900844 Datasheet, PDF (66/118 Pages) Freescale Semiconductor, Inc – Integrated Power Management IC for Ultra-mobile and Embedded Applications

FUNCTIONAL DEVICE OPERATION
POWER SUPPLIES
V21 Status/Control Registers and Bits Description
Reference the register map for read/write conditions and default state for each of these registers.
Table 28. V21 Status/Control Registers Structure and Bits Description
Name
Bits
Description
CTLV21 2:0
AOACCTLV21 5:3
V21CNT (ADDR 0x38 - R/W - Default value: 0x07)
V21 State Control
x0 = Reserved
x1 = Reserved
x2 = Reserved
x3 = Reserved
x4 = OFF
x5 = PFM
x6 = Automatic Pulse Skipping
x7 = PWM
V21 State Control during AOAC Exit (when EXITSTBY pin is asserted). These bits will be initialized by the system SPI
controller after power up
X0 = Do not copy
x1 = Do not copy
x2 = Do not copy
x3 = Do not copy
x4 = OFF
x5 = PFM
x6 = Automatic Pulse Skipping
x7 = PWM
Reserved 7:6 Reserved
V15
This is a 4.0 MHz fully integrated 2-switch synchronous Buck PWM voltage-mode control DC/DC regulator.
The switcher can operate in different modes depending on the load conditions. These modes can be set through the SPI and
include a PFM mode, an Automatic Pulse Skipping mode, and a PWM mode. The above selection is optimized to maximum
battery life based on load conditions.
V15 will be discharged every time the regulator is shutting down.
The output current is measured internally, digitized by the ADC, and stored in a register for the processor to access.
The peak current is sensed internally for over-current protection purposes. If an over-current condition is detected, the
regulator will limit the current through cycle by cycle operation and alert the system through the V15FAULT signal, which will in
turn assert the VRFAULT Interrupt signal.
VPWR
CIN 15
PVIN 15
V15
CO15
SW15
L15
PGND15
FB15
ISEN SE 5
Driver
Controller
Internal
Compensation _Z2
Z1
EA
V REF
CTLV15
AOACCTLV15
SELV 15
V15FAULT
SPI
Interface
Figure 32. V15 Detailed Internal Block Diagram
Main Features
• Uses the V_PWR rail as its power supply
• It is used as a pre-regulator to many LDO rails, for enhanced efficiency and reduced thermal dissipation. It also supplies power
to rails in the Platform controller hub
• Uses Integrated MOSFETs
900844
66
Analog Integrated Circuit Device Data
Freescale Semiconductor