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参数资料
| 型号： | SI1102EK |
| 厂商： | Silicon Laboratories Inc |
| 文件页数： | 7/16页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR SI1102 |
| 应用说明： | Si114x irLED Guide AppNote |
| 产品培训模块： | Si1102 & Si1120 |
| 标准包装： | 1 |
| 系列： | QuickSense™ |
| 传感器类型： | 近程，红外线 |
| 嵌入式： | 否 |
| 已供物品： | 板，电池 |
| 已用 IC / 零件： | Si1102 |
| 产品目录页面： | 626 (CN2011-ZH PDF) |
| 相关产品： | 336-1819-1-ND - SENSOR OPTICAL DETECTOR |
| 其它名称： | 336-1826 |
Si1102
3. Application Information
3.1. Theory of Operation
The Si1102 is an active optical reflectance proximity detector with a simple on/off digital output whose state is
based upon the comparison of reflected light against a set threshold. An LED sends light pulses whose reflections
reach a photodiode and are processed by the Si1102’s analog circuitry. If the reflected light is above the detection
threshold, the Si1102 asserts the active-low PRX output to indicate proximity. This output can be used as a control
signal to activate other devices or as an interrupt signal for microcontrollers. Note that when the proximity of an
object nears the pre-set threshold, it is normal for the PRX pin to alternate between the on and off states. The
microcontroller can take the time average of PRX (assigning 1 as “no detect” and 0 as “detect”) and then compare
the average to 0.5 to achieve a sharper in-proximity or out-of-proximity decision.
To achieve maximum performance, high optical isolation is required between two light ports, one for the transmit
LED and the other for the Si1102. The Si1102 light port should be infrared-transmissive, blocking visible light
wavelengths for best performance. This dual-port active reflection proximity detector has significant advantages
over single-port, motion-based infrared systems, which are good only for triggered events. Motion detection only
identifies proximate moving objects and is ambiguous about stationary objects. The Si1102 allows in- or out-of-
proximity detection, reliably determining if an object has left the proximity field or is still in the field even when not
moving.
An example of a proximity detection application is controlling the display and speaker of a cellular telephone. In this
type of application, the cell phone turns off the power-consuming display and disables the loudspeaker when the
device is next to the ear, then reenables the display (and, optionally, the loudspeaker) when the phone moves more
than a few inches away from the ear.
For small objects, the drop in reflectance is as much as the fourth power of the distance; this means that there is
less range ambiguity than with passive motion-based devices. For example, a sixteen-fold change in an object's
reflectance means only a fifty-percent drop in detection range.
The Si1102 proximity detector is designed to operate with a minimal number of external components. Figure 1
shows a circuit example using a single 3.3 V power supply. The potentiometer, R1, is used to set the proximity
detection threshold. The Si1102 periodically detects proximity at a rate that can be programmed by a single resistor
(R2). The part is powered down between measurements. The resulting average current, including that of the LED,
can be as low as a few microamperes, which is well below a typical lithium battery's self-discharge current of
10 μA, thus ensuring the battery's typical life of 10 years.
When enabled (SREN driven low by a microcontroller or R1 pull-down potentiometer exists), the Si1102 powers
up, then pulses the output of the LED driver. Light reflected from a proximate object is detected by the receiver,
and, if it exceeds a threshold set by the potentiometer at the SREN pin, the proximity status is latched to the active-
low PRX output pin. The output is updated once per cycle. The cycle time is controlled through the optional R2
resistor.
Although the thresholds are normally set using a potentiometer for R1 (or R2), it is possible to digitally control
various resistance values by using MCU GPIO pins to switch-in different value resistors (or parallel combinations of
resistors). To activate the chosen resistor(s), the GPIO pin is held low, creating a pull-down resistor. For the
unwanted resistors, those specific MCU pins are kept tri-stated, rendering those resistors floating.
Figure 2. Timing Diagram
Rev. 1.0
7
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PDF描述 |
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| SI1120EK | KIT EVAL FOR SI1120 |
| SIL05-1A85-76L3K | RELAY REED SPST 1A 5V |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SI1120_10 | 制造商:SILABS 制造商全称:SILABS 功能描述:PROXIMITY/AMBIENT LIGHT SENSOR WITH PWM OUTPUT |
| Si1120-A-GM | 功能描述:近程传感器 Proximity/Ambient Light Snsr w/PWM Out RoHS:否 制造商:Vishay Semiconductors 感应方式:Optical 感应距离:1 mm to 200 mm 电源电压:2.5 V to 3.6 V 安装风格:SMD/SMT 输出配置:Digital 最大工作温度:+ 85 C 最小工作温度:- 25 C 系列:VCNL3020 |
| SI1120-A-GMR | 功能描述:近程传感器 Proximity/Ambient Light Snsr w/PWM Out RoHS:否 制造商:Vishay Semiconductors 感应方式:Optical 感应距离:1 mm to 200 mm 电源电压:2.5 V to 3.6 V 安装风格:SMD/SMT 输出配置:Digital 最大工作温度:+ 85 C 最小工作温度:- 25 C 系列:VCNL3020 |
| SI1120EK | 功能描述:光学传感器开发工具 Si1120 Eval Kit RoHS:否 制造商:ams 工具用于评估: 接口类型: 最大工作温度: |
| SI1120-EK | 制造商:Silicon Laboratories Inc 功能描述: |
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