Control and indicator functions, Pson, Figure 4: pson# signal characteristics – SSI America EPS2U User Manual
Page 26: Table 28: pson, Signal characteristic, 1 pson
SSI
EPS2U Power Supply Design Guide, V2.1
8
Control and Indicator Functions
The following sections define the input and output signals from the power supply.
Signals that can be defined as low true use the following convention:
signal
#
= low true
8.1 PSON#
STATUS
Required
The PSON
#
signal is required to remotely turn on/off the power supply. PSON
#
is an active low signal that turns
on the +3.3 V, +5 V, +12 V, and -12 V power rails. When this signal is not pulled low by the system, or left open,
the outputs (except the +5 VSB and Vbias) turn off. This signal is pulled to a standby voltage by a pull-up resistor
internal to the power supply. Refer to Figure 3 for timing diagram.
Table 28: PSON
#
Signal Characteristic
Signal Type
Accepts an open collector/drain input from the system.
Pull-up to VSB located in power supply.
PSON
#
= Low
ON
PSON
#
= Open or High
OFF
MIN
MAX
Logic level low (power supply ON)
0 V
1.0 V
Logic level high (power supply OFF)
2.0 V
5.25 V
Source current, Vpson = low
4
mA
Power up delay: T
pson_on_delay
5 ms
400 ms
PWOK delay: T
pson_pwok
50
ms
Hysteresis
≥ 0.3V and/or other de-bounce method
Disabled
Enabled
≥ 2.0 V
PS is
disabled
≤ 1.0 V
PS is
enabled
1.0V
2.0V
0V
5.25V
Figure 4: PSON# Signal Characteristics
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