Eurotech BitsyXb - Page 5

Contents
110118-0001A 5
4.7 Discrete IOs ......................................................................................................................... 40
4.7.1 Digital IOs ................................................................................................................. 40
4.7.2 Analog Inputs ............................................................................................................ 40
4.7.3 Analog Outputs (PWM) ............................................................................................. 40
4.8 EMI/RFI and ESD Protection .............................................................................................. 41
4.8.1 Agency Certifications ................................................................................................ 41
4.8.2 Protecting the Power Supply Inputs .......................................................................... 41
5 Power and Power Management ....................................................................................................... 42
5.1 Power Management Modes ................................................................................................. 42
5.1.1 Power Management Modes ....................................................................................... 42
5.1.2 Power Management on the BitsyXb .......................................................................... 42
5.2 Architectural Overview and Power Management Features ................................................. 43
5.2.1 Power Supply Architecture ........................................................................................ 43
5.2.2 Subsystem Partitioning .............................................................................................. 44
5.2.3 System Sleep ............................................................................................................. 46
Power Failure Interrupt
RQOnOff Input
Software Control
5.2.4 System Wakeup ......................................................................................................... 46
RQOnOff Input
Touch Panel
Timed Wakeup
ADSmartIO/Keypad
5.2.5 Supercapacitors .......................................................................................................... 47
Charging
Discharging
5.2.6 Backlight Power ........................................................................................................ 48
5.2.7 Battery Trickle Charger (volume production option) ................................................ 49
5.2.8 Power Supply Efficiency ........................................................................................... 50
5.3 Designing for Optimal Power Management ........................................................................ 50
5.3.1 Create a Power Budget for Peripherals ...................................................................... 50
3.3 V Loads
5 V Loads
Loads on Main Supply
5.3.2 Power Loads During Sleep ........................................................................................ 51
5.4 Power Supply Examples ...................................................................................................... 51
5.4.1 Basic DC Supply ....................................................................................................... 51
5.4.2 Automotive System ................................................................................................... 52
5.4.3 Line Power and Battery with External Charger ......................................................... 52