Low-Line Overstress of Constant-Power Loads(3 of 4)

Solution

Once the problem is understood, the solution is usually straight forward.

• Select the turn-on voltage for the power supply
• design a sense circuit for this voltage with hysteresis
• use the circuit to inhibit turn-on until the proper voltages are reached
• add soft start to minimize the load transient at turn-on
• and then by means of simulation and lab measurements, check the transient stress on components during turn-on and turn-off, especially the V-I trajectories of semiconductor switches in relation to their safe-operating area

Do not use this information for design without independent verification of the information.

Editor: Jerrold Foutz