World's first ambient light sensor LSIs compatible under any light source
BH1600FVC (Analog Output Type) / BH1710FVC (Digital Output Type)

ROHM recently completed development of two ambient light sensor LSI models. The BH1600FVC (analog output type) and BH1710FVC (digital output type) feature outstanding spectral sensitivity and are ideally suited for portable electronic devices such as mobile phones as well as LCD TVs. Sample shipments will begin in January 2007 at a unit price of 100 yen for the BH1600FVC and 250 yen for the BH1710FVC, with mass production slated for April 2007 at a monthly rate of one and two million units (BH1600FVC and BH1710FVC, respectively). ROHM APOLLO DEVICE CO., LTD. (in Fukuoka, Japan) will be in charge of the primary stage of production and ROHM FUKUOKA CO., LTD. the secondary stage.

It is possible to improve both the performance efficiency and visibility of LCDs (e.g., mobile phones, TVs, notebook PCs) by making brightness adjustments based on the ambient light. Precise control is needed in order to maximize the effects of these improvements. However, the brightness sensitivity range of conventional ambient light sensors differs greatly from that of the human eye. Furthermore, the measurement results of conventional ambient light sensors vary between different light sources, such as sunlight and artificial light. ROHM's BH1600FVC and BH1710FVC ambient light sensors, on the other hand, feature spectral sensitivity characteristics similar to the photopic luminous efficiency of the human eye, making it possible to measure a broad range of illumination intensities, from darkness to direct sunlight. In addition, the sensitivity is greatly improved - approximately 10% compared with up to 4 times (400%), depending on the type of light source applied (i.e. fluorescent vs. incandescent light), resulting in stable operation. Moreover, both analog and digital output sensors are available, making them compatible with a wide variety of applications.

The BH1600FVC analog output type ambient light sensor features a two-level output current gain adjustment - an industry first - as well as low voltage operation. The BH1710FVC digital output type incorporates a 16-bit A/D converter, is capable of precisely measuring a wide range of intensities in 1-lux increments, and can directly output the illumination intensity digitally - also an industry first - making it possible to eliminate conventionally required external operation processing.

The market for electronic products is constantly expanding. ROHM will continue to develop products that improve the efficiency and performance of electronic devices such as LCDs, maintaining its reputation as a world-class semiconductor manufacturer.

ROHM's advanced product development capabilities will be utilized to meet the needs of customers while increasing its lineup of highly reliable, sophisticated products.

· Main Features of BH1600FVC and BH1710FVC

1. Spectral sensitivity characteristics close to the photopic luminous efficiency of the human eye.
2. Unique photo IC technology minimizes the difference in output resulting from different light sources, resulting in stable operation.

· Main Features of BH1600FVC

1. Current output with two-level gain adjustment (60 µA/100 lux and 6 µA/100 lux).
2. Integrated shutdown function.
3. Wide operating supply voltage range: 2.4 to 3.6 V.

· Main Features of BH1710FVC

1. Compatible with the I²C bus interface.
2. Supports a wide optical input range (equivalent to an illumination intensity range from 1 to 65,536 lux).
3. Incorporates an A/D converter, eliminating the need for external components.
4. Half the power consumption of competing products.

· Glossary

• Spectral sensitivity characteristics:
  The sensitivity to optical wavelengths that can be expressed in a graph where the x-axis represents wavelengths and the y-axis denotes the relative sensitivity.
• Photopic luminous efficiency:
  Human eyes have a sensitivity to light in the wavelength range between 380 and 760nm and are most sensitive to light with a wavelength of 555nm (green). The spectral sensitivity characteristics of the human eye are referred to as photopic luminous efficiency.

Illuminance Senser LSI