13.56 MHz 互補式金氧半導體無線充電器之設計

Abstract

近年來，各式穿戴型消費性電子產品發達，已成為日常生活不可或缺的一部分。電池能量密度始終有進步空間，很多使用者需要為他們裝置一天充電不只一次，這讓人十分困擾。而且有線的電源傳輸接口，對產品防水防塵的設計是另外一個挑戰。隨著無線充電技術的普及還有通用規格的確立，有些產品已經採用無線充電來解決這類問題。傳統架構會在AC-DC整流器之後掛載一個線性穩壓器，來將直流輸出降到系統所需電壓大小。不過這樣的方式在目標電壓比較低時效率不佳。 本論文提出一種具有電池充電的電磁共振式的倍壓整流系統，共振在13.56 MHz的操作頻率，目標輸出電壓區間為1.2-3.3V，並同時透過局部整流及全域整流兩種方式。局部整流是一個脈衝省略模式系統，在接收端穩壓輸出的電壓。全域整流在目標電壓較低的時候，依然能比傳統系統有更高的效率。此外整合了電池充電階段的涓流充電及定電壓充電到局部整流系統中，並簡化了電池充電器，使它更有效率及減少外部元件的使用。本論文的晶片使用台積電 0.18 製程製造，晶片面積約佔0.62 mm2。量測在輸出電壓為3V時候，整個系統傳輸效率為53.4%。

In recent years, wearable electronic devices have been part of our daily life. The energy density still has more room to improve. Many users were upset because they should recharged their devices one or two times in a single day. Besides, the I/O hub of power hub makes difficult to waterproof and dustproof design. With wireless power transfer (WPT) technology innovation and the universal standard have been established, some consumer products already have adopted WPT. Traditional architecture would add a low dropout linear regulator (LDO) behind the AC-DC regulator, and the efficiency is poor when the target voltage is low. This thesis proposed a resonant regulating doubler with battery charger WPT system which resonant frequency is 13.56 MHz. The proposed system has two regulation methods, global regulation and local regulation, which provide wide output voltage 1.2 – 3.3V without LDOs. Local regulation is pulse-skip modulation, regulating the output voltage in receiver Rx. Global regulation improves the power efficiency at low voltage. To simplify the battery charger, trickle current mode and constant voltage mode are combined into regulating doubler, reducing power loss and cost of external components. This chip is fabricated in TSMC 0.18 μm technology with 0.62 mm2 chip sizes. The measurement results show a total 53.4% peak efficiency at output voltage 3V.