ACT8931A
Rev 3, 29-Nov-12
Advanced PMU for Rockchip RK2928/RK2926 Processors
Rockchip RK2928/RK2926 processors. It is ideal for a
FEATURES
wide range of high performance portable handheld
applications such as tablet or pad devices. This device
Three Step-Down DC/DC Converters
TM
integrates the ActivePath complete battery charging
Four Low-Dropout Linear Regulators
and management system with seven power supply
TM
Integrated ActivePath Charger
channels.
2 TM
I C Serial Interface
This device features three step-down DC/DC
converters and four low-noise, low-dropout linear
Advanced Enable/Disable Sequencing Controller
regulators, along with a complete battery charging
Minimal External Components
TM
solution featuring the advanced ActivePath
Tiny 55mm TQFN55-40 Package
system-power selection function.
0.75mm Package Height
The three DC/DC converters utilize a high-
Pb-Free and RoHS Compliant
efficiency, fixed-frequency (2MHz), current-mode
PWM control architecture that requires a minimum
number of external components. Two DC/DCs are
capable of supplying up to 1100mA of output
current, while the third supports up to 1200mA. All
four low-dropout linear regulators are high-
performance, low-noise regulators that supply up to
GENERAL DESCRIPTION
320mA of output current.
The ACT8931A is a complete, cost effective, highly- The ACT8931A is available in a compact, Pb-Free
TM
efficient ActivePMU power management solution, and RoHS-compliant TQFN55-40 package.
optimized for the unique power, voltage-
sequencing, and control requirements of the
TYPICAL APPLICATION DIAGRAM
TM
Innovative Power - 1 - www.active-semi.com
TM TM
ActivePMU and ActivePath are trademarks of Active-Semi.
2 TM
I C is a trademark of NXP.
Copyright 2012 Active-Semi, Inc.
ACT8931A
Rev 3, 29-Nov-12
TABLE OF CONTENTS
General Information ..................................................................................................................................... p. 01
Functional Block Diagram ............................................................................................................................ p. 03
Ordering Information .................................................................................................................................... p. 04
Pin Configuration ......................................................................................................................................... p. 04
Pin Descriptions ........................................................................................................................................... p. 05
Absolute Maximum Ratings ......................................................................................................................... p. 07
2
I C Interface Electrical Characteristics ........................................................................................................ p. 08
Global Register Map .................................................................................................................................... p. 09
Register and Bit Descriptions ...................................................................................................................... p. 10
System Control Electrical Characteristics .................................................................................................... p. 15
Step-Down DC/DC Electrical Characteristics .............................................................................................. p. 16
Low-Noise LDO Electrical Characteristics ................................................................................................... p. 17
TM
ActivePath Charger Electrical Characteristics .......................................................................................... p. 18
Typical Performance Characteristics ........................................................................................................... p. 20
System control information .......................................................................................................................... p. 26
Control Signals ................................................................................................................................. p. 27
Push-Button Control ......................................................................................................................... p. 27
Control Sequences ........................................................................................................................... p. 28
Functional Description ................................................................................................................................. p. 29
2
I C Interface ..................................................................................................................................... p. 29
Voltage Monitor and Interrupt ........................................................................................................... p. 29
Thermal Shutdown ........................................................................................................................... p. 30
Step-Down DC/DC Regulators .................................................................................................................... p. 31
General Description .......................................................................................................................... p. 31
100% Duty Cycle Operation ............................................................................................................. p. 31
Synchronous Rectification ................................................................................................................ p. 31
Soft-Start .......................................................................................................................................... p. 31
Compensation .................................................................................................................................. p. 31
Configuration Options ....................................................................................................................... p. 31
OK[ ] and Output Fault Interrupt ....................................................................................................... p. 32
PCB Layout Considerations ............................................................................................................. p. 32
Low-Noise, Low-Dropout Linear Regulators ................................................................................................ p. 33
General Description .......................................................................................................................... p. 33
Output Current Limit ......................................................................................................................... p. 33
Compensation .................................................................................................................................. p. 33
Configuration Options ....................................................................................................................... p. 33
OK[ ] and Output Fault Interrupt ....................................................................................................... p. 33
PCB Layout Considerations ............................................................................................................. p. 33
TM
ActivePath Charger .................................................................................................................................. p. 35
General Description .......................................................................................................................... p. 35
ActivePath Architecture .................................................................................................................... p. 35
System Configuration Optimization .................................................................................................. p. 35
Input Protection ................................................................................................................................ p. 35
Battery Management ........................................................................................................................ p. 35
Charge Current Programming .......................................................................................................... p. 36
Charger Input Interrupts ................................................................................................................... p. 36
Charge-Control State Machine ......................................................................................................... p. 38
State Machine Interrupts .................................................................................................................. p. 38
Thermal Regulation .......................................................................................................................... p. 39
Charge Safety Timers ...................................................................................................................... p. 39
Charger Timer Interrupts .................................................................................................................. p. 39
Charge Status Indicator.................................................................................................................... p. 39
Reverse-Current Protection ............................................................................................................. p. 39
Battery Temperature Monitoring ...................................................................................................... p. 39
Battery Temperature Interrupts ........................................................................................................ p. 40
TQFN55-40 Package Outline and Dimensions ........................................................................................... p. 41
Revision History ........................................................................................................................................... p. 42
TM
Innovative Power - 2 - www.active-semi.com
TM TM
ActivePMU and ActivePath are trademarks of Active-Semi.
2 TM
I C is a trademark of NXP.
Copyright 2012 Active-Semi, Inc.