80W DC/DC POWER SUPPLY FOR CARPC
1  Function Description
DC/DC ATX power supply for automobile application, 7V-20VDC input, +5V,+12V,+3.3V,-12V,+5VSB and PG (power good signal) outputs.
2  Operation Environment
Item Unit Minimum Typical Maximum Test Conditon
Temperature ?äðDIV> -20   50   
RH %RH 40   90 No Condensation  

3 Technique Requirement
3.1 Input Characteristic
Item Unit Minimum Typical Maximum Test Conditon
DC INPUT Vdc 9.0   20   
Iput Current A         
Input Inrush Current A     10   
  

3.2  Output Characteristic
3.2.1  Output Voltage Regulation
Output Min. Load Max. Load Peak Load Output Voltage range Ripple??pk-pk????rated load??20MHz limit??*
+5V 0.5A 5A 6A 4.75~5.25V 50mV
+12V 0.1A 2A 4A 11.40~12.60V 120mV
+3.3V 0.5A 5A 6A 3.14~3.55V 100mV
-12V 0A 0.3A   -11.0~-13.2V 120mV
+5VSB 0.1A 1.5A 1.5A 4.75~5.25V 100mV
PG       4.75~5.25V   


*: Need to add 47?̆/16V tantalum capacitor and 0.1?̆ high frequency capacitor on test point when testing.
3.3V and + 5V total output power not to exceed 40W
3.3V, + 5V and +12V total output power not to exceed 60W
3.2.2 Cross Regulation
The output voltage and output ripple should satisfy the following specification under the below 4 conditions

Input Output Loading Output Range Ripple
9VDC +5V 5A 4.75~5.20V 50mV
+12V 2A 11.4~12.6V 120mV
+3.3V 5A 3.10~3.40V 100mV
-12V 0.3A 11.0~13.2V 120mV
+5VSB 0.5A 4.75~5.25V 50mV
9VDC +5V 0.5A 4.75~5.20V 50mV
+12V 0.2A 11.4~12.6V 120mV
+3.3V 0.4A 3.04~3.40V 100mV
-12V 0.1A 11.0~13.2V 120mV
+5VSB 1.5A 4.75~5.25V 50mV
20VDC +5V 5A 4.75~5.20V 50mV
+12V 0.2A 11.3~13.0V 120mV
+3.3V 5A 3.10~3.40V 100mV
-12V 0.3A 11.0~13.2V 120mV
+5VSB 0.5A 4.75~5.25V 50mV
20VDC +5V 0.5A 4.75~5.20V 50mV
+12V 2A 11.5~12.9V 120mV
+3.3V 2A 3.10~3.40V 100mV
-12V 0.3A 11.0~13.2V 120mV
+5VSB 1A 4.75~5.25V 50mV


3.2.3 Others Output Characteristics
Item Unit Minimum Typical Maximum Test Conditon
Output Power W     72W DC output power  
Efficiency % 80     Rated load
            
Turn on Overshoot %     10   
Rise Time ms     10 Output voltage up from 0% to 95%??rated load
Hold up Time ms 2     Rated load

3.3  EMC Requirement
Item Request Standard Judgement Grade
Conducted interference  CLASS A, 3dB margin GB9254-1998 Ensure system pass the CLASS A and have 3dB margin
Radiation interference CLASS A, 3dB margin GB9254-1998 Ensure system pass the CLASS A and have 3dB margin
Harmonic Current   GB17625.1??1998   

3.4  Protection Function
Item Unit Yes/No Minimum Typical Maximum Recovery Characteristic  
Input invertion protection   Yes         
+5V OVP V Yes 5.8   6.8 Latched, need to re-apply DC input to recovery
+12V OVP V Yes 13.2   15.6 Latched
+3.3V OVP V Yes 3.9   4.3 Latched
Output Over Power Protection??+5V,+12V?? Ratio to rated load Yes   150%   Latched


  
Output Over Power Protection??+3.3V?? Ratio to rated load Yes   250%   Latched
Short CircuitProtection??+5V,+12V,+3.3V??   Yes       Lached

      

4  Monitoring ,Signal Control
4.1 Process Sequence
Item Name Characteristic   
1 Ignition
(The Ignition signal controlled by the voltage signal from the key) 1)     Ignition=OFF, Nothing happens??waiting for Ignition signal ON??
2)     Ignition=ON??wait for 3-4s??open ??5VSB output??after another 1s the MCU sends an ??ON?? signal to the motherboard via the 2 wires connected to the motherboard??s ON/OFF pins. The motherboard will turn ON and your system should start booting??
3)     Ignition=ON?? nothing happens??your computer will remain ON.
4)     Ignition=OFF ,wait about 10s and then it turned motherboard OFF by sending a signal to the motherboard??s ON/OFF switch. Your computer should turn off gracefully. During this time, power will still be available for your PC to perform shutdown??
5??Ignition=OFF after 10s. Power will still be provided for another 50s, long enough for most soft shutdown processes. In the event where the shutdown processes is hanging, power will be shutdown hard, turn off your computer??s main power source to prevent battery drain.
6??Go back to step 1??until ignition is turned ON again??   
2
  Controlled
motherboard
signal??PS-ON?? PS-ON is to control motherboard ON/OFF switch for ??soft?? start/stop sequence.. PS-ON is activated 5s after the ignition circuit is turned on and 10s after the ignition turned off.
   
3

  Power good signal
??PG?? The PG signal comes from the  No. pin8 of the 20pin output connector, it indicate the power supply working condition, this ??TTL?? signal is the result of ??AND?? relationship with DC output and DC input voltage . On working condition, if the DC input voltage is well within it??s operation range, then the PG signal is sent out (PG is in H logic) after 100-500ms delay. If the DC input voltage down and below to 11V, or the one of DC output voltage out of it??s normal range, then send out Power Fall signal (that is: PG is in L logic). The Power Fall signal fall to below 0.3V, should have 1ms (at least) before the +5V output down to 4.5V,. And the PG signal??s slop during the rise up and fall down
Should be smooth and no any oscillation happened.  PG signal should have the capacity to drive 6 standard TTL loading.
Following is the under voltage level of each output:
Output +5V  +12V +3.3V -12V
UVP level +4.5V +10.8V   -10.4V
  
   
4

  Sleeping mode control
(ON/OFF) The ON/OFF signal comes from the  No. pin14 of the 20pin output connector, is to control the power supply??s working state. (Be active in ??L?? level). If the ON/OFF signal is in floating, the power supply will have no output (except 5VSB ) and in sleeping mode . The 5VSB should be within the range of 4.75-5.25V under 1.5A loading condition, and no any audible noise can be heard. If the ON/OFF signal is shorted to ground, the power supply will be in normal working condition and have normal output voltage.   
5 Battery Protection The power supply will shutdown hard when the battery voltage below 11V, and the power supply will recovery ON when the battery voltage back and exceed 12V.
      
6 Hand control The power output set by the jumper wire. when it??s set in automation mode, the power supply will work according to the process of the item 1.
When it??s set to hand control mode, it controlled by external switch:
1)     Ignition=OFF, Nothing happens??waiting for Ignition signal ON??
2)     Ignition=ON??wait for 3-4s??open ??5VSB output??the power supply go into sleeping mode, waiting for switch ON/OFF.
3)     Ignition=ON??press the switch button one time, sends an ??ON?? signal to the motherboard .The motherboard will turn ON and your system should start booting??
4)     Ignition=ON, during power be in ON condition, press the switch button one time (<1s transient time). Nothing happens.
5)     Ignition=ON, during power be in ON condition, press the switch button for 3-4s, then send an ??OFF?? signal to the motherboard, the power supply go into sleeping mode.
6)  Ignition=OFF, during power be in ON condition, wait about 10s and then it turned motherboard OFF by sending a signal to the motherboard??s ON/OFF switch. Your computer should turn off gracefully. During this time, Power will still be provided for another 50s, long enough for most soft shutdown processes. In the event where the shutdown processes is hanging, power will be shutdown hard, turn off your computer??s main power source to prevent battery drain.
7?? Ignition=OFF after 10s. during power be in OFF condition. Power will be shutdown include +5VSB output.
8??Go back to step 1??until ignition is turned ON again??