Output Protection; No Load Operation; Over Current Operation (Ocp); Over Temperature Protection (Otp) - TDK-Lambda CPFE500 Application Note

Figure 13 – Method to permanently enable the PSU

5. OUTPUT PROTECTION

NO LOAD OPERATION

There is no minimum load required for correct output voltage regulation.

OVER CURRENT OPERATION (OCP)

The PSU has constant current limiting with automatic recovery.
The OCP threshold is fixed and cannot be adjusted.
Note that continuous short circuit or overload for more than 30seconds might result in damage to the PSU.

OVER TEMPERATURE PROTECTION (OTP)

The PSU may activate over temperature protection if the cooling baseplate exceeds 90~115DegC for 12V
models or 105~130DegC for all other models. OTP will shutdown the main output. The Auxiliary output is not
affected during OTP condition.
To restart the PSU main output, allow the unit to cool and either :-
(i) remove the ac supply for 10 seconds and then reapply, or
(ii) cycle the on/off control

OVER VOLTAGE PROTECTION (OVP)

An overvoltage on the main output will cause the main output to shutdown. The Auxiliary output is not
affected during OVP condition.
To restart the PSU main output, either :-
(i) remove the ac supply for 10 seconds and then reapply, or
(ii) cycle the on/off control
Overvoltage threshold will vary according to PSU model as follows :-
Model OVP threshold range
12V model 15.0V ~ 17.4V
24V model 35.0V ~ 40.6V
28V model 35.0V ~ 40.6V
48V model 60.0V ~ 69.6V
CPFE500F Application Note Document Number : 61066 iss 2 Page 11 of 17