900844 Datasheet, PDF (62/118 Pages) Freescale Semiconductor, Inc – Integrated Power Management IC for Ultra-mobile and Embedded Applications

FUNCTIONAL DEVICE OPERATION
POWER SUPPLIES
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 a cycle by cycle operation and alert the system through the VDDQFAULT signal, which will in turn assert the
VRFAULT Interrupt signal.
VDDQ is originally prepared to provide 1.8 V by connecting VDDQ output voltage directly to FBDDQ node, refer to Figure 27.
To provide flexibility, VDDQ can also be set to 1.5 V by adding a resistor divider from VDDQ output to the FBDDQ using VCORE
as voltage reference, refer to Figure 28. The following are the recommended resistor values for the feedback divider:
• RFBDDQ15_1 = 680 Ω
• RFBDDQ15_2 = 2.21 kΩ
VPWR
CINDDQ
PVINDDQ
VDDQ
CODDQ
SWDDQ
LDDQ
PGNDDDQ
FBDDQ
ISENSE 5
Driver
Controller
Internal
Compensation _Z2
Z1
EA
V REF
CTLVDDQ
AOACCTLVDDQ
VDDQFAULT _SPI
Interface
Figure 27. VDDQ Detailed Internal Block Diagram (VDDQ at 1.8 V)
VDDQ
VPWR
CINDDQ
PVINDDQ
SWDDQ
LDDQ
CODDQ _PGNDDDQ
RFBDDQ15_1
FBDDQ
RFBDDQ15_2
ISENSE5
Driver
Controller
Internal
Compensation _Z2
Z1
EA
VREF
CTLVDDQ
AOACCTLVDDQ
VDDQFAULT
SPI
Interface
VCORE
Figure 28. VDDQ Detailed Internal Block Diagram (VDDQ at 1.5 V)
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 CPU (central processing unit), Platform controller hub, and the platform
• Uses Integrated MOSFETs
• 4.0 MHz switching frequency
• High efficiency operating modes depending on load conditions
• Output can be discharged through the low side switch.
• Peak current sensing with over-current protection
900844
62
Analog Integrated Circuit Device Data
Freescale Semiconductor