Ambient Light Sensors Control LCD Displays and Save Power

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A broad portfolio of ambient light sensors allow electronic products like LCD displays and street lights to respond to light in ways similar to the human eye through screen intensity adjustment and on/off control.

The portfolio is based on photo transistor technology which eliminates the need for an external amplifier and simplifies design with a two-pin connection. The portfolio includes surface mount and leaded packages to meet the demands of every application.

Design implementation is supported by a unique development kit that includes Windows®-based software that allows gain and sampling rate control. It displays illumination in Lux, µA, voltage, decimal and hexidecimal.

 

 

Features Spectral response similar to human eye Phototransistor output No amplifier needed Peak wavelength sensitivity of 570nm

Applications Automatic adjustment of LCD displays Backlight control in mobile devices Street and security lighting Safe alternative to CdS photo resistors

 

 

Providing a simple two-pin connection, these sensors will be used to reduce power consumption in consumer electronics applications by controlling keypad backlights and to adjust the brightness of LCDs. In automotive applications, the sensors will enable automatic headlight control, tunnel sensors, and displays that adjust automatically to changes in ambient brightness. As phototransistors, these sensors eliminate the need for an external amplifier.

The three devices give designers a choice of surface mount 0805 (TEMT6200F) or leaded 5mm flat-top (TEPT5700) or 3mm (TEPT4400) packages. The angle of half intensity is ±60° for the TEMT6200F, ±50° for the TEPT5700 and ±30° for the TEPT4400. The TEMT6200F peak wavelength sensitivity is 550nm, while the TEPT5700 and TEPT4400 are 570nm, green-yellow on the visible spectrum. These devices join the the TEMT6000 in the surface mount 1206 package and TEPT5600 in narrow angle 5mm package to give designers an ambient light sensor portfolio that meets the needs of every application.

In addition to improving display visibility and reducing power consumption, these devices are an environmentally friendly alternative to cadmium-based photo resistors, the elimination of which has been mandated by Restriction of Hazardous Substances (RoHS) legislation. All devices are lead (Pb)-free and in accordance with RoHS 2002/95/EC and WEEE 2002/96/EC.

 

Sensor	Package	Angle of Half Sensitivity	Peak Sensitivity Wavelength (nm)
TEMT6000	SMD 1206	±60°	570
TEMT6200F	SMD 0805	±60°	550
TEPT4400	3mm	±30º	570
TEPT5600	5mm	±20°	570
TEPT5700	5mm Flat Top	±50°	570

 

 

Vishay's Ambient Light Sensor Development Kit Simplifies Design Effort for Next-Generation Lighting Applications

New Kit Integrates I²C and RS-232 Interface with Windows®-Based Software

 

 

In a move to reduce time to market for designers using its ambient light sensors, Vishay has developed a new light sensing development kit that allows development engineers to measure and display ambient illumination, tune the sensor, define their software program responses, and complete a hardware layout. The development kit supports Vishay's recently introduced ambient light sensor portfolio.

For hardware, the built-to-order development kit includes an adapter board and sensor board. The sensor board includes the ambient light sensor chosen to be evaluated by the customer, an analog-to-digital converter, and I²C interface. The adapter board converts the I²C output from the sensor board to the RS-232 interface for direct PC connection. With the direct PC connection, development engineers can use the sensor and adapter board combination to quickly define system responses to various lighting conditions. To reduce prototype development time and cost, engineers can integrate the sensor board, connecting the I²C interface directly to their product's controller.

For software, the development kit includes Microsoft® Windows®-based software that displays the ambient illumination in a variety of formats including lux, microamps, voltage, decimal and hexadecimal. In addition, a bar graph displays the ambient light in lux. The software is used to tune the sensor by programming the sampling rate and gain. There are two data sampling modes: continuous sampling at user defined intervals and single or trigger mode where a single data reading is taken.

Vishay's ambient light sensors help reduce power consumption in consumer electronics applications by controlling keypad backlights and adjusting the brightness of LCDs. In addition to improving display visibility and reducing power consumption, the sensors are an environmentally friendly alternative to cadmium-based photo resistors, the elimination of which has been mandated by Restriction of Hazardous Substances (RoHS) legislation.

Build-to-order kits are available. Lead-time is approximately 4 weeks.

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
TEMT6000		Ambient Light Sensor in 1206 Chip Package
TEMT6000DEVKIT		Development Kit for TEMT6000
TEMT6200F		Ambient Light Sensor in 0805 Chip Package
TEMT6200FDEVKIT		Development Kit for TEMT6200F
TEPT4400		3mm Ambient Light Sensor
TEPT4400DEVKIT		Development Kit for TEPT4400
TEPT5600		5mm Ambient Light Sensor
TEPT5600DEVKIT		Development Kit for TEPT5600
TEPT5700		5mm Flat Top Ambient Light Sensor
TEPT5700DEVKIT		Development Kit for TEPT5700

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