Dc-To-Dc Power Supply - Compaq LTE Elite Maintenance And Service Manual

o Battery charging circuitry and battery contacts [10] for battery pack
o External input/output (I/O) connectors (Figure 1-4)
o DC-to-DC power supply (refer to "DC-to-DC Power Supply" in this section)
o 256 Kbyte flashable shared system ROM and keyboard ROM
o 4 or 8 MB base RAM (depending on the model)
o System controller, which provides the following:
- Interface to the processor board for memory management (including
memory refresh)
- Two DMA controllers
- Two interrupt controllers
- Clock generator
- Programmable interval timer
- System management interrupt (SMI) support logic
- Power management features
o Peripheral controller, which provides the following:
- Integrated keyboard controller
- Industry Standard Architecture (ISA) support logic
- Circuit for interfacing to the hard drive
- Control of parallel and serial interfaces, including serial interfaces
for a numeric keypad, mouse/keyboard, and internal trackball
o PCMCIA controller
o Local bus video controller
o Diskette drive controller
o Docking sense logic
o Secondary temperature sensor for controlling the fan (refer to
"Temperature Sensors")

DC-to-DC Power Supply

The DC-to-DC power supply is integrated into the system board. It converts
DC voltage input to regulated 3.3 volts, 5 volts, and 12 volts DC. The DC