pc电源中PWR_OK的作用是什么?

PS_ON# is an active-low, TTL-compatible signal that allows a motherboard to remotely
control the power supply in conjunction with features such as soft on/off, Wake on LAN*,
or wake-on-modem. When PS_ON# is pulled to TTL low, the power supply should turn
on the four main DC output rails: +12VDC, +5VDC, +3.3VDC and -12VDC. When
PS_ON# is pulled to TTL high or open-circuited, the DC output rails should not deliver
current and should be held at zero potential with respect to ground. PS_ON# has no effect
on the +5VSB output, which is always enabled whenever the AC power is present. Table
16. lists PS_ON# signal characteristics.
The power supply shall provide an internal pull-up to TTL high. The power supply shall
also provide de-bounce circuitry on PS_ON# to prevent it from oscillating on/off at startup
when activated by a mechanical switch. The DC output enable circuitry must be SELVcompliant.
The power supply shall not latch into a shutdown state when PS_ON# is driven active by
pulses between 10ms to 100ms during the decay of the power rails.

看功能描述,觉得就是点晶二次侧监控IC的PGO脚位的功能.就是告诉后面的主板电源已经工作正常.PGO为高电平时表明电源工作良好,低电平时说明电源有问题.从IC的PGO脚出来会先接一个拉高电阻.
把PWR_OK的线剪断,主板照常启动,可能是因为拉高电阻的原因,让主板端接受的信号是高电平.(楼主也说了测主板端PWO_OK脚有5v电压,是高电平.)
猜测是这样.

楼上的兄弟,你说的是PS_ON,好像跟PWR_OK不一样

看错里,哈哈,抄的啊


PWR_OK is a “power good” signal. This signal should be asserted high by the power
supply to indicate that the +12 VDC, +5 VDC, and +3.3 VDC outputs are within the
regulation thresholds listed in Table 15 and that sufficient mains energy is stored by the
converter to guarantee continuous power operation within specification for at least the
duration specified in Section 3.2.9. Conversely, PWR_OK should be de-asserted to a
low state when any of the +12 VDC, +5 VDC, or +3.3 VDC output voltages falls below
its under voltage threshold, or when mains power has been removed for a time
sufficiently long such that power supply operation cannot be guaranteed. The electrical
and timing characteristics of the PWR_OK signal are given in Table 21 and in Figure 2.

是给主板信号说明电源已经OK,但在实际中发现把PWR_OK这根线剪断,主板也照常起动,是因为有的主板有自己的PWN_OK信号,不用电源的PWN_OK信号的原因.