Abstract: A method for driving a capacitive load using a target voltage waveform having a peak voltage and an average rise and fall slew rate, wherein the average rise and fall slew rates comprise at least one voltage step, the method comprising supplying power from an input to an output for charging a capacitive load to obtain a peak voltage and average rise slew rate in response to the target waveform; discharging the capacitive load to obtain an average fall slew rate in response to the target waveform, and returning the discharged power from the capacitive load to the input.

Abstract: A driver circuit (1) for driving a capacitive load (2) with a drive pulse having a rise time, a predetermined voltage period and a fall time. The driver circuit (1) includes an inductance (6), switches (10, 11, 12), and a transformer (8) having a primary side (8) and secondary side (9). The switches (10, 11, 12) are controlled by a controller (13) to charge the inductance (6) from a power supply (4), and, when the capacitive load (2) is to be driven, to enable a charge path from the inductance (6) to the capacitive load (2) during the rise time, to disable the charge path during the constant peak voltage period and to enable a discharge path via the primary side (8) of the transformer (7) during the fall time. As the capacitive load (2) discharges through the primary side (8) of the transformer (7), charge is induced on the secondary side (9) of the transformer (7) and is used to charge the inductance (6), thereby saving power and enabling a lower voltage power supply to be used.

Abstract: A method for driving a capacitive load using a target voltage waveform having a peak voltage and an average rise and fall slew rate, wherein the average rise and fall slew rates comprise at least one voltage step, the method comprising supplying power from an input to an output for charging a capacitive load to obtain a peak voltage and average rise slew rate in response to the target waveform; discharging the capacitive load to obtain an average fall slew rate in response to the target waveform, and returning the discharged power from the capacitive load to the input.

Abstract: A driver circuit (1) for driving a capacitive load (2) with a drive pulse having a rise time, a predetermined voltage period and a fall time. The driver circuit (1) includes an inductance (6), switches (10, 11, 12), and a transformer (8) having a primary side (8) and secondary side (9). The switches (10, 11, 12) are controlled by a controller (13) to charge the inductance (6) from a power supply (4), and, when the capacitive load (2) is to be driven, to enable a charge path from the inductance (6) to the capacitive load (2) during the rise time, to disable the charge path during the constant peak voltage period and to enable a discharge path via the primary side (8) of the transformer (7) during the fall time. As the capacitive load (2) discharges through the primary side (8) of the transformer (7), charge is induced on the secondary side (9) of the transformer (7) and is used to charge the inductance (6), thereby saving power and enabling a lower voltage power supply to be used.