Patent ID: 6853570

Claim:
A circuit for driving a capacitive load so that a quasi-square-wave voltage is imposed on it, said circuit comprising: voltage supply means for providing a first and a lower potential; an inductance, said capacitive load being connected between a first end of said inductance and said lower potential of said voltage supply; a first switch means and a first diode means connected in series between said first potential of said voltage supply and a second end of said inductance, said first diode means having its polarity orientated so that it allows current flow from said first potential of said voltage supply to said second end of said inductance; a second switch means and a second diode means connected in series between said second end of said inductance and said lower potential of said voltage supply, said second diode means having its polarity orientated so that it allows current flow from said second end of said inductance to said lower potential of said voltage supply; means for applying a square wave drive signal to said first and second switch means, said first switch means being closed on a first level of said drive signal and open on a second level of said drive signal and said second switch means being open on said first level of said drive signal and closed on said second level of said drive signal; a first zener diode means in parallel with said first switch means and poled to allow said first switch means to block voltage as normal; and a second zener diode means in parallel with said second switch means and poled to allow said second switch means to block voltage as normal.