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The DP022 is a fully compliant ATX power supply designed to power a low power PCs from a single 12V power source.
The DP022 power supply has an MCU that controls and monitors various functions of the power supply
operation. Also, it realizes voltages monitoring, temperature monitoring and communication via COM-port
with computer. As well the MCU realizes a WatchDog timer to supervise the computer. A LED indicator
continually reports the power system status and health.
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There are four main operating modes of the DP022 - Deep Sleep, Sleep, Standby, Power On.
The DP022 has user selectable MCU driven timing settings, allowing you to choose various
ignition/shutdown vehicle computer timing schemes (settings). These settings are user
adjusted and saved in EEPROM.
One of most difficult tasks of operating a computer in a vehicle is power consumption while
the computer is OFF. Even if your computer is totally OFF (standby mode), a computer
will still consume a few hundred milliwatts, needed to monitor computer ON/OFF status.
All power supplies provide 5Vsb (5V standby) so that the motherboard can issue at least
a PSON signal. When the computer is in the suspend/sleep mode, it will consume even more power,
because the RAM needs to be powered at all times. The power consumption in the suspend mode
is few Watts. No matter how big your car battery is, it will eventually drain your vehicle
battery in a matter of days. The DP022 is addressing these issues by cutting off the 5VSB rail
after a pre-defined amount of time (timing settings). The DP022 monitors battery voltage to
protect against deep discharge. When battery level drops below predefined value for more than
predefined time, the DP022 will shut down and re-activate only when the input voltage is >
predefined value.
Of course, there is a traditional PC PSU mode setting with no ignition control (shutdown logic
bypassed) and it can be used in non-vehicle computer applications.
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User manual
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| Features |
- Wide input range (9-25V)
- Suitable for automotive applications
- Suitable for battery powered applications
- Complete with start-up/shut-down control (user adjusted, saved in EEPROM)
- Compatible with most ITX boards equipped with a 20pin ATX connector
- Extended lifetime due to ceramic capacitors using
- Silent operation (fanless, no moving parts)
- Temperature control
- Low heat dissipation (efficiency over 90%)
- pen frame, chassis mountable, measurements: 39x170x20
- Connection via COM-port with computer
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| Specification |
- Output power 55W.
- Input voltage : +9~25VDC (nominal - 13,5V).
- Output : +12V 0~2A | +5V 0~6A | +3,3V 0~6A | -12V 0~0,1A | +5Vsb 0~6A
(at 13,5V input)
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NOTICE: Total current on 5Vsb and 5V rails does not exceed 6A. Use the DP022 only with low
power motherboards (all VIA C3/C7 CPUs and Pentium-M / CoreDuo) that use V(core) from
the 5V rail. Do not use general purpose motherboards or 5.25” CDDs as they tend to use a lot
of current on the 12V rail. It's desirable to use 2.5” drives, SlimCDDs or FlashDisks
as they use only current from the 5V rail. Do not connect a Car Battery Charger directly
to the DP022.
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Connection to car electrical system
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The DP022 should be attached and tuned by specialized personnel only after familiarizing with
User manual
Please take a moment and read this manual before you install the DP022 in your vehicle.
Often rushing into installing the unit can result in serious damage to your DP022 converter,
computer and probably your car electrical system. The DP022 has several wires that need
to be installed in various places. When installing, always double check the polarity of
your wires with a voltmeter. NEVER use the cigarette plug as a power source; often the
contacts are not capable of delivering high current to your PC.
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Connect the IGNITION+ to the switched +12 Volt supply wire (“ignition” circuit or fuse box).
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Connect GND and POWER circuits with heavy gauge wire directly to the automotive
batteries (+) and (–) terminals. GND may also be connected with heavy gauge wire to
the Chassis if desired.
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Apply 12 Volts to IGNITION+ by turning on the ignition or by flipping a switch and you’re ready to go!
NOTICE! It is desirable to connect the DP022 to 12V car electrical system via surge protector (shown
hatched). This device should suppress glitches above 25V that sometimes occur in 12V car electrical system
and should provide conducted immunity according to ISO7637.
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The DP022 can be tested in the lab before being installed into the vehicle. Certain details need to be
noted for proper bench testing. When connecting bench power use between 12 to 16 Volts DC to POWER (+)
and GND (BATTERY) (-) terminals for best results. The best way to do successful bench testing is to use
an adequately sized 12V battery. Bringing in the battery from the car or using an extra one that has
at least a 10-AmpHour capacity will be sufficient in most cases. To aid in bench testing, do not connect
IGNITION+ anywhere. The DP022 will operate as “dumb PSU” with button “POWER” control.
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Connection to the battery that is charged by AC-DC charger;
Creation of high efficiency uninterruptable power supply (UPS)
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Connect GND and POWER circuits with heavy gauge wire directly to the batteries (+) and (–) terminals and
charger as shown on figure below. Charger should have rectangular output characteristic (constant current
with voltage limit) that has been complied with battery parameters. This compliance is quite difficult
and is beyond the scope of this application note and will not be discussed here.
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CAUTION! Wrong type of battery and charger maybe the cause of low efficiency this circuit and even
maybe the cause of demage of battery and charger.
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