V•I Chip long-life powertrain for high-performance projectors
Modern projector technologies are much more versatile than old slide projectors, enabling the display of images, video, and even data with high clarity, brightness and even portability. Liquid Crystal Display projection technology, for example, has contrast ratios in the range of 3000 to 1. This technology uses three LCD panels as prisms
to create full color.
The trend in the mobile projection market is toward smaller, yet more powerful projectors. One Vicor customer leveraged the small package size and high efficiency of our V•I Chip components to power the LEDs in their compact, advanced projectors designed for applications, such as high resolution imaging and motion simulation.
In the customer’s design, a discrete PFC AC-DC front end provided a nominal 384 Vdc to two 384 Vin – 48 Vout BCM bus converters in parallel. The 48 V bus enabled the customer to reduce line loss and to use PRM regulator and VTM current multiplier combinations at 200 W each to set up the three different voltage rails for red, green and blue LEDs respectively. The V•I Chip modules provided tight load regulation for Vout and very fast transient response for pulsed loads.
The displacement of Cathode-Ray Tube (CRT) displays by Liquid Crystal Display (LCD) technology is complete. Within LCDs, LEDs (light-emitting diodes) have replaced cold cathode fluorescent lamps (CCFL) to provide uniformly white backlight. LEDs offer significant benefits when compared with CCFLs, in terms of size, efficiency, purity and reliability. They also offer a reduction in the hazardous substances used to manufacture them.
LED backlighting provides the ability to modulate the light source from pixel to pixel, creating more realistic images with less motion blur. That’s exactly what one Vicor customer needed. Using a V•I Chip solution, they were able to utilize new high-brightness LEDs in a backlight LCD panel.
Their design is based on innovative patented technology for High Dynamic Range (HDR) image technology. This technology makes possible much brighter displays, i.e. ten times brighter than a conventional LCD. Every single LED in the backlight is individually addressable so the light levels can be changed dynamically frame by frame and spatially micro region by micro region. The result is pictures that display much more vividly, with brighter levels of light and a broader color spectrum than previously possible.
Previously, the LEDs were powered by a 5.5 Vdc, 500 A power supply, but that is too high a current to distribute efficiently inside the display. The customer based their new architecture on V•I Chip BCM converters. The BCM enabled them to distribute at 48 V at a much lower current which provides more efficient power distribution. The BCM is capable of directly powering individual LED driver ICs by stepping the voltage down to the high current 4V needed at the driver. The BCM’s high conversion efficiency and safe operating temperature range allowed the customer to complete the design without heat sinks.