TMPR3911 datasheet(259/462 Pages) TOSHIBA

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Chapter 12 Power Module

12-3

12.1.3

Power Supply Lines in the System

The description in this section assumes that the system has the following power supply lines.

Table 12.1.1 shows the status of each power supply line on each power state described in 12.1.2

In addition to these power supply lines a System Power Supply may provide other power supply lines

according to particular system requirements. For example a system may have a dedicated power supply line

for a PC Card slot to supply power during the Suspend State.

VSTANDBY: (VDD)

This line provides power for the TMPR3911/12 and other components in the system that must

never be powered off. This line should always be alive if there is either a good main battery or a

good backup battery, or if a battery charger is plugged in.

VCCDRAM:

This line provides power for the DRAM and/or SDRAM. This line must be off when

VSTANDBY is first powered, and remain off until the system is powered up by the assertion of

PWRCS. When the software subsequently powers down the system it may choose to keep this line

powered to preserve the contents of memory.

VCC3:

This line provides power for the ROM, system buffers, and other components in the system.

This line will be powered by the System Power Supply when PWRCS is asserted and will always

be powered off when the system is powered down.

Table 12.1.1 Power Supply Status

Power

State

Power On Reset

State

Normal State

Standby

State

Suspend

State

Battery Backup

State

VSTANDBY

VCCDRAM

Off

VCC3

Off

TMPR3911 Datasheet(PDF) 259 Page - Toshiba Semiconductor