Electronic ballast with frequency control
DCFirst Claim
1. An arrangement comprising:
- a pair of power line terminals at which is provided a power line voltage;
rectification and filtering circuitry connected with the power line terminals and operative to provide a DC supply voltage at a set of DC terminals;
the absolute magnitude of the DC supply voltage being substantially constant; and
inverter and load circuitry connected with the DC terminals and operative to provide an AC voltage at a pair of AC terminals with which is connected a gas discharge lamp;
thereby to cause an alternating lamp current to flow through the lamp;
the alternating lamp current having a peak magnitude and an RMS magnitude;
the AC voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter and load circuitry being additionally characterized by causing the peak magnitude of the alternating lamp current to be distinctly lower than twice its RMS magnitude.
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Accused Products
Abstract
A half-bridge inverter is powered from a constant DC voltage and loaded by way of an L-C circuit that has a natural resonance frequency equal to or lower than the inverter'"'"'s operating frequency. A gas discharge lamp is disconnectably connected across the tank capacitor of the L-C circuit and, when indeed so connected, is provided with a current-limited high-frequency (30 kHz) voltage. The magnitude of the resulting lamp current decreases as the inverter'"'"'s operating frequency is increased; which operating frequency is controlled by way of a negative feedback arrangement that causes the frequency to increase as a function of increasing magnitude of the current flowing through the tank capacitor. Thus, particularly with the lamp disconnected, the magnitude of the current flowing through the capacitor--and therefore also the magnitude of the voltage existing across it--will be regulated so as to be lower than it would be in the absence of the negative feedback.
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Citations
29 Claims
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1. An arrangement comprising:
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a pair of power line terminals at which is provided a power line voltage; rectification and filtering circuitry connected with the power line terminals and operative to provide a DC supply voltage at a set of DC terminals;
the absolute magnitude of the DC supply voltage being substantially constant; andinverter and load circuitry connected with the DC terminals and operative to provide an AC voltage at a pair of AC terminals with which is connected a gas discharge lamp;
thereby to cause an alternating lamp current to flow through the lamp;
the alternating lamp current having a peak magnitude and an RMS magnitude;
the AC voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter and load circuitry being additionally characterized by causing the peak magnitude of the alternating lamp current to be distinctly lower than twice its RMS magnitude. - View Dependent Claims (2, 3, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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4. A ballasting arrangement for a gas discharge lamp, comprising:
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a source providing a DC supply voltage at a set of DC terminals; and an inverter circuit assembly connected with the DC terminals and operative to provide an inverter output current from a pair of inverter output terminals;
the inverter output current being an alternating current of frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter circuit assembly also including a pair of lamp output terminals adapted to connect with and to supply a lamp current to a gas discharge lamp;
the inverter circuit assembly being otherwise characterized by having;
(i) an inductor means connected between one of the inverter output terminals and one of the lamp output terminals, the inductor means having a frequency-dependent impedance in the sense that its impedance increases with increasing frequency of any current flowing through it;
(ii) a frequency control sub-assembly operative, on receipt of a control action at a control action input, to control the frequency and thereby the magnitude of the inverter output current; and
(iii) an action-generating element-operative, in response to at least a part of the inverter output current, to provide a control action at a control action output;
the control action output being connected in communication with the control action input, thereby to supply thereto said control action, thereby to cause the frequency of the inverter output current to change in response to the magnitude of the inverter output current, thereby to cause the magnitude of the inverter output current to be different from what it would have been in the absence of providing the control action to the frequency control sub-assembly. - View Dependent Claims (5, 6, 7)
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8. An arrangement comprising:
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a source providing a DC supply voltage at a set of DC terminals; an inverter circuit connected with the DC terminals and operative to provide an AC inverter output voltage at a pair of inverter output terminals;
the AC inverter output voltage being of frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter circuit having a frequency-controlling sub-assembly having a control action input operative, on receipt of a control action signal, to control the frequency of the AC inverter output voltage;an output circuit connected between the inverter output terminals and a pair of lamp current output terminals;
the output circuit being characterized by including;
(i) a frequency-dependent impedance element, such as an inductor; and
(ii) a an action-signal-generating element having a control action output connected in communication with said control action input and operative to provide said control action signal in response to a current flowing in the output circuit, thereby to affect the frequency of the AC inverter output voltage and, therefore, the magnitude of said current;
whereby the magnitude of said current is different from what it would have been if said control action signal had not been provided to the control action input; anda gas discharge lamp connected with the lamp current output terminals. - View Dependent Claims (9)
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10. A ballasting arrangement for a gas discharge lamp, comprising:
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a source providing a DC supply voltage at a set of DC terminals; and an assembly of components connected with the DC terminals and operative to provide an AC voltage at a pair of first terminals;
the assembly being characterized by including various electrical components in addition to output circuitry having an action-generating element operative to provide a control action at a control action output in response to a current flowing in a certain conductor included as part of the output circuitry;
the AC voltage being of frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the assembly also including a pair of second terminals connected with the first terminals by way of the output circuitry;
the second terminals being adapted to connect with and to supply lamp current to a gas discharge lamp;
the assembly being otherwise characterized by;
(a) including an inductor as part of the output circuitry;
(b) having a control sub-assembly operative, on receipt of a control action at a control action input, to control the frequency of the AC voltage, the control action input being functionally connected with the control action output; and
(c) causing a current to flow through the certain conductor;
thereby;
(i) to cause said control action to be supplied from the control action output to the control action input, (ii) to cause the frequency of the AC voltage to be controlled in response to the current flowing through the certain conductor, and (iii) to cause the magnitude of this current to be different from what it would have been in the absence of providing the control action to the control action input. - View Dependent Claims (11)
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12. An arrangement comprising:
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a source providing a DC supply voltage at a set of DC terminals; an inverter circuit assembly connected with the DC terminals and operative to provide an AC inverter voltage at a pair of AC inverter terminals;
the AC inverter voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter circuit assembly being characterized by including a control subassembly operative, on receipt of a control action at a control action input, to control the frequency of the AC inverter voltage; andload circuitry connected with the AC inverter terminals;
the load circuitry being characterized by;
(a) including a disconnectable gas discharge lamp;
(b) including an inductor;
(c) including a conductor;
(d) including an action-generating element connected in circuit with the conductor and operative to provide a control action at a control action output in response to a current flowing through the conductor; and
(e) having the control action output connected in communication with the control action input, thereby;
(i) to provide the control action such as to cause;
(i) the frequency of the AC inverter voltage to be controlled in response to the magnitude of the current flowing through the conductor, and (ii) the magnitude of this current to be different from what it would have been in the absence of providing the control action to the control action input. - View Dependent Claims (13, 14)
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15. An arrangement comprising:
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a source providing a DC supply voltage at a set of DC terminals; and inverter and load circuitry connected with the DC terminals and operative to provide an AC voltage at a pair of AC terminals;
the AC voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the inverter and load circuitry being characterized by including (i) an inductor, (ii) a capacitor, (iii) a gas discharge lamp, and (iv) an intermittently conducting transistor;
the AC voltage being characterized by having a waveform consisting of;
(i) a first time-segment during which the instantaneous magnitude of the AC voltage remains at a substantially constant negative level, (ii) a second time-segment during which the instantaneous magnitude of the AC voltage increases in a substantially continuous manner, (iii) a third time-segment during which the instantaneous magnitude of the AC voltage remains at a substantially constant positive level, and (iv) a fourth time-segment during which the instantaneous magnitude of the AC voltage decreases in a substantially continuous manner;
the inverter and load circuitry being further characterized in that substantially no current flows through the transistor during the second and fourth time-segments.
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16. An arrangement comprising:
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a source providing a DC supply voltage at a set of DC terminals; and inverter and load circuitry connected with the DC terminals and operative to provide an AC voltage at a pair of AC terminals with which is connected a gas discharge lamp;
the AC voltage being of a frequency substantially higher than that of the power line voltage on an ordinary electric utility power line;
the gas discharge lamp being characterized by drawing a lamp current from the AC terminals at certain times and not at other times;
the inverter and load circuitry being characterized in that the frequency of the AC voltage is different during the times when lamp current is being drawn as compared with times when lamp current is not being drawn. - View Dependent Claims (17)
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Specification