Light-to-digital converters seek small displays

Plano, Texas — Texas Advanced Optoelectronic Solutions, Inc. (TAOS) is beefing up its Light-to-Digital Converter offering with two low-voltage versions for mobile phones, PDAs, portable media players, cameras, handheld games and camcorders.

Like TAOS' preceding TSL2560 and TSL2561 Light-to-Digital converters, which convert light intensity to a digital signal output that is capable of direct I2C or SMBus interfacing for use in display panels 9LCD, OLED, etc., the TSL2562 and the TSL2563 Light-to-Digital Converters combine a visible light blocking photodiode with a broadband photodiode on a single CMOS integrated circuit.

This combination enables either device to be used to calculate light intensity in lux over an effective 20-bit dynamic range with a 16-bit resolution without the use of an expensive filter.

Two integrating analog-to-digital (A/D) converters convert the photodiode currents to an SMBus (TSL2562) or I2C (TSL22563) digital output that represents the irradiance measured on each channel. This output data can be input to a microprocessor where illuminance (i.e. ambient light level) in lux is derived using an empirical formula that is less than 200 bytes of code.

The TSL2562 permits an SMB-Alert style interrupt and the TSL2563 supports a traditional style interrupt that remains asserted until the firmware clears it.

The TSL2562 and the TSL2563 can measure light levels ranging from 0.1 lux to 40,000 lux. No external circuitry is required for signal conditioning, according to TAOS. In ambient light sensing applications, the integrating conversion technique used in both devices eliminates the effect of fluorescent flicker, thereby increasing the stability of the measurement, the company said.

A single-supply operation (2.38 volts to 2.62 V) makes both devices practical for mobile applications. Moreover, when not in use, a power down mode ensures that the TSL2562 and the TSL2563 consume as little power (8 microwatts) as possible.

An Evaluation Module with a USB-interface is available with a suggested resale price of $125.00.

See related block diagram

The TSL2562 and the TSL2563 Light-to-Digital Converters are available now in two standard 6-pin packages: Chipscale (1.7 x 1.2 x 0.7 mm) and Transfer Molded Board (3.8 x 2.6 x 1.4 mm). The TSL2562/2563 has a suggested resale price of $1.25 in 1,000-piece quantities. Click here for the TSL2562 and TSL2563 data sheets.

TAOS , 1-972-673-0759,

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