Personal Computer User Manual

Intel® PXA27x Processor Family Power Requirements

Application Note 33

8.2 Features of a PMIC

The basic features of a PMIC for use with the PXA27x processor include:

• Multiple channels of regulated power output

• Dynamic voltage management (DVM) capability for the PXA27x processor core supply

• Debounced push button ON/OFF and user-reset inputs

• AC adapter detect capability

• Power-on / user reset output to the PXA27x processor nRESET input

• nBATT_FAULT signal, signifying main battery removed

• nVDD_FAULT signal, indicating any power regulator out of spec

• Automatic switch over from main battery to backup battery when main battery is discharged or

removed

• Responds to the PXA27x processor mode change requests by switching regulators on or off

• Control and Status registers accessible through I

C interface

• Provides USIM power FET control to supply 3.0 V or 1.8 V to USIM card

The features of a PMIC for battery charging also include:

• Charging capability for lithium-ion or lithium-polymer main battery

• Support for either rechargeable or non-rechargeable backup battery

• Digital output battery level monitor (“fuel gauge”) for main and backup batteries (optional)

• Battery charging current and temperature monitoring, for fast charging of main battery

(optional)

Table 9. General PMIC Characteristics

Characteristic Description

Highly Integrated,

Multi-Function

Incorporating buck, boost, buck-boost, and LDO regulators for the PXA27x processor

and surrounding system elements, with dynamic voltage management (DVM) logic for

the core supply. It includes power-up, power-down, and sleep mode power sequencing,

and generates correct nRESET, nBATT_FAULT, and nVDD_FAULT outputs for the

system. Ideally, it also incorporates battery charger circuits and an output to notify the

system when AC power input is present; touchscreen and audio CODECs would be a

plus, if they can meet industry-standard noise and distortion requirements when

combined on the same silicon.

Low-Cost High integration provides a packaged device that must be lower cost than the

alternative comprised of discrete power supply devices.

High Efficiency Converters operate in the 85-95% efficiency range under all load conditions, and with

very low quiescent current and shutdown currents (off or sleep mode).

C Interface Must be standard I

C interface operating at either 40 kHz standard mode or 160 kHz

fast-mode clock rate.

Stable and Accurate Meets ± 3% accuracy or better at the PMIC output signals over input variation, load

variation, and temperature for all regulators and converter outputs. Switching

regulators must minimize noise propagated into regulator outputs.

Reliable Current and thermal limiting on all regulators.