User Guide

PAMS
Technical Documentation
RAE-5
4. User Interfaces
Page 4 – 14
Issue 1 04/02
Functional description
Power distribution and control signals
The following block diagram describes the distribution of power supplies within
DL2.
Battery voltage VB is fed directly to the illumination LEDS (CMT keymat and
CMT display)
The regulated band supply VBB generated on the KL8 module supplies the
CMT display, control logic and PDA display supply.
A power switch is used to remove the voltage supply from the control logic and
PDA display when the display is turned off.
Figure 2. Power distribution and control signals of UL2.
PDA LCD
backlight
Keyboard
backlight backlight
CMT
LCD
PDA LCD Bias power
VB
VBB
GND
KBLIGHTSBACKPWM
and control logic
CMT LCD
16mA typ
110mA 20mA typ 10mA typ
300uA max
typical
LCDPWR