Hercules-EBX CPU User Manual V1.02
Page 30
4.23 Low-Voltage Power Input Connector – J29
1
+Vin
2
+Vin
3
Ground
4
Ground
5
+12V
6
Ground
7
+Vin
8
-12V
9
-5V
10
Power Supply ON
Table 24: J29 – Main Power Input Connector Pinout
Signal Name
Definition
+Vin
Main Input Power (+5V - +28V input range * : see below)
Ground
0-V (Ground) power return path
+12V
Power Supply for in-board 12V devices (including hard drives, auxiliary
power, PC/104 power, and LCD Backlight). Range should be 11.9V-
13.5V measured at this connector
-12V
Power Supply for PC/104+ -12V devices (no on-board devices)
-5V
Power Supply for PC/104+ -5V devices (no on-board devices)
Power Supply ON
Feedback pin for external ATX supply (when needed) – pulled low when
on-board power is inactive
The standard Hercules-EBX Input power is supplied either through J29 from an external mid-
range supply. (An option for higher-voltage power supply input may be available).
Hercules-EBX in the standard, mid-range power input configuration supports a voltage range from
+4.75V - +28V (with some restrictions). For input voltages from +4.75V to 6V (measured at J29),
the function of some 5V devices may be affected due to high-current draw and voltage dips
encountered due to these current variations. Specifically:
•
Hard Drives attached to the system may not power up correctly and/or may reset;
•
Hard Drives, CD-ROMs, and other high-power devices may also draw too much power at
these low voltages, causing the system to reset – External power supplies for high-power
devices are strongly recommended when the input supply is likely to be this low;
•
PS/2 and USB devices may function erratically (or not at all) at low input voltages (an external
powered USB hub may alleviate this problem somewhat) – NOTE : this includes USB
keyboards, mice, and especially USB boot devices (floppy drives and USB flash drives)
•
RS232 range and functionality may suffer;
•
Audio Speaker output power may be limited; and
•
Data Acquisition accuracy may potentially be slightly affected.
At input voltage ranges above 6V (6V – 28V), these concerns are no longer issues. This main
input voltage (“Vin”) is used to derive all on-board voltages and power supplies via on-board
switching regulators.
The “+12V” power supply input is intended for all on-board (and board-controlled) 12V power
supplies, including the PC/104+ 12V supplies, the external hard drive power supply (through J15,
described above), and the LCD backlight. If these devices are not to be used, then the “+12V”
input may be left unconnected.
