SPELLMAN High voltage power supply dynamic loadcharacteristics

The 406921-001 X3815 is SPELLMAN high voltage power supply,Spellman’s high frequency switching power supplies haveminimal output capacitance, inherent by design. Dynamicload changes can quickly discharge output capacitance,causing the output voltage to drop out of static regulationspecification. Even if the load step draws current that iswithin the rated current of the power supply, there may besome “droop” in the output voltage. This droop is sensedby the voltage feedback divider, which in turn causes thevoltage loop to command the power supply to increase theoutput voltage to bring the unit back within static voltageregulation specification. None of this happens instantly, itall take time to accomplish. Typically recovery times forSpellman’s power supplies (when specified and meas-ured) are in the order of individual to tens of milliseconds.

The amount of droop is mostly influenced by the followingparameters:

1.)Capacitance of the power supply’s output sectionand any external, stray or load capacitance

2.)Magnitude of load current being drawn fromthe supply

3.)Duration of load step event

The voltage recovery waveform time period and overallshape (under damped, over damped or critically damped)are dependent upon the parameters outlined above inaddition to the compensation characteristics of both thevoltage and current loops of the power supply.