Intersil公司的ISL29010是集成了I2C接口的数字输出的光传感器,它集成了两个光电二极管阵列,能把光转换成电流,有些二极管对可见光和红外光敏感,而有些二极管则仅对红外光敏感. ISL29010内部还集成了基于电荷平衡转换技术的15位ADC以及I2C接口,可广泛应用于移动设备如智能手机,PDA和GPS,计算设备如笔记本电脑和UMPC,消费类电子如LCD TV,数码相机的显示器和键盘背景光调光以及工业和医疗照明传感等.本文介绍了ISL29010的主要特性,方框图以及典型应用电路.
Light-to-Digital Output Sensor with High Sensitivity, Gain Selection, and I2C
Interface
The ISL29010 is an integrated light sensor with I2C interface. It has an internal signed15-bit integrating type ADC designed based on the charge-balancing conversion
technique. This ADC is capable of rejecting 50Hz and 60Hz flicker caused by artificial light sources. The lux range select feature allows the user to program the lux range for
optimized counts/lux.
The ISL29010 contains two photodiode arrays which convert light into current. Some diodes are sensitive to both visible and infrared light, while the others are only sensitive to
infrared light. Using the infrared portion of the light as baseline, the visible light can be extracted. After light is converted to current during the light data process, the current output is converted to digital by a single built-in integrating type signed 15-bit Analog-to-Digital Converter (ADC). An I2C command reads the visible light intensity in counts.
The converter is a charge-balancing integrating type signed 15-bit ADC. The chosen method for conversion is best for converting small current signals in the presence of an AC periodic noise. A 100ms integration time, for instance, highly rejects 50Hz and 60Hz power line noise simultaneously.
The built-in ADC offers user flexibility in integration time or conversion time. There are two timing modes: Internal Timing Mode and External Timing Mode. In Internal Timing Mode,
integration time is determined by an internal dual speed oscillator (fOSC), and the n-bit (n = 4, 8, 12, 16) counter inside the ADC. In External Timing Mode, integration time is determined by the time between two consecutive I2C External Timing Mode commands.
A good balancing act of integration time and resolution (depending on the application) is required for optimal results. The ADC has four I2C programmable range select to
dynamically accommodate various lighting conditions. For very dim conditions, the ADC can be configured at its lowest range. For very bright conditions, the ADC can be configured at its highest range. In normal operation, power consumption is typically 250μA.
Furthermore, a power-down mode can be controlled by software via the I2C interface, reducing power consumption to less than 1μA.
Designed to operate on supplies from 2.5V to 3.3V, the ISL29010 is specified for operation over the -40°C to +85°C ambient temperature range.
ISL29010主要特性:
Range select via I2C
-Range 1 = 0 lux to 2,000 lux
-Range 2 = 0 lux to 8,000 lux
-Range 3 = 0 lux to 32,000 lux
-Range 4 = 0 lux to 128,000 lux
Human eye response (540nm peak sensitivity)
Temperature compensated
Signed 15-bit resolution
Adjustable resolution: up to 20 counts per lux
1 bit I2C address selection
Simple output code, directly proportional to lux
IR + UV rejection
50Hz/60Hz rejection
2.5V to 3.3V supply
6 Ld ODFN (2.1mmx2mm)
Pb-free (RoHS compliant)
Operating temperature range: -40°C to +85°C
ISL29010应用:
Display and keypad backlight dimming for
-Mobile Devices: Smart phone, PDA, and GPS
-Computing devices: Notebook PC, UMPC web pod
-Consumer devices: LCD-TV, digital picture frame, and digital cameras
•Industrial and medical light sensing
图1. ISL29010方框图
图2. ISL29010典型应用电路 |
|
