Patent ID: 7342436

Claim:
A bipolar supply voltage generator which produces a positive and negative supply voltages from a unipolar power source, comprising: an inductor; a first diode whose anode and cathode are connected to a first end of said inductor and a positive voltage output of said bipolar supply voltage generator, respectively; a second diode whose cathode and anode are connected to a second end of said inductor and a negative voltage output of said bipolar supply voltage generator, respectively; a first switch which connects the first end of said inductor to ground; a second switch which connects the second end of said inductor to the unipolar power source; and a controller which controls said first and second switches by modulating the pulse width with a fixed frequency, while turning off the first switch and the second switch at separate times and maintaining the first and second switches in an off state simultaneously for a time within one signal cycle every time prior to one of the first switch and the second switch being turned on.