|
|
|
Circuit Drives Mixed Types & Quantities of LEDs - 10/03/02
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 RX;
IDS=I0).....(design idea) |
|
Get Just Enough Boost Voltage - 05/27/04 EDN-Design Ideas:
Adding a current-mirror circuit to a typical boost circuit
allows you to select the amount of boost voltage and to ensure a
constant difference between the input and the output voltages.
See this circuit, which is useful for high-side-drive
applications.....(design idea) |
|
