User`s guide

Hardware Components
20 M1 System Management Board User’s Guide
PS_ON# Signal
The ATX supply plugs in to the J72 connector. The PS_ON# signal is the main switch for the ATX supply. The signal
logic is controlled by the signal AFS_PS_ON on the M1AFS1500-FG484 device.
Power_OK Signal
The PWR_OK signal is an output of the ATX supply. It is a flag set by the ATX supply if all output voltages are good.
The PWR_OK is continuously monitored by the M1AFS1500-FG484 device using a regular I/O pin
IN_POWER_OK.
5VSB Signal
The 5VSB signal on the J72 ATX supply is routed directly to the 5VSB pin on the J73 ATX connector. It does not go to
the M1AFS1500-FG484 device. This signal is a sense voltage, which is an input signal to the ATX supply from a
plugged in daughter board.
Gate Driver
All input voltages (12 V, 5 V, 3.3 V) are monitored through the AV pads on the M1AFS1500-FG484 device (Figure 2-
8 on page 18). The input voltage goes to a P-Type Power MOSFET (FDS7079ZN3). All three voltages can be switched
On/Off using the gate driver (AG) controlling the FET.
COM 16
COM 17
N/C 18
PS_ON# 14
PWR_OK 8
Table 2-9 · ATX Main Power Connect Pinout by Function (Continued)
Signal Function Pin Number
Table 2-10 · PS_ON# Signal Settings
AFS_PS_ON
(M1AFS1500-FG484)
PS_ON# (ATX) ATX Supply
01Off
10On
Table 2-11 · PWR_OK Signal Settings
PWR_OK (ATX)
IN_POWER_OK
(M1AFS)
ATX Supply
0 3.3 V BAD
5 V 0 GOOD