Method of driving a power converter

A method of driving a power converter, said power converter including first and second switching devices which are connected in series and interposed between first and second main power supply potentials, bootstrap type power supply means using a potential at a connecting node of said first and second switching devices as a reference, a power source using said second main power supply potential as a reference, and first and second drive means for driving said first and second switching devices, respectively, in response to an input signal from external input signal generating means, said first drive means using power supplied from said bootstrap type power supply means as power for driving said first switching device, said second drive means using power supplied from said power source as power for driving said second switching device, said bootstrap type power supply means including a diode and a capacitor, said diode having an anode connected to a positive output of said power source, and a cathode connected to a first power input portion of said first drive means, said capacitor having a first electrode connected to said first power input portion of said first drive means, and a second electrode connected to a second power input portion of said first drive means and said connecting node, said connecting node for providing an output, said input signal including a charging pulse signal for causing said second switching device to conduct in a pulse-like manner to charge said capacitor, and a PWM signal for placing said first and second switching devices into an PWM action, said method comprising the step of:

• continuously providing said charging pulse signal when said power source is in the ON state and said PWM signal is not provided after completion of charging said capacitor.