Eurotech Appliances ZEUS PXA270 - Manual (Page 63)

ZEUS Technical Manual Power and power management
© 2007 Eurotech Ltd Issue D 63
Power and power management
Power supplies
The ZEUS is designed to operate from a single +5V±5% (4.75V to +5.25V) input or the
onboard 10V to 30V DC/DC PSU.
DC input voltage (10-30V)
DC input voltage (10-30V) is connected through a front panel locking DC jack J3 (see
the section J3 – Power connector (10-30V) , page 78 ). When operating from the 10 to
30V input, the 5V connector (J2) is NOT fitted. The input rails are protected from
overcurrent, overvoltage, undervoltage and reverse battery conditions, and include
transient suppression to achieve compatibility with vehicle power supplies. The on-
board DC/DC converter can provide a maximum current of 5A at 5V at a temperature
range of 0-70°C (32-158°F).
For vehicle-based applications, the supervisory circuit monitors the auxiliary ignition
supply input (Vig), and provides feedback of ignition status to the PXA270 (IG_FAIL
signal at GPIO115). If the Vig falls below 9.2V, IG_FAIL becomes logic ‘1’. This can be
used to instigate an orderly shutdown or to store ignition status data.
5V only operation
For 5V only operation, the ATX style connector J2 is used as the main power input for
the ZEUS. In this case, connector J3 and the entire DC/DC PSU circuit is depopulated.
The power connector J2 has a +12V connection too, but it is not required for the ZEUS
under normal operation. It can be used to supply +12V to the PC/104 stack if required.
For details of the 5V power connector see the section J2 – Power connector (5V
option) , page 78 . Contact Eurotech Sales (see page 97 ) for details.
If a CompactFlash and an LCD display are used, ensure the total current
requirement on the 3.3V rail does not exceed 900mA. Please check the
datasheets of the devices you are using.