voltage of the pMOS transistor M1 is kept constant at the voltage reduced by the reference voltage E4 from the voltage of the AC adapter 10 by comparing the voltage reduced by 4 with the voltage. At this time, the diode D3 of the constant voltage circuit 18 blocks the current flowing from the gate terminal of the pMOS transistor M1 to the operational amplifier A1. After all, pMOS
The gate voltage of the transistor M1 is kept constant and pMO
The drain current of the S transistor M1, that is, the charging current output from the constant voltage circuit 18 is constant at the current value I3.
【００４０】しかし、ｐＭＯＳトランジスタＭ１の性能
により、所定のゲート電圧が印加されても、所定のドレ
イン電流が流れない場合がある。そこで、図４のよう
に、負荷抵抗Ｒ２を配置して、所定のドレイン電流が流
れるようにゲート電圧の微調整を行う。以上のようにし
て、二次電池１４は、電流値Ｉ２の定電流と電流値Ｉ３
のドレイン電流の両方で充電される。However, depending on the performance of the pMOS transistor M1, a predetermined drain current may not flow even if a predetermined gate voltage is applied. Therefore, as shown in FIG. 4, a load resistor R2 is arranged to finely adjust the gate voltage so that a predetermined drain current flows. As described above, the secondary battery 14 has the constant current I2 and the constant current I3.
It is charged by both drain currents.
【００４１】二次電池１４の電圧が上昇して、所定の電
圧Ｖ２に到達すると、定電圧回路１８のオペアンプＡ１
の出力電圧が上昇し、ダイオードＤ３を介して、オペア
ンプＡ１からｐＭＯＳトランジスタＭ１のゲート電圧へ
電流が流れるようになる。これにより、ｐＭＯＳトラン
ジスタＭ１のゲート電圧が上昇する。代わりに、充電電
流制御回路５０のオペアンプＡ４の出力は、ほぼ０Ｖま
で低下し、ダイオードＤ２を介して、オペアンプＡ４か
らｐＭＯＳトランジスタのゲート電圧へ電流が流れなく
なる。ｐＭＯＳトランジスタＭ１のゲート電圧が上昇す
ると、ｐＭＯＳトランジスタによって出力されるドレイ
ン電流は減少する。二次電池１４の充電がさらに進む
と、ｐＭＯＳトランジスタのゲート電圧がさらに大きく
なり、ｐＭＯＳトランジスタＭ１はカットオフする。こ
のとき、二次電池１４に流れる全充電電流は、定電圧充
電が完了したときに二次電池１４に流れる満充電電流に
等しい電流値Ｉ２である。When the voltage of the secondary battery 14 rises and reaches a predetermined voltage V2, the operational amplifier A1 of the constant voltage circuit 18
Output voltage rises, and current flows from the operational amplifier A1 to the gate voltage of the pMOS transistor M1 via the diode D3. As a result, the gate voltage of the pMOS transistor M1 rises. Instead, the output of the operational amplifier A4 of the charging current control circuit 50 drops to almost 0V, and no current flows from the operational amplifier A4 to the gate voltage of the pMOS transistor via the diode D2. When the gate voltage of the pMOS transistor M1 rises, the drain current output by the pMOS transistor decreases. When the charging of the secondary battery 14 further progresses, the gate voltage of the pMOS transistor further increases, and the pMOS transistor M1 is cut off. At this time, the total charging current flowing through the secondary battery 14 has a current value I2 equal to the full charging current flowing through the secondary battery 14 when the constant voltage charging is completed.
【００４２】制御端子電圧検出回路２２の基準電圧Ｅ２
を、ＡＣアダプタ１０の電圧から基準電圧Ｅ２だけ低下
した電圧が、ｐＭＯＳトランジスタＭ１がカットオフす
るようなゲート電圧に等しくなるように設定すると、制
御端子電圧検出回路２２は、制御トランジスタＭ１がカ
ットオフしたとき、充電制御回路２４に充電完了信号Ｓ
ｇ６を出力する。充電制御回路２４は、充電完了信号Ｓ
ｇ６が入力されると、定電圧回路１８および定電流回路
２０に、それぞれ、充電制御信号Ｓｇ５および定電流制
御信号Ｓｇ３を出力し、その動作を停止させる。Reference voltage E2 of control terminal voltage detection circuit 22
Is set so that the voltage obtained by lowering the reference voltage E2 from the voltage of the AC adapter 10 becomes equal to the gate voltage at which the pMOS transistor M1 cuts off, the control terminal voltage detection circuit 22 causes the control transistor M1 to cut off. Then, the charging completion signal S is sent to the charging control circuit 24.
Output g6. The charging control circuit 24 uses the charging completion signal S
When g6 is input, the charging control signal Sg5 and the constant current control signal Sg3 are output to the constant voltage circuit 18 and the constant current circuit 20, respectively, and the operation is stopped.
【００４３】本実施の形態による充電回路においては、
定電圧回路１８が駆動し始めた直後であっても、ｐＭＯ
ＳトランジスタＭ１に所定のゲート電圧を印加できる。
よって、二次電池１４に、ＡＣアダプタ１０の電流容量
やｐＭＯＳトランジスタＭ１の容量に依存することのな
い所定の定電流を供給できる。これにより、定電圧回路
１８が駆動し始めた直後であっても、二次電池１４に対
し、損傷を与えることのない適当な電流値の充電電流を
流すことができる。In the charging circuit according to this embodiment,
Even immediately after the constant voltage circuit 18 starts driving, pMO
A predetermined gate voltage can be applied to the S transistor M1.
Therefore, it is possible to supply the secondary battery 14 with a predetermined constant current that does not depend on the current capacity of the AC adapter 10 or the capacity of the pMOS transistor M1. Accordingly, even immediately after the constant voltage circuit 18 starts to be driven, a charging current having an appropriate current value that does not damage the secondary battery 14 can be supplied.
【００４４】本実施の形態による充電回路においては、
充電電流検出用の抵抗が不要であり、抵抗による発熱や
電力損失がなく、高精度に二次電池の満充電状態を検出
することができる。また、定電流回路２０から出力され
る電流の電流値を、それぞれ大きさの異なる電流値のな
かから選択することができるので、新たに回路を追加す
ることなく過放電電池等に対しても充電を行うことがで
きる。In the charging circuit according to this embodiment,
A resistor for detecting a charging current is unnecessary, heat generation and power loss due to the resistor are not generated, and the fully charged state of the secondary battery can be detected with high accuracy. In addition, since the current value of the current output from the constant current circuit 20 can be selected from the current values having different magnitudes, it is possible to charge an over-discharged battery without adding a new circuit. It can be performed.
【００４５】なお、本実施の形態による充電回路では、
制御端子電圧検出回路２２において、基準電圧Ｅ２を発
生する定電圧発生回路４２を利用し、その基準電圧Ｅ２
を、ＡＣアダプタ１０の電圧から基準電圧Ｅ２だけ低下
した電圧が、ｐＭＯＳトランジスタＭ１がカットオフす
るようなゲート電圧に等しくなるように設定する。しか
し、これは、充電完了電圧を発生する定電圧発生回路を
利用し、その充電完了電圧を、ｐＭＯＳトランジスタＭ
１がカットオフするゲート電圧に等しくなるように設定
することと同じことである。また、充電電流制御回路５
０において、基準電圧Ｅ４を発生する定電圧発生回路４
６を利用し、その基準電圧Ｅ４を、ＡＣアダプタ１０の
電圧から基準電圧Ｅ４だけ低下した電圧が、所定の定電
流を出力するｐＭＯＳトランジスタＭ１のゲート電圧に
等しくなるように設定する。しかし、これは、ある制御
電圧を発生する定電圧発生回路を利用し、その制御電圧
を、所定の定電流を出力するｐＭＯＳトランジスタＭ１
のゲート電圧に等しくなるように設定することと同じこ
とである。In the charging circuit according to this embodiment,
In the control terminal voltage detection circuit 22, a constant voltage generation circuit 42 that generates the reference voltage E2 is used, and the reference voltage E2
Is set so that the voltage reduced from the voltage of the AC adapter 10 by the reference voltage E2 is equal to the gate voltage at which the pMOS transistor M1 is cut off. However, this utilizes a constant voltage generation circuit that generates a charging completion voltage, and the charging completion voltage is set to the pMOS transistor M.
This is the same as setting 1 to be equal to the cutoff gate voltage. In addition, the charging current control circuit 5
Constant voltage generation circuit 4 for generating reference voltage E4 at 0
6, the reference voltage E4 is set such that the voltage obtained by lowering the voltage of the AC adapter 10 by the reference voltage E4 is equal to the gate voltage of the pMOS transistor M1 that outputs a predetermined constant current. However, this utilizes a constant voltage generating circuit that generates a certain control voltage, and outputs the control voltage from the pMOS transistor M1 that outputs a predetermined constant current.
It is the same as setting the gate voltage to be equal to.
【００４６】なお、図４において、制御トランジスタＭ
１はｐＭＯＳトランジスタであるが、図３に示すよう
に、バイポーラＰＮＰトランジスタであっても同様の効
果が得られる。この場合、制御端子電圧検出回路２２の
基準電圧Ｅ２は、ＡＣアダプタ１０の電圧から基準電圧
Ｅ２だけ低下した電圧が、バイポーラＰＮＰトランジス
タがカットオフするバイポーラＰＮＰトランジスタのベ
ース電圧に等しくなるように設定するとよい。また、定
電圧発生回路４６の基準電圧Ｅ４は、ＡＣアダプタ１０
の電圧から基準電圧Ｅ４だけ低下した電圧が、所定の定
電流を出力するバイポーラＰＮＰトランジスタのベース
電圧に等しくなるように設定すればよい。In FIG. 4, the control transistor M
Although 1 is a pMOS transistor, a similar effect can be obtained with a bipolar PNP transistor as shown in FIG. In this case, the reference voltage E2 of the control terminal voltage detection circuit 22 is set so that the voltage reduced from the voltage of the AC adapter 10 by the reference voltage E2 is equal to the base voltage of the bipolar PNP transistor that the bipolar PNP transistor cuts off. Good. The reference voltage E4 of the constant voltage generation circuit 46 is the AC adapter 10
It is only necessary to set the voltage that is lower than the voltage of 4 by the reference voltage E4 to be equal to the base voltage of the bipolar PNP transistor that outputs a predetermined constant current.
【００４７】なお、本実施の形態による充電回路におい
て、充電電流制御回路５０は、ｐＭＯＳトランジスタＭ
１のゲート電圧を一定に保持し、ｐＭＯＳトランジスタ
Ｍ１を介して二次電池１４に所定の定電流を流す。しか
し、ｐＭＯＳトランジスタＭ１を介して二次電池１４に
所定の定電流を流すことができれば、他の構成を用いて
もよい。そのような場合であっても、同様の効果が得ら
れる。ただし、図４および図６のように負荷抵抗Ｒ２を
配置する構成にすれば、ｐＭＯＳトランジスタＭ１に印
加されるゲート電圧の値を微調節することが容易であ
る。例えば、ｐＭＯＳトランジスタＭ１を、異なるメー
カーのｐＭＯＳトランジスタＭ１に交換する場合であっ
ても、そのｐＭＯＳトランジスタＭ１の性能に応じてゲ
ート電圧を容易に調整できる。これにより、ｐＭＯＳト
ランジスタＭ１の性能に関わらず、二次電池１４に所定
の定電流を流すことができる。In the charging circuit according to the present embodiment, the charging current control circuit 50 includes the pMOS transistor M
The gate voltage of 1 is held constant, and a predetermined constant current is passed through the secondary battery 14 via the pMOS transistor M1. However, another configuration may be used as long as a predetermined constant current can flow through the secondary battery 14 via the pMOS transistor M1. Even in such a case, the same effect can be obtained. However, if the load resistance R2 is arranged as shown in FIGS. 4 and 6, it is easy to finely adjust the value of the gate voltage applied to the pMOS transistor M1. For example, even when the pMOS transistor M1 is replaced with the pMOS transistor M1 of a different manufacturer, the gate voltage can be easily adjusted according to the performance of the pMOS transistor M1. As a result, a predetermined constant current can be passed through the secondary battery 14 regardless of the performance of the pMOS transistor M1.
【００４８】また、図４における充電回路において、定
電流回路２０が電流値Ｉ１のみを出力する定電流回路で
あってもよい。図６は、その場合の充電回路を示す図で
ある。定電流回路１４は、電流値Ｉ１を出力する単一の
電流源を備えており、充電制御回路２４から出力される
定電流制御信号Ｓｇ３によって制御される。Further, in the charging circuit in FIG. 4, the constant current circuit 20 may be a constant current circuit which outputs only the current value I1. FIG. 6 is a diagram showing a charging circuit in that case. The constant current circuit 14 includes a single current source that outputs a current value I1 and is controlled by the constant current control signal Sg3 output from the charge control circuit 24.
【００４９】二次電池１４の電圧が、所定の電圧Ｖ１よ
り小さい場合は、充電制御回路２４によって、定電流制
御信号Ｓｇ３が入力されて定電流回路２０が起動し、二
次電池は、電流値Ｉ１の電流のみで充電される。充電制
御回路２４は、電池電圧検出回路１６からの電池電圧信
号Ｓｇ２によって、二次電池１４の電圧が所定の電圧Ｖ
１に到達したことを検知すると、定電流回路２０に定電
流制御信号Ｓｇ３を送り、定電流回路２０の動作を停止
させる。さらに、充電制御回路２４は、充電制御信号Ｓ
ｇ５を出力し、定電圧回路１８と充電電流制御回路５０
とを起動させる。充電電流制御回路５０と定電圧回路１
８の動作は、図４の説明と同じである。When the voltage of the secondary battery 14 is smaller than the predetermined voltage V1, the constant current control signal Sg3 is input by the charging control circuit 24 to activate the constant current circuit 20, and the secondary battery has a current value of It is charged only with the current of I1. In response to the battery voltage signal Sg2 from the battery voltage detection circuit 16, the charging control circuit 24 determines that the voltage of the secondary battery 14 is the predetermined voltage V.
When it is detected that the current reaches 1, the constant current control signal Sg3 is sent to the constant current circuit 20 to stop the operation of the constant current circuit 20. Further, the charge control circuit 24 is configured to charge the charge control signal S
g5 is output and the constant voltage circuit 18 and the charging current control circuit 50 are output.
And start. Charging current control circuit 50 and constant voltage circuit 1
The operation of 8 is the same as the description of FIG.
【００５０】図６の充電回路において、ゲート電圧検出
回路２２の基準電圧Ｅ５は、図１および図４の充電回路
における基準電圧Ｅ２と異なる。この基準電圧Ｅ５は、
ＡＣアダプタ１０の電圧から基準電圧Ｅ５だけ低下した
電圧が、ｐＭＯＳトランジスタＭ１のドレイン電流が電
流値Ｉ２に等しくなるようにｐＭＯＳトランジスタのゲ
ート端子に印加される電圧と同一である。これにより、
充電が定電流充電から定電圧充電に移行し、ｐＭＯＳト
ランジスタＭ１のゲート電圧が上昇して、ＡＣアダプタ
１０の電圧から基準電圧Ｅ５だけ低下した電圧に到達す
ると、ゲート電圧検出回路２２から充電制御回路２４に
充電完了信号Ｓｇ６が出力される。充電制御回路２４
は、充電完了信号Ｓｇ６が入力されると、定電圧回路１
８と充電電流制御回路５０に充電制御信号Ｓｇ５を出力
し、それらの動作を停止させる。In the charging circuit of FIG. 6, the reference voltage E5 of the gate voltage detecting circuit 22 is different from the reference voltage E2 of the charging circuits of FIGS. This reference voltage E5 is
The voltage obtained by decreasing the voltage of the AC adapter 10 by the reference voltage E5 is the same as the voltage applied to the gate terminal of the pMOS transistor so that the drain current of the pMOS transistor M1 becomes equal to the current value I2. This allows
When the charging shifts from the constant current charging to the constant voltage charging and the gate voltage of the pMOS transistor M1 rises to reach a voltage lower than the voltage of the AC adapter 10 by the reference voltage E5, the gate voltage detection circuit 22 changes the charging control circuit. The charging completion signal Sg6 is output to 24. Charge control circuit 24
When the charging completion signal Sg6 is input, the constant voltage circuit 1
8 and the charging current control circuit 50 to output the charging control signal Sg5 to stop their operation.
【００５１】図６に示されるような充電回路において、
定電流回路２０は、単一の電流源を備えていればよいの
で、回路規模が小さくなり、その結果、製造コストが低
減される。In a charging circuit as shown in FIG. 6,
Since the constant current circuit 20 only needs to have a single current source, the circuit scale is reduced, and as a result, the manufacturing cost is reduced.
【００５２】[0052]
【発明の効果】本発明による二次電池の充電回路によれ
ば、定電圧回路から出力される充電電流を、抵抗を用い
ずに検出して充電を完了するため、抵抗による発熱や電
力損失がなく、高精度に二次電池の満充電状態を検出す
ることができるようになった。According to the charging circuit for a secondary battery of the present invention, the charging current output from the constant voltage circuit is detected without using a resistor to complete charging, so that heat generation and power loss due to the resistor occur. Instead, the full charge state of the secondary battery can be detected with high accuracy.
【００５３】また、本発明による二次電池の充電回路に
よれば、二次電池の電圧が所定の電圧より小さい場合
は、そのような場合に適した大きさの電流で充電を行う
ことができるので、過放電状態にある二次電池も充電で
きるようになった。また、それが、回路規模の増大を抑
えて実現できるので、製造コストの低減を図ることがで
きた。Further, according to the secondary battery charging circuit of the present invention, when the voltage of the secondary battery is lower than the predetermined voltage, charging can be performed with a current of a magnitude suitable for such a case. Therefore, the secondary battery in the over-discharged state can be charged. Further, since it can be realized while suppressing an increase in circuit scale, the manufacturing cost can be reduced.
【図１】 本発明の第１の実施の形態による充電回路を
示す図。FIG. 1 is a diagram showing a charging circuit according to a first embodiment of the present invention.
【図２】 （１）は、図１の回路における充電時間の経
過による二次電池の電圧の変化を示す図、（２）は、図
１の回路における充電時間の経過による充電電流の変化
を示す図、（３）は、図１の回路における充電時間の経
過によるｐＭＯＳトランジスタのゲート電圧の変化を示
す図。2 (1) is a diagram showing changes in the voltage of the secondary battery with the passage of charging time in the circuit of FIG. 1, and (2) shows changes in the charging current with passage of charging time in the circuit of FIG. FIG. 3C is a diagram showing changes in the gate voltage of the pMOS transistor with the passage of charging time in the circuit of FIG. 1.
【図３】 代替のバイポーラトランジスタを示す図。FIG. 3 shows an alternative bipolar transistor.
【図４】 本発明の第２の実施の形態による充電回路を
示す図。FIG. 4 is a diagram showing a charging circuit according to a second embodiment of the present invention.
【図５】 （１）は、図４の回路における充電時間の経
過による二次電池の電圧の変化を示す図、（２）は、図
４の回路における充電時間の経過による充電電流の変化
を示す図、（３）は、図４の回路における充電時間の経
過によるｐＭＯＳトランジスタのゲート電圧の変化を示
す図。5 (1) is a diagram showing changes in the voltage of the secondary battery with the passage of charging time in the circuit of FIG. 4, and (2) shows changes in the charging current with passage of charging time in the circuit of FIG. FIG. 6C is a diagram showing changes in the gate voltage of the pMOS transistor with the passage of charging time in the circuit of FIG.
【図６】 本発明の第２の実施の形態によるもう１つの
充電回路を示す図。FIG. 6 is a diagram showing another charging circuit according to the second embodiment of the present invention.
【図７】 従来の充電回路を示す図。FIG. 7 is a diagram showing a conventional charging circuit.
１０ ＡＣアダプタ １２ アダプタ検出回路 １４ 二次電圧 １６ 電池電圧検出回路 １８ 定電圧回路 ２０ 定電流回路 ２２ ゲート電圧検出回路 ２４ 充電制御回路 ４０、４２、４４、４６、４８ 定電圧発生回路 ５０ 充電電流制御回路 10 AC adapter 12 Adapter detection circuit 14 Secondary voltage 16 Battery voltage detection circuit 18 constant voltage circuit 20 constant current circuit 22 Gate voltage detection circuit 24 Charge control circuit 40, 42, 44, 46, 48 constant voltage generating circuit 50 Charge current control circuit
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 5G003 AA01 BA01 CA03 CA04 CA12 CC02 GA01 5H030 AA01 AA03 AS14 AS18 BB01 DD06 FF42 FF43 ─────────────────────────────────────────────────── ─── Continued front page F-term (reference) 5G003 AA01 BA01 CA03 CA04 CA12 CC02 GA01 5H030 AA01 AA03 AS14 AS18 BB01 DD06 FF42 FF43
Claims (18)
て、 所定の直流電源と前記二次電池との間に直列に接続さ
れ、入力された制御信号に応じて、あらかじめ設定され
た２つの定電流のうち一方を、前記二次電池に出力する
定電流回路部と、 前記定電流回路部に並列に接続され、前記二次電池に所
定の定電圧を印加して充電を行う定電圧回路部と、 前記二次電池の電圧を検出して出力する電池電圧検出回
路部と、 前記定電圧回路部からの電流出力が停止すると所定の充
電完了信号を出力する充電電流検出回路部と、 前記充電完了信号が入力されると、前記定電流回路部お
よび前記定電圧回路部の動作を停止させる充電制御回路
部とを備え、 前記充電制御回路部は、定電流回路部に対して、前記二
次電池の電圧が所定電圧未満の場合は、所定の第１の定
電流を出力させる制御信号を出力し、前記二次電池の電
圧が所定電圧以上の場合は、前記第１の定電流よりも大
きい所定の第２の定電流を出力させる制御信号を出力す
ることを特徴とする充電回路。1. A charging circuit for charging a secondary battery, comprising two preset constant circuits which are connected in series between a predetermined DC power source and the secondary battery and which are preset in accordance with an input control signal. A constant current circuit unit that outputs one of the currents to the secondary battery, and a constant voltage circuit unit that is connected in parallel to the constant current circuit unit and applies a predetermined constant voltage to the secondary battery to perform charging. A battery voltage detection circuit unit that detects and outputs the voltage of the secondary battery; a charging current detection circuit unit that outputs a predetermined charging completion signal when the current output from the constant voltage circuit unit is stopped; When a completion signal is input, a charging control circuit unit that stops the operation of the constant current circuit unit and the constant voltage circuit unit, the charging control circuit unit, the constant current circuit unit, to the secondary If the battery voltage is less than the specified voltage, the specified A control signal for outputting a first constant current, and when the voltage of the secondary battery is equal to or higher than a predetermined voltage, a control signal for outputting a predetermined second constant current larger than the first constant current. A charging circuit characterized by outputting.
する直流電源を備えることを特徴とする請求項１に記載
の充電回路。2. The charging circuit according to claim 1, further comprising a DC power supply that supplies a charging current to the secondary battery.
る電流の制御を行う充電電流制御回路部を備え、 前記充電電流制御回路部は、定電圧回路部に対して、定
電圧回路部の出力電流の最大値が所定値になるように動
作制御を行い、 前記充電制御回路部は、前記充電完了信号が入力される
と、さらに、前記充電電流制御回路部の動作を停止させ
ることを特徴とする請求項１または請求項２に記載の充
電回路。3. A charging current control circuit unit for controlling a current output from the constant voltage circuit unit, wherein the charging current control circuit unit is provided with respect to the constant voltage circuit unit with respect to the constant voltage circuit unit. The operation control is performed such that the maximum value of the output current becomes a predetermined value, and the charging control circuit unit further stops the operation of the charging current control circuit unit when the charging completion signal is input. The charging circuit according to claim 1 or 2.
結果を示す信号を出力する電圧比較器と、 前記比較結果を示す信号に応じた電流を、所定の直流電
源から前記二次電池に出力する制御トランジスタとを備
えることを特徴とする請求項１から請求項３のいずれか
に記載の充電回路。4. The constant voltage circuit unit compares a voltage of the secondary battery and the constant voltage with a constant voltage generating circuit that generates and outputs a predetermined constant voltage, and outputs a signal indicating the comparison result. 4. A voltage comparator for outputting, and a control transistor for outputting a current corresponding to the signal indicating the comparison result to the secondary battery from a predetermined DC power source, any one of claims 1 to 3. Charging circuit described in.
比較器へ流れる電流を阻止するダイオードを備えること
を特徴とする請求項４に記載の充電回路。5. The charging circuit according to claim 4, wherein the constant voltage circuit unit further includes a diode that blocks a current flowing to the voltage comparator.
回路と、 前記制御トランジスタの制御端子に印加される電圧と前
記第２定電圧とを比較し、その比較結果を示す信号を出
力する第２の電圧比較器と、 前記制御端子から前記第２の電圧比較器に流れる電流を
阻止する第２のダイオードとを備えることを特徴とする
請求項５に記載の充電回路。6. The charging current control circuit unit includes a second constant voltage generating circuit that generates and outputs a predetermined second constant voltage, a voltage applied to a control terminal of the control transistor, and the second constant voltage. A second voltage comparator that compares the voltage and outputs a signal indicating the comparison result; and a second diode that blocks a current flowing from the control terminal to the second voltage comparator. The charging circuit according to claim 5.
較器から出力される信号を検出し、その検出した信号か
ら前記定電圧回路部の出力電流が停止したことを検知す
る請求項４から請求項６のいずれかに記載の充電回路。7. The charging current detection circuit unit detects a signal output from the voltage comparator, and detects from the detected signal that the output current of the constant voltage circuit unit has stopped. The charging circuit according to claim 6.
回路と、 前記制御トランジスタの制御端子に印加される電圧と前
記第３定電圧とを比較し、その制御端子に印加される電
圧と前記第３定電圧が等しい場合に、充電完了信号を出
力する第３の電圧比較器とを備え、 前記第３定電圧は、前記制御トランジスタがカットオフ
するように前記制御端子に印加される電圧であることを
特徴とする請求項７に記載の充電回路。8. The charging current detection circuit unit includes a third constant voltage generating circuit for generating and outputting a predetermined third constant voltage, a voltage applied to a control terminal of the control transistor, and the third constant voltage. A third voltage comparator that compares the voltage and outputs a charging completion signal when the voltage applied to its control terminal is equal to the third constant voltage, wherein the third constant voltage is the control signal. The charging circuit according to claim 7, wherein the voltage is a voltage applied to the control terminal so that the transistor is cut off.
て、 所定の直流電源と前記二次電池との間に直列に接続さ
れ、前記二次電池に所定の定電圧を印加して充電を行う
定電圧回路部と、 前記二次電池の電圧を検出して出力する電池電圧検出回
路部と、 前記定電圧回路部からの出力電流が所定値になると、所
定の充電完了信号を出力する充電電流検出回路部と、 前記充電完了信号が入力されると、前記定電圧回路部の
動作を停止させる充電制御回路部とを備え、 前記定電圧回路部は、 所定の定電圧を生成して出力する定電圧発生回路と、 前記二次電池の電圧とその定電圧とを比較し、その比較
結果を示す信号を出力する電圧比較器と、 前記比較結果を示す信号に応じた電流を、所定の直流電
源から前記二次電池に出力する制御トランジスタとを備
え、 前記充電電流検出回路部は、 前記電圧比較器から出力される信号を検出し、その検出
した信号から前記制御トランジスタの出力電流が所定値
であることを検知して、充電完了信号を出力することを
特徴とする充電回路。9. A charging circuit for charging a secondary battery, which is connected in series between a predetermined DC power source and the secondary battery, and applies a predetermined constant voltage to the secondary battery for charging. A constant voltage circuit section, a battery voltage detection circuit section that detects and outputs the voltage of the secondary battery, and a charging current that outputs a predetermined charging completion signal when the output current from the constant voltage circuit section reaches a predetermined value. A detection circuit unit and a charge control circuit unit that stops the operation of the constant voltage circuit unit when the charging completion signal is input, and the constant voltage circuit unit generates and outputs a predetermined constant voltage. A constant voltage generating circuit, a voltage comparator that compares the voltage of the secondary battery and its constant voltage, and outputs a signal indicating the comparison result, and a current corresponding to the signal indicating the comparison result at a predetermined DC Control transistor that outputs from the power supply to the secondary battery The charging current detection circuit unit detects a signal output from the voltage comparator, detects from the detected signal that the output current of the control transistor is a predetermined value, and outputs a charging completion signal. A charging circuit characterized by outputting.
給する直流電源を備えることを特徴とする請求項９に記
載の充電回路。10. The charging circuit according to claim 9, further comprising a DC power supply that supplies a charging current to the secondary battery.
回路と、 制御トランジスタの制御端子に印加される電圧と前記第
２定電圧とを比較し、その制御端子に印加される電圧と
前記第２定電圧が等しい場合に、充電完了信号を出力す
る第２の電圧比較器とを備え、 前記第２定電圧は、前記制御トランジスタの出力電流が
所定値であるように前記制御端子に印加される電圧であ
ることを特徴とする請求項９または請求項１０に記載の
充電回路。11. The charging current detection circuit unit includes: a second constant voltage generating circuit that generates and outputs a predetermined second constant voltage; a voltage applied to a control terminal of a control transistor; and the second constant voltage. And a second voltage comparator that outputs a charging completion signal when the voltage applied to its control terminal is equal to the second constant voltage, wherein the second constant voltage is the control transistor. The charging circuit according to claim 9 or 10, wherein the output current is a voltage applied to the control terminal so that the output current has a predetermined value.
圧比較器へ流れる電流を阻止するダイオードを備えるこ
とを特徴とする請求項９から請求項１１のいずれかに記
載の充電回路。12. The charging circuit according to claim 9, wherein the constant voltage circuit unit further includes a diode that blocks a current flowing to the voltage comparator.
れる電流の制御を行う充電電流制御回路部を備え、 前記充電電流制御回路部は、定電圧回路部に対して、定
電圧回路部の出力電流の最大値が所定値になるように動
作制御を行い、 前記充電制御回路部は、前記充電完了信号が入力される
と、さらに、前記充電電流制御回路部の動作を停止させ
ることを特徴とする請求項１２に記載の充電回路。13. A charging current control circuit unit for controlling a current output from the constant voltage circuit unit, wherein the charging current control circuit unit is provided with respect to the constant voltage circuit unit with respect to the constant voltage circuit unit. The operation control is performed such that the maximum value of the output current becomes a predetermined value, and the charging control circuit unit further stops the operation of the charging current control circuit unit when the charging completion signal is input. The charging circuit according to claim 12.
回路と、 制御トランジスタの制御端子に印加される電圧と前記第
３定電圧とを比較し、その比較結果を示す信号を出力す
る第３の電圧比較器と、 前記制御端子から前記第３の電圧比較器に流れる電流を
阻止する第２のダイオードとを備えることを特徴とする
請求項１３に記載の充電回路。14. The charging current control circuit unit includes: a third constant voltage generating circuit that generates and outputs a predetermined third constant voltage; a voltage applied to a control terminal of a control transistor; and the third constant voltage. And a second diode that blocks a current flowing from the control terminal to the third voltage comparator, and a third voltage comparator that outputs a signal indicating the comparison result. The charging circuit according to claim 13.
続され、あらかじめ設定された定電流を、前記二次電池
に出力する定電流回路部を備え、 前記充電制御回路部は、前記定電流回路部に対して、前
記二次電池の電圧が所定電圧未満の場合は、前記定電流
回路部を駆動させ、前記二次電池の電圧が所定電圧以上
の場合は、前記定電流回路部を停止させることを特徴と
する請求項９から請求項１４のいずれかに記載の充電回
路。15. A constant current circuit unit, which is connected in parallel to the constant voltage circuit unit and outputs a preset constant current to the secondary battery, wherein the charging control circuit unit includes the constant current circuit. When the voltage of the secondary battery is less than a predetermined voltage with respect to the circuit unit, the constant current circuit unit is driven, and when the voltage of the secondary battery is a predetermined voltage or more, the constant current circuit unit is stopped. The charging circuit according to any one of claims 9 to 14, wherein the charging circuit is configured to:
次電池から前記制御トランジスタを介して前記直流電源
へ流れる電流を阻止する第３のダイオードを備えること
を特徴とする請求項１から請求項１５のいずれかに記載
の充電回路。16. The constant voltage circuit unit further includes a third diode that blocks a current flowing from the secondary battery to the DC power supply through the control transistor. Item 16. The charging circuit according to any one of Item 15.
型金属酸化膜半導体電界効果トランジスタであることを
特徴とする請求項４から請求項１６のいずれかに記載の
充電回路。17. The charging circuit according to claim 4, wherein the control transistor is a p-channel type metal oxide semiconductor field effect transistor.
ポーラトランジスタであることを特徴とする請求項４か
ら請求項１６のいずれかに記載の充電回路。18. The charging circuit according to claim 4, wherein the control transistor is a PNP bipolar transistor.
Priority Applications (11)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001287039A JP4502554B2 (en) | 2001-09-20 | 2001-09-20 | Secondary battery charging circuit |
| KR1020037014514A KR100572160B1 (en) | 2001-09-14 | 2002-09-12 | Secondary battery charging circuit |
| US10/467,682 US7012405B2 (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| CNB028094433A CN100350713C (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| KR1020057022622A KR100611583B1 (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| CN2007101547773A CN101123365B (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| EP02770193A EP1425837B1 (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| PCT/JP2002/009362 WO2003026095A1 (en) | 2001-09-14 | 2002-09-12 | Charging circuit for secondary battery |
| US11/259,186 US7205748B2 (en) | 2001-09-14 | 2005-10-26 | Charging circuit for secondary battery |
| US11/295,450 US7274171B2 (en) | 2001-09-14 | 2005-12-07 | Charging circuit for secondary battery |
| US11/755,226 US20070222420A1 (en) | 2001-09-14 | 2007-05-30 | Charging circuit for secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001287039A JP4502554B2 (en) | 2001-09-20 | 2001-09-20 | Secondary battery charging circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2003092843A true JP2003092843A (en) | 2003-03-28 |
| JP4502554B2 JP4502554B2 (en) | 2010-07-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001287039A Expired - Fee Related JP4502554B2 (en) | 2001-09-14 | 2001-09-20 | Secondary battery charging circuit |
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| JP (1) | JP4502554B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7554298B2 (en) | 2004-09-28 | 2009-06-30 | Nec Electronics Corporation | Charger and integrated circuit having first and second charging currents |
| CN110365076A (en) * | 2019-07-10 | 2019-10-22 | 东莞启益电器机械有限公司 | Can intelligent measurement charger maximum output charging current charging circuit |
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| CN110365076A (en) * | 2019-07-10 | 2019-10-22 | 东莞启益电器机械有限公司 | Can intelligent measurement charger maximum output charging current charging circuit |
| CN110365076B (en) * | 2019-07-10 | 2024-04-16 | 东莞启益电器机械有限公司 | Charging circuit capable of intelligently detecting maximum output charging current of charger |
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| Publication number | Publication date |
|---|---|
| JP4502554B2 (en) | 2010-07-14 |
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