Patent ID: 7348689

Claim:
A method of generating first and second switching signals for switching first and second switches of a switching circuit that further comprises an output and that receives a DC supply of nominal voltage +V S , and wherein switching between various combinations of on and off states of the first and second switches produces a voltage at the output with pulses at levels of +V S , 0V and −V S ; the method comprising the steps of: (a) receiving a voltage demand signal indicative of a desired voltage to be supplied at the cutout in a period; and (b) generating the first and second switching signals, wherein at least one of the first and second switching signals comprises a single pulse of a determined width within the period, wherein the determined width does not fall below a minimum pulse width, and further, wherein successive transitions between on and off states of the first switching signal or of the second switching signal that occur in different periods are separated in time by a minimum time interval, and wherein the determined width is such that the combination of the first and second switching signals when applied to the first and second switches respectively produce an average voltage at the output for the period that is substantially equal to the desired voltage in the period, wherein, at step b), the first switching signal comprises a single pulse of a first determined width within the period and the second switching signal comprises a single pulse of a second determined width within the period, wherein neither said first nor said second determined width falls below said minimum pulse width and wherein said first and second determined widths are such that the combination of the first and second switching signals when applied to the first and second switches respectively produce an average voltage at the output for the period that is substantially equal to the desired voltage, further comprising the step of increasing the first determined width by an amount that is equal in magnitude to the second determined width but compensatory in effect in that a voltage pulse at the output of +V S or −V S resulting from the pulse in the second switching signal is balanced by an equal width of voltage pulse at the output of −V S or +V S respectively resulting from the increased first determined width of the first switching signal.