Circuit drives mixed types and quantities of LEDs: 10/03/2002 EDN -
Design Ideas / Portable systems often use LEDs of different colors and
in varying quantities of each color. Some examples are white for the
display backlight, green for keypad illumination, and red for power.
Typically, the LEDs derive power from at least two power supplies: one
for "standard" LEDs (red and green) and one for white LEDs..
Circuit forms novel floating current source: 05/01/03 EDN-Design
Ideas / Figure 1 shows a polarization circuit applicable to ISFET
(ion-sensitive field-effect-transistor) sensors. ISFETs are solid-state
chemical sensors that measure the pH value of a solution in biomedical
and environmental applications, for example. The circuit in Figure 1 is
extremely simple; it sets fixed-bias conditions for ISFET sensors (VDS=I0