鋰電池目前是最常見的可充式電池之一，具有重量輕、高能量密度等優點，因此廣泛應用於行動裝置、電動汽車與能源儲存等領域，然而，為了避免電池過充電與過放電的問題，必須精確地控制電池的電壓和電流。
本論文依照鋰電池的充電特性，將充電晶片分為涓滴電流模式（Trickle-current mode）、定電流模式（Constant-current mode）以及定電壓模式（Constant-voltage mode）。當鋰電池電壓低於3V時，充電器將啟動涓滴電流模式，以提前將電池充電，隨著電池電壓超過3V，充電器轉為定電流模式，以縮短充電時間，最終，當電池電壓接近飽和值4.2V時，充電器切換至定電壓模式，避免過充電的發生。
目前市面上的充電器大多支援快速充電，為了縮短充電時間，通常會延長定電流充電時間並提高充電電流，然而，長時間的高電流充電會導致電池內阻的增加，降低電池可用容量，進而縮短電池的使用壽命，此外，電池操作溫度不應長時間超過40度攝氏，否則可能導致損壞，因此，本論文專注於設計電池溫度保護功能電路，該方法是根據熱敏電阻的規格表，找出0度到40度的參考阻值，並使用參考電壓電路產生器實現0度和40度的參考電壓，當熱敏電阻檢測到電池溫度時，會回傳一個電壓，與0度和40度的參考電壓進行比較，如果溫度超出正常工作範圍，則比較器會輸出保護訊號，切斷功率電晶體的電流路徑，將電池充電電流降低至零，以確保充電過程的安全性。
本晶片採用TSMC 0.18 um 高壓製程實現充電器電路，晶片面積為1.5 × 2.17 mm²。在此設計中，模擬充電效率達94.4%，實測充電效率為66%，並且充電器的電池溫度保護功能正常運作。

Lithium batteries, known for their lightweight and high energy density, are widely used in mobile devices, electric vehicles, and energy storage. Accurate control of battery voltage and current is essential to prevent overcharge and overdischarge.
This paper, based on the charging characteristics of lithium batteries, categorizes the charging chip into Trickle-current mode, Constant-current mode, and Constant-voltage mode. When the lithium battery voltage is below 3V, the charger initiates Trickle-current mode to begin charging the battery in advance. As the battery voltage surpasses 3V, the charger switches to Constant-current mode to expedite the charging process. Finally, as the battery voltage approaches the saturation value of 4.2V, the charger transitions to Constant-voltage mode to prevent overcharging.
Currently, most chargers on the market support fast charging. Typically, to reduce charging time, they extend the constant current charging duration and elevate the charging current. However, prolonged high-current charging results in an increase in the internal resistance of the battery, meaning the available capacity of the battery is reduced, and the battery's service life is shortened.
On the other hand, the battery should not be operated at high temperatures (exceeding 40 degrees Celsius) for an extended period; otherwise, it may lead to damage. Therefore, this paper focuses on designing the circuit for the battery temperature protection function.
This chip utilizes the TSMC 0.18 high-voltage process to implement the charger circuit, with a chip area of 1.5 × 2.17 mm². Within this, the simulated charging efficiency is 94.4%, the measured charging efficiency is 66%, and the battery temperature protection function of the charger operates normally.

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