Backlight control circuit
AssigneesInnocom Technology (Shenzhen) Co., Ltd., Chimei Innolux Corporation
InventorSha Feng
Life of this patent
Estimating the term…
Abstract
An exemplary backlight control circuit includes a transformer, a control circuit, a lamp. The control circuit and the transformer form an inverter circuit to providing an alternating current (AC) voltage for driving the lamp. When the backlight control circuit works in a startup mode, the backlight control circuit defines a first current path including the lamp and the first current path forms a first resonant circuit. When the backlight control circuit works in an operation mode, the backlight control circuit defines a second current path including the lamp and the second current path forms a second resonant circuit. The first and second resonant circuits have different resonant frequencies from each other.
Claims20
A backlight control circuit comprising:
- a transformer, a control circuit, and a lamp, the control circuit and the transformer forming an inverter circuit capable of providing an alternating current (AC) voltage for driving the lamp, wherein the transformer comprises a primary winding and a secondary winding, two terminals of the primary winding are coupled to the control circuit, and the AC voltage is outputted from the secondary winding;
- and
- a first capacitor, a reactance element, and a first switching element;
- wherein when the backlight control circuit works in a startup mode, the backlight control circuit defines a first current path comprising the lamp and the first current path forms a first resonant circuit, the first resonant circuit being formed by the lamp, the secondary winding and the first capacitor;
- and
- when the backlight control circuit works in an operation mode, the backlight control circuit defines a second current path comprising the lamp and the second current path forms a second resonant circuit, the second resonant circuit being formed by the lamp, the secondary winding, the first switching element, the reactance element and the first capacitor, the first and second resonant circuits having different resonant frequencies from each other.
A backlight control circuit comprising:
- a transformer comprising a primary winding and a secondary winding;
- a control circuit electrically connected with the primary winding of the transformer, and cooperating with the transformer to provide an alternating current (AC) voltage;
- a lamp electrically connected with an end of the secondary winding of the transformer;
- a first circuit electrically connected with the other end of the secondary winding of the transformer, and configured for defining a first resonant frequency, the first resonant frequency being predetermined to light up the lamp when the backlight control circuit works in a startup mode, the first circuit comprising a first capacitor;
- and
- a second circuit electrically connected with the other end of the secondary winding of the transformer, and configured for defining a second resonant frequency less than the first resonant frequency, the second resonant frequency being predetermined to keep the lamp lighted up when the backlight control circuit works in an operation mode, the second circuit comprising a first switching element, a reactance element and the first capacitor.
A backlight control circuit comprising:
- a transformer, a control circuit, a lamp, a first capacitor, a reactance element, a first switching element, and a second switching element, the control circuit and the transformer forming an inverter circuit capable of providing an alternating current (AC) voltage for driving the lamp, the transformer comprising a primary winding and a secondary winding, two terminals of the primary winding being coupled to the control circuit, and the AC voltage being outputted from the secondary winding;
- wherein when the backlight control circuit works in a startup mode, the backlight control circuit defines a first current path comprising the lamp and the first current path forms a first resonant circuit formed by the lamp, the secondary winding, the first switching element, and the first capacitor;
- and
- when the backlight control circuit works in an operation mode, the backlight control circuit defines a second current path comprising the lamp and the second current path forms a second resonant circuit formed by the lamp, the secondary winding, the second switching element, and the reactance element, the first and second resonant circuits having different resonant frequencies from each other.
Dependencies are inferred from the claim text.