MEC1404 Datasheet, PDF (70/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
3.4.3 POWER GOOD SIGNALS
The power good timing and thresholds are defined in the Section 43.1, "Voltage Thresholds and Power Good Timing,"
on page 504.
TABLE 3-3: POWER GOOD SIGNAL DEFINITIONS
Power Good
Signal
Description
VTRGD
VTRGD is an internal power good signal used
to indicate when the VTR rail is on and stable.
VCC_PWRGD VCC_PWRGD is used to indicate when the
main power rail voltage is on and stable.
Source
VTRGD is asserted following a delay after the
VTR power well exceeds its preset voltage
threshold. VTRGD is de-asserted as soon as
either of these voltages drop below this thresh-
old.
Note:
See Section 43.1.1, "VTR Thresh-
old and VTRGD Timing," on
page 504.
VCC_PWRGD Input pin
3.4.4 SYSTEM POWER SEQUENCING
The following table defines the behavior of the Power Sources in each of the defined ACPI power states.
TABLE 3-4: TYPICAL POWER SUPPLIES VS. ACPI POWER STATES
Supply
Name
VTR_33_18
VTR
VBAT
ACPI Power State
S0
(FULL
ON)
S1
(POS)
S3
(STR)
S4
(STD)
S5
(Soft Off)
G3
(MECH
Off)
Description
ON
ON ON/OFF ON/OFF ON/OFF
OFF
LPC/eSPI Host Interface
Power Supply.
ON
ON
ON
ON
ON
OFF
“Always-on” Supply.
(Note 3-3)
ON
ON
ON
ON
ON
ON
Battery Back-up Supply
(Note 3-4) (Note 3-4) (Note 3-4)
Note 3-3
Note 3-4
VTR power supply is always on while the battery pack or ac power is applied to the system.
This device requires that the VBAT power is on when the VTR power supply is on. External circuitry,
a diode isolation circuit, is implemented on the motherboard to extend the battery life. This external
circuitry ensures the VBAT pin will derive power from the VTR power well when it is on. Therefore,
the VBAT supply will never appear to be off when the VTR rail is on. See APPLICATION NOTE: on
page 69.
3.5 Clocks
The following section defines the clocks that are generated and derived.
3.5.1 RAW CLOCK SOURCES
The table defines raw clocks that are either generated externally or via an internal oscillator.
DS00001956D-page 70
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