Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
?
EE Times-Asia > Optoelectronics/Displays
?
?
Optoelectronics/Displays??

LED drivers with 'smallest' footprint

Posted: 06 Apr 2005 ?? ?Print Version ?Bookmark and Share

Keywords:national semiconductor? light-emitting diode driver? led driver? lm27953? lm2796?

National Semiconductor Corp. introduced three new charge-pump-based white light-emitting diode (LED) drivers for mobile phone display backlighting that feature a tiny chip-scale 18-pin micro SMD package, providing one of the smallest footprint in the industry.

The LM27953, LM2796 and LM27961 charge-pump-based white LED drivers provide highly efficient LED backlighting for portable devices, including digital still cameras, MP3 players, personal digital assistants, hard disk drives, wireless local area networks and other low-power, small form-factor products. These products operate from an extended Li-ion input voltage range of 2.7V to 5.5V. The voltage boost is achieved with a high-efficiency 3/2x gain charge pump.

The LM27953 drives four LEDs for display backlighting or other LED lighting applications. The regulated internal current sources deliver excellent brightness matching in all LEDs by providing low-side current drivers to accommodate common-anode-type LEDs, said National. The brightness of the LEDs can be adjusted independently with an external resistor.

The LM2796 drives up to seven LEDs in parallel with up to 20mA of current through each LED. The LED driver current sources are divided into two independently controlled, high-side driven groups. The primary four-LED group can be used to backlight up to a 2.5-inch display, while the secondary three-LED group can be used to backlight a second display or provide other LED lighting features.

The current sources of the LM27961 are divided into two independently controlled, high-side and low-side driven groups. The primary four-LED low-side group can be used to backlight up to a 2.5-inch display, while the secondary three-LED high-side group can be used to backlight a second display or provide other LED lighting features. The brightness of the two LED groups can be adjusted independently.

For 1,000-unit quantities, the LM27953 is priced at $1.20, the LM2796 at $1.60 and the LM27961 at $1.50. Evaluation boards are also available.




Article Comments - LED drivers with 'smallest' footprin...
Comments:??
*? You can enter [0] more charecters.
*Verify code:
?
?
Webinars

Seminars

Visit Asia Webinars to learn about the latest in technology and get practical design tips.

?
?
Back to Top