Ϊ310623 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種電池充電器，特別是關於一種線性 鋰電池充電器及其控制方法。 【先前技術】 典型的線性鋰電池充電器包含三個控制電路，分別是 定電流控制電路、定電壓控制電路及定溫控制電路。在應 ® 用上，當開始對電池充電時，電池充電器進入定電流模 式，定電流控制電路維持一穩定的充電電流對該電池充 電，直到該電池的電壓達到一預設值時，該電池充電器進 入定電壓模式，定電壓控制電路維持該電池的電壓，為了 維持該電池充電器的充電速度以及為防止因過熱而損 毀，定溫控制電路偵測該電池充電器運作時所產生的熱 能，使其不超過一定值。 φ Barcelo等人在美國專利第6,819,094號提出一種電 池充電器，在定電流模式時，其利用一第一電流迴路控制 一電流源提供一定電流對電池充電直至一預定值，在定電 壓模式時，其利用一第二電流迴路控制該電流源提供一可 變電流對電池充電，以維持該電池的電壓在該預定值，另 外一第三電流迴路提供一定功率電流以防止該電池充電 器過熱。然而，在定電流模式要轉為定電壓模式時，該第 一電流迴路與第二電流迴路會互相爭奪對該電流源的控 制權，因而產生明顯的非線性問題，再者，三個電流迴路 1310623 之間必須以二極體區隔，以防止電流逆流，故需耗費較大 的晶片面積及成本。 第一圖係MAXIM公司MAX1501晶片的電池充電器 100 ’其中電阻R1根據連接輸入接腳INp的電壓導通一電 流I經電晶體Ml對連接在輸出接腳BATT的電池充電，定 電流控制迴路包括放大器1〇2及1〇4，放大器102感測電 流I產生一信號給電阻R2，進而導通一電流is給放大器 1 04與參考電流Iref比較’以產生信號Si控制電晶體Ml， 定電壓控制迴路包括放大器108偵測該電池的電壓，以產 生信號Sv控制電晶體Ml，定溫控制迴路包括放大器110 及溫度感測器112，溫度感測器112感測電池充電器1〇〇 的溫度’放大益110則根據感測到的溫度與一參考溫度 TEMPREF比較，產生一信號St控制電晶體Ml，輸出驅動器 及邏輯電路106連接在信號S!、Sv及St與電晶體Ml閘極 之間’用來切換連接至電晶體Μ1的信號。然而，電池充 φ 電器在由定電流迴路轉為定電壓迴路時，其也同樣會 互相爭奪對電晶體Ml的控制權’以控制供應給該載負的 電流’因而產生明顯的非線性問題，非線性範圍約1 〇%， 而且也必須用二極體或電晶體將三個控制迴路區隔開 來，此外，放大器102的輸出端與外接輸出接腳setI連 接，容易造成不必要之漏電流。 第二圖係LTC公司的LTC4061晶片電池充電器2〇〇， 其中定電流控制迴路包括一放大器204控制電流源202所 供應的電流’定電壓控制迴路包括放大器206控制電流源 (¾ 1310623Ϊ310623 IX. Description of the Invention: [Technical Field] The present invention relates to a battery charger, and more particularly to a linear lithium battery charger and a control method therefor. [Prior Art] A typical linear lithium battery charger includes three control circuits, a constant current control circuit, a constant voltage control circuit, and a constant temperature control circuit. In the application, when the battery is started to be charged, the battery charger enters the constant current mode, and the constant current control circuit maintains a stable charging current to charge the battery until the voltage of the battery reaches a predetermined value. The charger enters the constant voltage mode, and the constant voltage control circuit maintains the voltage of the battery. In order to maintain the charging speed of the battery charger and to prevent damage due to overheating, the constant temperature control circuit detects the heat energy generated when the battery charger operates. So that it does not exceed a certain value. U.S. Patent No. 6,819,094, issued to U.S. Patent No. 6,819,094, the disclosure of which is incorporated herein by reference in its entire entire entire entire entire entire entire entire entire entire disclosure The second current loop is used to control the current source to provide a variable current to charge the battery to maintain the voltage of the battery at the predetermined value, and the third current loop provides a certain power current to prevent the battery charger from overheating. However, when the constant current mode is to be converted to the constant voltage mode, the first current loop and the second current loop compete for control of the current source, thereby causing significant nonlinear problems, and further, three current loops. The 1310623 must be separated by a diode to prevent current from flowing back, which requires a large wafer area and cost. The first picture is the battery charger 100' of the MAX1501 chip of MAXIM Company. The resistor R1 conducts a current I according to the voltage of the connection input pin INp. The battery connected to the output pin BATT is charged via the transistor M1. The constant current control circuit includes an amplifier. 1〇2 and 1〇4, the amplifier 102 senses the current I to generate a signal to the resistor R2, and then turns on a current is supplied to the amplifier 104 to compare with the reference current Iref to generate a signal Si to control the transistor M1, and the constant voltage control loop includes The amplifier 108 detects the voltage of the battery to generate a signal Sv to control the transistor M1. The constant temperature control circuit includes an amplifier 110 and a temperature sensor 112. The temperature sensor 112 senses the temperature of the battery charger 1 放大110 compares the sensed temperature with a reference temperature TEMPREF to generate a signal St to control the transistor M1, and the output driver and logic circuit 106 are connected between the signals S!, Sv and St and the gate of the transistor M1. Switch the signal connected to transistor Μ1. However, when the battery charging device is switched from a constant current circuit to a constant voltage circuit, it also competes for control of the transistor M1 to control the current supplied to the carrier, thus causing significant nonlinear problems. The nonlinear range is about 1 〇%, and the three control loops must also be separated by a diode or a transistor. In addition, the output of the amplifier 102 is connected to the external output pin setI, which easily causes unnecessary leakage current. . The second figure is LTC's LTC4061 wafer battery charger 2〇〇, where the constant current control loop includes an amplifier 204 to control the current supplied by the current source 202. The constant voltage control loop includes an amplifier 206 to control the current source (3⁄4 1310623).
皿所供應的電流，定溫㈣迴路包減大The current supplied by the dish, the constant temperature (four) circuit package reduction
RT控制電池充電器獅的溫度。在電池充電_中L 電壓控制迴路同樣會爭奪電_的 控制權’產生明顯的非線性問題，非線性範_ m，而 ^^路需要桃提供增益’故要耗費額外的 曰曰片面積及成本，其三個控制迴路之間也仍然 :此：’其放大器208的輸出蠕與外接輪出 相連接’谷易造成不必要的漏電流。 第三圖係電池充電器200供應給電池的電流斑充電電 池上電壓_係圖，—開始電池電麵〇，^也充電器· 供應-較低電流，肖HHM，對電池充電，當電池電壓到 達-定值時’、約3.0V,提高充電電㈣—較高的值，約 800mA，以加快充電速度，在電池電壓達到4·2ν時停止 充電並將電池的電壓維持在4· 2V。由第三圖可以很清I地 看出，當電池電壓約在4V到4. 2V時，發生非線=題。 因此，一種能縮小非線性範圍以及不需二極體或電晶 體區隔各控制迴路的電池充電器，乃為所冀。 【發明内容】 本發明的目的之一，在於提出一種雷、％_ 裡屬池充電器及其控 制方法，其可以縮小非線性的範圍。 本發明的目的之一，在於提出一種電池充電器及其控 制方法，其不需要二極體或電晶體區隔各控制迴路。八二 根據本發明，一種電池充電器及其控制方法包括一電RT controls the temperature of the battery charger lion. In the battery charging _ medium L voltage control loop will also compete for control of electricity _ to produce significant nonlinear problems, non-linear _ m, and ^ ^ road needs peach to provide gain 'so it takes extra slab area and Cost, the three control loops are still between: this: 'The output creep of its amplifier 208 is connected to the external wheel'. The third figure is the current charge of the battery charger 200 supplied to the battery. The voltage on the battery is charged _ system diagram, - start the battery power 〇, ^ also charger · supply - lower current, Xiao HHM, charge the battery, when the battery voltage When arriving at a constant value, about 3.0V, increase the charging power (4) - a higher value, about 800mA, to speed up the charging speed, stop charging when the battery voltage reaches 4·2ν and maintain the battery voltage at 4·2V. It can be seen from the third figure that when the battery voltage is about 4V to 4.2V, a non-linear problem occurs. Therefore, a battery charger that can narrow the nonlinear range and eliminate the need for diodes or transistors to separate the control loops is a problem. SUMMARY OF THE INVENTION One object of the present invention is to provide a lightning, %_ gen pool charger and a control method thereof, which can narrow the range of nonlinearity. One of the objects of the present invention is to provide a battery charger and a control method therefor that do not require a diode or a transistor to separate the control loops. According to the present invention, a battery charger and a control method therefor include an electric