New LED Driver Saves Power

By Veronica Hendricks
iApplianceWeb
(09/24/01, 08:51:38 AM EDT)

Semtech Corp. has found a way to keep LED backlighting from consuming all of the battery life in a PDA. This a new power management device for use in battery operated handheld equipment, the SC600 LED driver, incorporates Semtech's new mAhXLife (milli-amp hours extended life) technology to produce a highly efficient, tightly regulated, output voltage to power LED backlighting in color LCD displays.

The inductorless design uses only four external 1uF ceramic capacitors to provide a reduced-EMI solution in a small, low profile MSOP-10 package. The SC600 can support applications that require up to 120mA of output current with input voltages ranging between 2.85V to 6.5V. Three preset output voltages of 4.0V, 4.5V, or 5.0V are offered to accommodate the varying forward voltage requirements of blue and white LED or RGB LED arrays used for portable backlighting.

"Portable equipment demands higher feature integration, yet requires higher power conservation," said Eddie Yeow, director of the portable power management product line at Semtech. "Current designs employ more costly, high profile inductors and, thereby, increase system complexity and footprint size. With the new SC600, we addressed these concerns and created a highly dense, more power efficient solution that can power up to six LED's in a parallel configuration."

Designed for use in cellular phones, PDAs, handheld computers, portable electronics, wireless Web appliances, electronic books, and similar products, the SC600 LED driver incorporates the following additional features:

• Peak efficiency, over 95 percent -- Extends battery life while conserving board real estate.
  
• Selectable switching frequencies (from 8kHz to 650kHz) -- Maximize efficiencies with respect to load for optimized power management.
  
• Short circuit and over-temperature controls -- Ensure components are protected.
  
• Low input/output ripple -- Reduces system noise and filter components.

Link:
Semtech Corporation