EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: fqahmad66 on March 03, 2014, 07:30:09 am
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Hi,
Do the cheap China Power supplies (Hantek/Korad etc.) have actual OVP & OCP implimented? Anybody have any practical experience?
Regards
F
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Anyone??
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I have a Korad KA3005D. Has OVP and OCP. They both work fine once you get them set up.
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Thanks commonground,
How do you check it.?
Regards
F
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With the max output (OVP) voltage set, you enable the output. If the voltage rises above the set point, either externally or by raising the voltage while the output is still enabled, the output will turn off. With max (OCP) current set, the output will automatically turn off if the current draw rises above the set point. I haven't timed the shut-off delay, but both are very fast, so one would hope your circuit under test would be protected. I have to say, I don't use these functions too often. I tend to keep the current limit low to start with until I understand how the circuit is going to behave. Hate to see the magic smoke. ;)
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Be careful with the implementation of especially OVP. On some power supplies this means "disconnect the output on overvoltage", on others (HP/Agilent at least) it means "short out the terminals on overvoltage".
The latter one can be quite destructive when the overvoltage condition is caused by you connecting something like a battery to the output terminals :scared:
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Another implementation detail is that the better power supplies will have the OVP/OCP in an *independent* circuit. If the main processor goes out to lunch and decides it's time to apply max voltage, there's a backup to shut everything off quickly.
On cheap power supplies, I would be suspicious that it's only a software implementation. Not to say this can't handle many of the failure scenarios, but it's like putting the fox in charge of the chickens.