PAC5250_17 Datasheet, PDF (23/70 Pages) Active-Semi, Inc – Power Application Controller

PAC5250
Power Application Controller
Figure 10-5. Linear Regulators
VP
PAC5250
V (12V typical)
P
REGO
VSYS
VCCIO
(1)
4.7µF
V & V (5V)
SYS
CCIO
VCC33
VCC18
VSS
VSSA
1µF
1µF
(1) _{5V I/O connection shown.}
Connect instead to a 4.7µF
capacitor for 3.3V I/O.
10.3.3. Power Up Sequence
The MMPM follows a typical power up sequence as in the Figure 10-6 below. A typical sequence begins with input power
supply being applied, followed by the safe start up and start up durations to bring the switching supply output V P to 12V,
before the linear regulators are enabled. When all the supplies are ready, the internal clocks become available, and the
microcontroller starts executing from the program memory. During initialization, the microcontroller can reconfigure the
switching supply to a different VP regulation voltage such as 15V and to an appropriate switching frequency and switching
mode. The total loading on the switching supply must be kept below 25% of the maximum output current until after the
reconfiguration of the switching supply is complete. For AC input supply applications, the start up sequence includes an
additional charging time for VHM depending on the start-up resistor and capacitor values.
Figure 10-6. Power Up Sequence
V or V
IN
HM
V
P
V and V
SYS
CCIO
V
CC33
V
CC18
Internal clocks
14.8V
Power on reset
Safe start up
Start up
6ms
Regulators Power-on-
enabled reset delay
SOC.PWRCFG.TRESET + 10.5 ms
(default: 32ms + 10.5ms = 42.5ms)
4.3V
V (start up default)
P
4V
76%
Microcontroller
reset
Reconfiguration by firmware
Microcontroller
initializing
System operation
V or V
IN
HM
V (5V/12V/15V)
P
V and V (5V)
SYS
CCIO
V (3.3V)
CC33
V (1.8V)
CC18
Microcontroller
executing
10.3.4. Hibernate Mode
The IC can go into an ultra-low power hibernate mode via the microcontroller firmware or via the optional push button
(PBTN, see Push Button description in Configurable Analog Front End). In hibernate mode, only a minimal amount
(typically 18µA) of current is used by VHM, and the MMSS controller and all internal regulators are shut down to eliminate
power drain from the output supplies. The system exits hibernate mode after a wake-up timer duration (configurable from
125ms to 8s or infinite) has expired or, if push button enabled, after an additional push button event has been detected.
When exiting the hibernate mode, the power manager goes through the start up cycle and the microcontroller is
- 23 -
Rev 1.7‒April 15, 2016