Mother Board
ON/OFF
-
+
M3-ATX
6-24V Intelligent ATX Power Supply
Installation Guide
Version 1.0b
P/N M3-ATX-01
Before you start…
Please take a moment and read this manual before you install the M3-ATX in your
vehicle. Often times, rushing into installing the unit can result in serious damage
to your M3-ATX board, computer and probably your car’s electrical system. Always
double check the polarity of your wires with a voltmeter.
Avoid using the cigarette plug as a power source, often times the contacts are not
capable of delivering high current to your PC.
Introduction
Thank you for purchasing the M3-ATX power sequencer / vehicle ATX power supply.
The M3-ATX was designed to work with a wide variety of main boards such as the VIA
mini-ITX motherboards as well as Pentium-M / Celeron or full power Pentium systems.
M3-ATX Logic Diagram
Battery
Ignition SW
Amplifier
Enable
+
GND
2
Reverse and
forward protection
Switch Logic 6-24V DC-DC
8bit MCU
ATX PSU
6
8
M3-ATX
PC ATX
power
Status LED
Serial ctlr 4
1.2 M3-ATX Connection diagram
Power Input Connectors (right side)
Red Battery + (positeive, un-switched battery)
Black Battery - (negative)
White Ignition (switched battery, positive. Can test by connecting it to Battery +)
Power Output Connectors (left side)
Hard drive wire harness (HDD, SATA-HDD, Floppy)
ON/OFF and THUMP wire harness (connects to M3-ATX pin header)
-ON/OFF wire harness (red/back) to connect to motherboard’s ON/OFF pin headers.
-THUMP (white) to connect to amplifier remote ON/OFF connector.
P Off-delay Hard-off
Standard PSU mode
P0
5sec 1 min
P1
1 min 5 min
P2
30 min 2 hour
P3
custom custom
P4
Wire harness for motherboard ON/OFF
switch and Thump control (optional)
Wire harness for serial connection.
IMPORTANT: Always use the “Hibernate” feature on your PC, never use “Standby”.
P0: In this mode, the M3-ATX behaves like a regular ATX power supply.
M3-ATX User Guide Page 2
P1: Sends ON pulse to motherboard when ignition is ON for more than 2 seconds,sends
OFF pulse to motherboard 5 seconds after ignition is turned off. Waits another 1
minute and then shuts down 5VSB to conserve battery. In this mode, the M3-ATX
consumes less than 0.5mA. This is our recommended setting.
P2: Sends ON pulse to motherboard when ignition is ON for more than 2 seconds,
sends OFF pulse to motherboard 60 seconds after ignition is turned off. Waits another 5
minutes and then shuts down 5VSB to conserve battery.
P3: Sends ON pulse to motherboard when ignition is ON for more than 2 seconds,
sends OFF pulse to motherboard 30 minutes after ignition is turned off. Waits another 2
hours and then shuts down 5VSB to conserve battery.
P4: Can be set to any value. Setting can be done via an optional serial cable.
(Default values for P4 are Off-delay=30sec, Hard-off=30sec)
NOTE: To reset to the M3-ATX settings to the factory defaults (in case changes were
made via the serial uplink), simply power off the unit, connect a jumper as shown and
then power back up. The LED light will start to flash rapidly indicating that the factory
defaults were loaded. Don’t forget to Remove jumper when done!.
Power challenges in a Vehicle PC: One of most difficult tasks of operating a PC in a
vehicle is power consumption while the computer is OFF. Even when your computer is
OFF, it will still consume about 100mA on the 5V rail. When the computer is in the
suspend mode, it will consume even more power, because the RAM needs to be
powered at all times.
No matter how big your battery is, you will eventually drain it if proper actions are not
taken.
The M3-ATX is addressing these issues by cutting off the 5VSB rail after a pre-defined
amount of time (see jumper chart, HARDOFF). During the HARDOFF if the battery level
drops below 11.2V for more than one minute, M3-ATX will shut down and re-activate only
when the input voltage is > 12V.
Engine Cranks, under-voltage and over-voltage situations. Another difficult task is
maintaining stable power to your PC. While car batteries are rated at 12V, they actually
provide voltages in between 7-11V (engine cranks) or as high as 80 volts (load dump).
Most of the times, your battery will stay at 13.5V (while car is running) but extra
precautions need to take place in order to prevent such situations. M3-ATX can operate
as low as 6V and as high as 24V while providing strict regulation on all rails along with
input voltage clamping and reverse protection.
Loud amplifier pops when PC starts. If your PC is connected to your car amplifier, you
will hear a loud pop when the computer is first started. The M3-ATX has an ‘anti-thump’
control that will keep your amp OFF while the PC starts. Simply connect the white wire
from your M3-ATX cable harness to your amplifier remote control pin.
Mode of operation
1) Ignition=OFF. Nothing happens. M3-ATX is waiting for ignition signals.
2) Ignition=ON. M3-ATX waits for 2-3 seconds then turns on the 5Vsb rail. After another second M3-ATX
sends an“ON” signal to the motherboard via the 2 wires connected to the motherboard’s ON/OFF pins.
The motherboardwill turn ON and your system should start booting.
M3-ATX User Guide Page 3
3) Ignition=ON. Your computer will remain ON.
5VSB 1.5A 2A 1.5%
-12V 0.15A 0.2A 10%
12V 4-6A (see below) 8A (see below) 2%
When operating at <8V or >16V or extreme temperatures, de-rate by 25-50%, ventilat ion will be required.
12V Rail Output Current (buck/boost converter)
Input (V) 12V out current Input (V) 12V out current
6-8V 4A (6A peak) 11-16V 6A (8A peak)
8-11V 5A (7A peak) 16-24V 4A (7A peak)
4) Ignition=OFF. M3-ATX waits for “OFFDELAY” in seconds (see jumper chart) and then it turns the motherboard
OFF by sending a signa l to the motherboard’s ON/OFF switch. Your computer should turn off gracefully
(shutdown procedure). After shutdown,
5) 5VSB will still be p rovided for another “HARDOFF” seconds. In the event where the shutdo wn process is longer
than “HARDOFF” (Opera ting System gets frozen, etc), power will be shut do wn hard, turning off all power rails.
During the HARDOFF procedure, the battery levels will be constantly monitored to prevent deep discharge
situations.
6) M3-ATX will go to step 1, if ignition is tuned ON again.
NOTE. When al l config. jumpers are removed, M3-ATX acts as a regular power sup ply, no ignition timing, no
HARDOFF. M3-ATX will send a gratuitous “ON” pulse to the M/B when power is applied for the first time. Do not
connect the on/off switch if you don’t want your PC to be started automatically.
Troubleshooting
a) Motherboard is not turning ON: Check input cables.Make sure you have a a well
tighten wire harness. Measure the un-switched pin (red). You should see 12V (car on) or
0V (car off). NOTE: In P1, P2, P3 modes if V(In) is < 12V, the M3-ATX will not start.
b) Motherboard is not turning ON (cont): Ensure total system power consumption
does not exceed the M3-ATX specifications.
c) Motherboard is not turning ON (cont). Make sure that the ON/OFF wire harness
from the M3-ATX is connected to the ON/OFF switch of your M/B.
M3-ATX Characteristics
Minimum Input Operating. voltage 6V
Maximum input Operating voltage 24V (clamping wil l occur at 25-27V)
Deep-Discharge shutdown threshold 11.2V
Input current limit (fuse protected) 15A
Max Output Power 125 Watts (8-16V, see chart below)
Deep Sleep Current Consumption. < 0.5mA
Storage and operating temperature -55 to +125 degrees Celsi us (storage), -40 – 65C (operating)
MTBF 150,000 hrs @ 50C, 96,000 hrs @65C
Efficiency (Input 9- 16V) >94%, all rails combined, 50% load.
Input connectors Faston 0.25” terminal
Output Connector AT X Power 20 pin (Molex P/N 39-01-2200)
*Units starts failing at >125 Celsius. Operating at temperatures above 85C / 185F will drastically reduce the MTBF.
Maximum Power Characteristics
Output Rail Current (Max) Current Peak
5V 6A 8A 1.5%
3.3V 6A 8A 1.5%
(<30 seconds)
Regulation
M3-ATX User Guide Page 4
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