What is hold up time and power good signal?

Anarchist420

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They're both measured in ms if I'm not mistaken. Anyway, make ranges and grade them (A, B, C, D, or F), tell me under what circumstances those grades are (i.e., input voltage, input frequency, and AC power cord and house wire copper purity and gauge), and tell me what hold up time and power good signal mean/how they apply to the quality of the PSU.

Thanks in advance:)
 

Red Squirrel

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May 24, 2003
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I'm not sure what "power signal" is in terms of PSU without googling, but hold time is the time the PSU will continue to provide power when it's unplugged. The longer the better, especially for a critical system.

When buying a UPS, or more specifically building one, it's crucial to look at the transfer time of whatever you are using (relay, inverter-charger etc) so that it is lower than the hold time of the PSU(s) that will be connected to it.

A prebuilt UPS is designed for computers so normally their transfer time will be like <4ms. But if you buy an inverter-charger it may be like <15ms, I've even seen some that are 2 seconds, which is worthless for computers, maybe ok for motors. So you want to ensure any power supply connected to it has a hold time higher than the UPS or other backup equipment you have.
 

bononos

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Aug 21, 2011
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They're both measured in ms if I'm not mistaken. Anyway, make ranges and grade them (A, B, C, D, or F), tell me under what circumstances those grades are (i.e., input voltage, input frequency, and AC power cord and house wire copper purity and gauge), and tell me what hold up time and power good signal mean/how they apply to the quality of the PSU.

Hold up time for atx power supplies is around 16ms. Grade A=pass.
 

bryanl

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Oct 15, 2006
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Your questions make as little sense as your inflamatory statement about WWII.

Power Good status becomes true in 100-500ms after all the power supply voltages have become stable, and I haven't seen any PC power supplies built within the past 20 years that didn't implement this correctly. Prior to that, some cheap PSUs generated PG status with nothing but a resistor-capacitor timing network (with the wrong timing) or by connecting PG directly to +5V, which could lead to boot problems.
 

Anarchist420

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Power Good status becomes true in 100-500ms after all the power supply voltages have become stable, and I haven't seen any PC power supplies built within the past 20 years that didn't implement this correctly. Prior to that, some cheap PSUs generated PG status with nothing but a resistor-capacitor timing network (with the wrong timing) or by connecting PG directly to +5V, which could lead to boot problems.
Thanks:) Now I see what hold up time and power good time are and I feel dumb for not realizing what they were without asking.
Hold up time for atx power supplies is around 16ms. Grade A=pass.
Thanks:) However, the bare minimum of meeting the ATX spec shouldn't be grade A. For example, I'd feel much more comfortable having a PSU that had DC output ripple (on the 12v rail) of .1% vs something that was .95%.

I'd hope my Antec Sig 650 has a hold up time of at least 4 times what's required by the ATX spec.
I'm not sure what "power signal" is in terms of PSU without googling, but hold time is the time the PSU will continue to provide power when it's unplugged. The longer the better, especially for a critical system. When buying a UPS, or more specifically building one, it's crucial to look at the transfer time of whatever you are using (relay, inverter-charger etc) so that it is lower than the hold time of the PSU(s) that will be connected to it. A prebuilt UPS is designed for computers so normally their transfer time will be like <4ms. But if you buy an inverter-charger it may be like <15ms, I've even seen some that are 2 seconds, which is worthless for computers, maybe ok for motors. So you want to ensure any power supply connected to it has a hold time higher than the UPS or other backup equipment you have.
Thanks:)