Notification 701 – KP is too low, zero or negative

CATEGORY

ISSUE / RESULT

FIX / REFERENCE(S)

Error

The Minimum calculated KP is lower than 0.3. This may happen if the power capability of the product family has been exceeded. This results in the design to be in deep continuous current mode and therefore not optimum. The inductance value might get too big as well as the number of primary turns necessary not to saturate the magnetic core. A low KP also affects the Average/RMS current ratio resulting in a higher RMS current, therefore, more copper losses in the transformer windings.

The minimum KP value may be increased by increasing the maximum VOR and/or increasing the maximum frequency at which the Power Supply is allowed to operate. Pick a device with higher BVDSS or power capability.