"Arfa Daily" wrote in
:


"pimpom" wrote in message
...
Does anyone have specific information about the protection device at
the power supply inputs of hard disks?

I assume that it's a zener diode or something similar in action such
as an IC that acts like a precision zener diode. It's not difficult
to see how such a device would provide protection against spikes,
over-voltage and reverse voltage by shorting the power rail to ground
and thereby triggering PSU shutdown.

Devices in the BUX C*** series seem to be widely used, but I have not
been able to find a datasheet or other detailed info. Can anybody
shed some light on the matter?



BUX * devices are usually high voltage transistors

Arfa




the PSU itself usually has overvoltage protection,where it really counts;on
the +5 volt supply. The +12 is loosely regulated,and only runs the motor
drive.some have "balance" nodes,that trigger SD if one or more of the
supplies go too far outside a window.

Then you don't need the expense of OV protection on every hard drive.

--
Jim Yanik
jyanik
at
kua.net