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LED Controller Features 'In-Situ' Temperature Compensation

Wed, 07/22/2009 - 5:42am

EZ header Microchip 

Leadis Technology, Inc. (NASDAQ: LDIS), an analog and mixed-signal semiconductor developer of LED drivers for consumer electronic devices, today announced sample availability of the LDS9001 and LDS9003, two new LED controllers featuring Leadis' patent pending LED-Sense(TM) Temperature Compensation engine. This innovative feature allows for direct in-situ monitoring of the LED junction temperature without the need for an external temperature sensor, thereby optimizing LED brightness and reliability throughout the LED's full operating temperature range. Targeted at high-power lighting applications, the LDS9001 and 9003 can independently monitor one and three LEDs, respectively.

The LDS9001 and 9003 provide a new, straightforward way to address thermal reliability constraints in high-power LED lighting applications. Utilizing LED-Sense(TM), these LED controllers 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 are therefore able to 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 LD9001/9003 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 enables the system lighting designer to reduce the number of LEDs by 10 - 20% while achieving the same total luminance. Given the relatively high cost of high-power LEDs, the overall system costs can be significantly reduced.

"We're pleased to bring to the market these innovative LED controllers that can significantly reduce the customer bill of material and design time," said Skip Wong, Vice President of Sales at Leadis. "The LED lighting market is starting to take off, with cost and reliability being critical factors that require continued improvement. Our LDS9001 and 9003 provide a straightforward cost reduction path for system lighting designers. Beyond lighting, these products can also be used in high power automotive and signage applications."

About the LDS9001 /9003 
The LDS9001 and 9003 offer one and three temperature sensing and control channels, respectively. Both products can support WLED lighting, automotive, and signage applications. Since the LDS9003 supports multi-point thermal monitoring, it can also be used for multi-color LED applications, such as RGB. Eight I2C-programmable registers let users define the temperature de-rating profile as a function of the specific LED Diode used in the design. A 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. Interfaces are provided to support high side high LED current drivers and low cost microcontrollers in order to enable LED lighting designers to quickly and efficiently implement their electronics solution. The LDS9001/9003 are offered in 3mm x 3mm 8-pin DFN and 16-pin TQFN packages, respectively.

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 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.

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