High frequency high intensity discharge ballast
OwnerLouis Robert Neroneinventor
Life of this patent
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Abstract
A ballast with self-oscillating inverter and a high-voltage multiplier circuit is disclosed for providing a DC start mechanism for starting an HID lamp. The high voltage multiplier ignites the lamp using direct current (DC) voltage. This results in low component stresses and lower output voltages than can be realized either by pulse starting or resonant starting techniques. DC starting reduces an output voltage required to start the HID lamp, and can be applied continuously without damaging the inverter. Moreover, the inverter, in self-oscillating mode, is compact while able to operate the HID lamp at frequencies well in excess of 1 MHz. The self-oscillating inverter can also be employed to regulate lamp power.
Claims20
An electronic ballast for igniting and operating a high-intensity discharge (HID) lamp, comprising:
- a resonant circuit with a high-frequency bus coupled to the HID lamp and which provides voltage to the HID lamp during operation after ignition;
- a control circuit, coupled to the high-frequency bus;
- a self-oscillating inverter circuit with first and second gate drive circuits that generate a waveform input for the resonant circuit;
- a multiplier circuit that provides an initial DC voltage to ignite the HID lamp.
An electronic ballast for operating an HID lamp, comprising:
- a resonant circuit coupled to the HID lamp and including a resonant inductance and a resonant capacitance;
- a self-oscillating inverter circuit, coupled to the resonant circuit for inducing an AC current in the resonant circuit, the inverter circuit including:
- first and second switches connected between a bus conductor at a DC voltage and a reference conductor, and connected together at a common node through which the AC load current flows;
- and
- gate drive circuitry for controlling the first and second switches;
- a clamping circuit, operationally coupled to the resonant circuit and configured to limit a voltage generated by the resonant circuit to a value that does not damage components of the ballast;
- a multiplier circuit, connected across terminals of a ballasting capacitor serially coupled to the HID lamp, the multiplier circuit provides a DC voltage to boost an output voltage of the inverter to a value sufficient to ignite the HID lamp;
- and
- a control circuit that supplies power to the inverter for a predetermined time each cycle.
A method of igniting and operating an HID lamp, comprising:
- providing a voltage from a control circuit to a self-oscillating inverter circuit;
- generating an initial voltage in the inverter circuit and providing the initial voltage to a resonant circuit coupled to the inverter circuit;
- passing the initial voltage through terminals of a multiplier circuit, the terminals being connected across a ballasting capacitor serially connect to the HID lamp;
- and
- returning a DC boost voltage through the terminals to ignite the HID lamp.
Dependencies are inferred from the claim text.