Chapter 3 — Theory of Operation
46 CV30 Fixed Mount Computer Service Manual
Internal Power System
The CV30 power system consists of several bucks and boost converters,
power switches, and miscellaneous circuitry that orchestrate the power
subsystem. The main processor and PIC continuously monitor and control
various aspects of the power subsystem when operating.
The CV30 power system is separated into 3 main circuits:
• Heater system
• Main logic power system
• Backup power system
Many of these power nets can be independently powered down to conserve
power. This document will explain the major power planes, their respective
sources, and the controls required to operate this system. Each section
shows the relationship of each power plane to its “root source.”
The overall power block diagrams are illustrated in these three graphics:
• “Input Power, Heater, Charger, and Main Buck System” on page 46.
• “V5PO_MAIN Power Distribution System” on page 47.
• “MAIN_PWR Power Distribution System” on page 48.
Input Power, Heater, Charger, and Main Buck System
V12P0_SYS
FILTER
FILTER
HEATER
MAIN
V12P0
V12P0_HEATER
HEATER POWER
LT1619
VCC_ HEATER
(24V)
TOUCH
HEAT ER
CCFL
CONTROLLER
LT1768
LCD
CCFL
(ONLY WITH
851-070-003)
EXTERNAL
SOURCE
(AC/DC, DC/DC)
HIGH VOLTAGE
SYS_PWR
(12V)
BAT CHARGER
MAX1737
VIN=3.0V ~4.2V
BATTERY
18650
MAIN 4.5V BUCK
MAX1745
BK_P WR
SW
4.5V
MAIN _ P WR
MAIN 5V BUCK
MAX1745
V5 P0 _MAI N
FB
nBAT T FAULT DET
FB
V12P0_CCFL
FB
BACKLITE EN
OFF During Sleep and Deep Sleep
Always ON plane
OFF During Deep Sleep
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