Page 171 - The Art and Science of Analog Circuit Design

Jim Williams

•Dttilljflnnsistor
= 1QV/B«
jy|l i$ ttansformer
hiidi" into'Satura-
tion (trace B),

HORIZ = 500ns/DlV

Everything was still pretty fuzzy, but I had learned a few things. A
practical, highly efficient LCD backlight design is a classic study of com-
promise in a transduced electronic system. Every aspect of the design is
interrelated, and the physical embodiment is an integral part of the elec-
trical circuit. The choice and location of the lamp, wires, display housing,
and other items have a major effect on electrical characteristics. The
greatest care in every detail is required to achieve a practical, high effi-
ciency LCD backlight. Getting the lamp to light is just the beginning!
A good place to start was to reconsider the lamps. These "Cold
Cathode Fluorescent Lamps" (CCFL) provide the highest available effi-
ciency for converting electrical energy to light. Unfortunately, they are
optically and electrically highly nonlinear devices.

VIN

Figure 11-10.
Adding the resonat-
ing capacitor to the
Royer.
POWER
SWITCHING 1
G
FCHIN

BASE BIASING
AND DRIVE

153