Amplifier for driving large capacitive loads

Claim 2

An amplifier for driving a capacitive load, comprising: a power source; a plurality of capacitors arranged in series-connected stack relation; the connecting points between adjacent ones of said stacked capacitors each comprising a node; said power source being connected to one end of said stack; and switching means comprising plural switches, each said switch being associated with a respective one of said stacked capacitors, for sequentially connecting successively and one at a time, one or more of said stacked capacitors to a first side of said capacitive load, the second side of said capacitive load being maintained at ground potential, and thereafter for connecting in reverse sequence said one or more said stacked capacitors.

Claim 3

Apparatus in accordance with claim 1, wherein said switching means further comprises: means for opening the switch previously closed before closing the next succeeding switch, thereby to raise the load voltage applied to said capacitive load incrementally until a desired output voltage is applied to said capacitive load; and means for effecting a reversal of said stacked capacitor charge sequence by reversing the sequence of switch operations, thereby to sequentially discharge said capacitive load into said capacitor stack and increase the voltages at said nodes to store energy recovered from said capacitive load in said stacked capacitors; the thus-recovered energy being re-used during the subsequent load charge cycle.

Claim 4

Apparatus in accordance with claim 2, wherein the capacitance values of each of said stacked capacitors are substantially identical.

Claim 5

Apparatus in accordance with claim 3, wherein the capacitance values of each of said stacked capacitor are chosen to be large relative to the capacitance value of said capacitive.

Claim 6

Apparatus in accordance with claim 4, further comprising means for clamping the voltage across each one of said stacked capacitors to a predetermined maximum value.

Claim 7

Apparatus in accordance with claim 5, wherein said clamping means comprises a plurality of series-connected zener diodes each said diode being connected across a one of said stacked capacitors, the zener voltages being selected to be relatively high.

Claim 8

An amplifier for driving a capacitive load, comprising: a power source; a plurality of capacitors arranged in series-connected stacked relation; the connecting points between adjacent ones of said stacked capacitors each comprising a node; said power source being connected to one end of said stack; a first and a second array of current-steering diodes; the diodes of said first diode array being respectively connected to a first side of a corresponding stacked capacitor and the diodes of said second diode array being respectively connected to the opposite side of a corresponding said stacked capacitor; corresponding diodes of said first and second arrays being paired in series-connection with same-direction conduction; a first set of switch means for sequentially connecting diodes of said first array to one side of said capacitive load; a second set of switch means for sequentially connecting diodes of said second array to the other side of said capacitive load; said diode arrays and said switch sets sequentially connecting successive ones of said stacked capacitors to a first side of said capacitive load, said second side being at ground potential, thereby to raise the load voltage applied to said capacitive load incrementally until the desired output voltage is applied to said capacitive load; and said diode arrays and said switch sets effecting a reversal of said stacked capacitor charge sequence, thereby to sequentially discharge said capacitive load into said capacitor stack and thereby increase the voltages at said node to store energy recovered from said capacitive load in said respective stacked capacitors; the thus-recovered energy being re-used during the subsequent load charge cycle.

Claim 9

An amplifier for driving a capacitive load, comprising: a power source; a plurality of capacitors arranged in series-connected stacked relation; the connecting points between adjacent ones of said stacked capacitors each comprising a node; said power source being connected to one end of said stack; a first and a second array of current-steering diodes; the diodes of said first diode array being respectively connected to a first side of a corresponding stacked capacitor and the diodes of said second diode array being respectively connected to the opposite side of a corresponding said stacked capacitor; corresponding diodes of said first and second arrays being paired in series-connection with same-direction conduction; a first set of switch means for sequentially connecting diodes of said first array to one side of said capacitive load; a second set of switch means for sequentially connecting diodes of said second array to the other side of said capacitive load; said diode arrays and said switch sets sequentially connecting successive ones of said stacked capacitors to a first side of said capacitive load, said second side being at ground potential, thereby to raise the load voltage applied to said capacitive load incrementally until the desired output voltage is applied to said capacitive load; and said diode arrays and said switch sets effecting a reversal of said stacked capacitor charge sequence, thereby to sequentially discharge said capacitive load into said capacitor stack and thereby increase the voltages at said node to store energy recovered from said capacitive load in said respective stacked capacitors; the thus-recovered energy being re-used during the subsequent load charge cycle.

Claim 10

Apparatus in accordance with claim 7, wherein on completion of said discharge cycle of said capacitive load, the voltage drop across said capacitive load is substantially equal to the voltage drop across the first of said diodes in said first diode array.

Claim 11

Apparatus in accordance with claim 8, further comprising means including a blocking diode connected between said power source and one end of said capacitor stack, for selectively preventing charge from flowing back into said power source and for isolating said power source from said capacitive.

Claim 12

Apparatus in accordance with claim 9, wherein the capacitive values of each said stacked capacitors are substantially identical.

Claim 13

Apparatus in accordance with claim 10, wherein the capacitive values of each said stacked capacitor are chosen to be large relative to the capacitive value of said capacitive load.

Claim 14

Apparatus in accordance with claim 11, further comprising: means for clamping the voltage across each one of said stacked capacitors to a predetermined maximum value.

Claim 15

Apparatus in accordance with claim 12, wherein said clamping means comprises a plurality of series-connected zener diodes each said diode being connected across a one of said stacked capacitors, the zener voltages being selected to be relatively high.

Claim 16

Apparatus in accordance with claim 7, 8, 9, 10, 11, 12, or 13, wherein said first set of switches comprises P-channel MOSFET devices; said second set of switches comprises N-channel MOSFET devices; and said apparatus further comprises means including said MOSFET devices for effecting a continuous increase of voltage across said capacitive load during charging and for effecting a continuous decrease of voltage across said capacitive load during discharge.

Claim 17

Apparatus in accordance with claim 1, further comprising: actuator means driven by said amplifier, and means for applying said actuator means to a vibrating element to reduce vibrations.

Claim 18

Apparatus in accordance with claim 7, further comprising: actuator means driven by said amplifier; and means for applying said actuator means to a vibrating element to reduce vibrations.

Claim 19

Apparatus in accordance with claim 15 or 16, wherein said actuator means comprises predominately an electrostrictive material.

Claim 20

Apparatus in accordance with claim 15 or 16, wherein said actuator means comprises predominately a piexoelectric material.

Claim 21

Apparatus in accordance with claim 16, wherein said first set of switches comprises P-channel MOSFET devices; and wherein said second set of switches comprises N-channel MOSFET devices.