多功能传感器缩短设计时间

　　多功能传感器缩短设计时间

　　多功能传感器，结合近距离和环境光传感可能是智能手机设计师谁寻求节省更多的权力，减少房地产，并缩短其设计周期，以满足他们的时间到市场需求的答案。

　　这些高度集成的设备旨在节省能源，延长电池寿命，并在各种照明环境中提供优化的观看。这在智能手机应用中通常是必须具备的，并带有多媒体功能和触摸屏操作。

　　环境光传感器（ALS）通过检测环境光亮度来控制lcd屏幕的亮度。接近传感器检测当手机靠近用户的面部或耳朵以降低LCD屏幕的功耗以降低功耗。它还禁用液晶屏幕，以防止用户在电话交谈时不小心输入。

　　这些集成的设备也可以在许多其他消费电子应用中使用，并可能在平板电脑、GPS设备、数码相机以及工业型应用中找到家园。

　　Initially， these “2-in-1” multifunction devices only integrated the ambient light sensor and the proximity photodiode. The IR emitter （LED） was separate， which resulted in several challenges concerning the design of a shield， or barrier， to keep the emitter separate from the photodiode to prevent crosstalk， which impacts the performance of the proximity sensor.

　　Now， sensors such as Vishay Intertechnology‘s VCNL4000 series （Figure 1） fully integrated proximity and ambient light optical sensor contains all the circuitry （IR emitter， photo-pin-diode， ambient light detector， signal processing IC and 16-bit ADC） needed in one device to eliminate the need for light barriers and optical alignment of the IR emitter and photodiode. It’s also housed in a small package， measuring 3.95 x 3.95 x 0.75 mm， for further board space savings. The VCNL4000 series comes with an I²C communication interface， which further simplifies design. Vishay also offers the device in a rectangular package， designated as the VCNL4020.