User's Manual

Page 15 of 83

A Carrier Corp. Company

PART NUMBER T82002163

REV A

Power Save Mode “Suspend State”

Suspend state is the PXA270 SOM’s hardware power down state, allowing for lower power consumption.

The Suspend state is designed to reduce power consumption while the PXA270 is waiting for an event such

as a keyboard input. The suspend state is entered using Logic BSP’s by asserting the nSUSPEND signal or

through software. The PXA270 processor is put into Standby Mode. All power supplies remain active.

System context is retained. Internal clocks are stopped except RTC. An internal or external wakeup event

can cause the processor to transition back to Run Mode.

IMPORTANT NOTE: Although Suspend consumes less power than Run state, it consumes more power

than the Standby state. Thus, on a power failure, the PXA270 system will actually leave the Suspend state

and transition to the Standby state (the same thing occurs on a SW_nRESET).

During suspend state, the unit powers OFF the LCD backlight, printer head, and printer control board.

When user reinitiates activity, the unit returns to full active state of all devices.

If needed, user may engage the Reset Button located on the right-side of the unit.

Power Supply

The following are methods a user is able to supply power to the TripStripII device to charge/operate:

1. Dual Voltage 120/60 Hz (220/50 Hz) – 15VDC Wall Adapter

2. 12 VDC automobile DC adapter

3. 24 VDC trailer truck DC adapter

Internally, the TripStripII power supply consists of:

1. LT4356-1, Overvoltage Protection Regulator and Inrush Limiter IC

• The LT4356-1 surge stopper protects loads from high voltage transients.

• It regulates the output during an overvoltage event, such as load dump in automobiles, by

controlling the gate of an external N-Channel MOSFET.

• The output is limited to a safe value thereby allowing the loads to continue functioning.

• The LT4356-1 also monitors the voltage drop between the VCC and SNS pins to protect against

overcurrent faults.

• An internal amplifier limits the current sense voltage to 50mV.

• In either fault condition, a timer is started inversely proportional to MOSFET stress.

• If the timer expires, the /FLT pin pulls low to warn of an impending power down. If the condition

persists, the

MOSFET is turned off.

2. LTC4006, 4A, High Efficiency, Standalone Li-Ion Battery Charger

• The LTC4006 is a complete constant-current/constant voltage charger controller for 2-, 3- or 4-cell

lithium batteries.

• The PWM controller is a synchronous, quasi-constant frequency, constant off-time architecture

that will not generate audible noise even when using ceramic capacitors.

• Charging current is programmable with a single sense resistor to ±4% typical accuracy.

• Charging current can be monitored as a representative voltage at the IMON pin.

• A timer, programmed by an external resistor, sets the total charge time or is reset to 25% of total

charge time after C/10 charging current is reached.

• Charging automatically resumes when the cell voltage falls below 3.9V/cell.