FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
If SLEEP goes High to place the chip into the standby
mode while any of the WAKEB pins is Low, the chip can be
awakened again. This may happen if, when an WAKEB pin
and LSWO are connected, SLEEP goes High earlier than the
period of time (*1) specified by the external component of the
WAKEB pin.
START-UP CONTROL INPUT (SYSTEM CONTROL)
The latch is set at the rising edge of any WAKE1B-4B input
pin, and WAKE(int) goes High. WAKE1~4B inputs consist of
OR logic. At this time, the input pin which went Low keeps
latched until CLEAR goes High. After the latch is reset by
CLEAR, WAKE(int) goes Low when SLEEP goes High. The
latch is also cleared and WAKE(int) goes Low when SLEEP
goes High before the latch is cleared by CLEAR. In this case,
CLEAR keeps negated while PGOOD1, 2(Ext) is Low.
SLEEP keeps negated while PGOOD1, 2(Ext) is Low or
CLEAR is High. The period of time for which CLEAR and
SLEEP are negated can be set by the SEQ_SELECT pin.
Refer to Truth Table 5, on page 12 for the correspondence
between the SEQ_SELECT pin settings and negation period.
Also, if the period of time after WAKE(int) goes High until
CLEAR goes High from Low is longer than the time specified
by WATCHDOG, internal sleep will start up to place the chip
into the standby mode.
(*1: It is 30 µsec when a capacitor is not connected as the
external component.)
WAKEB
CLEAR
Time specified by WATCHDOG
WATCHDOG
WAKE(Int)
Figure 6. Start-Up Timing Diagram
STANDBY POWER SUPPLY CIRCUIT
LSWO
Short-circuit VBATT and LVB, and connect a
Schottky diode between VBATT and V_STDBY
only when using Ni_mh.
CLEAR
VBATT
VO1_SENSE
VBATT
LVB
HVB
Standby
Power
Supply
Control
PGOOD1
PGOOD1(Int)
V_STDBY
When using Li_ion, leave LVB open, and short-
circuit HVB and VBATT.
V_STDBY
Figure 7. Standby Power Supply Circuit Diagram
When PGOOD1(int) is Low, output LVB voltage to
V_STDBY pin. When PGOOD1(int) is High, output
VO1_SENSE voltage to V_STDBY pin. When CLEAR is Low,
LSWO is open. When PGOOD1(int) is High and CLEAR is
High, LSWO output voltage turns GND. When PGOOD1(int)
is Low and PGOOD1 is High, discharge the external
18730
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
FREESCALE [ Freescale ]
