Lamp starting and operating procedure in electronic ballast

Claim 2

An arrangement comprising: frequency-converting ballast means connected with the power line conductors of an ordinary electric utility power line and operative to provide an output voltage between a first and a second ballast terminal; the power line conductors being electrically connected with ground; any current flowing out of the first ballast terminal being identified as a first current; any current flowing into the second ballast terminal being identified as a second current; any difference between the first current and the second current being identified as a differential current; the frequency of the output voltage being substantially higher than that of the power line voltage present between the power line conductors; the frequency-converting ballast means having: (i) control means operative on receipt of a control action to control the magnitude of the differential current, and (ii) current sensing means operative to sense the magnitude of any differential current and to provide said control action to said control means whenever this magnitude exceeds a predetermined level; and gas discharge lamp means operative to connect between the first and second ballast terminals and, when indeed so connected, to cause a lamp current to flow therebetween; the lamp current flowing out of the first ballast terminal and into the second ballast terminal, thereby not causing any differential current to flow; an impedance means being at times connected between the first ballast terminal and ground, thereby at times causing a differential current to flow; whereby the arrangement is operative: (i) to permit differential current to flow; but (ii) to prevent the magnitude of this differential current from exceeding a first predetermined level even for a brief period of time.

Claim 3

The arrangement of claim 1 wherein the frequency-converting ballast means additionally includes means to sense lamp current and to prevent its magnitude from exceeding a second predetermined level.

Claim 4

An arrangement comprising: a source providing a substantially sinusoidal power line voltage at a pair of power line terminals; the power line terminals being electrically connected with earth ground; rectifier means connected with the power line terminals and operative intermittently and periodically to supply rectified power line current to a pair of DC supply terminals; a DC supply voltage existing between the DC supply terminals; energy-storing means connected in circuit with the DC supply terminals and operative to supply unidirectional current thereto during periods when rectified power line current is not being supplied thereto; the energy-storing means including a first and a second energy-storing capacitor means; a first DC voltage existing across the first energy-storing capacitor means; a second DC voltage existing across the second energy-storing capacitor means; the maximum absolute magnitude of the first DC voltage being no higher than than about half the peak absolute magnitude of the power line voltage; the maximum absolute magnitude of the second DC voltage being no higher than about half the peak absolute magnitude of the power line voltage; the absolute magnitude of the DC supply voltage being effectively prevented from: (i) decreasing below the absolute magnitude of the first DC voltage, and (i) increasing above the sum of the absolute magnitudes of the first DC voltage and the second DC voltage; the instantaneous absolute magnitude of the DC supply voltage therefore being substantially equal to the larger of: (i) the instantaneous absolute magnitude of the power line voltage, and (ii) the instantaneous absolute magnitude of the first DC voltage; inverter ballast circuit connected with the DC terminals and operative to provide an output voltage between a first and a second ballast terminal; any current flowing out of the first ballast terminal being identified as a first current; any current flowing into the second ballast terminal being identified as a second current; any difference between the first current and the second current being identified as a differential current; the ballast means having control means operative to limit the magnitude of the differential current; gas discharge lamp means operative to connect between the first and second ballast terminals and, when indeed so connected, to cause lamp current to flow therebetween; and impedance means connected between the first ballast terminal and earth ground, thereby causing a differential current to flow; the control means preventing the magnitude of the differential current from exceeding a predetermined level.

Claim 5

An arrangement comprising: a source providing a substantially sinusoidal power line voltage at a pair of power line terminals; the power line terminals being electrically connected with earth ground; rectifier means connected with the power line terminals and operative intermittently and periodically to supply rectified power line current to a pair of DC supply terminals; a DC supply voltage existing between the DC supply terminals; energy-storing means connected in circuit with the DC supply terminals and operative to supply unidirectional current thereto during periods when rectified power line current is not being supplied thereto; the energy-storing means including a first and a second energy-storing capacitor means; a first DC voltage existing across the first energy-storing capacitor means; a second DC voltage existing across the second energy-storing capacitor means; the maximum absolute magnitude of the first DC voltage being no higher than than about half the peak absolute magnitude of the power line voltage; the maximum absolute magnitude of the second DC voltage being no higher than about half the peak absolute magnitude of the power line voltage; the absolute magnitude of the DC supply voltage being effectively prevented from: (i) decreasing below the absolute magnitude of the first DC voltage, and (i) increasing above the sum of the absolute magnitudes of the first DC voltage and the second DC voltage; the instantaneous absolute magnitude of the DC supply voltage therefore being substantially equal to the larger of: (i) the instantaneous absolute magnitude of the power line voltage, and (ii) the instantaneous absolute magnitude of the first DC voltage; inverter ballast circuit connected with the DC terminals and operative to provide an output voltage between a first and a second ballast terminal; any current flowing out of the first ballast terminal being identified as a first current; any current flowing into the second ballast terminal being identified as a second current; any difference between the first current and the second current being identified as a differential current; the ballast means having control means operative to limit the magnitude of the differential current; gas discharge lamp means operative to connect between the first and second ballast terminals and, when indeed so connected, to cause lamp current to flow therebetween; and impedance means connected between the first ballast terminal and earth ground, thereby causing a differential current to flow; the control means preventing the magnitude of the differential current from exceeding a predetermined level.

Claim 6

The arrangement of claim 3 wherein : (i) to provide for effective lamp ignition, a certain amount of differential current has to flow; (ii) said certain amount of differential current is of magnitude below said predetermined level; and (iii) said certain amount of differential current is indeed allowed to flow.

Claim 7

The arrangement of claim 3 wherein: (i) a certain amount of differential current is indeed allowed to flow; and (ii) said certain amount of differential current is sufficiently low not to constitute an electrical shock hazard to human beings.

Claim 8

The arrangement of claim 3 wherein an electrical conduction path exists between the ballast terminals and the power line terminals; the electrical conduction path running through the rectifier means and being operative to permit the flow of substantive amount of current at the frequency of the output voltage.

Claim 9

An arrangement comprising: rectifier means connected with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage at set of DC terminals; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide an output voltage between a first ballast terminal and a second ballast terminal; any current flowing from the first ballast terminal being defined as a first current; any current flowing from the second ballast terminal being defined as a second current; any current flowing from the combination of the two ballast terminals being defined as a differential current; a gas discharge lamp means being disconnectably connected with the ballast terminals and, when indeed so connected, drawing therefrom a lamp current; an impedance means being connected between the combination of the two ballast terminals and earth ground; the impedance means being operative to draw a differential current; the electronic ballast means having control means connected in circuit with the ballast terminals and, in response to current flowing therefrom, being operative to permit the flow therefrom of the lamp current as well as the differential current; the magnitude of the differential current being prevented by said control means from exceeding a predetermined level even for a prief period of time; the predetermined level being so low as not to constitute an electric shock hazard to a person being subjected to said differential current.

Claim 10

An arrangement comprising: rectifier means connected with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage at set of DC terminals; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide an output voltage between a first ballast terminal and a second ballast terminal; any current flowing from the first ballast terminal being defined as a first current; any current flowing from the second ballast terminal being defined as a second current; any current flowing from the combination of the two ballast terminals being defined as a differential current; a gas discharge lamp means being disconnectably connected with the ballast terminals and, when indeed so connected, drawing therefrom a lamp current; an impedance means being connected between the combination of the two ballast terminals and earth ground; the impedance means being operative to draw a differential current; the electronic ballast means having control means connected in circuit with the ballast terminals and, in response to current flowing therefrom, being operative to permit the flow therefrom of the lamp current as well as the differential current; the magnitude of the differential current being prevented by said control means from exceeding a predetermined level even for a prief period of time; the predetermined level being so low as not to constitute an electric shock hazard to a person being subjected to said differential current.

Claim 11

The arrangement of claim 7 wherein the control means is additionally operative to prevent the magnitude of the lamp current from exceeding a pre-established level; the pre-established level being higher than the predetermined level.

Claim 12

An arrangement comprising: rectifier means connected with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage at set of DC terminals; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide a ballast output voltage to a gas discharge lamp means connected with a first ballast terminal; the ballast output voltage having a first magnitude when referenced to a second ballast terminal and a second magnitude when referenced to earth ground; any current flowing between the first ballast terminal and the second ballast terminal being defined as a load current; any current flowing between the first ballast terminal and earth ground being defined as a ground loop current; the electronic ballast means having control means operative, in response to receiving an electrical control signal, to control the magnitude of the ground loop current; a current sensor means being connected in circuit with the lamp terminals and operative, in response to current flowing therefrom, to provide said electrical control signal; the magnitude of the ground loop current thereby being permitted to be as high as, but prevented from exceeding, a predetermined level; the predetermined level being: (i) sufficiently high to permit the flow via the gas discharge lamp to earth ground of a starting aid current of sufficient magnitude to materially facilitate lamp ignition, but (ii) sufficiently low not to constitute an electric shock hazard to a person being subjected to said ground loop current.

Claim 13

An arrangement comprising: rectifier means connected with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage at set of DC terminals; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide a ballast output voltage to a gas discharge lamp means connected with a first ballast terminal; the ballast output voltage having a first magnitude when referenced to a second ballast terminal and a second magnitude when referenced to earth ground; any current flowing between the first ballast terminal and the second ballast terminal being defined as a load current; any current flowing between the first ballast terminal and earth ground being defined as a ground loop current; the electronic ballast means having control means operative, in response to receiving an electrical control signal, to control the magnitude of the ground loop current; a current sensor means being connected in circuit with the lamp terminals and operative, in response to current flowing therefrom, to provide said electrical control signal; the magnitude of the ground loop current thereby being permitted to be as high as, but prevented from exceeding, a predetermined level; the predetermined level being: (i) sufficiently high to permit the flow via the gas discharge lamp to earth ground of a starting aid current of sufficient magnitude to materially facilitate lamp ignition, but (ii) sufficiently low not to constitute an electric shock hazard to a person being subjected to said ground loop current.

Claim 14

The arrangement of claim 9 wherein the control means is also operative to prevent the magnitude of the load current from exceeding a certain pre-established level; the pre-established level being higher than the predetermined level.

Claim 15

The arrangement of claim 9 wherein: (i) a starting aid current is indeed caused to flow; and (ii) the magnitude of this starting aid current is sufficiently high to substantially facilitate lamp ignition, yet lower than the predetermined level.

Claim 16

An arrangement comprising: a source providing a power line voltage at a pair of power line terminals; one of the power line terminals being defined as a ground terminal; ballast means connected with the power line terminals; the ballast means having a first and a second ballast terminal; a first ballast voltage existing between the ground terminal and the first ballast terminal; a second ballast voltage existing between the ground terminal and the second ballast terminal; any current flowing between the first and the second ballast terminal being defined as a load current; any current flowing between the ground terminal and the combination of the two ballast terminals being defined as a ground loop current; the ballast means including control means operative, in response to receiving a control signal at a control input, to control the magnitude of the ground loop current; gas discharge lamp means disconnectably connected between the first and the second ballast terminal; the gas discharge lamp means, when indeed so connected, being operative to cause a load current to flow therebetween; impedance means connected between the first ballast terminal and the ground terminal; the impedance means giving rise to a ground loop current; the magnitude of this ground loop current being, in the absence of said control signal, larger than a certain level; and current sensor means connected in circuit with the control input as well as with the ballast and ground terminals; the current sensor means being operative to sense the ground loop current and to provide the control signal in response thereto; the control means thus being provided with said control signal, thereby causing the magnitude of the ground loop current to be controlled in such manner as to permit it to be as large as, but not to exceed, said certain level.

Claim 17

An arrangement comprising: a source providing a power line voltage at a pair of power line terminals; one of the power line terminals being defined as a ground terminal; ballast means connected with the power line terminals; the ballast means having a first and a second ballast terminal; a first ballast voltage existing between the ground terminal and the first ballast terminal; a second ballast voltage existing between the ground terminal and the second ballast terminal; any current flowing between the first and the second ballast terminal being defined as a load current; any current flowing between the ground terminal and the combination of the two ballast terminals being defined as a ground loop current; the ballast means including control means operative, in response to receiving a control signal at a control input, to control the magnitude of the ground loop current; gas discharge lamp means disconnectably connected between the first and the second ballast terminal; the gas discharge lamp means, when indeed so connected, being operative to cause a load current to flow therebetween; impedance means connected between the first ballast terminal and the ground terminal; the impedance means giving rise to a ground loop current; the magnitude of this ground loop current being, in the absence of said control signal, larger than a certain level; and current sensor means connected in circuit with the control input as well as with the ballast and ground terminals; the current sensor means being operative to sense the ground loop current and to provide the control signal in response thereto; the control means thus being provided with said control signal, thereby causing the magnitude of the ground loop current to be controlled in such manner as to permit it to be as large as, but not to exceed, said certain level.

Claim 18

The arrangement of claim 12 wherein the current sensor means is: (i) responsive to the load current as well; and (ii) operative to prevent the magnitude of the load current from exceeding a pre-estabslished level.

Claim 19

The arrangement of claim 12 wherein the fundamental frequency of the first ballast voltage is substantially higher than that of the power line voltage.

Claim 20

The arrangement of claim 12 wherein the impedance means includes a ground plane mounted adjacent the gas discharge lamp.

Claim 21

An arrangement comprising: rectifier and filter means connected in circuit with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage between a B- bus and a B+ bus; an AC power line voltage being provided at the power line conductors; the DC supply voltage being characterized as having a magnitude that varies periodically at a frequency equal to twice the frequency of the AC power line voltage; the rectifier and filter means being characterized by including a first series-combination of a first rectifier and a first energy-storing capacitor and a second series-combination of a second rectifier and a second energy-storing capacitor; the first rectifier having a cathode connected with the B+ bus; the second rectifier having an anode connected with the B- bus; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide a ballast output voltage between a first ballast terminal and a second ballast terminal; any current flowing from the first ballast terminal being defined as a first current; any current flowing from the second ballast terminal being defined as a second current; any current flowing from the combination of the two ballast terminals being defined as a differential current; a gas discharge lamp means being disconnectably connected with the ballast terminals and, when indeed so connected, drawing therefrom a lamp current; an impedance means being at times connected between the combination of the two ballast terminals and earth ground; the impedance means being operative to draw a differential current; the electronic ballast means having limiting means operative to permit the flow from the ballast terminals of the lamp current but to prevent the flow therefrom of a differential current having a magnitude in excess of a predetermined level.

Claim 22

An arrangement comprising: rectifier and filter means connected in circuit with the power line conductors of an ordinary electric utility power line and operative to provide a DC supply voltage between a B- bus and a B+ bus; an AC power line voltage being provided at the power line conductors; the DC supply voltage being characterized as having a magnitude that varies periodically at a frequency equal to twice the frequency of the AC power line voltage; the rectifier and filter means being characterized by including a first series-combination of a first rectifier and a first energy-storing capacitor and a second series-combination of a second rectifier and a second energy-storing capacitor; the first rectifier having a cathode connected with the B+ bus; the second rectifier having an anode connected with the B- bus; the power line conductors being referenced to earth ground; and electronic ballast means connected with the DC terminals and operative to provide a ballast output voltage between a first ballast terminal and a second ballast terminal; any current flowing from the first ballast terminal being defined as a first current; any current flowing from the second ballast terminal being defined as a second current; any current flowing from the combination of the two ballast terminals being defined as a differential current; a gas discharge lamp means being disconnectably connected with the ballast terminals and, when indeed so connected, drawing therefrom a lamp current; an impedance means being at times connected between the combination of the two ballast terminals and earth ground; the impedance means being operative to draw a differential current; the electronic ballast means having limiting means operative to permit the flow from the ballast terminals of the lamp current but to prevent the flow therefrom of a differential current having a magnitude in excess of a predetermined level.

Claim 23

The arrangement of claim 16 wherein the DC supply voltage is further characterized by having an instantaneous absolute magnitude substantially equal to that of the AC power line voltage for at least half the duration of each complete cycle of the AC power line voltage.

Claim 24

The arrangement of claim 16 wherein: (i) a first DC voltage exists across the first energy-storing capacitor; and (ii) the instantaneous absolute magnitude of the DC supply voltage is substantially equal to the larger of the instantaneous absolute magnitude of the first DC voltage and that of the AC power line voltage.