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US 7,888,885 B2Granted
Control circuit of a driving circuit for regulating the switching frequency of a discharge lamp
AssigneeSTMicroelectronics S.r.l.
InventorsLuca Giussani, Massimiliano Gobbi, Luca Salati
Life of this patent
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Abstract
A control circuit controls a driving circuit of a discharge lamp. The driving circuit comprises a half bridge and a clock generator that determines the switching frequency of the half bridge. The control circuit comprises a regulator that regulates the value of the switching frequency when the value of the voltage across the lamp exceeds a threshold value.
Claims31
A control circuit, comprising:
- a sensor structured to sense a voltage of a discharge lamp driven by a driving circuit that includes a half bridge and a circuit that determines a switching frequency of the half bridge;
- and
- regulating means for regulating the switching frequency when the voltage across the lamp exceeds a threshold value, the threshold value comprising a first value and a second value, the threshold value being the first value when the driving circuit ignites and being the second value when the driving circuit runs the discharge lamp.
A driving circuit for a discharge lamp, comprising:
- a half bridge structured to drive the discharge lamp;
- a clock generator structured to determine a switching frequency of the half bridge;
- and
- a control circuit structure to control the half bridge, the control circuit including:
- a sensor structured to sense a voltage across the lamp;
- and
- a regulator structured to regulate the switching frequency when the voltage across the lamp exceeds a threshold value, the threshold value comprising a first value and a second value, the threshold value being the first value during an ignition phase and being the second value during a run phase of the discharge lamp.
4 more elements
A method for controlling a discharge lamp, comprising:
- sensing a voltage across the discharge lamp;
- and
- regulating a switching frequency of a half bridge that drives the lamp, the regulating step occurring while sensing that the voltage across the lamp exceeds a threshold value, the threshold value comprising a first value and a second value, the threshold value being the first value during an ignition phase and being the second value during a run phase of the discharge lamp.
A lighting device, comprising:
- a discharge lamp;
- a half bridge structured to drive the discharge lamp;
- a clock generator structured to determine a switching frequency of the half bridge;
- and
- a control circuit structure to control the half bridge, the control circuit including:
- a sensor structured to sense a voltage across the lamp;
- and
- a regulator structured to regulate the switching frequency when the voltage across the lamp exceeds a threshold value, the threshold value comprising a first value and a second value, the threshold value being the first value during an ignition phase and being the second value during a run phase of the discharge lamp.
5 more elements
Dependencies are inferred from the claim text.