一種簡單的室內(nèi)照明能源獲取方法

　　太陽能收集為連接傳感器、控制節(jié)點、物聯(lián)網(wǎng)設(shè)備和其他嵌入式應(yīng)用提供了實用的解決方案。然而，它可以很難從太陽能電池中提取足夠的能量，以適應(yīng)這些應(yīng)用的小形狀因素。

　　不像大能量收集應(yīng)用，這些設(shè)計通常會產(chǎn)生少量的能量收集電源。在開發(fā)系統(tǒng)能夠在什么通常微瓦水平運行的設(shè)計師面臨多重挑戰(zhàn)。然而，通過使用電源管理IC（PMIC）Cypress半導(dǎo)體，工程師可以快速實現(xiàn)能量收集電源能夠在超低功率運行。

　　Limited energy

　　By harvesting power from ambient energy sources， engineers can create designs that can run indefinitely with no additional power source. For the IoT， this approach is particularly attractive for small， wireless systems that have relied solely on battery power in the past. Using energy harvesting， developers can eliminate batteries entirely. For more power intensive designs， energy harvesting can substantially extend battery life， largely eliminating the need for periodic battery replacement.

　　In many designs， a typical solar energy harvesting system requires large solar cells or arrays to provide sufficient power. For tiny sensor systems， however， large solar cells are not suitable due to a desire for compact designs， or limited installation space at the target location.

　　The need for smaller solar cells further complicates energy harvesting for a typical indoor IoT design. Indoor light sources generate very small illumination levels， ranging from about 100 to 200 lux in a typical home， and from 250 to 500 lux in an office. Even well illuminated areas， such as drafting tables or workshops， offer light levels that are orders of magnitude below sunlight illumination levels.

　　Solar cell manufacturers have responded to the need for indoor solar cells with technologies such as amorphous silicon. Unlike crystalline silicon used in traditional solar cells， amorphous silicon possesses an irregular structure that absorbs more light than crystalline structures. Constructed from these specialized materials， solar cells such as those in the Panasonic Amorton family can generate power even at very low light levels （Figure 1）.