Closed-loop/dimming ballast controller integrated circuits
First Claim
1. An integrated circuit for driving first and second MOS gated power transistors which are connected in a half bridge arrangement for supplying power to a fluorescent lamp associated with a lamp resonant circuit, the half bridge arrangement of the first and second MOS gated power transistors supplying an oscillating input voltage to the lamp resonant circuit, the input voltage having a phase, the resonant circuit having a current flowing therethrough, the current flowing through said resonant circuit having a phase, the integrated circuit comprising:
- means for determining the phase of the current flowing through the lamp resonant circuit; and
means for maintaining a substantially constant relationship between the phase of the input voltage and the phase of the lamp resonant circuit current, thereby regulating the lamp power.
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Accused Products
Abstract
A novel monolithic electronic ballast controller IC for driving two MOS gated power semiconductors, such as power MOSFETs or IGBTs, connected in a totem pole or half-bridge arrangement. Advantageously, the present invention provides programmable preheat time and current, programmable end-of-life protection, lamp fault protection, over-temperature protection. The first embodiment of the invention is a closed-loop ballast controller IC intended for multiple lamp configurations, with three current-sensing inputs and programmable lamp power. Closed-loop control is accomplished through phase control, or, more specifically, a phase-locked loop (PLL) around a resonant type output stage driving a fluorescent lamp. The second embodiment of the present invention has a similar architecture to that of the first embodiment, with some modifications which allow dimming down to low light levels.
126 Citations
14 Claims
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1. An integrated circuit for driving first and second MOS gated power transistors which are connected in a half bridge arrangement for supplying power to a fluorescent lamp associated with a lamp resonant circuit, the half bridge arrangement of the first and second MOS gated power transistors supplying an oscillating input voltage to the lamp resonant circuit, the input voltage having a phase, the resonant circuit having a current flowing therethrough, the current flowing through said resonant circuit having a phase, the integrated circuit comprising:
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means for determining the phase of the current flowing through the lamp resonant circuit; and means for maintaining a substantially constant relationship between the phase of the input voltage and the phase of the lamp resonant circuit current, thereby regulating the lamp power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification