Abstract: A control device for multiple lamp currents of a liquid crystal display (LCD) backlight source, comprising an electronic power switch, a transformer, an inverter and an IC pulse width modulation (PWM) control module. The transformer has a primary side connected to the electronic power switch and a secondary side having two ends each connected to an end of a set of lamp composed of two lamps. The inverter has two sets of coil connected to the other end of the two sets of lamp. The IC PWM control module is connected between the inverter and the electronic power switch and through which the currents flown through the two sets of lamp may be balanced. Meanwhile, the current flown through the inverter is feedback to the IC PWM control module by which a control signal is outputted to the electronic power switch by determining and processing the feedback current, thereby controlling an output signal from the electronic power switch. Therefore, luminance of the multiple lamps may be controlled and maintained.

Abstract: A double frequency signal generator to which a synchronization signal having a duty cycle of 1% to 999% is inputted. The synchronization signal is used for triggering of a switching component at positive and negative edges to generate a triangular-wave signal. An average of voltages of the triangular-wave signal is acquired and compared with the triangular-wave signal at a comparator to generate a square-wave having a duty cycle of 50%. Then, the square-wave signal is used for triggering at positive and negative edges to generate a double frequency signal. As such, the high cost issue and the limitation of a square-wave input signal occurred in the prior art may be efficiently overcome.

Abstract: A double frequency signal generator to which a synchronization signal having a duty cycle of 1% to 999% is inputted. The synchronization signal is used for triggering of a switching component at positive and negative edges to generate a triangular-wave signal. An average of voltages of the triangular-wave signal is acquired and compared with the triangular-wave signal at a comparator to generate a square-wave having a duty cycle of 50%. Then, the square-wave signal is used for triggering at positive and negative edges to generate a double frequency signal. As such, the high cost issue and the limitation of a square-wave input signal occurred in the prior art may be efficiently overcome.

Abstract: A bridge type phase detection device comprises one or more than one transformer, a plurality of tubes, a voltage-detecting protection circuit and a first, second and third impedance, wherein a first tube of said plurality of tubes has a phase opposite to that of a second tube of said plurality of tubes, and a first end of said first impedance coupling with a secondary side of said transformer and a first end of said first tube, a first end of said second impedance coupling with said secondary side of said transformer and a first end of said second tube, then a second end of said first impedance connecting to a second end of said second impedance to form a detection point, said detection point coupling with said third impedance and said voltage-detecting protection circuit; said detection point having a voltage value derived from calculating a sum of said phase of said first impedance and that of said second impedance, then an output voltage divided among said first, two and third impedance, resulting in appro

Abstract: A bridge type phase detection device comprises one or more than one transformer, a plurality of tubes, a voltage-detecting protection circuit and a first, second and third impedance, wherein a first tube of said plurality of tubes has a phase opposite to that of a second tube of said plurality of tubes, and a first end of said first impedance coupling with a secondary side of said transformer and a first end of said first tube, a first end of said second impedance coupling with said secondary side of said transformer and a first end of said second tube, then a second end of said first impedance connecting to a second end of said second impedance to form a detection point, said detection point coupling with said third impedance and said voltage-detecting protection circuit; said detection point having a voltage value derived from calculating a sum of said phase of said first impedance and that of said second impedance, then an output voltage divided among said first, two and third impedance, resulting in appro

Abstract: The invention discloses a feedback sampling control circuit for a lamp driving system having a feedback loop, in that the feedback sampling control circuit includes a switch and an effective current sampling controller. The switch is electrically coupled in the feedback path of the lamp driving system. The effective current sampling controller controls switching of the switch based on a voltage or current signal from a high voltage terminal of the lamp, such that an effective current actually sampled by a feedback controller in the lamp driving system is controlled so that a current component of a parasitic capacitance contained in the effective current is minimized. Thereby, the disadvantage caused by the leakage current through the parasitic capacitance can be eliminated and it is thus possible to precisely control the lamp current and to obtain a stable brightness quality.

Abstract: The invention discloses a feedback sampling control circuit for a lamp driving system having a feedback loop, in that the feedback sampling control circuit includes a switch and an effective current sampling controller. The switch is electrically coupled in the feedback path of the lamp driving system. The effective current sampling controller controls switching of the switch based on a voltage or current signal from a high voltage terminal of the lamp, such that an effective current actually sampled by a feedback controller in the lamp driving system is controlled so that a current component of a parasitic capacitance contained in the effective current is minimized. Thereby, the disadvantage caused by the leakage current through the parasitic capacitance can be eliminated and it is thus possible to precisely control the lamp current and to obtain a stable brightness quality.

Abstract: A liquid crystal display (LCD) device has a housing acting as a conductor, a plurality of circuits, and at least a filter unit. Each circuit has a reference voltage terminal electrically connected to a reference voltage level. When the reference voltage terminal of each circuit is electrically connected to the housing, one filter unit is electrically connected between the housing and a ground terminal. When the housing is electrically connected to the ground terminal, a plurality of filter units are respectively connected between the housing and the reference voltage terminal of each circuit.

Abstract: A liquid crystal display (LCD) device has a housing acting as a conductor, a plurality of circuits, and at least a filter unit. Each circuit has a reference voltage terminal electrically connected to a reference voltage level. When the reference voltage terminal of each circuit is electrically connected to the housing, one filter unit is electrically connected between the housing and a ground terminal. When the housing is electrically connected to the ground terminal, a plurality of filter units are respectively connected between the housing and the reference voltage terminal of each circuit.