Ballast for instant-start parallel-connected lamps

An arrangement comprising:

• a source operative to provide a substantially constant magnitude DC supply voltage at a pair of DC terminals;
• inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at an inverter output;
• the inverter circuit including a frequency control sub-circuit operative on receipt of a control signal at a control input to control a certain parameter of the inverter output voltage;
• the absolute instantaneous magnitude of the inverter output voltage being substantially constant;
• an LC circuit connected with the inverter output;
• the LC circuit having a natural resonance frequency;
• the LC circuit having a tank-capacitor having a pair of capacitor terminals across which exists a substantially sinusoidal AC voltage having an RMS magnitude;
• the RMS magnitude being a function of the frequency of the inverter voltage;
• voltage-magnitude-sensing circuit connected with the LC circuit and operative to provide an output signal indicative of the RMS magnitude;
• the output signal being supplied to the control input, thereby:
• (i) to constitute the control signal, and (ii) to control the inverter frequency;
• thereby, irrespective of the amount of any power drawn from the capacitor terminals, to control the RMS magnitude and prevent it from exceeding a predetermined level, yet without changing the magnitude of the DC supply voltage;
• and
• plural series-combinations;
• each series-combination:
• (i) including a gas discharge lamp series-connected with a current-limiting reactance means, and (ii) being connected across the capacitor terminals.

An arrangement comprising:

• a source operative to provide a DC supply voltage between a first and a second DC terminal;
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• an LC series-circuit effectively connected across the inverter output terminals;
• the LC series-circuit having a natural resonance frequency;
• the LC circuit having a tank-inductor series-connected with a tank-capacitor;
• a substantially sinusoidal AC voltage existing across the tank-capacitor;
• and
• plural series-combinations parallel-connected across the tank-capacitor;
• each series-combination including a gas discharge lamp series-connected with a current-limiting reactance means.

An arrangement comprising:

• a source operative to supply a DC supply voltage between a first and a second DC terminal;
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• a current-limiting circuit connected with the inverter output terminals and operative to provide a manifestly current-limited main AC voltage between a reference terminal and a main AC output terminal;
• a current-limiting reactance means connected between the main AC output terminal and each of plural individual AC output terminals;
• and
• a gas discharge lamp disconnectably connected between each individual AC output terminal and the reference terminal;
• such that, irrespective of how many lamps may be so connected, the current available from any given one of the plural individual AC output terminals is manifestly limited by the current-limiting reactance means associated therewith.

An arrangement comprising:

• a source operative to provide a DC supply voltage between a first and a second DC terminal;
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• an LC series-circuit effectively connected across the inverter output terminals;
• the LC series-circuit having a natural resonance frequency;
• the LC circuit having a tank-inductor series-connected with a tank-capacitor;
• a substantially sinusoidal AC voltage existing across the tank-capacitor as well as across a pair of capacitor terminals;
• and
• a series-combination disconnectably connected across the capacitor terminals;
• the series-combination including a gas discharge lamp series-connected with a current-limiting reactance device.

An arrangement comprising:

• a source operative to provide a constant-magnitude DC supply voltage between a pair of DC terminals;
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• an LC series-circuit being effectively connected across the inverter output terminals;
• the LC series-circuit having a natural resonance frequency;
• the LC circuit having a tank-inductor series-connected with a tank-capacitor;
• a sinusoidal AC voltage existing across the tank-capacitor as well as across a pair of capacitor terminals;
• the magnitude of the AC voltage remaining substantially constant irrespective of the magnitude of any current drawn from the capacitor terminals;
• and
• a gas discharge lamp disconnectably connected with the capacitor terminals by way of a current-limiting reactance device.

An arrangement comprising:

• a source operative to provide a constant-magnitude DC supply voltage between a pair of DC terminals;
• and
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• an LC series-circuit being effectively connected across the inverter output terminals;
• the LC series-circuit having a natural resonance frequency;
• the LC circuit having a tank-inductor series-connected with a tank-capacitor;
• a sinusoidal AC voltage existing across the tank-capacitor as well as across a pair of capacitor terminals;
• a control sub-assembly, being connected in circuit with the inverter circuit as well as with the LC series-circuit, is functional to cause the magnitude of the AC voltage to remain substantially constant irrespective of the magnitude of any current drawn from the capacitor terminals;
• the capacitor terminals being operative to connect with a lamp load that includes a gas discharge lamp.

An arrangement comprising:

• a source operative to provide a constant-magnitude DC supply voltage between a pair of DC terminals;
• an inverter circuit connected with the DC terminals and operative to provide an inverter output voltage at a pair of inverter output terminals;
• an LC series-circuit being effectively connected across the inverter output terminals;
• the LC series-circuit having a natural resonance frequency;
• the LC circuit having a tank-inductor series-connected with a tank-capacitor;
• a sinusoidal AC voltage existing across the tank-capacitor as well as across a pair of capacitor terminals;
• the magnitude of the AC voltage remaining substantially constant irrespective of the magnitude of any current drawn from the capacitor terminals;
• and
• a gas discharge lamp connected with the capacitor terminals by way of a capacitor whose capacitive reactance determines the magnitude of any current flowing through the lamp.