高效率太陽(yáng)能電池充電器的設(shè)計(jì)

　　工程師們?cè)谠O(shè)計(jì)太陽(yáng)能電池充電器時(shí)有很多選擇。除了基本的電路設(shè)計(jì)技術(shù)外，越來(lái)越多的集成設(shè)備提供了專門為建造高效率、太陽(yáng)能電池充電器系統(tǒng)而設(shè)計(jì)的解決方案。設(shè)計(jì)師可以找到合適的芯片和相關(guān)評(píng)估套件從線性技術(shù)、國(guó)家半導(dǎo)體、NXP、意法半導(dǎo)體、德克薩斯文書。

　　面板滲漏

　　由于其大的連接區(qū)域，太陽(yáng)能電池板具有泄漏設(shè)備的特點(diǎn)。如果沒有適當(dāng)?shù)念A(yù)防措施，面板泄漏會(huì)導(dǎo)致電池在低照度或無(wú)照明期間顯著放電。傳統(tǒng)上，太陽(yáng)能電池板的設(shè)計(jì)考慮到面板泄漏，其中包括二極管與面板串聯(lián)，這種方法通過漏電大大降低了電池的放電量，但由于二極管正向壓降中的能量損失，導(dǎo)致整體效率較低。集成電路等技術(shù)對(duì)傳統(tǒng)的線性ltc4412系列二極管提供了一個(gè)簡(jiǎn)單的選擇。這些集成電路被設(shè)計(jì)用來(lái)控制一個(gè)外部P溝道MOSFET，提供近乎理想的二極管功能。

　　Beyond reducing battery discharge through panel leakage， engineers need to design their solar chargers with battery protection capabilities to ensure both battery life and safety. ICs such as Linear‘s LTC4071 provide basic overcharging protection by shunting current away from the battery as battery voltage reaches the float voltage. Along with a current-limiting resistor for higher current solar panels， designers can build a basic solar power battery charger using only the LTC4071， an additional shunt resistor， capacitor， and leakage-protection diode （Figure 1）。 Along with its overcharge protection， the LTC4071 protects the battery from over discharge by disconnecting the load from the battery when the battery discharges to the point where VCC falls below the low battery disconnect voltage （VLBD）。