The LDS8161/41 introduces a new, straightforward way to address thermal reliability constraints in portable LED backlights. Utilizing LED-Sense™, these LED drivers provide real-time monitoring of the LED's junction temperature. Every few seconds, the LED junction temperature is measured in-situ and the current is adjusted on each LED channel using a programmable current versus temperature de-rating profile. This optimizes luminosity while ensuring reliable LED operation. System designers can therefore reduce guardbands they typically employ, while safely biasing the LEDs at higher currents over the LED's operating temperature range. As the temperature of the system increases above a pre-set point, the LDS8161/41 intelligently reduces the LED drive current, thereby ensuring that the LEDs operate in a specified safe temperature zone. As a result, at typical operating temperatures the LEDs can be safely driven at higher currents resulting in greater luminance per LED. This has two major implications for system designers. First, the system designer can reduce the number of LEDs while achieving the same total luminance and contrast. Second, in situations where a larger screen size would normally dictate 8 series-connected LEDs, it may be possible to use 6 parallel-connected LEDs to achieve the same total luminance.
"We're pleased to bring to the market these innovative LED Drivers that can significantly reduce the customer bill of material and design time," said Donato Montanari, Vice President at Leadis. "Today's trend in mobile phones is to increase the size of the display, however it is cumbersome and expensive to adopt LED-in-parallel configurations when more then 6 LEDs are required. Our LDS8161 can extend the life of the parallel configuration by allowing system designers to safely drive more current through the individual LEDs. Moreover, our LDS8141 is a straightforward cost reduction path for display modules that currently require 5 or even 6 LEDs."
The LDS8161/41 offer multiple additional advantages for designers of portable applications. For longer battery life, the efficiency is increased up to 98% by the inclusion of both the proprietary PowerLite™ Current Regulator and the exclusion of boosting circuits that are not needed with most of today's LEDs. This last feature offers the additional advantage of significantly reducing EMI noise. The ultra low dropout PowerLite™ Current Regulator provides a transition threshold of 50mV, allowing customers to adopt any LED with a Vf lower than 3.4V. For improved dynamic brightness control a 12-bit logarithmic PWM generator is integrated on chip. This generator allows customers to send a dimming command by adjusting the PWM duty cycle through the I2C interface without having to keep "pulsing" a PWM bus. This innovation dramatically improves the power consumption of the system, especially if frequent dimming is required. The LDS8161/41 are offered in a 3mm x 3mm 16-pin TQFN package.
About the LDS8161/41
The LDS8161/41 are 6 / 4 -channel white LED drivers with integrated high temperature compensation and current de-rating circuitry. They can support WLED backlighting, keypad, and other lighting functions in portable applications. Eight I2C-programmable registers let users define the temperature de-rating profile as a function of the specific LED Diode used in the design. Three programmable, 8-bit DACs set the current level for each LED bank (A, B, & C) from 0 to 32mA in 0.125mA steps. Each channel contains a linear LDO current regulator (driver) in a common cathode high side driver topology. The LDO drivers have a typical dropout voltage of 50mV at maximum rated current. This provides a low power/low EMI solution in Li-ion battery applications without voltage boosting and associated external capacitors and components. The 12-bit PWM generator with "smooth" logarithmic control supports the high temperature LED current de-rating adjustments. The PWM generator is programmable via an I2C serial interface. User programmed 8-bit codes are converted to 12-bit resolution logarithmic steps of ~0.17 dB per step. The PWM frequency is ~280 Hz to minimize noise generation.
For more information, visit www.leadis.com.
About Leadis Technology, Inc.
Leadis Technology, Inc., headquartered in Sunnyvale, California, designs, develops and markets analog and mixed-signal semiconductors that enable and enhance the features and capabilities of portable and consumer electronics devices. Leadis' product offerings include capacitive touch controller ICs, which enable highly reliable touch-based input controls and attractive industrial design options for both mobile and non-mobile applications; LED drivers, which provide controlled levels of current required to drive light emitting diodes in diverse applications including mobile backlight units; and color display drivers, which are critical components of displays used in mobile consumer electronic devices.
Cautionary Statement
Certain statements in this press release including, but not limited to, the features and benefits of Leadis' new LDS8161 and LDS8141 LED drivers are forward-looking statements that are subject to risks and uncertainties that could cause results to be materially different than expectations. Such risks and uncertainties include, but are not limited to, lack of market adoption of the LDS8161/41 products, delays associated with ramping new products into production, lack of market acceptance of the LDS8161/41 products, that pending patent applications will not result in issued patents or that any issued patents may not be sufficiently broad to protect our proprietary technologies, delays in the integration of our products into consumer electronic devices, our reliance on third-party manufacturers, general mobile handset and semiconductor industry trends, and other risks detailed from time to time in Leadis' reports filed with the Securities and Exchange Commission including its Form 10-K for the year ended December 31, 2008 and Form 10-Q for the quarter ended March 31, 2009. Leadis disclaims any obligation to update these forward-looking statements.
Contact Information: Julie Pestka Schardt 408-331-8603
