Power supply circuit employing piezoelectric voltage transforming device

Claim 2

A power supply circuit for use with a piezoelectric voltage transforming device, including in combination: a piezoelectric voltage transforming device having driving primary and loading secondary terminals and an electromechanical voltage transformation therebetween for transforming low primary alternating voltage to high secondary alternating voltage corresponding to the electrical loading in said loading terminals, said device having a plurality of mechanical vibrational modes for effecting said voltage transformation and a range of operating resonant frequencies in each mode with one mode being an optimum mode, a driving circuit connected to the driving primary terminals of said device for applying alternating drive signals thereto to cause said device to operate in said optimum mode at a preselected operating frequency, an electrical load connected to the loading terminals of said device for deriving power directly therefrom, a positive feedback circuit loop coupling said primary alternating voltage of said device to said driving circuit for forcing said drive signals to alternate at said preselected operating frequency, said positive circuit loop including a first frequency selective means selectively passing the range of operating frequencies of said optimum mode and excluding the operating frequencies of all other modes whereby the operation of said device in other vibrational modes is prevented, and said device comprising a second frequency selective means while operating at said preselected frequency and through coupling said preselected frequency to said driving circuit whereby the operating resonant frequency of said device is stabilized at said preselected frequency and said electromechanical voltage transformation is stabilized to provide a constant high level secondary voltage potential from said power supply circuit.

Claim 3

The power supply circuit of claim 1 wherein said piezoelectric voltage transforming device comprises a ceramic ring and said optimum mode is a fundamental hoop mode.

Claim 4

The power supply circuit of claim 1 wherein said electrical load is a variable load and changes therein cause corresponding changes in the operating resonant frequency of said device from said preselected frequency and corresponding changes in said electromechanical voltage transformation, said primary alternating voltage being coupled through said positive circuit loop to said driving circuit is a primary feedback voltage, said positive circuit loop includes a phase shifter control means for selectively adjusting the phase of said primary feedback voltage with corresponding changes in the operating resonant frequency of said device, and a negative feedback circuit loop monitors changes in said secondary alternating voltage to sense said changes in said operating resonant frequency and electromechanical voltage transformation resulting from load variations and couples said changes in secondary voltage to said phase shifter control means for controlLing the phase adjustment thereof to effect a corresponding change in operating resonant frequency and electromechanical voltage transformation for said device whereby regulation of said secondary alternating voltage is achieved to provide a constant secondary output voltage from said power supply circuit for use with said variable load.

Claim 5

The power supply circuit of claim 3 wherein said phase shifter control means includes a load inductor coil of a saturable reactor and said negative feedback circuit loop includes a control inductor coil of said saturable reactor, and said changes in the secondary alternating voltage of said device cause corresponding changes in the inductance of said control coil to provide corresponding changes in the inductance of said load coil resulting in said phase adjustment of said primary feedback voltage.

Claim 6

The power supply circuit of claim 1 wherein said driving circuit includes switching means comprising a pair of alternately conducting transistors for developing said alternating drive signals supplied to said driving primary terminals of said device.

Claim 7

The power supply circuit of claim 1 wherein said first frequency selective means in said positive feedback circuit loop comprises a low pass filter network.

Claim 8

The power supply circuit of claim 1 wherein said first frequency selective means in said positive feedback circuit loop comprises a composite filter network having both low pass and band pass filtering characteristics.

Claim 9

In a television receiver including a picture tube having changing video patterns to comprise a varying electrical load, a power supply circuit for supplying a constant high level voltage potential thereto, including in combination: a piezoelectric voltage transforming device having driving primary and loading secondary terminals and electromechanical voltage transformation therebetween for transforming low primary alternating voltage to high secondary alternating voltage with said device operating at a first resonant frequency within a range of operating resonant frequencies, said electromechanical voltage transformation and said first resonant frequency changing with variations in said electrical load to effect changes in said secondary alternating voltage of said device, a driving circuit having switching means for developing alternating drive signals and coupling said signals to the driving primary terminals of said device to cause said device to operate at said first resonant frequency, a positive feedback circuit loop coupling said primary alternating voltages of said device to said driving circuit for forcing said switching means to alternate said drive signals at the particular operating resonant frequency of said device within said range including said first resonant frequency, and said positive circuit loop including a phase shifter control means for selectively adjusting the phase of the primary alternating voltage being coupled through said positive circuit loop, a negative feedback circuit loop monitoring changes in said secondary alternating voltage to sense said changes in electromechanical transformation and said operating resonant frequency caused by said load variations and coupling said changes in said secondary alternating voltage to said phase shifter control means for determining the phase adjustment thereof to effect corresponding changes in operating resonant frequency and electromechanical voltage transformation for said device whereby regulation of said secondary alternating voltage is achieved to provide a constant secondary output voltage from said power supply circuit for use with said variable electrical load.

Claim 10

In a television receiver including a picture tube having changing video patterns to comprise a varying electrical load, a power supply circuit for supplying a constant high level voltage potential thereto, including in combination: a piezoelectric voltage transforming device having driving primary and loading secondary terminals and electromechanical voltage transformation therebetween for transforming low primary alternating voltage to high secondary alternating voltage with said device operating at a first resonant frequency within a range of operating resonant frequencies, said electromechanical voltage transformation and said first resonant frequency changing with variations in said electrical load to effect changes in said secondary alternating voltage of said device, a driving circuit having switching means for developing alternating drive signals and coupling said signals to the driving primary terminals of said device to cause said device to operate at said first resonant frequency, a positive feedback circuit loop coupling said primary alternating voltages of said device to said driving circuit for forcing said switching means to alternate said drive signals at the particular operating resonant frequency of said device within said range including said first resonant frequency, and said positive circuit loop including a phase shifter control means for selectively adjusting the phase of the primary alternating voltage being coupled through said positive circuit loop, a negative feedback circuit loop monitoring changes in said secondary alternating voltage to sense said changes in electromechanical transformation and said operating resonant frequency caused by said load variations and coupling said changes in said secondary alternating voltage to said phase shifter control means for determining the phase adjustment thereof to effect corresponding changes in operating resonant frequency and electromechanical voltage transformation for said device whereby regulation of said secondary alternating voltage is achieved to provide a constant secondary output voltage from said power supply circuit for use with said variable electrical load.

Claim 11

The power supply circuit of claim 8 wherein said piezoelectric voltage transforming device includes a plurality of mechanical vibrational modes for effecting said electromechanical voltage transformation and has a range of operating resonant frequencies in each mode with one mode being an optimum mode and including said first resonant frequency, said positIve circuit loop includes a first frequency selective means selectively passing the range of operating frequencies of the said optimum mode and excluding the operating frequencies of all other modes for preventing operation of said device in other vibrational modes, and said device comprises a second frequency selective means while operating at said particular operating frequency within said range including said first resonant frequency and through coupling said particular operating frequency to said driving circuit whereby the operating resonant frequency of said device is stabilized at said particular operating frequency until a subsequent variation of said electrical load occurs.

Claim 12

The power supply circuit of claim 9 wherein said device comprises a ceramic ring and said optimum mode is a fundamental hoop mode.

Claim 13

The power supply circuit of claim 9 wherein a rectifying means is coupled to said loading secondary terminals of said device for rectifying said high secondary alternating voltage prior to supplying said constant high level voltage potential to said picture tube.

Claim 14

In a television receiver, a power supply circuit for supplying a constant high level voltage potential to a varying electrical load, including in combination: a piezoelectric voltage transforming device having a plurality of mechanical vibrational modes and a range of operating resonant frequencies in each mode with one mode being an optimum mode, and having driving primary and loading secondary terminals and an electromechanical voltage transformation therebetween for transforming low primary alternating voltage to high secondary alternating voltage, said electromechanical voltage transformation changing with variations in said electrical load to effect changes in said secondary alternating voltage of said device, a driving circuit connected to the driving primary terminals of said device for applying alternating drive signals thereto to cause said device to operate in said optimum mode at particular operating frequencies within said range of frequencies corresponding to variations in said electrical load, a positive feedback circuit loop coupling said primary alternating voltage to said driving circuit for forcing said drive signals to alternate at said particular operating frequencies, said positive circuit loop including a first frequency selective means selectively passing the range of operating frequencies of said optimum mode and excluding the operating frequencies of all other modes for preventing operation of said device in other vibrational modes, and including a phase shifter control means for selectively adjusting the phase of the primary alternating voltage being coupled through said positive circuit loop, and a negative feedback circuit loop monitoring changes in said secondary alternating voltage to sense said changes in electromechanical transformation and operating resonant frequency for said device caused by said load variations and coupling said changes in said secondary alternating voltage to said phase shifter control means for determining the phase adjustment thereof to effect corresponding changes in electromechanical voltage transformation and operating frequency for said device whereby regulation of said secondary alternating voltage is achieved to provide a constant secondary output voltage from said power supply circuit for use with said variable electrical load.

Claim 15

In a television receiver, a power supply circuit for supplying a constant high level voltage potential to a varying electrical load, including in combination: a piezoelectric voltage transforming device having a plurality of mechanical vibrational modes and a range of operating resonant frequencies in each mode with one mode being an optimum mode, and having driving primary and loading secondary terminals and an electromechanical voltage transformation therebetween for transforming low primary alternating voltage to high secondary alternating voltage, said electromechanical voltage transformation changing with variations in said electrical load to effect changes in said secondary alternating voltage of said device, a driving circuit connected to the driving primary terminals of said device for applying alternating drive signals thereto to cause said device to operate in said optimum mode at particular operating frequencies within said range of frequencies corresponding to variations in said electrical load, a positive feedback circuit loop coupling said primary alternating voltage to said driving circuit for forcing said drive signals to alternate at said particular operating frequencies, said positive circuit loop including a first frequency selective means selectively passing the range of operating frequencies of said optimum mode and excluding the operating frequencies of all other modes for preventing operation of said device in other vibrational modes, and including a phase shifter control means for selectively adjusting the phase of the primary alternating voltage being coupled through said positive circuit loop, and a negative feedback circuit loop monitoring changes in said secondary alternating voltage to sense said changes in electromechanical transformation and operating resonant frequency for said device caused by said load variations and coupling said changes in said secondary alternating voltage to said phase shifter control means for determining the phase adjustment thereof to effect corresponding changes in electromechanical voltage transformation and operating frequency for said device whereby regulation of said secondary alternating voltage is achieved to provide a constant secondary output voltage from said power supply circuit for use with said variable electrical load.