US 5,264,752 A · Amplifier for driving large capacitive loads

Abstract

An amplifier design for a capacitive load reduces power supply requirements by recovering, during the discharge of the capacitive load, a substantial amount of the stored energy without causing noise signals to be created. The recovered energy is stored in novel series-connected capacitors to be reused during the subsequent load charge cycle. The stack becomes an effective multiple power supply source. The capacitors are successively switched and thus sequentially harnessed to the load capacitor so that the voltage across the load capacitor is increased by selected step increments instead of by one large voltage jump which causes circuit noise. By using MOSFET devices for the switches, the voltage increase during charging and decrease during discharging is continuous, thus eliminating the step function which causes much of the deleterious noise. The amplifier is especially useful as a driver for an actuator in an active control system for quieting noise-causing vibrations in buildings and other structures, which can be a health hazard.

Claims19

Dependent claims

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.

3 more elements

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.

10 more elements

Dependencies are inferred from the claim text.

Amplifier for driving large capacitive loads

Life of this patent

Amplifier for driving large capacitive loads

Life of this patent

Abstract

Claims19