OPUS
ATX/ITX DC-DC 90W Power Supply User Guide
Solutions, Inc.
www.opussolutions.com
©
OPUS Solutions, Inc. 2002,2003; UG-DCX3.xx09 14-MAR-04
2
General Information
Power input
Powered by 12Volt or 24 Volt battery systems. The Computer on and off sequence is determined by the state of ignition/switch
input. The DCX3.xx09 power supply is compatible with ATX/SFX power specification.
Normal operating condition
When the computer is properly assembled, cabled, configured and power applied to the DC-DC power supply it should
function as described below.
Idle state (ignition off):
In an idle (ignition off) condition, the Status Green LED light in the power supply will blink for 100ms ON and OFF for
approximately 2.5 sec. The PC is powered down. Only standby power is supplied to the motherboard. The power
consumption should be at very minimum. (The idle state power consumption varies depending on the motherboard
manufacturer, bios setup, amount of memory modules installed and other hardware installed).
PC ON State:
When the ignition switch is turned on the Status LED light will be ON constantly with in 9 seconds. This indicates that proper
handshakes and controls were accomplished between DC-DC power supply and the motherboard, and they are operating
normally. The operating system should be booting, coming out of standby or hibernate mode. The PC is ready for your use.
Back to Idle state:
When the ignition switch is turned off, The DC-DC power supply will delay going into shut down, stand-by or hibernate modes.
The delay time is set by a jumper located on the narrow side the DC-DC power supply (Refer to the heading ‘Setting the turn
off delay’). Once the delay time has elapsed, the DC-DC power supply hand shakes and controls with the motherboard to go
into one of three states namely shut down, standby or hibernate mode if supported by the motherboard.
If the ignition is turned on again, while shut down delay is in progress, the DC-DC power supply will turn off the delay function
and the PC will continue operate normally. If the PC is manually put into stand-by mode, taping the keyboard or pointing
device will start the PC as long as Ignition is on and the mother board BIOS is setup for the this function. If the PC is manually
put into power down mode, to restart the PC the ignition must be turned off for at least 5 sec and turned on again.
Abnormal condition:
If the green LED light flashes at a faster rate, this indicates a problem condition. Count the number of flashes and refer to
trouble shooting section to determine the nature of the fault.
Battery management
The normal full load operating voltage range of the power supply hardware is between 7.5V to 18VDC. However, if the battery
voltage dips below the set low battery voltage level for more than 10 sec. Continually the microcontroller in the DCX3.xx09
smart power supply will go into shut down sequence. This prevents the battery from deep discharge, which may cause
permanent damage or shorten life of the battery, and it is saved for its main intended purpose, to start the vehicle.
Stand-by power control
The Stand-by power to motherboard operation is controlled by a pair of pins on JU1 on the DC-DC power supply.
Jumper not installed:
The stand by power is turned off immediately after shut down sequence. In this setup, the
computer system can only go into power down or hibernate mode but CANNOT go into stand-by
mode. The power drain on the battery will be the minimum, less than 0.25W.
Jumper installed:
The stand-by power is maintained after shut down sequence. If the battery voltage dips below the
low battery voltage limit during idle state of the computer system, the stand-by power will be turned
off to protect the battery. It is also turned off if an error condition is detected during shut down
sequence. In this set up the computer system can go into power down or stand-by modes. The
power drain on the battery is determined by the motherboard make and model, I/O devices that are
enabled for stand-by, amount of memory, etc. The power drain on the battery can be between 1 to
8Watts.
Power-up on interrupt
The computer system can be powered up by an interrupt source without ignition or On/Off input being enabled. In this mode
the computer system will go into shut down sequence 20 minutes after interrupt wake up or power up. This
mode of
operation
is useful if you need to wakeup the computer system for software updates, up or down loading files from
the vehicle
computer
system over wireless network without physically turning on the ignition or ON/OFF input to the vehicle computer system.
