Illumination apparatus, electronic ballast therein and method for protecting the same
AssigneeDelta Electronics (Shanghai) Co., Ltd.
InventorsWei-Qiang Zhang, Jian-Ping Ying
Life of this patent
Estimating the term…
Abstract
An electronic ballast includes an inverter circuit, a variable inductor unit and a control circuit. The variable inductor unit is electrically coupled between the inverter circuit and an illumination device. The control circuit controls the variable inductor unit according to an operation mode of the inverter circuit such that an equivalent inductance of the variable inductor unit has a variation fed back to the inverter circuit, to further change the operation mode of the inverter circuit. An illumination apparatus and a method for protecting the electronic ballast are also disclosed.
Claims19
An electronic ballast comprising:
- an inverter circuit;
- a variable inductor unit electrically coupled between the inverter circuit and an illumination device;
- and
- a control circuit configured to control the variable inductor unit according to an operation mode of the inverter circuit such that an equivalent inductance of the variable inductor unit has a variation fed back to the inverter circuit to switch the operation mode of the inverter circuit;
- wherein the control circuit regulates the variable inductor unit when the inverter circuit operates under a capacitive mode of operation, such that an equivalent inductance of the variable inductor unit increases and the inverter circuit switches to operate under an inductive mode of operation.
An electronic ballast comprising:
- an inverter circuit comprising a first switch device and a second switch device, the first switch device and the second switch device being coupled at an operation node;
- a variable inductor unit having one end electrically coupled to the operation node and having the other end electrically coupled to an illumination device;
- and
- a control circuit electrically coupled to the variable inductor unit, the control circuit being configured to regulate the variable inductor unit according to a sensing signal when the inverter circuit operates under a capacitive mode of operation, such that an equivalent inductance of the variable inductor unit increases and the inverter circuit switches to operate under an inductive mode of operation.
An illumination apparatus comprising:
- an illumination device;
- and
- an electronic ballast electrically coupled to the illumination device, the electronic ballast comprising:
- an inverter circuit;
- a variable inductor unit electrically coupled between the inverter circuit and the illumination device;
- and
- a control circuit configured to regulate the variable inductor unit when the inverter circuit operates under a capacitive mode of operation, such that an equivalent inductance of the variable inductor unit increases and the inverter circuit switches to operate under an inductive mode of operation.
A method for protecting an electronic ballast, the method comprising:
- detecting an operation mode of an inverter circuit;
- generating a sensing signal when the inverter circuit operates under a capacitive mode of operation;
- controlling a variable inductor unit according to the sensing signal such that an equivalent inductance of the variable inductor unit has a variation;
- and
- the inverter circuit switching to operate under an inductive mode of operation according to the variation of the equivalent inductance of the variable inductor unit.
Dependencies are inferred from the claim text.