【正文】 er electronic equipment, and portable instrumentation. Appropriate float voltage, in normal use (to prevent overdischarge, overcharge, overcurrent), maintenancefree leadacid battery float life of up to 12 ~ 16 years float voltage deviation of 5% shorten the life of 1/2. Thus, the charge has a major impact on this type of battery life. Photovoltaic, battery does not need regular maintenance, the correct charge and reasonable protection, can effectively extend battery life. Charging and protection IC is the separation of the occupied area and the peripheral circuit plexity. Currently, the market has not yet real, charged with the protection function is integrated on a single chip. For this problem, design a set of battery charging and protection functions in one IC is very necessary. design and considerations The system mainly includes two parts: the battery charger module and the protection module. Of great significance for the battery as standby power use of the occasion, It can ensure that the external power supply to the batterypowered, but also in the battery overcharge, overcurrent and an external power supply is disconnected the battery is to put the state to provide protection, the charge and protection rolled into one to make the circuit to simplify and reduce valuable product waste of resources. Figure 1 is a specific application of this Ic in the photovoltaic power 內(nèi)蒙古工業(yè)大學畢業(yè)論文外文翻譯 generation system, but also the source of this design. Maintenancefree leadacid battery life is usually the cycle life and float life factors affecting the life of the battery charge rate, discharge rate, and float volta ge. Some manufacturers said that if the overcharge protection circuit, the charging rate can be achieved even more than 2C (C is the rated capacity of the battery), battery manufacturers remend charging rate of C/20 ~ C/3. Battery voltage and temperature, the temperature is increased by 1 176。 charge less than the ambient temperature of 0 176。 the M0, M1, M2, R0 is the offset portion of the circuit to provide bias to the poststage circuit, the resistance, Ro, determine the circuit39。 M15, DO, a reference voltage, the parator input with the inverting input is fixed (V+), partial pressure of the resistance R1, R2, R3, the input to the inverting input of the parator, when the normal working of the power supply voltage, the inverting terminal of the voltage detection is lost to the inverting terminal voltage of the parator is greater than V+. Comparator output is low, M14 cutoff, feedback circuit does not work。 R1 M14 is the feedback loop of the undervoltage signal。 at 45 176。 C means that the battery float voltage. Ordinary charger for the best working condition at 25 176。電路同時采用了低功耗設計。圖 7所示的整體仿真波形圖 是保護模塊隨著電池電壓的變化從通常工作模式轉(zhuǎn)換到過充電模式，然后回到通常工作模式，接著進入過放電模式，最后再回到通常工作模式。當欠壓發(fā)生時，分壓電阻 R1， R2， R3反應比較敏感，當電阻分壓后輸給反相端的電壓小于 V，比較器的輸出電壓為高，此信號將 M14開啟，使得 R 兩端的電壓變?yōu)?M兩端的飽和電壓，趨近于 0V，從而進一步拉低了 R1R2分壓后的輸出電壓，形成了欠壓的正反饋。 并且 保護電路的設計要簡單、實用，此處設計了一種 CMOS 工藝 下 的欠壓保護電路，此電路結構簡單，工藝實現(xiàn)容易，可用做高壓或功率集成電路等的電源保護電路 。當芯片的供電電壓在過放電檢測電壓之 下 (VddVdl)，則此時電池處于過放電狀態(tài)，如果這種狀態(tài)保持相應的過放電延時時間 tdl， 芯片將禁止電池放電，此時充電控制端 CO為高電平，而放電控制端 DO為低電平，芯片處于過放電模式。當芯片的供電電壓在正常工作范圍內(nèi)，且 VM管腳處的電壓在過電流 I檢測電壓之 下 ，則此時電池處于通常工作狀